The International Copper Trade [Lslf ed.] 1855730715, 9781855730717, 9781855738744

Table of contents :
Preliminaries......Page 2
3 Exploration, mining and refining of copper......Page 6
1 History and background......Page 16
2 Origins and location of copper......Page 26
4 Fabrication of copper and its alloys......Page 82
5 Main types of copper and its alloys......Page 96
6 Qualities of copper and its alloys......Page 120
7 End uses of copper and its alloys......Page 134
8 Structure of the market......Page 156
9 International trade in copper......Page 192
Appendices: World’s major coppermines and plants......Page 220

Citation preview

The international copper industry

The international copper industry John Jessop and Martin Thompson

Wo o d h e a d p u b l i s h i n g l i m i t e d Cambridge, England

Published by Woodhead Publishing Limited, Abington Hall, Abington Cambridge CB1 6AH, England www.woodhead-publishing.com First published 2002, Woodhead Publishing Ltd © 2002, Woodhead Publishing Ltd The authors have asserted their moral rights. This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. Reasonable efforts have been made to publish reliable data and information, but the authors and the publisher cannot assume responsibility for the validity of all materials. Neither the authors nor the publisher, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming and recording, or by any information storage or retrieval system, without permission in writing from the publisher. The consent of Woodhead Publishing Limited does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from Woodhead Publishing Limited for such copying. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. ISBN 1 85573 071 5 ISSN 1477-853X Typeset by SNP Best-set Typesetter Ltd., Hong Kong Printed by Astron On-Line, Cambridgeshire, England

Contents

Preface Acknowledgements About the authors Index 1 1.1 1.2 1.3 1.4 1.5

History and background Early history Later periods Modern period Electricity Outlook

2 2.1 2.2 2.3

Origins and location of copper Origins Location of copper mines Copper production of the main producing countries

3 3.1 3.2 3.3 3.4 3.5 3.6

Exploration, mining and refining of copper Exploration, discovery and initial development of copper mines Mining Extraction of copper from its ore Copper and copper alloy shapes Oxygen-free high conductivity copper and its alloys Use of copper and copper alloy scrap

4 4.1 4.2 4.3 4.4 4.5

Fabrication of copper and its alloys Shaping from molten metal Shaping from solid metal Shaping by joining metals Shaping powdered metal Copper shot

5 Main types of copper and its alloys 5.1 Inner structure of copper and its alloys

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Contents

5.2 5.3 5.4 5.5 5.6 5.7

Role of oxygen in various types of copper Types of produced and traded copper Specifications in general Main grades of copper and its alloys Alloys where copper is the base metal Alloys where copper is not the main constituent

6 6.1 6.2 6.3 6.4 6.5

Qualities of copper and its alloys Good electrical and thermal conductivity Capacity to produce useful alloys Attractive appearance Physical and mechanical properties Other useful qualities

7 7.1 7.2 7.3 7.4 7.5 7.6

End uses of copper and its alloys Electrical engineering applications Engineering applications Applications in construction and building services Applications in domestic goods Applications in transport Other applications

8 8.1 8.2 8.3 8.4 8.5 8.6

Structure of the market The market in exploration and development licences The market for copper concentrates The market for blister and anode The market in refined copper The market in copper and alloy semi-wrought products The market in copper and alloy scrap and copper-containing ashes, slags and residues 8.7 The trade in copper warrants 9 9.1 9.2 9.3 9.4 9.5 9.6

International trade in copper The early market Establishment of the London Metal Exchange Development of the LME Copper pricing Clearing the market Hedging

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9.7 9.8 9.9 9.10 9.11

Options Other markets LME and Comex warehouses LME procedures and requirements Future of the LME

Appendices: World’s major copper mines and plants Appendix 1 Mines and owners Appendix 2 Smelters and owners Appendix 3 Refineries and owners

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Preface

Copper is a metal that is both ancient and modern. It is ancient, because it was the first useful metal to be discovered, and was for many centuries the only one available for the countless practical uses to which metals are put. It is modern, because in addition to the many uses to which it has been put for thousands of years, such as in water pipes, roofing and coins, it is also the principal conductor of electricity on which our civilisation now depends. This description of the metal, its extraction, the industry that produces it, its many uses and how it is sold, is intended both for those who are new to copper and those who are already familiar with it, and who require a thorough yet compact account. The book was started, and much of it written, by John Jessop, who for many years was a well-known figure in the metals world and most knowledgeable on copper. Very sadly, he died before he could finish the book, a task that has devolved to myself. This book is intended for all those who need a wide-ranging, reasonably detailed and yet compact survey of the copper industry. It includes its origins and history, the locations of this relatively rare element, its mining extraction and fabrication into the myriad shapes and forms in which it is used and the uses to which they are put, the markets for copper in its various forms and the curious yet ultimately practical operations of the London Metal Exchange. Statistics of world production and consumption are included, as are the details of the principal mines, smelters and refineries. It is intended for all those who need such a source of information, be they new to the metal and require a thorough introduction to the industry, or those who need a work of reference. There are many who may find it useful, including metal brokers, those in metal companies, stockbrokers, economists, academics and journalists. Above all, the story of copper is fascinating; it is the material which brought the Stone Age to an end, and which, thousands of years later, brought the age of electricity into being. Martin Thompson

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Acknowledgements Needless to say, many publications and individuals have contributed to this book, but although a list of works probably used by John Jessop has kindly been supplied by his widow, we do not know whether it is complete, nor do we have the names of individuals whom he may have consulted. However, books which either one or both of us have used include The London Metal Exchange – a Commodity Market by Robert Gibson-Jarvie, Metals in the Service of Man by William Alexander and Arthur Street, Trading in Metals by Metal Bulletin Books Ltd, A Concise Encyclopaedia of Metallurgy by A D Merriman, Copper – the Anatomy of an Industry by Sir Ronald Prain, Sixty Centuries of Copper by B Webster Smith, The International Zinc Trade by Ken Hewitt and Keith Patten, The London Metal Exchange by the Economist Intelligence Unit Ltd, Rocks and Minerals of the World by Charles Sorrel and George Sandström, The Macdonald Encyclopaedia of Rocks and Minerals by A Mottana, R Crespi and G Liborio, Trading in Commodities edited by C W J Granger, Modern Merchant Banking edited by C J J Clay and B S Wheble, A Common Man’s Guide to the Common Market by Hugh Arbuthnott and Geoffrey Edwards, The Living Rock by A J Wilson, Copper by Ira B Joralemon, Managing Metals Price Risk with the London Metal Exchange edited by Phillip Crowson with Ray Sampson, Non-Ferrous Metals by Lotte MüllerOhlsen, and The Base Metals Handbook edited by myself. Valuable statistical information has been obtained from the International Copper Study Group, where my thanks go to Chief Statistician Thomas Baack and Assistant Statistician Ana Maria Rebelo, to the World Bureau of Metal Statistics and its General Manager, Sue Eales, The Copper Development Association (UK) and to The International Wrought Copper Council and its Assistant Secretary, Mark Loveitt. I have received help and advice from numerous people, including Christopher Green, formerly Chairman of the London Metal Exchange, Vin Callcut, formerly Manager of the Copper Development Association, and Jim Squire, Chris Torrible and Jane Robb of Rio Tinto. Finally I would like to thank my wife, who has performed the wearisome task of typing the whole book. Martin Thompson

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About the authors

John Jessop was a highly respected and well known figure throughout a 40 year career in the metals market, who sadly died before completing this book, his first, on the international copper industry. He began his career at ICI Central Purchasing Department, London, as a buyer of non-ferrous metals and scrap and later transferred to British Kynoch Metals (a subsidiary of ICI), where he specialised in copper and began daily attendance on the floor at the LME. He worked for eight years as Manager of Lead and Zinc at Entores Ltd, and was Director of its subsidiaries, Entores Metal Brokers and S F Jones and Co., Ltd. John Jessop was a member of the LME panel of arbitrators for 15 years, and was particularly knowledgeable on the workings of the LME and the way it is used by miners, fabricators, merchants and investors. He lectured on the metals market as a representative of the LME, and for 20 years wrote and edited weekly reports for Entores and Ametalco. From 1976 until his retirement in 1987, Mr Jessop was Sales Executive at Ametalco Ltd where he dealt in speciality copper and plater’s anodes.

Martin Thompson retired as Commercial Adviser from Rio Tinto plc in 1999, having joined the company in 1968. Initially he was involved in iron ore and pyrites, but from 1976 onwards he dealt mainly with the base metals, specialising in copper. He has written regularly on the metal, and has undertaken an examination of an international trade dispute on behalf of GATT. He was Chairman of the British Copper Development Association, Vice Chairman of the European Copper Institute, and Chairman of the Statistical Committee of the International Copper Study Group. Previously he worked for Consolidated Tin Smelters Ltd, and the merchant bank N.M. Rothschild and Sons, in London and Rhodesia.

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1 History and background

1.1

Early history

1.2

Later periods

1.3

Modern period

1.4

Electricity

1.5

Outlook

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1.1 Early history Like many other materials by which we are surrounded, copper usually excites little interest. A common metal of no great intrinsic value, it is used primarily to conduct electricity, in which role it is usually hidden from view in insulated cables or within electrical appliances. It often appears in the alloys bronze and brass. An athlete coming third may well be awarded a bronze medal – the poor relation of gold and silver. Yet this apparently humdrum metal has had as important (some would argue the most important) a role in the history of humanity as any of the countless materials which have been pressed into service since our early ancestors started to distance themselves from the apes that they once so closely resembled. It is no accident that, of the four most recent ‘ages’ into which the progress of humankind towards modern life has been divided – the Stone Age, the Chalcolithic or Copper Period, the Bronze Age and the Iron Age – one takes its name from the metal itself and another from its most widely used alloy. The most important role of copper in the early years of human history is that it was the material whose discovery brought an end to the Stone Age, by offering a much more effective material for tools or weapons than the sharpened flint, bone or wood which was all that had previously been available (expertly though some stone spear and arrow heads and axes had been shaped). However, this change did not take place overnight, nor can we be sure when or where copper was first used. It is probable that copper and gold were the first metals to be brought into use, since both are occasionally found in solid form, or nuggets, called ‘native copper’ in the case of the former, and both can be hammered into shapes. According to A J Wilson’s The Living Rock, the earliest hand-made metal object so far discovered is a perforated copper pendant, found in northern Iraq and dated as early as 9500 . Gold was also found, and similarly hammered into shapes, but this metal was found to be much softer than copper, and although this made it easier to hammer into a great variety of decorative shapes, it could hardly be made into a tool or a weapon. Gold became prized for its beauty, its rarity and the ease with which it could be worked into the most intricate shapes, but for practical purposes it was virtually useless. Copper was different. It was more abundant (although in the early years only tiny quantities were used) and, most importantly, it could be given a sharp point and edges; it could be turned into a much better spear or arrow-head than

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could be fashioned out of stone, bone or wood. It was also of an attractive reddish colour, which from the time of its discovery made copper a decorative as well as a practical metal. It was used from the beginning for personal adornment as well as for weapons, and like gold it did not corrode or decay. Needless to say, the early history of the use of copper has gone unrecorded, and archaeologists can only shed intermittent light on its progress. The most important steps in its early history were the discoveries of the effect of fire on copper metal and what is now called copper ore. The use of fire allowed copper to be melted and cast into many more shapes than before, while it enabled copper ore to be smelted. The copper content was separated from the other chemical contents of the ore in a fairly, sometimes very, pure form, so that supplies of copper did not depend on relatively rare nuggets. It is impossible to say when either of these operations first took place although it is fairly certain that the discoveries took place quite separately in different continents and at different times, rather than spreading from one place. However, it is clear that, as humans learnt to make a fire, so in due course they also learnt that a lump of copper would melt in fire and harden afterwards into whatever shape (‘mould’) it had melted. Ultimately of much greater importance, humans learnt that certain rocks if heated strongly would also produce copper metal. Finally, charcoal – carbonised wood that has not been completely burned and produces a hotter fire than ordinary wood – was discovered. It proved to be a much more effective means by which copper ore, which is what such copper-bearing rocks are called, could be smelted and the copper extracted in the form of metal. Two of the many facts that history does not relate are the date and place of the first smelting of copper ore. However, research suggests that copper was smelted at Timna, in what is now Israel, in at least the fifth century  and possibly earlier. Here the remains of primitive smelting operations, tiny by modern standards but capable of producing copper of near 99% purity, have been discovered. Mining and smelting of copper took place in other sites in the Middle East, so that gradually metal implements spread and stone ones disappeared. Copper was bringing the Stone Age to an end. As with the discovery of copper itself and the smelting process, it is not possible to say when or where it was first discovered that if tin was mixed with copper the combination of these two elements would produce an alloy which, while retaining the characteristics of copper, was

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also tougher and could be made sharper; it would make better tools – and weapons. It is known that when the Sumerians arrived in Mesopotamia from south west Persia in the fourth millennium , they had mastered the art of making bronze. Supplies of copper came from what is now the Persian Gulf, Armenia and Cilicia, and they became highly competent at working in copper, bronze and precious metals. Gradually this new technology spread and bronze largely replaced copper in many applications, although for several centuries around the end of the fourth millennium the Sumerians and others reverted to using copper, presumably because supplies of tin failed. However, gradually this alloy became more common and it became particularly important because for over two thousand years bronze performed many of the roles that iron, and later steel, were eventually to perform. Iron, which requires substantially greater heat to smelt, did not make its appearance in any quantity until the first millennium , and until it did, bronze remained by far the most efficient metal for applications that required sharp edges and strength: armour, tools and, in particular, weapons. In due course these would be made from iron, which is much more plentiful, and for these functions is more suitable, but until iron became available, bronze, which is mainly copper, was the metal for these roles. Meanwhile, copper was becoming known in other parts of the world, although our knowledge of its early development outside Europe and the Near and Middle East is even more sketchy than it is in these parts of the world. Copper was probably being developed in the Honan province of China before 2500 , and around Lake Superior in the USA possibly as long ago as 3000 , although here there may well have been enough native copper to make the smelting of copper ore unnecessary. Until the arrival of iron, copper, first by itself and then through its principal alloy, bronze, had been by far the most important metal in the life of humankind. Certainly gold and, to a lesser extent, silver, were the most esteemed; who would have a copper bracelet when they could have a gold one instead? But for usefulness, copper and bronze had no equals. The few other metals that were known were, of course, valued; tin was at least a good-looking material in its pure state, although its most important use was as an addition to copper to make bronze. Lead was easily worked and convenient for a number of applications, although too soft for many. Zinc as a metal was to remain unknown for centuries, although brass (a copper–zinc alloy) was eventually made

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using zinc ore. Although copper lost its position as the most used metal to the much more plentiful iron in the first millennium , it retained many of its applications, as it has to this day. It was the preferred material by the wealthy for all sorts of objects – cooking utensils, cups, plates, some furniture, even mirrors before glass was used, were all of copper and brass, while copper pipes for water dating from the early third century  have been found in Abusir in Egypt. King Solomon adorned his temple with bronze ornaments and capitals (‘so great was the quantity of bronze used in their making that the weight of it was beyond all reckoning’ 1. Kings 7.47). Early in the second century , the portico and huge dome of the Pantheon in Rome were sheathed in copper, while the Romans, like us, carried copper coins. Not only had copper and bronze been popular from the earliest times for decorative purposes, to adorn people as well as buildings, but they also came to be used by sculptors; a clay model would be made and when finished it would be cast in bronze. Many early sculptures have survived, although the largest of them, and possibly the largest ever made, has disappeared. It was the Colossus of Rhodes, a bronze statue of a man probably 30 m (100 ft) high, bestriding the entrance to Rhodes harbour, erected in 290 . As the demand for copper and bronze grew, its production spread to new areas. One important source was the island of Cyprus, which was to give its name to the metal; cyprium aes is Latin for cyprian copper, which was to be corrupted to cuprum by the late Roman period, and in due course to ‘copper’ in English. Another was the Rio Tinto mine in what is now Andalusia, in southern Spain. Here a vast mining complex has been worked by a number of different nationalities, starting probably with the Iberians in the second millennium , followed by the Phoenicians, Carthaginians, Romans, Visigoths, Vandals, Moors, Spaniards and British (under whom for a time it was again to be the biggest copper mine in the world), before once again reverting to Spanish management. While little is known of its early history, both the scale on which the Romans mined, aided no doubt by a huge workforce of slaves, and the efficiency of their operation are abundantly clear from the remains. Large waterwheels have been discovered deep underground to pump water from the mines, and huge slag heaps, arising from Roman copper smelting works, still lie across the land. Very little copper is left in them.

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1.2 Later periods The invasion of Western Europe by barbaric tribes (including the Angles and Saxons) and the eventual extinction of the Roman Empire in the West in 476  heralded a long period of decline in civilisation in Western Europe which has been termed the Dark Ages. While they may not have been quite as dark as the name suggests, nevertheless art and the sciences generally decayed, cities were abandoned and the demand (if not the need) for metals shrank. It is difficult to think of any use of copper dating from the Dark Ages, or even the Middle Ages, except perhaps for guns and for bells, which are mainly copper and during the Middle Ages were used in almost every village whose church had a tower to hang them in. Guns were often made of bronze or brass and this new weapon first appeared in the fourteenth century. By the middle of the fifteenth century, the Turks were building guns of 14 tons. However, although from the late fifteenth century onwards life generally became more comfortable, at least for the more prosperous, and many more implements made of metals were used, it was not until the so-called ‘Industrial Revolution’, which began in England during the middle of the eighteenth century, that the use of metals, including copper, started to increase dramatically.

1.3 Modern period Although iron, from which engines and machinery were principally made, was the key metal in the early days of industrialisation, copper and its compounds played an important part. They were often used for valves, cocks, gauges and other components of steam engines. The number of implements made in copper, bronze and brass (the latter made more easily since the discovery of zinc) multiplied and the invention of new processes greatly increased demand for copper. Thomas Bolsover’s process of plating copper with a thin layer of silver (a technology known to the ancient Greeks and Romans) was patented in 1742; later it was to be superseded by electroplating. Meanwhile the introduction of the die and mould process led to the mass production of an infinite variety of objects, from saucepans to buttons. On a different scale, it was discovered that the bottoms of ships could be plated with copper in

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order to stop weeds from fouling them and ‘teredos’ or molluscs from boring into wood. ‘Copper bottomed’ as a term for security has passed into the language.

1.4 Electricity Although the Industrial Revolution had greatly increased the demand for copper, as it had for all the known non-precious metals, there was another application which was to far exceed any other use for the metal. Since the eighteenth century men had been experimenting with the phenomenon that had come to be called electricity and copper was used in the first battery built by Volta. However, it was not until 1831 that Faraday discovered electric and magnetic induction, which led to the controlled generation and transformation of electricity. In this, copper was to prove to be the key element. It is by far the best conductor of electricity after silver, which is not much better but much more expensive, while copper’s physical attributes, which enable it to be made hard and unyielding for switches or strong but flexible for wire, are ideally suited to conducting electricity. Its electrical conductivity is 60% greater than that of aluminium, the next best conductor (which was not known in the 1830s). Not surprisingly, copper quickly became the essential element in the generation, transforming and application of electricity, and so it has remained. Its uses are considered in greater detail in Chapter 7. It will be seen that many uses, including piping, roofing, currency, sculpture and ornaments have continued for literally thousands of years, but it is electricity that has transformed the history of copper during the last 170 years. To understand this, one has only to consider the role that electricity plays in our lives, providing light and heat and energy for transport, cooking, washing, communication, computing and entertainment and then to consider the metal, always concealed, that generates, transforms and carries the electricity and the switches that control it.

1.5 Outlook The future of copper is inevitably still bound tightly to that of electricity and to possible rivals for its role as its principal conductor. Such rivals, in the shape of the ‘superconductors’, do exist, and may become

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threatening. However, so far the technical problems involved in producing a superconductor that can operate at normal temperatures remain and as yet there is no obvious likelihood of their becoming a threat in the foreseeable future. In any event, there would still be a need for copper in great quantity in the electrical industry, and any new material that would significantly reduce the cost of electricity would thereby increase demand for it. Otherwise, the prospects for electricity, and therefore copper, are bright. The demand for telephones, computers and, indeed, most electrical appliances remains strong, while concerns about the long term availability of oil for the internal combustion engine may yet resurface. There is no lack of threats to other applications, such as plastic piping for water and heating systems, while at the same time there is some hope for copper in car radiators. Perhaps the most important defence from substitution that copper possesses, apart from its outstanding ability to conduct electricity, is the fact that its average cost of production has declined significantly since about 1980, and may decline further. In any event, in the absence of a totally revolutionary new means of conducting electricity, this most ancient of metals is promised a bright future.

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2 Origins and location of copper

2.1

Origins

2.2

Location of copper mines

2.3

Copper production of the main producing countries 2.3.1 Chile 2.3.2 USA 2.3.3 Indonesia 2.3.4 Canada 2.3.5 Australia 2.3.6 China 2.3.7 Peru 2.3.8 Russia 2.3.9 Other countries

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2.1 Origins This chapter deals first with the geological origin of copper – how the deposits found in the Earth’s crust were formed and the locations where deposits have been discovered in sufficient concentration for mining to be a commercial proposition. Copper is one of the rarer elements, comprising possibly 0.005% of the Earth’s crust; much less than around 5% for iron and 8% for aluminium. However, as with all minerals, in places it is found in deposits concentrated to a level far above its average and this makes its extraction on a large scale feasible. Although nuggets of almost pure ‘native’ copper are occasionally found, these are rarely in mineable quantities and copper is normally found in minerals chemically combined with other elements. These copper ore deposits are by their origin either ‘magmatic’ (that is, arising from ‘magma’ – the molten and gaseous products generated in the interior of the earth) or ‘sedimentary’ (formed by the combined operation of rocks being broken up by weathering and then deposited in beds at lower levels). Copper is found in 160 different minerals, but in two main forms: • copper sulphide ores – which constitute almost 85% of all discovered deposits • copper oxide ores – (including carbonates, sulphates and silicates) which arise as the result of the action of water on sulphide deposits. Geologists do not fully understand all the processes involved in the creation of mineable copper deposits. Some of the main features are reasonably clear, such as the interplay between water and the magma, the effect of water percolating through established ore-bodies or the redistributive action of the forces of erosion. However, other matters are less clearly understood and are the subject of theories which have not yet been scientifically verified. There is the problem of where the water in the magma comes from. It could be rainwater percolating downwards from the surface, or it could come from water vapour of deep-seated origin seeping upwards owing to the pressures within the magma. Some argue that the ascending water, in the form of super-heated steam, concentrates particles of metallic minerals in the Earth’s crust, and deposits them in veins and fissures as it cools. Others suggest that the minerals are dissolved at greater depth and rise as vapours or solutions. The latter

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theory has received some support from a deep-drilling experiment carried out by Russian scientists who found mineralised solutions at 11km below the surface. At such depths heat and pressure are so great that most metallic minerals would dissolve and remain in solution until they rise to cooler areas near the surface, where they would crystallise out, with the different ores being segregated by their differing temperatures of formation. Copper is found in three main types of deposit, two of magmatic and one of sedimentary origin: • In veins or lodes – these are directly caused by volcanic activity, often being comparatively rich (or ‘massive’) deposits that lend themselves to underground mining. • ‘Porphyry’ or disseminated deposits – here the ore is scattered through large volumes of ‘country’ rock (known in mining as ‘gangue’ or waste rock). At the moment, porphyries can only be mined economically by open-pit methods. • Sedimentary deposits – these are sometimes known as ‘placer’, ‘stratiform’ or ‘bedded’ deposits. They are formed when surface erosion or glaciation has redistributed copper laid down in former times. Many mining areas provide cases where these types of deposit are intermingled, as in the Rocky Mountains of the USA, where enormous porphyry deposits are found close to rich veins, or the Copper Belt of central Africa, where older sedimentary beds are interpenetrated by newer vein deposits. The processes whereby copper, which represents such a small proportion of the Earth’s crust, has been concentrated into deposits rich enough to be mined, are complicated and are by no means always certain. Elemental copper is generally thought by geologists to originate from within the mass of molten rock and gases (magma) on which the Earth’s crust floats, and to be concentrated and distributed in that crust during a vast circular movement that takes place over the aeons of geological time during which ore-bodies are formed. Copper moves from the magma into the upper rocks by means of volcanic activity. The upper rocks in time become eroded and the particles of copper are eventually washed into the oceans, where they become suspended in seawater, or deposited as alluvial mud on the ocean floor. Minute marine organisms are thought to concentrate copper in their bodies from seawater, alluvial

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mud and from the copper minerals that are found around hot springs and submarine volcanoes. These concentrations of copper particles move back into the magmas as the tectonic plates on the ocean floor slide under a continent or a group of islands and melt again. The magma is constantly in motion and its uppermost surfaces tend to form domes (called batholiths) which press upwards and thus come into contact with the cooler rocks of the Earth’s outer crust, a process that can lead to the creation of new copper deposits when conditions are right. Vein deposits are formed when hot copper-bearing solutions rise through the batholiths, which are often to be found in the central cores of major folded mountain ranges. The process by which this type of deposit is formed is thought to occur when water that has penetrated through the Earth’s crust, or that is present in the magma, dissolves particles of sulphur, copper and other metals that may be lying deep within the batholith. This hot aqueous solution comes under great pressure and is forced towards the surface through faults in the cooling batholith and in the rocks above. As the solution rises it cools and deposits its metallic minerals (mostly as sulphides) in the cracks and crevices of the country rock to create vein deposits. Thus copper sulphide minerals are classified as being of high, medium or low temperature origin. On the other hand, most copper oxides, carbonates, silicates and sulphates are formed by secondary enrichment and concentration of existing sulphide vein or porphyry deposits. The main agent for change is the leaching effect of rainwater, which is high in oxygen, percolating down through the top level of sulphide ores and creating an enriched area immediately below the surface (known as the ‘supergene zone’). The sulphides are dissolved by the water and are carried down in the form of oxides, carbonates, silicates or sulphates according to the particular elements that have been picked up by the water in its movement through the country rock. These are deposited in a zone of oxidised enrichment immediately above the water table. Here carbonates like azurite or malachite, oxides like cuprite, silicates like chrysocolla or sulphates like chalcanthite or brochantite are found. Further down, the available water lacks the oxidising ions present in groundwater and as a result a zone of sulphide enrichment occurs, where secondary sulphides like chalcocite and bornite are deposited. Lower still in the area of the vein that is generally unaffected by water, lies what is termed the primary zone. Lacking the water-concentrated deposits of the enriched areas, the primary zone is rarely worth mining. Compared with porphyry

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deposits, vein deposits are usually small and the level of copper content (the copper ‘grade’) varies considerably. Other metals are likely to be present in quantities that make their recovery feasible; such co- or byproducts may include lead, zinc, tin, tungsten, silver and gold. Porphyry deposits are formed by a process called ‘contact metamorphism’ in which chalcopyrite is disseminated in igneous (i.e. previously molten) rock. This occurs when magma is injected into cold rock. Copper minerals can be formed by this process at or near the contact area between the cooling magma and the colder rocks of the Earth’s crust. Around the igneous rock created by the cooling magma is a metamorphosed zone termed a ‘contact metamorphic aureole’ (or halo). It is within this halo that porphyry copper deposits are formed. Porphyry deposits are usually very large and low grade although the copper content may sometimes reach as much as 2% or more. Sedimentary deposits are formed by the erosion of older ore-bodies as a result of the action of water, ice and wind. Mechanical weathering, operating mainly through the agency of ice, breaks the rock down into particles without changing the identity of the constituent minerals. Chemical weathering by air and water also wears down the rock through chemical reactions that often do change the nature of the constituent minerals. The weathered particles are moved by water, wind and ice and deposited in layers in rivers, flood plains, deltas, lakes and oceans. Copper minerals are usually recovered from the lowest portions of such placer, stratiform or bedded deposits. Sedimentary deposits are usually smaller than the porphyry, but copper grades can be expected to be higher at 2–4%. Silver and cobalt may occur as by-products. Table 2.1 gives details of some of the more important ores of copper. As mentioned earlier, about 85% of all copper mined at the time of writing comes from one sulphide ore – chalcopyrites. This mineral is found in very large disseminated porphyry deposits, in sedimentary deposits and in high-temperature vein deposits. Copper also arises as a constituent of mixed ores, i.e. where more than one metallic element is present in significant quantities. Table 2.1 provides examples of such minerals including bornite (a copper–iron sulphide), enargite (a copper–arsenic sulphide) and tetrahedrite (a copper–iron–antimony sulphide). From a commercial point of view, and more important than these mixed ores, is the fact that minerals of other important non-ferrous and precious metals are often found in or adjacent to copper deposits. This

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Table 2.1 Some of the more important copper-bearing minerals Name

Colour

Typically % of copper contained

Where formed

Native Copper

Red

99.9

Old lava flows Oxidisation zone of sulphide deposits

Sulphide ores Chalcopyrite Copper iron sulphide [CuFeS2]

Golden yellow, brassy

34.5

Dark grey, black

79.8

Porphyries, veins and sedimentaries – ~85% of all mined copper Enriched zone of veins

Dark blue

66.5

Enriched zone of veins

Gold, blue and brown

63.3

Porphyries, veins and sedimentaries

Black

48.4

Veins

Black, grey, brown

46.7

Veins

Red, ruby red

88.8

Vein oxidation zones

Dull black powder

79.8

Vein oxidation zones

Chalcocite Copper sulphide ‘Copper Glance’ ‘Redruthite’ [Cu2S] Covellite Copper Sulphide [CuS] Bornite Copper iron sulphide ‘Peacock Ore’ ‘Erubescite’ ‘Horseflesh Ore’ [Cu5FeS4] [Cu3FeS3] Enargite Copper arsenic sulphide [Cu3AsS4] Tetrahedrite Copper iron antimony sulphide [(Cu, Fe)12 Sb4S13] Oxide ores Cuprite Copper oxide ‘Ruby copper’ [Cu2O] Melaconite Copper oxide ‘Tenorite’ [CuO]

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Table 2.1 Continued Name

Colour

Typically % of copper contained

Where formed

Azurite Hydrous copper carbonate ‘Chessylite’ [Cu3(CO3)2(OH)2] Malachite Hydrous copper carbonate [Cu2CO3(OH)2] The same chemical composition as verdigris Brochantite Hydrous copper sulphate [Cu4(SO4)(OH4)] Chrysocolla Hydrous copper silicate [(Cu, Al)2H2Si2O5 (OH)4.n H2O] [CuSiO3.nH2O]

Blue

55.3

Vein oxidation zones

Green

57.5

Vein oxidation zones

Bright green

56.2

Vein oxidation zones

Bright green or bright blue

56.4

Vein oxidation zones

occurs because many copper ore-bodies are of hydrothermic origin (i.e. created by hot aqueous solutions arising from deep within the magma). In these situations a range of different minerals can form in sequence as the solution cools. Thus deposits that are mined primarily for their copper content often produce valuable metallic by-products, which frequently play an important part in the overall profitability of the project. The most important by-products that arise from copper mining are gold, silver and molybdenum. It may also be produced with lead, zinc, tin and uranium. Arsenic and antimony are also often present but represent a mixed blessing (if not an unmixed curse) both environmentally and metallurgically. In some cases gold is present in important amounts in copper deposits. An extreme example is the famous (but ill-fated) copper mine on Bougainville Island off Papua New Guinea (see page 11) which was, at the height of its operations, not only the third or fourth largest copper mine in the world but also ranked among the top ten gold producers. At times, when copper prices were low, it received more revenue from gold than it did from copper.

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2.2 Location of copper mines Workable copper-bearing minerals deposits have, so far, been found in comparatively few areas of the world and of these many are located in some of the least accessible and most inhospitable regions of the Earth; high in the Rocky Mountains of the USA and Canada, in the Atacama desert in the Chilean Andes, deep in the Australian ‘outback’, in central Africa or in the frozen wastes of Siberia. The OK Tedi mine in the inaccessible Star Mountains of western Papua New Guinea is a good illustration of the problems that all too often face copper mining companies. There are no road or rail links between the coast and the mine at Mount Fibulan in the razor-backed mountain spine of the country, so concentrated ore has to be piped as a slurry (a mixture of crushed ore and water) 160 km from the mill to Kiunga on the Fly River. There it is filtered, dried and loaded into barges for an 850 km river journey to Umuda Island at the river’s mouth where it is loaded into ore-carrying vessels for shipment. Situated near the equator, the region has one of the highest rainfalls in the world, yet even this cannot be relied on and river transport has been regularly disrupted by lack of water. The key to the uneven distribution of copper deposits and their concentration in remote areas lies in their volcanic origins. The bulk of known reserves (in vein and porphyry deposits) lies along major fault lines in the Earth’s crust, often where mountain building is taking place. As explained above, batholiths (the domes of molten magma that press up into the Earth’s crust) play a major role in establishing copper deposits. They tend to be located in the central cores of major folded mountain ranges. Thus, well over half of the total tonnage of copper mined each year comes from mainly porphyry deposits in the clearly defined volcanic belts on either side of the Pacific Ocean, known more picturesquely as ‘The Pacific Ring of Fire’. One arm starts in the high Chilean Andes, runs north through Peru to western Mexico, on into the semi-deserts of south-western USA, through Arizona and New Mexico, north again into the Rocky Mountains in Utah, Nevada, Idaho and Montana, and thence to British Columbia and Alaska. The other arm extends from the largely unexplored Kamchatka region of eastern Siberia, via southern Japan, through the Philippines to Indonesia and Papua New Guinea. There is thought to be another branch in the Near East which so far has produced mines in Iran, Turkey and the Balkans. Other major deposits are also found in igneous rocks of mountain areas

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in Kazakhstan, the Kola peninsula of Russia and in the Canadian Shield. The rest of the world’s major copper mines are mainly on older sedimentary deposits. The central African ‘Copper Belt’ straddling northern Zambia and south-eastern Congo (which includes some vein deposits) was for many years by far the most important mining area after the Americas’ porphyry deposits. There are massive sulphide deposits in eastern Canada, northern central USA, southern Europe, southern Africa and Australia. In Eastern Europe today only Poland is a sizeable producer, while in Western Europe, Portugal and the former Yugoslavia are the largest. As shown in Table 2.2, since 1970 there have been dramatic changes in the distribution of copper mine production, as reserves are depleted and new deposits are developed. Production is sometimes interrupted, restricted or sent into decline owing to political problems; two-thirds of Western World production comes from developing countries where political regimes are sometimes as unsettled as the geology. The relentless decline of the copper price in real terms since the early 1960s has led to the permanent closure of some mines which have become uneconomical, while the introduction of SX-EW production (see Chapter 3) has greatly boosted the output of those areas where it can be established. In the Western World, the most obvious changes to the distribution of mine production since 1970 have been the proportionate decline in US production, the catastrophic actual decline in African production and the huge increase in Chilean output. In 1970 the USA’s annual production of over 1.5 million tonnes (t) was over twice the size of that of Chile which had under 700 000 t, while the second most important producing area after North America was the central African Copper Belt, where the united production of The Congo (then Zaire) and Zambia exceeded 1 million t. In the 1980s US production fell back from over 1.5 million t in 1981 to little more than 1 million t two years later, reflecting the wholesale closure of high cost mines, including well-known names such as Superior, Twin Buttes, New Cornelia and Sacaton. Although, contrary to the expectations of many, the US copper mining industry recovered by abandoning uneconomic capacity, ruthlessly cutting costs and forcing unions into a more realistic attitude, and has since risen to a peak of nearly 2 million t in 1997, Chilean output has continued to expand, often rapidly, and now far exceeds 4 million t. By 2000 it represented 42% of Western World production, and 35% of World production.

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Table 2.2 Copper mine production (including SX-EW production) (thousands of tonnes of copper) 1970 Western Europe Finland Norway Portugal Spain Sweden Former Yugoslavia Other

1980

1990

2000

30.9 19.9 3.7 19.9 23.1 98.0 14.2

36.8 28.9 5.2 47.5 42.8 116.8 6.5

12.6 19.7 159.7 15.4 73.5 119.0 1.2

11.6 0.0 76.3 23.3 77.8 41.9 0.0

Total

209.7

284.5

401.1

230.9

Africa Botswana Morocco Namibia South Africa Zaire/Congo Zambia Zimbabwe Other

0.0 3.2 22.8 144.2 387.1 684.1 23.0 18.3

15.6 7.2 39.2 211.9 459.7 595.8 27.0 1.5

20.6 13.8 32.5 196.8 355.5 496.0 14.7 0.1

22.7 6.5 5.1 147.6 33.0 249.1 4.0 0.0

1282.7

1357.9

1130.0

468.0

Asia Burma Cyprus India Indonesia Iran Japan Malaysia Oman Philippines Turkey Other

0.1 19.5 9.7 0.0 1.0 119.5 0.0 0.0 160.3 31.1 14.8

0.1 0.0 27.6 59.0 1.0 52.6 27.0 0.0 304.5 21.3 1.8

4.4 0.5 51.6 169.5 65.8 13.0 24.3 13.7 182.3 39.8 0.1

26.7 5.7 33.8 1004.6 145.0 1.2 0.0 0.0 31.9 70.0 1.0

Total

356.0

494.9

565.0

1319.9

North America Canada USA Mexico

610.3 1560.0 61.0

716.4 1181.1 175.4

793.7 1625.0 291.3

634.4 1466.2 364.6

Total

2231.3

2072.9

2710.0

2465.2

0.0 4.6 691.6

0.0 1.4 1067.9

0.4 36.4 1588.4

145.2 31.0 4602.4

Total

South America Argentina Brazil Chile

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Table 2.2 Continued 1970

1980

1990

2000

Peru Other

212.1 16.7

366.8 5.2

317.6 0.5

554.0 2.3

Total

925.0

1441.3

1943.3

5334.9

Oceania Australia Papua New Guinea

157.8 0.0

243.5 146.8

327.0 170.2

829.0 203.1

Total Western World Total Other Countries Albania Bulgaria Czechoslovakia German DR Poland Romania USSR Georgia Kazakhstan Russia Uzbekistan China Mongolia North Korea Other

157.8

390.3

497.2

1032.1

5162.5

6041.8

7246.6

10851.0

5.6 40.3 10.7 18.0 82.9 32.0 925.0

10.8 62.0 11.5 16.2 343.0 28.0 980.0

13.2 32.9 3.6 3.6 329.3 31.7 900.0

0.0 76.0

454.1 21.0

100.0 0.0 13.3 0.4

165.0 44.0 12.0 3.3

295.9 123.9 12.0 2.0

8.0 430.2 525.0 65.0 589.0 130.2 12.0 21.0

Total

1228.2

1675.8

1748.1

2331.5

World Total

6390.7

7717.6

8994.7

13182.5

Source: International Copper Study Group (ICSG), World Metal Statistics (WMS).

Other Latin American countries have also increased production significantly, notably Peru, Mexico and the new producer, Argentina, so that now the region is responsible for nearly half of Western World mine output. Elsewhere, the most important new copper producing country is Indonesia, where output has risen from nothing around 1970 to over 1000000 t in 2000, mostly from the Freeport mine, while Australian production now comfortably exceeds 800000 t. While these countries have achieved major increases in production, contributing to a 113% rise in Western World mine production between 1970 and 2000, others have seen the output decline dramatically. Chief of these are the two Copper Belt countries, Zambia and the

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Congo (former Zaire), whose united production represented 21% of Western World output in 1970 and less than 3% in 2000. Zambian production during the period 1970–2000 declined from 684000 t to 249000 t, owing primarily to government incompetence. This has also afflicted the Congo, although here intermittent civil unrest and civil war have hastened the decline in production which has fallen from 460000 t in 1980 to an estimated 33000 t in 2000. In both countries once flourishing industries have been heavily taxed and starved of investment by regimes desperate for revenue and suspicious of foreign investment. Other countries which have seen their production fall dramatically include the Philippines, where uneconomic mines and environmental problems have reduced the production from over 304000 t in 1980 to less than 32000 t in 2000, and Japan, where production has virtually ceased for the same reasons. Meanwhile, Papua New Guinea has seen its production capacity halved by the closure of the Bougainville mine by the civil war between the Bougainville islanders and the mainland. Many of the statistics for the other countries are uncertain, but the most obvious increase since 1970 has been in Poland, where mine production rose from 83000 t in 1970 to 454000 t in 2000, and China, from an estimated 100000 t in 1970 to 589000 t in 2000. Mongolia also started production during the period and now has exceeded the 130000 t per annum level. Production in the former USSR and its new independent states has also increased, from about 980000 t in 1980 to 1028200 t in 2000. As mentioned previously, the main factor in determining the distribution of copper mine production is, of course, the location of the ore reserves, particularly those which are more easily accessible and of economic quality. However, a number of other factors influence the capacity of a country to produce copper (the same as for any other metal). First, the types of ore-bodies are important. Porphyry deposits, particularly those found in Chile and the Rocky Mountains, lend themselves to large-scale open pit mining with comparatively low costs. Their location can also be crucial, since they must have adequate access to a deepwater port if the production is to be shipped. Here Chile is at an advantage, because nowhere in that country is very far from the sea, but some US mines are far inland and also remote from the main areas of consumption. The situation of a mine will inevitably have environmental implications, which are of increasing concern today. No matter how responsible a mining company may be, it is impossible to create a large mine

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without making a monumental mess of the landscape. An open cast pit will not be refilled, so the spoil will remain as a giant heap; a huge tailings lake is needed to dispose of the liquid from the flotation process; dust, and in the case of a smelter, smoke, are generated in quantity. Luckily, many mines are situated in relatively remote areas, far away from existing centres of population, where their impact on people is restricted to those who work there or who live in the mine’s townships, that is, settlements which have grown up around the mine. Once again, Chile benefits from the fact that much of its production comes from mines in the Atacama desert, which is mainly uninhabited, or in the foothills of the Andes, so their mining industry is less restricted by environmental concerns than in some other countries. However, deserts have their drawbacks, especially regarding water, which is needed in great quantity for the mine’s concentrating process. This is always a potential problem in Chile, as in other countries, although amazingly in the Atacama desert, where the surface is often too dry to support life of any sort, underground there are immense ‘aquifers’ or natural reservoirs of water which can be used by the mines. Although the geographical distribution of copper production must ultimately be dictated by nature, inevitably people take a hand in it, both in promoting and in inhibiting. The attitude of a country’s government to its own mining industry, particularly to taxation and foreign investment, will have a strong influence on the speed and extent of the development of the country’s mineral resources. The Chilean government has been generally co-operative, and much of the massive increase in the country’s mine production can be attributed to this; the Zambian government’s policy has been the opposite, with obvious results. Nor has opposition to foreign ownership of mines been restricted to the developing countries, as the Australian government has demonstrated. Potentially even more damaging to a country’s mining industry are unstable political regimes, which inevitably discourage companies from investing in the country, even if the current tax regime and government policy towards foreign investment are acceptable. Although a number of countries have experienced violent changes in government without serious interruption to their industries, because revolutionary governments need revenue as much as those they replace, when instability, civil war and civil unrest become endemic, then mining and other industries can be ruined. The classic example of this is the currently named Democratic Republic of the Congo (previously the Belgian

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Congo and Zaire) where almost uninterrupted internal disruption and unrest, and at intervals open warfare, have starved its mining industry of investment, management and supplies to the point at which it has virtually ceased to exist. Other factors include the availability of a good infrastructure and a skilled workforce. Neither are essential, because one can be built and the other, in due course, trained by the expatriates that are needed initially; however, both are highly desirable. The former can considerably reduce the capital cost of the project, while the existence of the latter in Chile, with its long tradition of mining, has been an important factor attracting investors to that country (although the proliferation of mines there has inevitably created shortages), while the existence of a large pool of mining skills in the USA must have helped the quick recovery of the mining industry after its severe contraction in the 1980s. While government regulations may inhibit the opening of new mines in some countries, especially those like the USA and Canada, where environmental regulations are particularly strict, they may also inhibit existing mines from closure, particularly in the same two countries. Regulations regarding redundancy payments to the workforce and environmental work on abandoned mines may make closure so expensive that it may be cheaper to modernise the mine than to close it. The famous Bingham Canyon mine in the USA owes its survival to this paradox. Appendices 1, 2 and 3 at the end of this book list respectively the principal copper mines, smelters and refineries by country; the following are brief notes on the mining industries in the major primary copper-producing countries.

2.3 Copper production of the main producing countries 2.3.1 Chile Chile’s production was 4.6 million t of copper in 2000. The biggest mining company is the state-owned Corporacion Nacional de Cobre de Chile (Codelco-Chile). This company has five wholly owned mines; Chuquicamata, El Teniente, Andina, Radomiro Tomic and Salvador, and 49% of El Abra. Total capacity in 2001 was 1.79 million t. Radomiro Tomic and El Teniente are being expanded. In the past, private participation in

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Codelco’s existing mines has been prevented, although participation in joint ventures such as El Abra is now possible. The biggest single mine (and the biggest in the world) is Escondida (BHP/Rio Tinto/Japanese smelters) with a capacity of nearly 900000 t in 2001; additional capacity is planned to offset falling grades. Other large mines (over 100000 t per annum capacity) are Collahuasi (Minorco/Falconbridge/Mitsui/ Nippon), Los Pelambres (Antofagasta/Nippon/Mitsubishi), Los Bronces (Disputada de Las Condes), Zaldivar (Placer Dome) and Cerro Colorado (Rio Algom). The capacities of these mines total over 1.1 million t. There are a number of medium-sized mines with a total capacity of over half a million t, and various small mines delivering to the Enami smelters (and some owned by Enami), of about 70000 t total capacity, although production tends to fluctuate with the copper price. Capacity in 2000 was 4.6 million t (of which 1.42 million t was SX-EW) and with new developments it is likely to exceed 5.4 million t by the middle of the decade (production had already reached 4.6 million t in 2000). With large reserves, the geographical and industrial advantages mentioned above and a stable government (at least by South American standards) which is understandably well disposed to the industry which provides the bulk of its revenue, Chile’s predominant position as a copper producer looks assured for the foreseeable future.

2.3.2 USA The USA’s production was 1.47 million t of copper in 2000. The biggest mining group in the USA is Phelps Dodge, which in 1999 merged with Cyprus Amax; the total annual capacity of its mines in the USA (including minority interests and temporary closures and cutbacks) is close to 900000 t. Its main mines are Morenci, Bagdad, Miami and Sierrita in Arizona and Tyrone and Chino in New Mexico. Its largest mine (and also the largest in the country) is Morenci, with 50000 t concentrate capacity and 350000 t SX-EW; it is planned to end concentrate production and expand SX-EW to 400000 t by 2004. It has smelters at Hurley and Miami, and a large refinery at El Paso, Texas. The Asarco Group, which was bought by Grupo Mexico in 1999, has a total mine capacity in the USA of about 280000 t, notably the Mission Complex and Ray in Arizona. It runs the Hayden Smelter in Arizona, and a large refinery at Amarillo, Texas. Kennecott owns the Bingham Canyon mine in Utah, with a smelter and refinery nearby at Garfield. The Magma mines and plants

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were bought by the Australian group Broken Hill Proprietary (BHP), but by 1999 all the mine capacity (apart from small SX-EW plants), totalling about 280000 t, and their large smelter and refinery at San Manuel in Arizona had been either closed or put on standby owing to the low copper price. Other, mainly small, operating mines have a total of around 40000 t capacity. As previously mentioned, in the 1980s the US copper mine industry staged an impressive recovery from the depredations of low copper prices; it was aided by the rise in SX-EW production, which currently accounts for nearly half of total production. However, in the 1990s there was still a substantial tonnage of relatively high cost capacity, some of it, such as Robinson and Continental, only recently opened, and the collapse of the copper price in 1998 led to widespread closures and a decline in production of over 20% in 2000.

2.3.3 Indonesia Indonesia produced 1.005 million t copper in 2000. Up until 1998 Indonesian production came exclusively from the Ertsberg/Grasberg mine (Freeport/Rio Tinto) in Irian Jaya. The mine expanded rapidly to 0.809 million t in 1998 (in 1994 it produced only 0.334 million t) but since then grades have declined and future production will be less. However, 1999 saw the first trial shipment of concentrates from the new Batu Hijau mine (Newmont/Sumitomo Corp) and with a designed annual capacity of 0.245 million t this mine has raised Indonesia’s total production to 1 million t.

2.3.4 Canada Canada produced 0.634 million t copper in 2000. Copper mining in Canada is divided into three areas: in Manitoba on the so-called ‘Canadian Shield’ surrounding Hudson Bay, in southern Quebec and in British Columbia. All the smelters are in Eastern Canada and little, if any, concentrate is shipped to them from distant British Columbia, which instead exports its production to the Far East. Although still a major producer, by 2000 Canada’s output had declined significantly from its 1991 level of 0.811 million t. The 1990s saw a number of mine closures, especially in British Columbia, including Island, Similco, Afton, Bell and Goldstream, while Gibraltar closed

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temporarily. In 1999 production fell a good deal further, to an estimated 0.620 million t. Most of the this decline can be attributed to the closure of the country’s largest mine, the 170000 t per annum Highland Valley (Cominco/Rio Algom) for much of 1999, owing to the low copper price, although it has since reopened. After Highland Valley, the next biggest producer is Inco Ltd, with several poly-metallic mines around Thompson in Manitoba and Sudbury in Ontario producing around 125000 t in all (and likely to decline) with a smelter and refinery at Sudbury, followed by Falconbridge’s 55000 t per annum Kidd Creek at Timmins, Ontario, with a smelter and refinery, and Hudson Bay with Trout Lake and Flin Flon, also with a smelter. Little is left of Noranda’s mine capacity, but they still have smelters at Horne and Gaspé in Quebec and a large refinery in Montreal. Like the USA, the Canadian mining industry has shown considerable resilience over the years, aided by excellent infrastructure (although many deposits are remote and in harsh environments) and a pool of skilled labour maintained by regular mine closures; however, it is a country of high taxes, pervasive government and militant environmentalists and new projects do not always surmount these hurdles.

2.3.5 Australia Australia produced 0.829 million t copper in 2000. Copper mining is widely dispersed through most of the Australian states. The biggest mine for many years was Mount Isa (MIM/Asarco/Teck/MG), which, with its smelter, is situated in the semi-arid region of north west Queensland, about 500 miles west of MIM’s refinery at Townsville. Mount Isa’s mine capacity is currently about 180000 t per annum copper; it is also a major producer of lead and zinc. The new Enterprise orebody is being developed. However, the newer copper mine in South Australia, Olympic Dam, an underground mine which also produces uranium, has now overtaken Mount Isa’s position as the largest producer; it expanded its capacity to 220000 t per annum in 2001. It also has its own smelter (which is necessary because of the uranium content of the ore) and a refinery. MIM also owns the newly opened Ernest Henry mine; the ore from this 95000 t per annum mine provides intake for MIM’s smelter which has been expanded to 250000 t per annum capacity. The other larger mines include Goonumbla (Northparkes) with 60000 t capacity, Western Metal’s Mt. Gordon (previously Gunpowder),

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an expanded SX-EW operation producing some 50000 t per annum and Placer’s Osborne Copper with a similar production. In 1998 the veteran Mount Lyell mine, which opened in 1893, closed, but it has since been restarted by the Indian company and former customer Sterlite. Much of the rest of Australia’s copper production comes from the increasing number of SX-EW operations. In addition to the Mount Isa and Olympic Dam smelters, a 120000 t custom smelter and refinery now owned by Furukawa and other Japanese interests, is situated at Port Kembla in New South Wales. Like Chile, the USA and Canada, Australia has been a major mining country and producer of copper since the nineteenth century; however, the workforce, although skilled, is also relatively militant and Australian mines, plants and ports have been more often troubled by strikes than have those of most other comparable countries. A further complicating factor has been the ‘Australianisation’ policy of the government, which is intended to keep control of the country’s resources in Australian hands.

2.3.6 China China produced 0.589 million t copper in 2000. Production has expanded reasonably steadily from just under 0.3 million t in 1990, with the incentive of domestic demand which has risen by over 135% since 1994 and is now estimated to stand at over three times the level of mine production. The main areas in which copper is currently mined in China lie on the middle reaches of the Yangtze river in the provinces of Jiangxi, Anhui and Hubei. The Jiangxi Copper Company is the largest primary copper producer in the country and operates to the south of the river some 110 miles east of Nanchang. Its main mine, Dexing, is by far the largest in China, producing some 130000 t per annum copper; it also owns the largest smelting and refining complex situated at Guixi and a refinery at Shanghai. The other producer is the Tongling Non-Ferrous Metals Company, Tongling being south of the Yangtze and about 100 miles south-west of Nanjing. It has several mines south of the river, none of them large, and the Anqing mine to the north; its smelter and refinery are at Tongling. The rest of China’s mines are spread fairly widely across the country, feeding local and often very small smelters. The 150000 t Daye smelter in Hubei province treats imported concentrates. As with mines and smelters, there are a great number of small refineries

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in China; the large ones, in addition to the Jianxi and Tongling plants, include the Baiyin refinery in Jinquan, Huludao (Huludao Zinc) in Liaoning, and Xinxing (Shenyang), in the 60–100000 t per annum capacity range and Yunnan with 150000 t per annum. Although the Chinese claim to have large reserves of copper and galloping demand, a great increase in their domestic mine production is not generally considered likely, at least in the near future. Ore grades generally are not good, investment is severely limited and copper, unlike aluminium, is not a priority for the investment that is available. In fact, the Chinese have shown considerable interest in investing in mine capacity overseas, including Chile and Zambia, in preference to their domestic deposits. Although some foreign investment has taken place in the Chinese copper industry, for instance Sumitomo have taken an interest in Tongling smelting and refining, so far it has been tentative in comparison with other mining countries. Far-reaching reforms of government companies and public services are underway in China, which in many ways is becoming more akin to Western countries; there are also huge areas of the country which have yet to be properly explored. However, if China is to become a much bigger producer of copper than it is at present, the increase is unlikely to come about soon.

2.3.7 Peru Peru produced 0.554 million t copper in 2000. From 0.367 million t in 1980, Peruvian production had declined to below 0.3 million t by 1988. This lacklustre performance can be ascribed not to lack of reserves but, as in several other countries, ultimately to a doctrinaire and incompetent government. The combination of an extremely unhelpful tax regime, problems in remitting funds, high costs, social unrest and arbitrary government action, together with a serious terrorist problem, effectively restricted foreign investment and there was little investment available from domestic sources. However, the election of President Fujimoro in 1990 marked a gradual improvement in the country’s government and during the 1990s a growing number of foreign companies have started to participate in Peruvian copper mining. Ironically, throughout Peru’s troubles, the biggest mines, Cuajone and Toquepala, with a capacity at the time of writing of some 350000 t, were controlled by Americans, since SPCC, their owner, for years was majority owned by Asarco (now controlled by Grupo Mexico); the

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Marmon Group and Phelps Dodge also have interests. Both are open pit mines with SX-EW operations in the south of the country, Cuajone being near Moquegua and Toquepala near Tacna, with SPCC’s Ilo smelter and refinery lying between them on the coast 80 miles south of Arequipa. Phelps Dodge also owns most of the 75000 t Cerro Verde SX-EW operation near Arequipa, BHP have the 80000 t Tintaya mine near Cuzco and the American company Doe Run bought the Cobriza mine at Huancavalica (30000 t), which were all previously state-owned. Doe Run also own the La Oroya smelter and refinery 100 miles east of Lima. There are numerous small mines. After the long hiatus in Peruvian mine development, there are now a number of projects being studied, usually by foreign companies, and a large new development, Antamina (Billiton/Noranda/Teck/Mitsubishi) which will produce as much as 310000 t per annum. Expansions to Cuajone, Cerro Verde and Tintaya are also possible. A significant increase in Peru’s output in the coming years can be expected.

2.3.8 Russia Russia is estimated to have produced 0.525 million t in 2000. Until its break-up in 1990 there was little doubt that the Soviet Union ranked third in the hierarchy of copper producing nations despite the difficulty in obtaining reliable statistical information, and by 1980 it was estimated to be producing around 980000 t of mined copper a year. Since then, however, there has been a considerable decline in the total output of its former constituent states (although taken as a whole they would still rank third in the world). In addition to the political uncertainties arising from the splitting up of the old Soviet Union into independent states, the mining industry was faced with a number of economic problems, including a sharp decline in domestic demand arising both from economic decline in the various states and much reduced military demand, lack of funds for investment and higher production and transport costs because mines no longer enjoyed the protection of a centrally planned economy. As a result, a substantial amount of capacity has ceased to be economic. Russia remains the largest copper producer among the former Soviet Union states, with the bulk of its output coming from the copper–nickel sulphide deposit at Norilsk, north of the Arctic Circle in eastern Siberia. The total capacity of the Norilsk combine is in the

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region of 400000 t per annum, with most of the production coming from the 240000 t per annum Oktyabriskiy underground mine and most of the rest from the Komsomolskiy and Taymirskiy mines (also underground). Most of the other Russian mines are situated in the Urals, with the 50000 t per annum Gai mine (Krasnouralsk Mining) being the largest. The copper–nickel deposits south and east of Murmansk on the Kola Peninsula in the north west corner of the country also produce some copper through the Pechenganickel complex. There are smelters at Norilsk and Nadezhdinsky in east Siberia, Kirovgrad, Krasnouralsk, Mednogorsk and Sredneuralsky in the Urals and Pechenganickel and Severonikel on the Kola Peninsula; there are refineries at Norilsk, Kyshtym and Pyshma in the Urals and Monchegorsk on the Kola. Although Russia has the potential for substantially increased copper production, which no doubt will one day be realised, the short term prospects are not good. The financial crisis in 1998 created further delays to recovery and it may well be some years before adequate funds are made available for the exploration necessary to replace those reserves which have been exhausted or rendered uneconomic by the introduction of a market economy. Nor can foreign investment be looked upon as an immediate remedy; while the Russian government, at least in theory, is well disposed towards participation by companies from abroad, the practical problems involved in establishing a business in Russia are such that the initial enthusiasm by foreign companies to invest in Russia, that was so evident in the first few years after the breakup of the Soviet Union, has been seriously eroded.

2.3.9 Other countries Production from other countries reached 2.978 million t copper in total in 2000. The rest of the World’s copper mine production is spread fairly widely. As previously mentioned, Zambia has fallen from being a leading producer in the early 1980s to only a moderate sized one today; however, after years of fruitless negotiation, major foreign investment now seems possible, with the acquisition from ZCCM, the state mining company, of the majority of the Mufulira division and Nkana mines by Glencore and First Quantum, with China’s Non-Ferrous Metals Company’s plan to reconstruct the Chambishi mine and with Anglo American’s controlling interest in the Nchanga and Konkola divisions and the Napundwe mine. They will certainly bring some much needed

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finance to this capacity, but whether they will be allowed to bring about a real recovery in Zambian production remains to be seen. Meanwhile, in the neighbouring Democratic Republic of the Congo, Iscor hope to rehabilitate Gecamines’ Kamoto mine to produce up to 50000 t per annum, but this depends on a return to stability in the region; with the passage of time the chances of the Congo’s production being restored to anything like its former level become smaller. In South Africa, production at the one large mine, Palabora, will continue, but at a lower rate as it goes underground. In Europe, the largest producers (both modest by global standards), Portugal and the former Yugoslavia, have seen their production decline, owing to lower grades for the first, and war for the second; however, RTB-Bor’s Veliki Krivelj mine in the former Yugoslavia has been expanded, while in Spain the MRT’s Cerro Colorado reopens and closes again as the price fluctuates.

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3 Exploration, mining and refining of copper

3.1

Exploration, discovery and initial development of copper mines

3.2

Mining 3.2.1 Underground mines 3.2.2 Open pit mines

3.3

Extraction of copper from its ore 3.3.1 Extraction of copper from sulphide ores Ore dressing and concentration Smelting Refining

3.3.2 Extraction of copper from oxide ores Solvent extraction-electrowinning

3.4

Copper and copper alloy shapes

3.5

Oxygen-free high conductivity copper and its alloys

3.6

Use of copper and copper alloy scrap

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The previous chapters considered where the World’s known copper resources are located. It is now time to outline briefly how copperbearing ores are discovered, how they are extracted from the place in the Earth’s crust where they have been created and how they are then purified and transformed into metal of a quality and form suitable for the many roles it plays. In this movement from copper ore in the ground through to the copper-based end product in its multitude of forms, there are a number of stages during which the partly processed ore or metal is traded – that is, not only passed from one purifying or processing company to another in the natural progression of refining and fabrication, but also bought and sold by merchants and traders, who do not modify the material in any way and yet play an important part in the smooth operation of the whole cycle of production. (The role of the merchant and trader is discussed in detail in Chapters 8 and 9.)

3.1 Exploration, discovery and initial development of copper mines The production of copper in all its aspects is a high risk and expensive business that attracts a particular type of entrepreneurial talent. Nowhere is this more true than in the discovery and development of new ore-bodies. Here the need is for a combination of expertise, professional competence and luck – as well as access to a great deal of finance. All these factors must be present if a major mining project is to be brought to fruition. The first decision that has to be made by any exploration company is where to go to find a viable copper deposit. The choice will be dictated by two primary factors – geology and politics. As was explained in Chapter 2, certain parts of the world offer far greater promise of finding viable ore-bodies than others. The geological profile of these areas, the evidence of previous discoveries and their geographical location and the availability of sites for exploration will all play their part in deciding where to begin exploring. However, unless geological factors appear to be exceptionally favourable, mining companies will be reluctant to commit the considerable funds needed for exploration to a country which is politically unstable or where a positive attitude towards inward investment is lacking or unlikely to persist. Therefore they will prefer to operate whenever possible where there is a fair expectation of sound

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government being maintained, a reasonably stable currency and most important of all, a favourable tax regime. Exploring for minerals has been likened to trying to find a comparatively small needle in an enormous haystack. The ‘needle’ in this case is a geological anomaly, which could be an indication of the presence of mineral deposits. The days are long gone when obvious indications on the surface of the Earth can lead to important discoveries – like when William Collier shot a roan antelope in the Northern Rhodesian bush (in what is now Zambia) and found that it had fallen across a mineral outcrop stained green by the presence of copper. This turned out to be one of the richest deposits on the Zambian Copper Belt and the resulting mine, called Roan Antelope, eventually gave its name to one of the great mining companies operating in the area, Roan Selection Trust. Such romantic chance finds are much rarer now. Geologists now have to use the most sophisticated scientific techniques to discover geological anomalies usually occurring far below the surface. Two branches of science have been developed largely to meet the needs of geological exploration – geophysics (a combination of geology and physics) and geochemistry (applying chemistry to geology). Mainly by using airborne surveying techniques, geophysicists measure the Earth’s magnetic field and its resistance to electrical currents. They analyse unusual variations in magnetism, electromagnetism, density, gravity, radioactivity, electrical conductivity, polarisation and resistivity in specific areas of rock in order to locate potentially interesting anomalies. For example, gravity surveying is employed to detect granite plutons, which often indicate the presence of batholiths (or domes in the magma that can sometimes bear copper and other minerals). Airborne magnometers are used to detect high degrees of magnetism in rocks, also often an indicator of the presence of batholiths. An electromagnetic picture of the geological strata is built up by measuring resistivity so that computerised data mapping and imaging can provide a visual presentation of the results. These are then used to decide the best sites on which to begin drilling. Another ground-based technique is the potential field method. In this operation, induced polarisation is created by inserting electrodes into the ground. A current is applied for a short time and then switched off. A fraction of a second after switching off the power, the potential between electrodes is measured. Large metallic ore-bodies retain a measurable electric charge for a short period after the power is switched off and so can be detected by this method. Another widely used

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technique is seismic surveying, whereby small explosive charges are detonated in shallow bore-holes, or mechanical vibrations are emitted by specially adapted vehicles. The shock waves produced are detected by a complex arrangement of geophones (hearing devices). Different rocks have different sound absorption and refractive patterns so that by utilising this technique a map of the underlying geological strata can be built up. Ground penetrating radar is also used to investigate shallow deposits. Geochemical methods are used to analyse the mineral content of the soil and vegetation on the surface in areas where deposits are considered likely to be found. Abnormal concentrations of certain chemical elements can often indicate deposits of special interest lying far below. Once a promising anomaly has been identified, the prospecting company faces the risky, time consuming and expensive business of drilling and analysing test bore-holes, to try to prove what is really there far below the surface. It is then that the needle-in-a-haystack analogy truly comes into its own. The drilling of bore-holes is carried out with diamond impregnated bits, rotated at the end of a series of hollow iron rods. The rotary movement enables a core of rock to rise up through the centre of the device and be extracted for analysis, while waste material (earth, water, lubricant etc.) passes up to ground level between the outer surface of the rods and the wall of the bore-hole. A special drilling mud is used which acts as lubricant, coolant, scourer and cleaner. Sir Ronald Praine, former head of Rhodesian Selection Trust and author of Copper – the Portrait of an Industry estimated that only one in a thousand exploration prospects turns out to be a viable proposition and actually becomes a mine. Despite all the technology that science can muster, the process remains at bottom a ‘hit-or-miss’ business. He also likened it to the children’s party game where a blind-fold person tries to pin the donkey’s tail in the right place. Yet many potentially lucrative ore-bodies must remain to be discovered and not only small ones. The ore body that sustains the Escondida mine in Chile, the biggest copper mine in the world, was unknown in 1980, in spite of its lying within half a mile of a railway line (its discovery is said to have resulted from an exploration bore-hole being mistakenly drilled deeper than intended). If a drilling programme continues to yield promising results and has enabled a sufficiently precise three-dimensional outline of the deposit to be established, the next step is to produce a viability report. Here commercial assessments are matched to the technical data so far

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evaluated. An estimate is made of the average grades of copper in the ore-body and of any by-products found in the minerals so far detected. In addition, an assessment is made of the volume of ore reserves likely to be available. From these calculations the potential life of the mine is estimated at various rates of extraction. Then it has to be decided, given the expected costs of production for the project and the anticipated level of copper and by-product prices over the life of the mine, whether the find can be developed into a profitable mine. The costs of production have to take into account a number of factors including: • the type of mine that can be envisaged – i.e. an open-pit or the much more expensive underground operation • the type of mining technique that can be employed, given the geological structure of the area • the average percentage of copper and useful by-products that can be expected to be found in the ore-body • the availability of water – sufficient, too little, or too much • the quality of local labour • the availability and cost of power, transport, services and general communications in the region of the projected mine, especially its distance from the nearest port or potential consumer • the cost of environmental factors • the infrastructural requirements needed to provide adequate accommodation and facilities for the workers and their families, particularly when large numbers of expatriates are involved. To be a commercially viable proposition today, the copper content of the ore from an open-pit mine is likely to assay in excess of 0.5% copper while for an underground operation it will probably be at least in the region of 1–2%. The next stage in the initial development process is the preparation of a detailed report on how the project will be financed – its capital cost, its running costs, the tax regime under which it will operate and the interest charges that will be incurred. The development stage could well have to be financed for a number of years before adequate income begins to flow on a regular basis. From all these data, a calculation of the discounted cash-flow will be produced for the project. For this, a copper price level over a number of years into the future must be assumed. In practice, it is impossible to forecast the price of copper, or any other freely traded commodity, with any degree of real confidence; however, a

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guide to the likely profitability or otherwise of a project can be found in the costs of production of those other primary producers which will be operating when the project in question is in production. Although the copper price can fluctuate widely, behave erratically and is seldom even moderately stable for long, overall it is governed by costs of production. In the long term the average copper price must be of a level high enough to provide for supplies of copper metal that are adequate to satisfy demand, but no more. Since the bulk of supplies are primary copper, it is mining costs which have the greatest influence on the price level in the long term. Therefore, the most important consideration for any company contemplating the development of a new mine is not the copper price as such, but the range of costs of the other mines which will be operating when it goes into production. Provided their project will be far enough down the range of mines’ costs, and that there will be enough other mines which will have a higher cost than it, then it should succeed. Obviously, the comparison of future costs is surrounded by imponderables, notably the rate of growth of copper demand which ultimately governs the level of supply, the level of secondary production, which in turn is largely determined by the price level, what other mines will be developed during the project’s lifetime and developments in mining technology which may affect mine costs. Also, the financial evaluation of a project must inevitably require copper price assumptions. Nevertheless, the principal reassurance which the investor in a new mine will ultimately look for is likely to be how it will compare in cost with other mines. Some companies specialise in exploration, and would withdraw at this stage (or earlier), by selling the mineral development rights to a more financially powerful group for a sum which would cover its costs and enable it to make a reasonable profit. Others specialise in buying into existing projects. Many mining companies would, however, want to develop an interesting find either on their own or in association with others. A company, especially a large one, may be able to finance the new development out of its own resources; however, for a large project this is not always feasible or advisable. Other sources of finance commonly used include: • Joint ventures – this means offering other companies a share of the project in return for taking over an agreed proportion of the

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•

•

•

•

financial burden and risk. This method is being resorted to increasingly as the cost of developing large-scale operations is often too great to be carried comfortably even by a large group. Sometimes the mine’s prospective customers will participate in this way. Many Japanese smelters are ensuring future supplies of concentrates and blister copper by taking a share in the mining projects that are to supply them. Loan finance – can be sought from a bank or consortium of financial institutions by which funds are provided at either a fixed rate of interest or at flexible rates over a period. Project finance – particularly attractive projects may be financed by loans which are repaid from the cash flow generated, with the assets standing as collateral security. Equity finance – this involves issuing new shares in the company which is developing the project, either as a rights issue (selling to existing shareholders) or selling to the public. Other forms of finance – national governments may provide financial backing in countries which will either be selling mining equipment etc. to the project or importing its production; Japan, which is a very big importer of copper concentrates, provides examples of finance provided against long-term concentrate sales contracts. Loans may be raised from international agencies such as The World Bank or the European Investment Bank.

3.2 Mining As has been explained in Chapter 2, copper ore-bodies are found widely distributed across the Earth’s surface, all too often in the least accessible places. They are exceptional occurrences, freaks of nature, brought about by very special geological conditions. For this reason no two ore-bodies are ever identical. Some ore-bodies contain only copper with no other useful elements present in sufficient quantities as by-products to make a contribution to mining costs; however, most copper mines have a variety of other metals present in the ore-body. Some of these will be valuable byproducts that will make a useful contribution to mine costs. In this category fall precious metals – silver, gold or platinum group metals – lead,

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zinc or molybdenum. Other elements present may be less than useful because they have to be removed during the process of purification, either to ensure that the refined copper meets the required standards, or because the elements are potential pollutants in the environment. Bismuth and antimony fall into the former category, while cadmium and arsenic are examples of the latter. Beryllium and tellurium fall into both categories. Poly-metallic deposits are where one or more valuable metals are present in addition to copper, in large enough amounts to raise them out of the category of by-products. For example, in the Sudbury basin in Ontario, Canada, many deposits contain substantial amounts of both nickel and copper. At Mount Isa in northern Queensland, Australia, operations began by mining lead. At Olympic Dam in South Australia the main ore-body is a large copper–uranium deposit with by-product gold, silver and rare earths; a second area is a gold ore-body with copper and uranium as no more than by-products, while a third area is rich in silver, copper and uranium. Finally, there are ore-bodies where copper itself is a valuable by-product and not the principal metal mined. The method by which copper is mined will depend upon how deep the main ore-body is below the surface, the rock formation in which the ore is embedded and the general geological nature of the surrounding area. As previously explained, today there are basically two types of copper mine, underground and open pit.

3.2.1 Underground mines Underground mines mostly operate by sinking vertical shafts from ground level to the vicinity of the ore-body which is then reached by a series of horizontal tunnels. Where geological conditions permit, the mine shaft may be replaced or supplemented by a spiral ramp or ‘decline’, giving vehicles direct access to the working levels, as, for example, at the Neves Corvo mine in Portugal. Another variation used in mountainous terrain is to drive ‘adits’, or gently inclining tunnels, upwards into the steep hillside to gain access to the various levels of the ore-body. Some parts of the giant El Teniente mine in the Chilean Andes operate in this manner. However, in most cases there is no alternative but to sink a vertical shaft sometimes thousands of feet into the earth. Great chambers are then dug out of the rock to house equipment such as

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crushers and ventilating and pumping machinery. Conveyor belts or light railway systems are installed to transport the ore from the working faces (called ‘stopes’) to the shaft. The shaft not only has to transport the miners underground and lift the crushed ore to the surface, but also houses the ventilation, electricity and water supply lines, and in the case of a wet mine, provides the channels through which unwanted water is removed. There are many techniques used for extracting the copper-bearing ores from their place in the deposit. Most deep mines operate variants of two basic methods – ‘stoping’ and ‘block caving’. Stoping involves clearing the ore face and then drilling holes in it to take explosive charges. The rock shattered by the explosion is moved by dump truck or conveyor belt directly to underground primary crushers or to storage areas, to await movement to the surface. ‘Block caving’ does not require the use of explosives, but is only suitable where the ore-body is sufficiently thick and uniform. An area (called an under-cut) is excavated beneath the selected block of ore. When supports below the block are removed, it caves in. The shattered ore-bearing rock is then dealt with in the same way as it is with stoping. In many underground mines when the ore-bearing rock has been removed from a particular section, that area is refilled with a mixture of waste rock and concrete to prevent subsidence.

3.2.2 Open pit mines Open pit mines are huge quarries or terraced holes in the ground, where the ‘overburden’ (or barren overlying rock) has been removed to give access first to the water-enriched zone of oxide ores, and below them to the ‘supergene’ zone of the main sulphide deposit. The outer faces of the individual terraces are systematically removed by the use of explosive charges and the lumps of ore-containing rock are swept up by a variety of enormous mechanical shovels and moved to primary crushers in giant dump trucks, the largest of which can currently handle a pay-load of over 200 t. Thus open pits are constantly being enlarged, so that in the case of long-established operations such as Chuquicamata in Chile or Bingham Canyon in Utah, USA, the dimensions of the hole are measured in miles or kilometres. Bingham Canyon, currently the largest (and also the oldest), is 2.25 miles wide by 2.0 miles long and half a mile deep.

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The advantage that the open pit mine enjoys is that operating above ground, it is able to utilise the latest and largest mechanical aids and keep mining costs much lower than can an underground mine. It is therefore able to work economically on much leaner ore-bodies. Its disadvantage is that it can only work ore-bodies that are relatively close to the surface, but nevertheless this is far outweighed by the quantities of ore, and therefore copper, that can be extracted. It is difficult to see how the industry could have met anything like the modern demand for copper without open pit mining. The introduction of open pit mining was not easy. For many years after the discovery of extensive disseminated porphyry deposits in south-western USA and Chile, they could not be exploited because no way had been found to treat economically sulphide ores with a copper content of around 2% – at that time considered to be of too low a quality to provide the basis for a viable mine. Moreover, the means were not yet available to handle the enormous volume of rock that would have to be moved from such deposits, in which the particles of copper are more or less uniformly scattered throughout large areas of the host rock – often a hard porphyry, or sometimes a schist. Until early in the twentieth century the World’s copper requirements were met from comparatively rich vein deposits, with a copper content often of 6% or more. However, the First World War, and a rapid increase in the use of electricity, caused the demand for copper to soar. Existing sources were insufficient to meet the need. Therefore new techniques had to be found so that these extensive porphyry deposits could be economically exploited. In 1907 Daniel C Jackling was working at Bingham Canyon in Utah, USA on a new mining technique that was to change the face of the copper industry. He realised that the lowgrade porphyry copper ores – even those with less than 2% copper content – could be exploited by open pit mining methods more profitably than most underground vein deposits where the copper content of the ore could be three times higher, provided they could be mined in sufficient quantity. Jackling saw that, when harnessed to mass production methods, the open pit system of mining would enable unit costs to be reduced to levels that would more than compensate for the massive tonnage of rock that would have to be handled. At about the same time an answer was found to the other problem, how to concentrate efficiently low-grade sulphide ores, which is described in the following section.

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3.3 Extraction of copper from its ore To separate the copper from waste material (gangue) in the ore is the first stage in the long process of purification. Copper ores are treated in two ways according to their type: • Sulphide ores are currently treated pyrometallurgically – i.e. fire is used to removed unwanted impurities. • Oxide ores follow a hydrometallurgical route, whereby the copper is extracted from the ore by an acid leaching process and then recovered by electrolysis.

3.3.1 Extraction of copper from sulphide ores Sulphide ores, which represent the bulk of copper mined, are treated by a three-fold process: 1 Ore-dressing – this involves the initial separation of the copperrich particles in the ore from the mass of ‘host rock’ or ‘gangue’. This is done by crushing and grinding, followed by concentration by a selective flotation process. 2 Smelting – the concentrated ore is smelted to remove residual gangue, most of the sulphur, iron and other metallic impurities, as well as some of the oxygen content. 3 Refining – most of the residual impurities are removed from the copper together with much of the oxygen to produce metal with the purity required by industry. This is effected either by a process of fire refining or by electrolytic refining. Ore dressing and concentration Ore dressing is the first stage in the purification of copper sulphide ores. It involves the separation of the particles of copper from the great bulk of barren host rock or gangue. First the ore-containing rock passes through a series of crushers. The pieces of rock are reduced to about the size of a walnut before being broken down further in rod or ball mills. These are essentially revolving drums in which steel rods or balls wet grind the material to a fine grit, thus separating most of the valuable particles from the waste gangue. In earlier days the rock was only broken into small pebble-sized pieces, the ore-containing pieces being crudely divided from the waste on an inclined water table. This crude and ineffi-

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cient system of concentration was only remotely viable if very high grades of ores were being treated. As often occurs in history, a need brings forth a solution. The answer is said to have originated in Britain, although some American writers dispute the location. The story goes that a Derbyshire lead miner’s wife noticed that when washing her husband’s working clothes, the particles of galena (lead ore), instead of falling to the bottom of the wash-tub, adhered to the surface of the soap suds. From this simple observation it is said that the selective flotation method of concentrating non-ferrous metal ores was evolved. Technically this selective flotation process operates on the principle that different minerals have different ‘whetting’ characteristics. This means that by the use of reagents, copper minerals can be rendered hydrophobic and so can be induced to adhere to air bubbles, while other particles, including the valueless gangue, do not. A non-technical explanation of the process is that the finely ground ore, mixed with water and the appropriate agent, is fed into flotation cells, while air is blown through the agitated fluid from below. Particles of copper ore adhere to the air bubbles on the surface which are skimmed off into thickening (or settling) tanks. They then pass through a series of filters and presses to remove much of the water. The unwanted particles of gangue drop to the bottom of the cell to be removed as ‘tailings’ to waste dumps. By repeated processing, 95% or even more of the copper mineral in the ore can be recovered by this process. Concentrate of important by-products like molybdenum can also be extracted by using different chemical reagents and varying the temperature in the flotation cells. Copper concentrate consists of elemental copper, oxygen, sulphur, iron, other metals, residual gangue and, of course, water. The percentage of copper varies from less than 20% to over 40%, according to the copper minerals in the ore; the average is around 30% copper. Sulphur is likely to amount to around 30%, and iron 25%. Smelting The next stage in the purification of sulphide ores is the complex process of smelting. It consists of three distinct stages – roasting (not always necessary), actual smelting and converting. The purpose of roasting is to dry and heat the concentrate before it goes into the furnace, and to improve the concentration of copper. It involves heating the concentrate to drive off excess sulphur and iron.

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Improving grades of concentrates has reduced the need for roasting. What remains is called ‘calcine’, which consists of a fine mixture of copper and iron sulphides and oxides, together with residual gangue and other non-volatile materials. In smelting, the concentrate is heated in a furnace to about 1200 °C to produce a slag containing the residual gangue and some of the iron, which is tapped off and dumped, leaving a sulphide of copper and iron called ‘copper matte’ containing between, say, 35% and 65% copper. Converting turns the copper matte into metallic copper by the removal of virtually all the sulphur and iron (as well as some other impurities) using copper’s lower affinity for oxygen than either sulphur or iron. Converting is normally carried out in a cylindrical vessel into which air or oxygen is blown under pressure. Little additional heat is needed in this process because the oxidation of iron and sulphur itself releases more than enough heat to keep the material molten. The introduction of air initiates a complex series of reactions. Initially the oxidation of copper, iron and sulphur takes place close to where the air (or oxygen) is introduced. The copper oxide thus formed immediately reacts with any residual iron sulphide to produce copper sulphide and iron oxide. As the reaction proceeds the only iron present is in the form of iron oxide, with copper as copper sulphide. The sulphur that had been combined with the iron (as iron sulphide in the copper matte) is liberated as sulphur dioxide. The iron oxide is then converted into a slag by the addition of a silica flux, tapped off and dumped. After the removal of the iron, the continued blowing of air (or oxygen) into the melt allows for further oxidation of the copper and residual sulphur. The copper oxide so formed then reacts with the copper sulphide to release more sulphur dioxide, eventually leaving only molten metallic copper with small amounts of copper oxide and other metallic impurities; this is called ‘blister’ copper. The sulphur dioxide produced during the converting is used to make sulphuric acid. The blister copper is then either cast into cakes, or, more often, is further purified in an anode furnace and cast into rectangular slabs or ‘anodes’. These have special lugs cast on top to enable them to be hung in an electrolytic refining tank (or cell). Blister copper assays a minimum of 98% pure copper, but can sometimes assay up to 99.5%. This material gets its name from the fact that as the molten metal cools, sulphur dioxide, held in solution, is expelled giving the casting its characteristically bubbly or blistered surface. Its residual impurities, brittleness and

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porosity make it unsuitable for fabrication or direct electrolytic refining. It is therefore used in fire refineries to produce anodes or occasionally refinery shapes (see pages 14–15, 21–23). Anode copper generally assays around 99.8% purity, having had some oxygen and residual sulphur removed in the anode furnace. These smelting processes have evolved over many years, becoming ever more sophisticated in order to meet changing technical, economic and social circumstances. The mining of ore which was too low grade to be used as direct smelter feed led to the introduction of ore concentration. Rising fuel costs speeded the introduction of flash smelting technology, while ever more stringent environmental regulations have led to the capture of nearly all the considerable quantities of sulphur which the processes generate. In the past, many operations caused serious pollution, not only by sulphur dioxide but from the emission of toxic substances such as arsenic, antimony, cadmium or lead into the surrounding atmosphere. With the advent of much greater public awareness of the dangers of industrial pollution, totally enclosed systems have been evolved, which bring all smelting and converting processes together in one large reactor. The most modern smelter technology divides itself into two main categories: flash smelters and converters pioneered by Outokumpu of Finland and also developed by Inco (International Nickel of Canada) and Mount Isa of Australia, and bath smelting technology, developed by Noranda of Canada and Mitsubishi of Japan. In both methods, the sulphur content of the feed is efficiently utilised as fuel, the heat generated in the reaction creating temperatures needed for the smelting operation; the surplus may be harnessed to produce electricity. The whole process is intensified and speeded up by the injection under pressure of various mixtures of oxygen, air and natural gas, often utilising thermic lances thrust deep into the heart of the melt. With the whole reactor completely sealed it is possible to limit environmental pollution to a small fraction of that of older systems. In addition to reduced energy costs and greater pollution control, the new technologies offer improved operational efficiency, with fewer personnel needed in the plant and lower running costs. The obvious disadvantage of introducing the new technologies is the very high cost of building new plants and the consequent burdens of finance and depreciation. While a new plant may be cheaper to run, its

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total operating cost per pound weight of metal produced is likely to be far higher than that of an old plant which is likely to be largely amortised, provided that it has been updated sufficiently to meet the local environmental requirements. Also, new capacity from the expansion of an existing plant, which can often be affected by ‘de-bottle necking’ where one part of a plant may be restricting the full usage of the capacity of the rest of it, will almost invariably be considerably cheaper than new ‘greenfield’ capacity, because relatively little needs to be done to achieve it. Indeed, one of the most important developments has been the numerous cases of existing smelters being expanded, often as a result of modernisation made necessary by environmental demands. This has had important consequences for the custom concentrate market (see Chapter 8). It is not surprising, therefore, that while the use of flash smelting and other relatively modern processes such as Noranda and Mitsubishi have has spread rapidly, older plants continue to represent a significant proportion of total smelting capacity. According to International Copper Study Group (ICSG) figures, modern technology represents about half of global smelting capacity, nearly 60% in Western countries but little more than one-quarter in Eastern countries, where reverbatory furnaces account for 46% (32% in the West), and blast furnaces, which have almost disappeared in the West, still account for over 20%. Electric furnaces amount to some 5% of total capacity. The efficient capture of sulphur in some areas may also itself pose a problem because while in many countries the resulting sulphuric acid may be sold at a profit, local oversupply of acid may on occasion leave smelters with unwanted tonnages of a substance which is notoriously difficult to dispose of when not in demand. Refining For thousands of years fire refining was the only way to carry out the final stage (and indeed any stage) of the purification of copper. However, modern applications for copper, especially those relying on the electrical and mechanical properties of the metal, demand a purity greater than can be achieved by fire refining, and the bulk of refined copper now is the product of electrolytic refining or electrowinning (the latter is described in the section on hydrometallurgical processes on page 18). Most smelters are integrated with electrolytic refineries, so molten blister can be poured into an anode casting furnace for casting into flat

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slabs of metal of a shape suitable for the refinery. ‘Custom’ or non-integrated electrolytic refineries purchase anode. Table 3.1 shows the distribution of refined copper production and Appendix 3 lists the major refineries. Nevertheless, nearly one million tonnes of fire-refining capacity remains, although of the 700000 t in Western countries about two-thirds is for treating scrap, and its production has to be further refined in electrolytic plants if it is to be sold as high grade refined copper. In fire refining, blister and/or good quality scrap is melted in a furnace and air is injected into the melt to oxidise residual impurities. The oxygen level is then reduced, usually by blowing in natural gas or propane. The resulting copper should contain at least 99.85% copper with between 0.02 and 0.05% oxygen and will normally be cast into anodes (flat slabs) for further refining in an electrolytic refinery; however, in some cases the metal may be cast into ‘cakes’ (slabs) or ‘billets’ (cylinders) for casting by fabricators into products such as sheet, strip and tube. Not all impurities can readily be treated by pyrometallic methods. This is particularly true of those elements that do not form stable oxides and have appreciable solubility in copper, such as selenium, tellurium, nickel, silver, gold and other precious metals. These can only be satisfactorily removed by electrolysis. Fire-refined shapes are now less frequently used in the fabrication of semi-wrought products as residual impurities tend to lower the performance of the finished products and because using them would involve the loss of the precious metals that are often found (and paid for) in the blister copper. In the electrolytic refining process the copper in the anode is electrochemically dissolved and transferred to a cathode in a purer form than can be achieved by fire refining. In the process most of the remaining impurities are discarded, along with precious metals which can subsequently be recovered. The process takes place in a tank or cell in which the relatively impure anodes are suspended in an acidified copper sulphur solution (electrolyte) alternately between thin starter sheets of pure copper, which will become the cathodes. The anode is connected to the positive lead of an electric circuit, while the negative lead is connected to the starter sheet onto which the copper will be deposited. When the electric current is switched on, positively charged ions (atoms of copper which have lost electrons) in the solution move to the cathode, being deposited as pure copper. For each ion deposited onto the cathode, another ion

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Table 3.1 Production of refined primary and secondary copper including leach cathode (thousands of tonnes) 1970 Western Europe Austria Belgium Finland France Germany Italy Norway Portugal Spain Sweden UK Former Yugoslavia

1980

1990

2000

22.0 276.0 34.0 33.6 405.8 15.5 25.8 4.0 79.7 51.2 206.2 89.3

31.3 288.9 40.5 46.5 373.8 12.2 26.7 4.5 153.7 55.7 161.3 131.3

49.7 331.9 65.1 44.0 532.9 83.0 36.5 0.1 170.6 97.3 121.6 151.4

81.4 423.0 114.0 0.0 709.4 72.8 27.0 0.0 313.6 131.6 3.0 45.6

1243.1

1326.4

1684.1

1921.4

Africa Egypt South Africa Zaire/Congo Zambia Zimbabwe

1.8 75.3 251.2 580.7 29.5

2.0 147.9 279.4 607.1 7.1

4.0 133.0 173.2 478.6 24.4

4.0 100.5 29.0 227.4 7.0

Total

938.5

1043.5

813.2

367.9

Asia Burma Cyprus India Indonesia Iran Japan Oman Philippines South Korea Taiwan Turkey

0.0 0.0 9.3 0.0 6.0 705.3 0.0 0.0 5.2 3.8 14.1

0.0 0.0 23.2 0.0 1.0 1014.3 0.0 0.0 72.9 19.5 18.8

0.0 0.0 38.7 0.0 47.8 1008.0 12.0 125.9 187.0 16.1 84.2

26.7 5.7 260.0 158.4 155.9 1437.4 24.3 150.0 468.0 0.0 64.1

Total

743.7

1149.7

1519.7

2750.5

North America Canada USA Mexico

493.3 2034.5 53.7

505.2 1686.0 102.8

515.8 2017.4 151.9

551.4 1793.7 411.0

Total

2581.5

2294.0

2685.1

2756.1

Total

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Table 3.1 Continued 1970

1980

1990

2000

South America Argentina Brazil Chile Peru

0.0 18.6 465.1 36.2

10.0 0.0 810.7 224.8

11.9 156.8 1191.5 181.8

16.0 185.3 2668.3 451.6

Total

519.9

1045.5

1542.0

3321.2

Oceania Australia

145.5

182.4

274.0

487.3

Total

145.5

182.4

274.0

487.3

6172.2

7041.5

8518.1

11604.4

4.0 38.3 16.7

9.0 63.0 25.6

10.9 24.3 24.6

50.0 16.0 72.2 12.2 1075.0

95.4 27.8 357.3 65.0 1300.0

56.7 6.0 346.1 24.7 1260.0

120.0 15.0

295.0 23.0

561.5 30.0

0.0 33.0 0.0 0.0 0.0 0.0 486.0 13.3 0.0 394.7 816.0 75.0 5.0 1371.1 15.0

Total

1419.4

2261.1

2344.8

3209.1

World Total

7591.6

9302.6

10862.9

14813.5

Western World Total Other Countries Albania Bulgaria Czechoslovakia Slovakia German DR Hungary Poland Romania USSR Kazakhstan Russian Fed. Uzbekistan Mongolia China North Korea

Source: International Copper Study Group (ICSG), World Metal Statistics (WMS).

enters the solution from the anode. The anode is eventually consumed and in the process its impurities either remain in the solution or fall to the bottom of the cell, as what are known as slimes. In this way a pure copper cathode is formed and any valuable precious metals such as gold, silver, platinum or palladium, present in the anode, can be recovered from the slimes. It usually takes about 14 days to produce a marketable cathode of say 110–125 kg weight, so that a large refinery will consist of a big tank-house containing hundreds of cells. One anode is likely to produce two cathodes.

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Gold and platinum group metals are not soluble in the electrolyte and so are not transferred to the cathode. Silver dissolves, but can be precipitated from the electrolyte as AgCl by dissolving NaCl or HCl in the electrolyte. These metals can be recovered from the slimes or undissolved material left at the bottom of the cell after the copper refining process has been completed. The soluble impurities are subsequently removed from the electrolyte. Electrolytic copper cathodes assay from a minimum of 99.90% up to 99.99% purity. About 0.03% (300 parts per million) of oxygen is purposely left in the copper. This small amount does not unduly affect its high level of electrical conductivity, but improves its denseness and avoids porosity when the cathodes are melted and cast into what are termed electrolytic high-conductivity copper shapes. In official specifications, the oxygen content is not stated as an impurity, except in the cases of the oxygen-free range of special coppers and fire-refined tough pitch copper cathodes.

3.3.2 Extraction of copper from oxide ores The other major category of copper ores, those that are generally classified as oxides, follow a rather different path before they become commercially pure copper. Most do not lend themselves to being concentrated efficiently by selective flotation, but can be treated by leach extraction techniques, taking advantage of the fact that certain solvents will readily take the various copper oxide compounds into solution. Some low grade sulphide ores, and both oxide and sulphide mine waste, are also treated by the hydrometallurgical process. The first stage of hydrometallurgical extraction is the passing of a leaching agent, usually dilute sulphuric acid (although ammonia and hydrochloric acid are used occasionally) through the copper-bearing material. The means by which this is done varies according to circumstances, although all require an impervious base to catch the liquid after it has passed through the ore. The principal methods are the following: • Dump leaching: Low grade waste arising from previous mining operations is treated where it lies; at intervals the leachant is poured over it, and after percolating through it is collected. Since the ore does not have to be moved, this method can be very economical.

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• Heap leaching: This is similar to dump leaching, except that the ore is first crushed and then heaped onto an impervious pad with drainage channels; the leachant is applied continuously. • In situ leaching: The ore is treated where it lies in the ore-body, possibly after being broken up by explosives, rather than being moved first. This method is comparatively rare, but since the ore does not have to be shifted, like dump leaching, it can be very low cost. • Vat leaching: Rather than the leachant being sprinkled onto or pumped into the ore, as in the first three methods, having been first ground fairly small, the ore is immersed in a vat of leachant which may be stirred. In the latter case, the ore may have been previously concentrated. The length of time of a leaching cycle, that is, the interval between applying the leachant and the ‘pregnant solution’ (copper-carrying liquid) being drawn off, varies enormously according to the grade of material, the method used and other circumstances. In situ and dump leaching may take years, heap leaching can take months, while vat leaching, especially when agitated (stirred) can complete the cycle in a matter of days; agitated fine concentrates do so in hours. Sulphide ores and wastes, which are usually only treated by heap or in situ leaching, take longer than oxides because they are not soluble in sulphuric acid unless they are able to oxidise. Recovery of copper is likely to be between 50 and 85% for sulphide ore, and 90% for oxides. In the first stage of the hydrometallurgical process, therefore, the leaching solution is brought into contact with the ore. The copper oxides readily dissolve in dilute sulphuric acid, although sulphide minerals will only do so slowly in oxidising conditions; the presence of bacteria (that live without organic matter) may assist the process. The copper is thus carried into the solution, while the gangue (waste rock) is left. In the past the recovery of the copper from the leachant was usually effected by cementation, in which the pregnant solution was poured over lumps of scrap steel on which the copper was precipitated, the precipitate being detached in powder form. The principal drawback of this process was the fact that the copper precipitate, which typically contained 85% copper, was inevitably heavily contaminated by the iron and required purification in a smelter and electrolytic refinery.

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With the advent of solvent extraction (electrowinning) the cementation process has all but disappeared. Solvent extraction-electrowinning The solvent extraction-electrowinning (SX-EW) process has arguably been the most important development in the copper industry in recent years, providing scores of new sources of production, varying in size from a few thousand tonnes to hundreds of thousands of tonnes, and at an average cost per tonne significantly below that of production following the pyrotechnical route. The process has enabled the exploitation of many deposits, and indeed waste dumps, which would otherwise have been ignored, thus greatly increasing the reserves of copper available for economic extraction. It provides a means of treating oxide ores which do not lend themselves to concentration and flotation as do sulphide ores but which are often present in quantity at the early stages of the development of a mine. Low grade waste dumps and, on occasion, ore-bodies in a mine, can be treated very economically since no mining or transport costs are incurred. In the first stage, therefore, the leaching solution, sometimes containing bacteria which assist the process, is brought into contact with the ore. The copper oxides are dissolved, the copper being carried into solution whilst the gangue (waste rock) is unaffected. Then to ensure the maximum possible recovery of copper, a complex process of washing, filtering, settling and concentrating is carried out. Recovery is likely to be between 50 and 85% of the copper in the sulphide ore, and 90% for oxide ore. The leach solution is then purified to remove soluble iron and other impurities before the copper-rich liquor passes into the next stage, which is termed solvent extraction and electrowinning. It is basically a modified form of electrolytic refining as described previously. With the development of special reagents or organic extractants, the SX-EW technique has become much more effective for large scale operations. The copper is first removed from the leach solution by mixing it with an organic extractant. It then passes into the electrolyte – a solution of sulphuric acid and copper sulphate. This is pumped into electrowinning tanks where the copper in the electrolyte is plated onto a cathode. The electrowinning process differs from electrorefining in that an insoluble anode (usually of lead) is the positive terminal of the cell, but, as before, the negative terminal is attached to a starter sheet of stainless steel or titanium onto which the pure copper is deposited. It

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takes about seven days to produce a 100 pound (45 kg) cathode from each side of the starter sheet. Being thinner and lighter than conventional cathodes is an advantage for some applications, such as alloying. For a number of years, after large scale electrowinning operations began in the USA and Chile, the quality of the resulting cathodes was lower than that of conventional electrolytic cathodes produced from copper anodes. In particular, a comparatively high lead content made electrowon copper only suitable for brass mill applications where lead is a constituent of some alloys. In a casting mill it tended to be ranked with a good ‘number one’ grade copper scrap, and was sold at a discount to standard cathode. However, in the 1980s stronger leach solutions became possible with new reagents and this resulted in a considerable improvement in general quality, so that this type of cathode is now acceptable to leading copper mills around the world, including those making wire and cable products, and brands of electrowon cathodes are now registered as good delivery against the London Metal Exchange or Comex Copper contracts (see Chapter 9). Some exceptionally pure ‘five nines’ (99.999%) electrowon copper has been produced. At the time of writing, over 18% of the World’s production of primary copper is produced by the SX-EW process, and since nearly all the SX-EW capacity is in Western countries, the proportion in the West is over 30%. The ICSG estimated that the World’s total SX-EW production in 2000 was over 2.3 million t. In theory, at least, the scope for further expansion of SX-EW capacity may be restricted by the limited amount of oxide ore reserves available and the exhaustion of suitable waste heaps; also, the average life of an SX-EW operation is generally reckoned to be markedly shorter than that of a sulphide mine. However, the ICSG estimate that total actual and planned SX-EW capacity by 2005 will be over 3.3 million t, 26% more than in 2000, and no doubt there are many more potentially economic deposits yet to be discovered.

3.4 Copper and copper alloy shapes When the copper ore has been purified, at least to the stage of anode quality, the point has been reached when it is usually cast into a special shape – what is termed in the trade a ‘refinery shape’. These shapes are produced in copper and most of its alloys in foundries or casting shops attached to refineries. They generally represent the raw

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materials for the process of fabrication – that is, the production of semiwrought products such as wire, plate, sheet, strip, section and tube (see Chapter 4 for details of these processes). There are seven main refinery shapes: • Anodes are mostly cast as the first stage in the production of cathodes in the electrolytic refinery. These massive shapes are produced in copper only but not in alloy. The thick slabs usually measure about one metre (39 inches) square and weigh up to 400kg each (880 pounds). However, there are also much smaller shapes called platers’ anodes which are used in the electroplating industry and are produced in both pure and phosphorised copper; the small amount of phosphorus – 400 to 600 parts per million – improves the efficiency of plating in bright acid baths. These platers’ anodes come in many shapes and sizes, but there are two main types – bar anodes and balls or chunks. Balls and chunks generally measure between one and three inches across (25–76 mm) and weigh from 4 to 5 ounces up to 6–7 pounds each (from 0.15 up to 3 kg). Bar anodes generally measure up to 3 inches (76 mm) across and can be as much as 96 inches (2438 mm) long when used in really large plating tanks. Such anodes can weigh 220 pounds each (100 kg). • Cathodes are not, strictly speaking, refinery shapes, but are used to cast the highest quality refinery shapes or are melted to produce continuously cast semi-wrought products (see Chapter 4). Cathodes are the product of the electrolytic refinery, usually measure about one metre (39 inches) square and can weigh up to 139 kg. • Billets are of cylindrical shape, generally range in diameter from 3 to 16 inches (75–400mm) and can weigh up to 2 tonnes each. This shape is increasingly being produced by continuous casting techniques, except in the very large sizes. It is mainly used to extrude rod, bar, sections and tubular products, and to provide the basic stock for forging and pressing operations (for details of these techniques see Chapter 4). • Cakes are rectangular shaped and are produced in pure copper and many of its alloys. They come in many sizes, from those weighing as little as 60 kg (130 pounds) up to ‘specials’ which can be several tonnes in weight. Again the trend is towards production

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by continuous casting techniques, except in the case of the largest sizes. Cakes are hot rolled to produce sheet, strip, plate and shapes such as circles (see Chapter 4). • Ingots are a light shape, generally weighing between 10 and 15 kg each (22–35 pounds) and are usually notched to facilitate breaking into smaller pieces. They are used primarily in casting shops and foundries for casting copper alloy shapes and products. • Ingotbars are similar to ingots but are generally twice the size and contain more notches. They are used for the same purposes. • Wirebars were once the most important of all copper shapes, but their use has virtually ceased with the advent of the continuous casting of copper rod. Sometimes they are the product of fire refining.

3.5 Oxygen-free high conductivity copper and its alloys There is one final stage in the refining of copper which carries its purity beyond that called for by normal commercial specifications. This is the production of oxygen-free high conductivity copper. This special material is supplied to companies which are making goods intended to operate at the furthest frontiers of technological knowledge. Oxygenfree high conductivity copper and its alloys play a major role in ‘hightech’ applications, the importance of which belies their relatively small output – currently around 130 000 t of semi-wrought products a year (something less than 1% of the total production of copper and copper alloy semis worldwide). Oxygen-free high conductivity copper is defined by the ASTM (American Society for Testing and Materials) as copper not containing more than 10 parts per million (0.001% oxygen) and produced without the use of metallic or metalloidal deoxidisers. It is the most pure commercially produced copper and a comparatively low volume, high cost product. It must be distinguished from the deoxidised coppers which use oxygen scavenging elements, like phosphorus, to remove from solution oxygen picked up during melting and casting operations. The addition of effective scavenging elements creates problems, since it is difficult to judge the precise amount of deoxidant necessary for individual melts. Any surplus not used up in capturing oxygen, remains in

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solution, and together with residual impurities, can sharply reduce electrical conductivity. Oxygen-free high conductivity copper is produced without the use of a deoxidant. Top quality electrolytic cathodes are melted in an electric furnace, then transferred and cast in sealed units so that the molten metal is continuously under the pressure of a protective and reducing gas atmosphere, which both excludes and removes oxygen and other impurities. At the time of writing, three refinery shapes are cast in oxygen-free copper and alloys: billets, cakes and platers’ anodes.

3.6 Use of copper and copper alloy scrap Somewhere in the region of one third of all the copper that is used has been made from scrap; the ICSG has estimated that between 1965 and 1995 scrap usage ranged between 30 and 38% of global consumption. The importance of scrap to the copper industry is therefore clear. Scrap is able to meet a large proportion of the World’s need for copper, in part because the metal is admirably suited to recycling. Only a very small amount of the refined copper that is produced (mainly oxide powder for fungicides) is converted into a form which prevents the metal being recovered after use; no matter how often copper is recycled, its quality remains unaffected; very little is lost in the resmelting and refining processes; and the production of secondary copper requires much less energy than the production of primary. However, while the characteristics of the metal itself invite recycling, the forms in which it is used make its recovery difficult and therefore expensive. In products consisting entirely of copper, such as piping or roofing, its recovery is relatively straightforward (although it may be many years before these items become available for recycling) but most copper is used for electrical purposes, often forming only a minute part of the appliance or machine in which it is installed, or in an insulated cable, sometimes buried underground. Scrap may be divided into two categories, according to the means by which the metal will be recycled: clean or process scrap, which is pure enough to be used directly in the semi-fabricating process, and less pure scrap, including old or collected scrap, ‘manufactured’ scrap and copper-bearing residues, which require treatment in a smelter (or hydrometallurgical process) and then electrolytical refining.

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Process scrap arises directly from the operation of the fabricating industry (see Chapter 7) and is usually clean and of the highest quality, requiring no treatment or re-refining. Much of it is promptly remelted within the fabricators’ works, where it is cast into refinery shapes (billets or cakes) for reprocessing into semi-wrought products. The exception is process scrap arising at copper rod, wire and cable-making plants, where only the highest grade of cathode is used in production. Copper rod and wire process scrap, therefore, goes to make the highest quality products at the so-called ‘brass mills’, to some specialist foundries, to ingot makers and master alloy makers. (The term brass mill is misleading because it is used not only to cover the operations of first stage fabricators of alloy products like brass sheet, strip or extensions, but also those who make them in pure copper.) Copper alloy process scrap (straight brasses, leaded brasses, bronzes, cupro-nickels, nickel silvers and many other grades) follows a slightly different path. During the melting and casting processes, alloys, especially those with zinc as a constituent, suffer much higher melting losses than does pure copper scrap. Therefore even carefully segregated alloy process scrap has to be mixed in the furnace with substantial amounts of pure copper cathode or ingot, as well as pure zinc and any other alloying constituents, to ensure that the cast shape will emerge to precisely the correct specification. Moreover, with alloy scrap the possibility of mixing qualities and the risk of contamination is much higher than is the case with pure copper scrap. Therefore the molten alloy has to be tested much more frequently. First stage fabricators often buy back process scrap from their own customers at agreed terms – known as ‘mills return prices’. The scrap comes in the form of ‘webbing’ scrap and clippings (waste sheet and strip that has been through a stamping or other fabricating machine) and ‘swarf’ (a form of metal sawdust, fine turnings and clippings, which mainly arise from operations where free turning and stamping quality brasses are used). The generators of process copper and alloy scrap are therefore cable-makers, wire mills, tube mills, brass mills, manufacturers of keys, locks, coinage blanks and similar products, as well as those serving the plumbing and tube using trades. These generators of new scrap are mainly found in major industrial areas. The main users of this newly created scrap are fabricators such as brass and tube mills, foundries, ingot makers, copper shot makers, master alloy makers and to some extent

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refineries, although process scrap is too expensive to be generally of interest to them. Thus the producers and consumers of process scrap tend to be found in major industrial areas, so that trade tends to be directly between them, rather than via the merchants. In the second category of scrap – what might be called old scrap – there are three main types: • ‘manufactured’ scrap • collected scrap • residues. Manufactured scrap arises mainly from digging up and stripping various types of underground and submarine cable. Such cables have protective coverings, including lead and steel (in the case of armoured cables). These have to be removed by heavy stripping machinery before the copper core can be salvaged. Protective grease and a variety of insulating materials must also be eliminated by burning, mechanical or chemical treatment. Every effort is made to avoid contamination from lead or soldered end so that after processing the result is a high quality pure copper scrap. Another important category is old telephone cable and domestic electric wiring scrap. This is paper, cotton or plastic covered copper wire that needs careful treatment to get rid of all nonmetallics, and to sort out any tinned, enamelled or fine ‘hair’ wire. The traditional way of treating this class of material has been by burning. However, expensive changes in processing techniques have been forced upon the scrap trade by new legislation on environmental pollution. The treated wire scrap is often compressed into small bundles, or cut up into convenient lengths for ease of handling. Good quality clean burnt copper wire scrap (known in the trade as number one burnt copper wire scrap) is sold to refineries, foundries, brass mills, tube mills, anode makers, ingot makers, copper shot and most alloy makers. Lower quality burnt wire (known as number two burnt copper wire scrap) which can contain degrees of tin, solder, lead or ash as well as some fine or enamelled wire, is normally sold as smelter feed. Primary smelters use this and other lower grades of scrap as a normal part of their input to reduce their costs. There are also some specialist secondary smelters who use scrap as their main feed. Clean ‘heavy copper’ scrap mostly finds its way to fire refineries and to anode foundries and ingot makers.

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In a sense, scrap is also manufactured when it is recovered from redundant heavy electrical machinery (such as generators or transformers) or stripped down telecommunications equipment. Other sources of copper and alloy scrap are dismantled automobile parts (such as radiators, engines or bearings) and consumer white goods (for example, refrigerators, air-conditioning units and computers). This process of plant stripping overlaps the ‘collected’ scrap aspect of the trade. Here the collecting starts with small operators who collect household scrap, clear small factories and strip smaller items of machinery and motor vehicles. They sort and roughly segregate the scrap arising from their operations and generally sell on to larger merchants, who accumulate bigger parcels for sale to consumers. Finally, there is the trade in ashes, slags and residues, material that sometimes contains as little as 20% copper. This material, together with mixed alloy and contaminated scrap, finds its way mainly to secondary smelters. The most lucrative aspect of the residues trade arises from the sale of electrolytic refinery slimes – the material that falls to the bottom of refinery tanks and in which are found the precious metals that were contained in the original anode. Old collected scrap tends to arise in and around areas of dense population rather than in the industrial areas where it is consumed; hence there is a need for a structured and active scrap trade. The level of production from scrap varies considerably and is affected by a number of factors. The availability of new scrap to a large extent reflects the level of semi-fabricating and manufacturing production; the higher the level of production, the more new scrap is generated and consumed, while because its recovery is relatively cheap, its availability is unlikely to be greatly affected by the copper price. However, there are continuing efforts to reduce wastage in the manufacturing processes which generate new scrap, so its availability may be increasingly restricted by technological advance. The most important factor in the availability of old scrap, however, is the copper price. The recovery of old scrap is not always straightforward and is often relatively labour intensive, so the price can be crucial (although it is not only the price itself, but also the level of the discount below the copper price which is applied to scrap). The cost of recovering much of the old scrap is by no means small and a low copper price may make its recovery uneconomic, or the holder of the scrap reluctant to sell it, preferring to wait for the

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price to recover. The abnormally low level of secondary refined production during 1998/99 can be ascribed mainly to the low prices obtaining during much of the period. However, low prices are not the only factor in inhibiting secondary production and it is possible that its recent low level also reflects a long term tendency for scrap to account for a declining proportion of total refined production. While the trend is not yet fully confirmed by statistics, there have been several developments in recent years which have militated against secondary production. In a depressed market, scrap is, in effect, in competition with primary copper, and since about 1970 the average cost of production of primary copper, in real terms, declined dramatically, as demonstrated by Figure 3.1, which shows the price expressed in real terms; technical improvements, the closure of high cost operations and the advent of low cost electrowon being the obvious reasons. However, while there have been some technological advances in the recovery of copper scrap, there is no evidence of a decline in its costs that is in any degree comparable to the decline in those of primary copper. Indeed, in some respects, scrap recovery costs may be increasing. Since about 1970 there has been a widespread move to reduce the amount of metal in copper (and other metal) products wherever possible in order to save weight, space and costs; the walls of copper tubes have got thinner, the gauge of wires smaller, and components in

350 300

US c/Ib

250 200 150 100 50 0 1960

1970

1980 Money terms

1990 1999 terms

3.1 LME settlement price in money terms and real 1999 terms.

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machines and appliances wherever feasible have been made smaller. As copper is being used in smaller amounts in many applications, with much of it being dissipated in often minute quantities in electrical appliances such as computers and screens, the effort needed to recover a given quantity must be greater than it was when the amount of metal in the same applications was greater. The influence of the copper price on the level of secondary copper production is an important factor in the behaviour of the copper market and it has regularly had a moderating effect on its fluctuations. As the price falls, so do supplies of old scrap, which reduces secondary refined production which in its turn restricts total refined production. By moderating supply, the market is helped towards regaining its balance. For example, in 1998 the copper price fell by 27% owing to a growing supply surplus; primary production rose by 6% but secondary production fell by 8% resulting in an increase in total refined production of less than 4%. While all cutbacks in scrap supplies will not last indefinitely, as some holders of scrap will give up waiting for the price to recover, in the past, reduced secondary production has regularly proved to be an important factor in bringing the market back into balance during periods of oversupply. Likewise, low prices are likely to reduce supplies of direct use scrap, forcing fabricators to use more cathode in its place, thus increasing refined consumption. Finally, the rise of environmentalism may well be having a serious impact on costs, as well as the future of the scrap trade itself. Not only is it forcing expensive (and often justified) changes to traditional methods of treating scrap – particularly in respect of burning techniques and waste disposal – but the introduction of more stringent regulations could ultimately curtail many of the trade’s basic activities. The rigid application of the principle ‘let the polluter pay’, ever more stringent effluent standards, and the branding of all scrap as toxic waste under the Basel Convention, could not only drive many Western World scrap merchants and processors out of business by pushing their costs through the roof, but could even seriously inhibit the movement of scrap worldwide. If this occurs, many aspects of the copper industry would be denied one of their important sources of raw material. It is to be hoped that a fair and reasonable solution will emerge so that the environment can be safeguarded without putting insuperable barriers in the way of the production, distribution, processing and trade in copper and alloy scrap, residues, slags and ashes.

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4 Fabrication of copper and its alloys

4.1

Shaping from molten metal 4.1.1 Sand casting 4.1.2 Die casting 4.1.3 Continuous casting Copper rod Continuous casting of sheet, strip and tube

4.2

Shaping from solid metal 4.2.1 Forging 4.2.2 Hydraulic pressing 4.2.3 Extrusion 4.2.4 Rolling 4.2.5 Tube making Seam welding Drawing seamless tubing Extrusion

4.2.6 Drawing 4.2.7 Stamping 4.2.8 Turning 4.3

Shaping by joining metals 4.3.1 Brazing 4.3.2 Soldering 4.3.3 Welding

4.4

Shaping powdered metal

4.5

Copper shot

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Once copper has been extracted and purified by the various smelting and refining processes detailed in Chapter 3, it still has to pass through several stages of fabrication before emerging in the particular form in which it is needed, whether it be as an electric cable, a refrigerator tube, part of an automobile or a computer, a coin or one of the thousands of other items that are made from copper and its alloys. The first stage in this fabricating process is generally called semifabrication, wherein the purified metal, either as cathode or cast into refinery shapes (billet, cake or ingot) is worked into one of the eight basic forms – called semi-wrought products – in preparation for the later stages of fabrication. These are: • wire rod (thick round wire usually 6 or 8mm in diameter) • bar (a length of solid metal of rectangular, hexagonal or circular cross-section) • tube (a hollow cylinder) • sheet and plate (comparatively wide flat-rolled product, plate being in the thicker and sheet in the thinner ranges) • strip and foil (thin gauge, narrow width flat-rolled product; foil is the thinnest) • extruded or drawn rod and section (a section is a length of rod with a special profile which is then cut at right angles to the length; often used to make intricate items, such as the brass parts of an electric plug, or windscreen frames) • powders • shot (irregular-shaped pieces of copper used in the manufacture of chemicals). The ‘semis’ mentioned above derive from five main operations by which copper and its alloys are treated in the process of initial fabrication: 1 shaping from molten metal by means of various casting techniques 2 shaping of hot or cold solid metal – by rolling, extruding, forging or forming hot metal, or rolling, drawing, stamping, turning or forming cold metal 3 shaping by joining metal by brazing, soldering or welding 4 shaping of powdered metal 5 copper shot, although not strictly produced by a shaping

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operation, is nevertheless an intermediate stage in the production of many copper-based chemicals and should be mentioned in this section.

4.1 Shaping from molten metal All fabricating processes begin with the melting of copper, together with any alloying elements. Carefully selected and segregated scrap is also often used. Pure copper is usually provided in the form of cathode or ingot, and alloying elements by ingot, slabs or briquettes. Copper scrap is often used in the form of best quality wire compressed into briquettes, or what is known as process scrap from rolling, drawing or extrusion mills. Alloy scrap comes as brass mill process scrap, including swarf (or metal sawdust and chippings) and occasionally remelted scrap in the form of secondary ingot. These constituents are melted in a foundry which may operate a variety of furnaces ranging from small crucibles (used at the time of writing mostly by laboratories for quality testing), to massive reverberatory furnaces, which are needed when large tonnages of metal are involved. The majority of copper and alloy melting takes place using electrical power in high- or low-frequency induction furnaces, electrical resistance furnaces and protective atmosphere furnaces (which are needed in continuous casting and oxygen-free high conductivity copper operations). Newer technologies using consumable-arc vacuum melting and electron beam melting have so far not found any major applications in melting copper and its alloys. Apart from the casting of refinery shapes, the main fabricating processes involving molten metal are the production of casting: • foundry castings – of large finished shapes like bells or ships’ propellers – of smaller items produced by sand or die casting • continuous casting – of rod, sheet and strip. There are three main techniques used in casting; sand casting, die casting and continuous casting.

4.1.1 Sand casting Sand casting is the oldest and best known method of producing shapes direct from molten metal; although increasingly sophisticated

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methods have been devised, ultimately they are all only variants of the original, centuries old, technique by which molten copper and its alloys have been poured into a hardened sand mould, sometimes using separate cores to provide the holes or recesses needed within the individual cast. Great skill and an elaborate technique are needed to produce large items such as bells or ships’ propellers (the latter are cast in an aluminium bronze with added magnesium and can be as large as 100 t cast weight, 75 t finished weight).

4.1.2 Die casting The main difference between sand casting and die casting is that with the former the sand mould is destroyed in each operation, while the latter works with a permanent steel or cast iron mould which divides into two parts. • Gravity die casting is so called because the molten metal is poured into the die cavity and settles under its own weight. • Pressure die casting is a method whereby the metal is injected into a water- or oil-cooled mould under pressure to give very accurate castings of complex shapes. • Centrifugal die casting is a process in which the mould is spun to impart maximum accuracy to castings. • Investment or lost wax casting uses an expendable wax pattern to produce a very accurate but brittle mould into which the molten metal is carefully poured. The casting is recovered when cold by breaking away the brittle mould. The technique produces extremely accurate castings without the joint (mould) lines inevitably present in diecasting. The process has been used for millennia to produce all types of high-precision castings, especially in brass and bronze. Together with centrifugal casting it is an important technique in the creation of costume jewellery.

4.1.3 Continuous casting Continuous casting of refinery shapes (cylindrical billets, rectangular cakes and platers’ bar anodes) has already been described (pages 22–23 in Chapter 3). The other form of continuous casting that has

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developed since the mid-1970s has been the production of important semis like copper rod, sheet, strip and tubing direct from molten metal. Copper rod Copper rod is the basic semi from which wire and cable are produced, and as such is by far the most important because they are used in countless applications in power production and transmission and in the telecommunications industry, representing the largest single use of copper. Some now regard copper rod as a refinery shape rather than as a semi-wrought product and suggest that with the move by copper producers to obtain the maximum added value from their operations, an increasing amount of copper rod will be made in future at refineries in copper producing areas. They also suggest that one day it could replace cathode as the most traded of all refinery products. In earlier times copper rod was produced from wirebar, which for many years was the most important refinery shape and the largest volume of copper traded on free terminal markets like the London Metal Exchange. A wirebar is an almost square sectioned copper bar with end dimensions of some 4–5 inches (102–127 mm), a length of between 50 and 60 inches (1270 and 1524 mm) and weighing between 200 and 300 pounds each (90–136 kg), although heavier pieces were sometimes produced. To facilitate feeding into a rolling mill, the ends were often chamfered (symmetrically bevelled). The limiting weight factor was the ability of two men to lift the piece of red-hot copper into the groove between two contrarotating rollers. As it emerged from these rollers, the elongated bar of red-hot copper was caught in a pair of large pincers by a man on the other side of the mill and looped into the smaller groove in the next set of rollers. This process continued until the rod had been rolled to the required diameter (usually one-quarter or three-eighths of an inch or 6 or 8 mm), quenched in water and coiled. This was a spectacular, hot and dangerous job, with snakes of red hot rod whipping across the floor of the mill! The process had disadvantages: the oxide film had to be removed in an acid bath before the rod could be drawn down to wire and the restricted weight of the individual wirebars limited the length of the resulting coil of rod and thus the unbroken length of wire that could be drawn from it. In the 1960s a technological breakthrough occurred with the development of a method of continuously casting copper rod. This semi (known in the trade as CC rod) starts with the melting of top quality

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copper cathode in a reducing (i.e. oxygen removing) atmosphere within a shaft furnace. The very pure molten copper remains under an inert (oxygen excluding) atmosphere, moving through a close ‘launder’ (channel), a tilting rotary holding furnace and thence into the sealed casting machine. These are usually based either upon a grooved watercooled wheel sealed by a steel belt, or on a twin belt system, which feeds a continuously produced hot billet through a series of rolling and straightening mills. At the end of the process, a clean bright copper rod emerges (in 6 or 8 mm diameter size) to be wound into the required size of coil, strapped and plastic wrapped, ready for delivery to a wire or cable works anywhere in the world. Not only does this technology enable massive coils each weighing 5 t or more to be produced, but the material is of oxygen-free high conductivity quality (to ASTM specification B 170 Grade 1, CDA 101 or DIN 1708-SE Kupfer grade) with less than 10 parts per million of oxygen present. This means that all continuous cast rod is suitable for the finest commercial quality wires, including hair wire, which has a diameter of 0.0124 inches (0.315 mm) or smaller. Continuous casting of sheet, strip and tube A similar type of process has evolved in the USA, which enables copper or alloy sheet or strip to be continuously cast. In this process, two water-cooled steel bands at the top and bottom with side walls made from small bronze blocks feed the cooling metal through synchronised hot and then cold rolling mills. It is claimed that one recently installed 52 inch (1320 mm) sheet caster can produce up to 135000 t of top quality sheet in a year. New developments in the technique of continuously casting strip are expected eventually to eliminate the need to hot roll at all. Meanwhile the Finnish company, Outokumpu, have evolved a system for semi-continuously casting seamless copper tubes. It is based upon the continuous casting of tube shells (i.e. hollow billets or cylinders of copper), automatically cutting them to an appropriate length and then ‘planetary rolling’ them round a mandrel (or internal rod) to produce over 100 m lengths (325 feet) of ‘redraw tubing’ (i.e. tubing ready to be drawn down to finished dimensions). This new process cuts tube fabrication from three to two stages by removing the need for reheating the tube shells. Planetary rolling can best be described as using three rotating rollers, shaped not unlike a child’s spinning top, which roll the tube shell round the central mandrel with each head spinning independently and at the same time being able to rotate on its axis.

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4.2 Shaping from solid metal Solid metal may be shaped into numerous forms without being melted; by forging, hydraulic pressing, extrusion, rolling, tube making by various methods, drawing, stamping and turning.

4.2.1 Forging Forging is when a heated piece of copper or alloy is shaped by a mechanical hammer which lands on it from a height. The succession of blows not only shape the piece by means of dies in the hammer head or on the anvil, but also strengthen it by creating a finer crystalline structure throughout. The blows will also tend to remove residual hydrogen that might be remaining in suspension at grain boundaries. This could cause embrittlement during gas welding, brazing or bright annealing.

4.2.2 Hydraulic pressing The technique of hydraulic pressing uses a very powerful press to squeeze a billet (solid cylinder) or slug (small cylindrical piece) into a shape determined by a die. The process also imparts a more uniform grain structure and greater strength to the metal. One of its uses is to fabricate artillery shell and small arms cartridge cases from ‘70/30 Quality’ brass.

4.2.3 Extrusion The extrusion process is analogous to squeezing toothpaste from a tube with the shaping die, as it were, positioned in the mouth of the tube. In direct extrusion, a red-hot billet (solid cylinder) of copper or alloy is rammed under great pressure through a die. The particular shape of the die will result in the production of a rod, bar or more intricate shapes, such as are required for curtain rails, small cog-wheels and many other applications. In the direct extrusion method the metal is squeezed through the die, while in indirect extrusion the die is forced through the metal. The advantage of the latter method is that it requires less power and provides a more uniform product; however, the press itself is more complex and expensive. By using a composite die and mandrel (internal rod), seamless tubing for redrawing can be produced. Most extruded

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semis are finished by redrawing cold through sizing dies. In the case of tubing, this improves the accuracy of the outside diameter while the insertion of mandrels and plugs deals with the internal diameter.

4.2.4 Rolling Rolling is a process by which a copper or alloy cake (flat rectangular slab) is squeezed between contrarotating rollers. The metal is usually rolled first hot and then cold. It is much easier to reduce the thickness of hot metal, but cold rolling imparts a smoother surface, better finish and greater dimensional accuracy. Therefore the initial breakdown of the cake is carried out by hot rolling while the finishing process is achieved by cold working. After the hot rolling phase it is often necessary to ‘scalp’ the surface of the metal to remove oxide inclusions and any surface pitting that could result in defects in the sheet or strip as it passes through the cold finishing mills. The cold working process for strip often involves the material initially passing through a series of tandem mills (individual rolling machines grouped together with rolling speeds carefully co-ordinated so that the strip passes from one to another in a single continuous rolling operation). Finished sheets are cut to size and shape – circles being needed for applications like domestic hot water cylinders. Strip (which is of narrower width) is cut to size and coiled for delivery to its next stage of fabrication. When pressure is applied to the surface of copper and its alloys by rolling, drawing or forging, a phenomenon called work hardening occurs. This means that the crystalline structure of the metal becomes changed in such a way as to make it harder, less ductile and resistant to further working. In order to achieve any further reduction in shape, it is necessary to soften the surface by what is termed process annealing. Annealing is a heat treatment operation that involves holding the metal for some time at its annealing temperature, which is well below its melting point, then slowly cooling it. For pure copper this is just below 200 °C, but varies very widely for its alloys. This process not only softens the metal, making further work on it possible, but improves its capacity to be machined, removes internal stress, refines the crystalline structure, increases ductility and eliminates dissolved gases. Annealing furnaces are often cylindrical, electrically heated and sufficiently large to take the appropriate size of coil, or flat to take sheets. The process is usually

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carried out under an inert (oxygen excluding), or a reducing (oxygen removing) atmosphere to prevent surface oxidation and keep the material in a bright, as rolled, condition. This is termed bright annealing. On most large strip production lines, intermediate anneals (i.e. those annealing operations that are needed in the middle of the cold rolling process) are carried out in a continuous annealing tunnel. Individual coils are spot welded together to make one continuous length which, after being annealed, can pass straight on to the next stage of cold rolling, thus saving a great deal of time compared to the batch annealing of individual coils. It is often desirable to impart specific mechanical properties to the finished semi. Varying degrees of hardness can be given to sheet and strip according to the amount of work hardening inflicted upon the metal during the process of cold rolling it. Its final condition is designated accordingly as hard, half hard, quarter hard etc. Among other heat treatment processes used to impart desirable qualities are quenching (rapid cooling in water), solution heat treatment (to dissolve, for a time at least, hard intermetallic compounds), age-hardening (to produce a spontaneous hardening during storage at atmospheric temperature over a period after treatment) and surface heat treatment (processes to enhance surface hardness and improve resistance to wear and fatigue).

4.2.5 Tube making Copper and alloy tubes are made by three processes. Seam welding Seam welding is a process whereby longitudinally rolled copper or alloy strip is wrapped round an accurately produced hole and then welded. The welded tube is then drawn through a die to create an accurate outside diameter with a mandrel (internal rod), plug or sizing bar to provide the exact internal diameter. Drawing seamless tubing Drawing seamless tubing is produced from a tube shell (a hollow cylindrical billet). The end of the tube shell is pointed to enable it to pass through a die with a mandrel and plug in it; the tube is pulled through the die and over the mandrel and plug.

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Extrusion The general process of extrusion has been described above. In tube-making a die with a circle of holes in it is used. The molten streams of metal coalesce into a tube on the far side of the die and the extruded tube is then redrawn through a sizing die and mandrel to its finished dimensions. Fairly recent innovations have been the production of bimetal, finned, thin-wall and inner-grooved tubing by various drawing and roll-finishing techniques. These special types of tube are mostly used in various forms of heat exchangers like refrigerators or air conditioning equipment.

4.2.6 Drawing Drawing also features as the finishing process for other types of semis. These are wire, thin rod and sections (sometimes known as profiles). Copper and alloy wire are produced when 6 or 8mm rod is pulled through a succession of progressively smaller dies, the partly drawn wire being looped round a rotating roller beyond each die. Wire to be used in the telecommunications industry may be tin coated to provide additional corrosion resistance and improved soldering capability. A similar drawing process is used in the finishing of alloy rod, shapes and sections. These are also drawn through a succession of dies until the required dimensions and shapes are achieved.

4.2.7 Stamping Parts stamped out of copper or alloy strip, sheet or rod are cheaper to produce and are usually lighter than the equivalent piece made by casting or forging. The strip, sheet or rod passes under the stamping machine and the individual pieces or ‘blanks’ stamped out then move on through a variety of other forming operations, until they are ready to take their place in a finished product, whether it be as the eyelet holes in a pair of shoes, a heat sink in a computer, part of a valve in a motor car tyre, a coin, a brass button or one or other of the multitude of uses that have been found for this type of product. The punctured waste strip or sheet, known as webbing scrap, passes on to be recycled, often in the adjacent foundry or via the scrap trade. To facilitate stamping and forging operations, lead is often added to the specification of the material, so brass stamping or forging rod and sections contain between 1 and 2.5% lead.

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4.2.8 Turning Turning is another important fabricating process, whereby component parts are produced by a turning operation on a lathe. When copper and most of its alloys are turned, long spirals of waste material tend to clog the cutting tool, so metal destined for turning may contain some embrittling constituent, so that chippings rather than turnings are produced at the lathe. A small amount of sulphur (0.3%) or tellurium (0.5%) is introduced into the rod to effect this change without affecting electrical or thermal conductivity unduly; such additions also provide improved corrosion resistance. In free-turning brass rod, when electrical conductivity is normally not important but cutting speed is, anything from 2.5 to 4.5% of lead is introduced, particularly when screw-threaded products are being turned out. Such alloys produce at the lathe a fine sawdust called swarf.

4.3 Shaping by joining metals A copper product may be shaped by brazing, soldering or welding.

4.3.1 Brazing Brazing is a type of soldering, sometimes known as hard soldering, from the fact that it uses a higher melting point of soldering medium – a form of brass (typically 60% zinc and 40% copper) in contrast to a low melting point lead-tin ‘soft solder’. A brazed joint is considerably stronger than one made with the more expensive soft solder and is made by melting the brazing rod with a gas torch at about 850 °C and allowing the molten solder to effect the join.

4.3.2 Soldering Soft soldering is widely used in electronics, telecommunications and other aspects of the electrical industry to make permanent connections between electrical components, wires and cables. The advantage of soft soldering is that the various grades of lead-tin alloy used melt at comparatively low temperatures (200–250 °C) which makes this tech-

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nique appropriate for more intricate work than is practical with the higher temperatures involved in brazing. Silver solders (typically 60% silver, 30% copper, 10% zinc) provide an even stronger joint. However, their high cost restricts their use to jewellery and special electronic applications.

4.3.3 Welding The techniques used to weld copper and its alloys fall into two categories. First, those involving pressure, generally with heating nearly to melting point. They include forge, spot and seam welding. In the latter two cases a high electrical current at low voltage passes between electrodes to heat the area to be welded and a sound joint is effected by pressure being applied. Second are those involving gas fusion using oxy-fuel gases (like oxyacetylene) or electric arc welding. Oxyacetylene welding is often used to join larger pieces of brass or other alloys where spot or seam welding is not appropriate and where additional filler metal in the form of welding rod is needed. Among other techniques developed are the use of TIG (tungsten inert gas) and MIG (metal inert gas) welding, laser, ultrasonic and diffusion welding. The main technical difficulty involved in soldering, brazing or welding copper is the possibility of oxygen in solution (in the form of cuprous oxide) reacting with hydrogen that may gain entry during the process of heating the area to be joined. Hydrogen easily penetrates hot copper and reduction of the oxide produces water vapour. This cannot readily escape and causes a weakening of the metallic structure in the area of the joint caused by embrittlement or microporosity. In applications where this would cause a serious problem, OFHC (oxygen-free high conductivity) copper would be specified, as it often is where a particularly good adhesion of solder to copper is needed.

4.4 Shaping powdered metal Copper and alloy powders are produced in three ways: by atomisation, where a thin stream of molten copper or alloy is poured through a high-speed jet of air, nitrogen or argon; by hydrogen reduction, where hydrogen is used to remove the oxygen from copper oxide; and by deposition, where copper powder is deposited by electrolysis. This method

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can be used during the leaching/solvent extraction/electrowinning process for treating oxide ores or mine residues. The fabrication process begins with copper powder or, where necessary, with powders mixed to make the required alloy. Non-metallic ingredients may also be blended in, such as friction materials when brake linings or clutch facings are being produced. Graphite is introduced into bronzes to make internally self-lubricating bearings or carbon is introduced into copper powder to make bushes for electrical motors. The blended powder is mixed with a small amount of lubricant and compressed in a die cavity. The shape is then sintered (heated up to 60–90% of its melting point) in a protective atmosphere to produce the finished article. The advantage of powder metallurgy lies in its efficient use of metal with very little wastage or scrap. Also alloys can be produced and nonmetallic elements introduced more easily and with greater precision than is possible by the pyrotechnic methods generally used in the copper industry.

4.5 Copper shot Copper shot is made by pouring molten copper through a sieve and into a bath of warm water. The result is the production of small, irregular, porous, sponge-like lumps of copper generally at a size of around one inch (25 mm) in diameter. The porous formation provides copper with the highest possible area-to-weight ratio, which makes it ideal for the production of copper chemicals where the process involves dissolving in acid.

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5 Main types of copper and its alloys

5.1

Inner structure of copper and its alloys

5.2

Role of oxygen in various types of copper

5.3

Types of produced and traded copper 5.3.1 Blister copper 5.3.2 Anode copper

5.4

Specifications in general

5.5

Main grades of copper and its alloys 5.5.1 Copper cathode 5.5.2 Electrolytic tough pitch copper 5.5.3 Phosphorus deoxidised coppers 5.5.4 Deoxidised copper 5.5.5 Copper alloys based upon OFHC copper

5.6

Alloys where copper is the base metal 5.6.1 Brasses 5.6.2 Bronzes 5.6.3 Aluminium bronzes 5.6.4 Cupro-nickels 5.6.5 Nickel silvers 5.6.6 Other alloys

5.7

Alloys where copper is not the main constituent

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In order to gain some understanding of the behaviour of copper and its main alloys as well as an appreciation of how they gain the qualities explained in Chapter 6, it is necessary to take a brief look at the technicalities of their inner structure and to note the role that oxygen plays, particularly in the various grades of pure copper.

5.1 Inner structure of copper and its alloys A microscopic piece of pure copper can be illustrated as a very large number of cube-shaped lattices in very close proximity to one another with one copper atom at each corner of the cube and one in the centre of each face. This regular arrangement of fourteen atoms is called a facecentred cubic lattice. Another arrangement sometimes found in copper alloys (such as higher zinc brasses) is a nine body-centred lattice. Each lattice represents an individual grain of copper. The atoms of individual metals differ in size, so that when one metal is alloyed with another and they exist together in ‘solid solution’1 with each other, the atoms of the added element usually find themselves a place in the lattice of the base metal. This may, as a result, become distorted or even changed, making the alloy harder and stronger than the parent base metal. When an alloy is created from two metals with markedly different sized atoms and lattice patterns, such as copper and zinc, or copper and tin, the range of alloys produced divide into what are called phases. The appearance of a new phase indicates a change in the arrangement of the atoms. If intermetallic compounds2 are created, this usually results in the atoms forming an entirely new type of lattice and the matrix of the solid solution has particles of the intermetallic compound floating in it. This produces a considerable strengthening of the mechanical properties of the alloy; however, the presence of too much intermetallic compound can produce a uselessly brittle alloy.

1

2

A solution is defined as an intermingling of one substance with another so closely that the dissolved substances cannot be distinguished or separated by mechanical means. Intermetallic compounds may be formed as an alloy cools and the base metal is unable to hold all the alloying element in solid solution. As that element comes out of a solution it generally forms a hard compound with the base metal, as occurs in the Duralumin and ‘Y’ alloys, which after cooling forms minute particles of an intermetallic compound CuAl2, greatly strengthening the alloy.

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In the case of brass, the introduction of larger zinc atoms to create the copper-based alloy increasingly distorts the face-centred copper lattice adding to the hardness and reducing the ductility of the alloy. In a brass containing up to 36% zinc, all the zinc remains in solid solution with the copper. This is termed the alpha phase, giving rise to the term alpha brasses. Above 36% zinc, the face-centred distorted lattice becomes unstable and a new body-centred lattice begins to appear. This new body-centred lattice is termed the beta phase. In an alloy containing between 36 and 42% zinc, the alpha and beta phase material exist together, with the beta phase becoming predominant as the percentage of zinc rises. Also, the hardness of the alloy increases more rapidly than occurs when only the alpha phase is present. This second phase produces what are known as alpha/beta brasses. In the alloy range 42–50% zinc the structure is entirely beta phase, producing the beta brasses. At each phase the mechanical properties of the brass alloys change quite sharply. In the case of the copper-tin alloys – the bronzes – an even more complex situation ensues, which accounts for the surprising strength shown by many bronze alloys that are made from two such comparatively ductile metals. In the case of the coppernickel alloys there are less complications because the atoms are of similar size and both form face-centred cubic lattices. It is for this reason that they are able to form a continuous range of solid solution alloys from the low nickel/high copper right through to the high nickel/low copper alloys.

5.2 Role of oxygen in various types of copper Many common gases like hydrogen, oxygen and sulphur dioxide are soluble in molten copper, but it is the amount of oxygen taken up during casting and the effect this has on the behaviour of the metal that plays the greatest part in delineating the various grades of pure copper that are used by the fabricating industry. Oxygen can normally be present in copper in three different conditions: 1 as oxides of those impurities whose affinity for oxygen is greater than that of copper 2 in solid solution 3 as discrete particles of cuprous oxide.

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Condition 1 must be satisfied before oxygen can start to be absorbed into solid solution and condition 3 cannot exist until condition 2 has reached saturation. Many refinery shapes (i.e. billets, cakes, ingots and platers’ anodes) are at the time of writing cast direct from high grade cathode, which is guaranteed to a quality of 99.98% minimum copper, that is, with only up to 200 parts per million of impurities (0.02%). However, melting cathode creates a new complication because the usual method of casting sound shapes is to introduce oxygen into the molten copper. The reason for doing this is that when molten copper solidifies without oxygen being present, it tends to shrink. To avoid cavities and holes in the casting, conventional practice first relies on the gas coming out of solution to prevent shrinkage and secondly controls the evolution of that gas by the oxygen level in the copper. The resulting material is called ETP (electrolytic tough pitch) copper. This is sound and has good electrical conductivity, but at a price – an increase in impurities in the form of oxygen. The silver plus copper content is reduced to around 99.90% and the oxygen content generally lies between 200 and 500 parts per million (0.02–0.05%). The oxygen not only helps to create a sound casting, but it also ties up many of the impurities in the form of oxides, taking them out of solution and depositing them at the grain boundaries. This has the effect of, as it were, clearing a path to allow good electrical conductivity – 100% IACS (International Annealed Copper Specification). However, the relatively high level of oxygen contained means that ETP copper is not suitable for applications involving brazing, welding or bright annealing. This is because if oxygen-bearing copper is heated to a relatively high temperature in a reducing atmosphere containing hydrogen, the hydrogen diffuses into the copper and reacts with the oxygen to form water vapour, which develops a sufficiently high pressure to disrupt the structure of the metal and make it brittle. If electrolytic copper cathode is melted in a fuel-fired furnace, where oxidising gases are in contact with the melt, or the metal is cast or transferred in air, it is impossible to prevent the molten copper from taking up significant amounts of oxygen, even though these may be less than are typically found in the tough pitch copper. However, the introduction during casting of an effective oxygen scavenging element like phosphorus, or occasionally lithium, can remove oxygen from solution, although this too creates problems. The process needs to be carefully controlled because any of the deoxidising agent not consumed in

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scavenging oxygen will remain in solution and this, together with other impurities also in solution, will obstruct the flow of electricity through the copper and sharply reduce its conductivity. It is particularly difficult to assess the exact amount of deoxidising agent needed to scavenge the precise amount of oxygen present, because this can vary from melt to melt. The usual deoxidising agent used is phosphorus and this grade of copper is therefore known as phosphorus deoxidised copper. If both high conductivity and freedom from oxygen are required, then a casting technique must be established that can produce a sound casting without relying upon the presence of substantial amounts of oxygen or deoxidising agents. Because oxygen will not be present to tie up impurities, the refining process itself must be carefully controlled to keep impurities low. Such a technique produces oxygen-free high conductivity (OFHC) copper, the purest commercially produced copper of them all. In this case it is cast from the best quality cathode in electric furnaces under a special protective gas atmosphere. The transfer of the molten metal and the continuous casting operation are also carried out in this oxygen-excluded atmosphere.

5.3 Types of produced and traded copper 5.3.1 Blister copper Blister copper is the form of copper that emerges at the end of the process by which sulphide ores are smelted either by the modern flash or bath smelting techniques or by the older, traditional converter/reverberatory furnace methods (see Chapter 3). Blister copper generally contains small amounts of copper oxide, residual impurities and oxygen. It assays a minimum of 98% pure copper, but may occasionally contain as high as 99.5%. The chief residual impurities are iron, oxygen and sulphur together with variable, but small, quantities of other metals like zinc, manganese, selenium, tellurium, cobalt, nickel or bismuth. In addition there may be small amounts of precious metals like silver, gold or platinum group metals that are recoverable as tank-house slimes in the process of electrolytic refining. Residual sulphur and iron, as well as contributing to the brittleness and porosity of the cast cake, make blister copper unsuitable either for final refining or fabrication. This grade of copper gets its name from the characteristically blistered surface of the

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casting, which occurs when sulphur dioxide that has been held in solution is expelled during cooling. There is no official specification for blister copper, even though it is widely traded, because there are so many variations within acceptable qualities that it is not practical to formulate an effective standard.

5.3.2 Anode copper Anode copper is the outcome of the first stage in the refining process. As described more fully in Chapter 3, blister copper, usually together with good quality copper scrap, is melted in an electric, reverberatory or rotary furnace and then refined by air or oxygen being blown through the molten metal to oxidise and remove volatile impurities such as iron, manganese, cobalt, nickel or bismuth. The high oxygen content is adjusted to between 200 and 500 parts per million (between 0.02 and 0.05%) by ‘poling’ the melt (i.e. burning green tree trunks in it) or bubbling town gas through it. This initial refining operation reduces the sulphur, iron and oxygen content of the copper to limits acceptable for electrolytic refining and fabrication. However, impurities like selenium, tellurium, nickel and precious metals are not susceptible to removal by fire refining and can only be extracted by electrolysis. Therefore much of the blister copper produced is fire refined and cast into anodes for electrolytic refining, during which any precious metals present can be removed. Anode copper generally assays a minimum of 99.9% copper, but does not have any standard specification, since it is not as widely traded as other forms of copper metal, often being produced by the works where electrolytic refining takes place. This anode copper should not be confused with the refinery shapes called platers’ anodes that are cast in two main types – bar anodes and balls or ‘chunks’ (irregularshaped) anodes. These platers’ anodes are produced in pure copper and phosphorised copper for use in the electroplating trade.

5.4 Specifications in general The types of copper detailed below are covered by a variety of specifications. In most of Europe the British Standard Specifications (BSS) are generally used, and these follow the Copper Development Association (CDA) classification for various grades of copper and its

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alloys. In Germany the standard reference is the DIN specifications issued by the Deutsche Normanausschuss (DNA). In the United States of America and the rest of the Americas, the American Society for Testing Materials (ASTM) provides another internationally recognised set of standards using the UNS (unified numbering system as detailed in ASTM-E527) to classify the various grades – a system that is very similar to that of the CDA. Under ASTM-B224, definitions of the grades of refined copper are laid down, together with those of refinery shapes and fabricators’ copper products. It also adds the statement that, in accordance with general usage in the trade, material is termed as copper (as opposed to an alloy of copper and other elements) when it contains 99.85% or more of copper, with silver being counted as copper. It adds that ‘Coppers may contain small amounts of certain elements intentionally permitted to impart specific properties, without excessively lowering electrical conductivity. The total copper plus specific permitted elements normally include, but are not limited to, arsenic, cadmium, chromium, lead, magnesium, silver, sulphur, tin, tellurium, zinc, and zirconium, plus deoxidisers, up to specific levels adopted by the International Standards Organisation.’ BS-6017 also lays down definitions for the shape, dimensions and mass of refinery products but in less detail than ASTM-B224.

5.5 Main grades of copper and its alloys 5.5.1 Copper cathode There are three main specifications for copper cathode: • ASTM-B115: electrolytic cathode copper grade 1 and grade 2 (designated CATH-1 and CATH-2) • BS-6017: copper refinery shapes cathode grade 1 and grade 2 (designated Cu-CATH-1 and Cu-CATH-2) • DIN-170: Huttenkupfer-Kathoden Electrolytkupfer (designated KE-CU). At the time of writing cathode copper is the most important and widely used form of refined copper and is by far the most regularly traded. It is the principal source of refined copper from which refinery

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Table 5.1 Chemical composition of Grade 1 copper cathodes (maximum permitted concentrations of impurities – in parts per million) Group

Impurities

ASTM B115

Group

BS 6017 Cu-

Group

Cath-1 2 2 2

maximum

Selenium Tellurium Bismuth

Grade 1 4 2 2

maximum

1

5 2

Chromium Manganese Antimony Cadmium Arsenic Phosphorus

not specified not specified 5 not specified 5 not specified

3 not specified not specified 4 not specified 5 not specified

not specified 3

Lead

8

15 5

8 4

Sulphur

25

5 15

25 5

Tin Nickel Iron Silicon Zinc Cobalt

10 10 15 not specified not specified not specified

15 not specified not specified 10 not specified not specified not specified

20 (iron and nickel only) 6

Silver

25

20

15 25

Oxygen (maximum allowable) impurities not including oxygen copper

200



15 not specified

90

not specified

by difference

not specified

Note: Where an element is not specified, if it is present, it counts in the tally of maximum impurities present. One part per million equals 0.0001%.

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shapes (billets, cakes, ingots, platers’ anodes and wirebars) are produced in copper and its alloys for use by the fabricating industry. It is also the only form of copper deliverable against the London Metal Exchange and Comex market contracts. Copper cathodes are basically produced by the electrolytic deposition of copper. They are made by two related processes in electrolytic refineries. The first deals with material originating from sulphide ores and consists of a copper anode being suspended in a warm solution of sulphuric acid and copper sulphate. The anode is connected to the positive lead of an electrical circuit, while a ‘starter sheet’, on which the pure cathode is to be deposited, is connected to the negative lead. The second method deals with material arising from the range of oxide ores and uses the solvent extraction-electrowinning (SX-EW) process. In this, oxide ores and low quality residues are dissolved in an acidic leaching solution and then electrolytically deposited as a cathode (full details of both processes are given in Chapter 3). The electrolytic refining process is capable of being finely regulated by special techniques such as those evolved for analysing the electrolyte (the copper-rich acid solution) and controlling the electrical throughput. In these ways impurity levels in the finished cathode can be reduced to the limits necessary to meet commercial specifications. The most widely used specifications for cathode copper are the ASTM-B115 and BS-6017, both of which set limits for a wide range of impurities in the chemical composition of high purity cathodes (see Table 5.1). It is interesting to note the differences between the two specifications shown in the table, the ASTM being slightly less stringent than that of the British Standards Institution.

5.5.2 Electrolytic tough pitch copper The specifications for electrolytic tough pitch copper are: • ASTM-B5: electrolytic tough-pitch copper refinery shapes – designated ETP • BS-6017: Copper refinery shapes – electrolytically refined toughpitch copper (standard grade) • CDA-110 • UNS-C11000 • DIN-1708 F: Kupfer.

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Tough pitch copper is a commercially pure (99.9% minimum purity) oxygen-bearing copper that contains minute particles of cuprous oxide (Cu2O), but in small enough amounts to leave the electrical conductivity largely unaffected. This usually runs between 100 and 101% IACS. It is prepared from blister copper in an oxidising atmosphere into which, as explained in Chapter 3, additional oxygen is introduced to enable sound castings to be produced. Some volatile impurities (such as sulphur, zinc, arsenic and lead) are removed as oxides in this process while others (such as iron, manganese, cobalt, nickel and bismuth) are removed in a slagging operation. Any residual impurities are taken out of solution by the oxygen and deposited at grain boundaries where they do not impede electrical conductivity. The excessive oxygen (mostly in the form of cuprous oxide) is removed by a ‘poling’ operation whereby green logs are destructively distilled by being thrust into the melt. Of the two main specifications, the ASTM-B5 is less stringent, stipulating merely that the chemical composition of the metal shall be 99.9% minimum copper (including silver), adding that, by agreement, the addition of silver up to a nominal 30 troy ounces per short ton (0.12%) is permitted. BS-6017 also stipulates the chemical composition as 99.9% minimum for copper plus silver but adds the following obligatory maxima of bismuth 10 parts per million (0.001%), lead 50 parts per million (0.005%) and total impurities not to exceed 300 parts per million (0.03%), excluding silver and oxygen. ETP is the grade of copper most widely used in the fabrication of semi-wrought products (see Chapter 4) and includes a range of silverbearing ETP coppers (CDA-113 with 8 ounces, CDA-114 with 10/15 ounces and CDA-116 with 25/30 ounces of silver).

5.5.3 Phosphorus deoxidised coppers The specifications for phosphorus deoxidised copper are: • ASTM-B379: Phosphorised coppers – refinery shapes • ASTM-B224: Standard classification of copper • UNS Grades: – DLP-C12000 – phosphorus deoxidised, low residual phosphorus – DHP-C12200 – phosphorus deoxidised, high residual phosphorus – DPA-C14200 – phosphorus deoxidised with arsenic – FPTE-C14500 – phosphorus deoxidised with tellurium

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• BS-6017: Copper refinery shapes grade Cu-DHP • CDA-120/122 • DIN-1708: SE Kupfer. Phosphorus deoxidised copper is a grade of copper in which the oxygen has been locked out of solution by the addition of a deoxidising (or oxygen scavenging) agent such as phosphorus or occasionally lithium. As explained above, while the scavenging agent will effectively lock up the oxygen, the amount introduced needs to be very carefully controlled, because any quantity of the deoxidant not consumed in scavenging oxygen will remain in solution in the copper as an impurity, reducing elemental copper properties, particularly conductivity. Since for a number of applications the effects of oxygen are considered to be worse than those of the deoxidant, it is common practice to add more deoxidant than is essential to neutralise all the oxygen that could possibly be present. In this way the detrimental effects of oxygen can be eliminated for applications involving brazing, welding or bright annealing – but at the cost of a considerable drop in conductivity, thus precluding its use in virtually all electrical and electronic applications.

5.5.4 Deoxidised copper Specifications: • ASTM-B170: oxygen-free electrolytic copper – refinery shapes, grade 1 and grade 2 • CDA-101 and 102 • UNS-C10100 and C10200 • BS-6017: copper refinery shapes – oxygen-free refined copper, electronic grade (‘Cu-OFE’) and oxygen-free electrolytically refined copper (‘Cu-OF’) • DIN-1708: grade SE Kupfer. Oxygen-free high conductivity copper (generally known in the trade as OFHC) is defined in ASTM specification B-170 as a copper not containing in excess of 10 parts per million (0.001%) oxygen and produced without the use of metallic or metalloidal deoxidisers. It is the most pure commercially produced copper and is a low volume, high cost product. The production of this grade represents a very small proportion of the total tonnage of refined copper produced each year. However,

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its importance in high-tech industries belies its comparatively small output. Oxygen-free high conductivity copper is produced by melting the highest quality electrolytic cathodes in an electric furnace. The molten metal is then transferred through enclosed launders (channels) and cast, utilising continuous or semi-continuous techniques, ensuring that at all times it is covered by a positive pressure of an inert protective gas atmosphere so that no oxidation or other contamination can take place. The special characteristics of this type of copper are: • High purity – grade 1 is guaranteed to assay a minimum 99.99% copper and grade 2 a minimum of 99.95% copper plus silver. Both grades guarantee a maximum oxygen content of 10 parts per million (0.001%) but generally assay less than half that figure. In addition grade 1 guarantees that all significant impurities shall not exceed 40 parts per million (0.004%). This exceptionally high purity permits glass to copper sealing (important in electronic tube or valve manufacture) and is essential for the production of many electronic components. • High degree of uniformity – giving predictability in performance, hence it is specified for use in particle accelerators and other research apparatus. • The highest commercially available conductivity – 101% IACS (international annealed copper specification) for grade 1 and 100% IACS for grade 2; this combined with high purity, the highest commercially available thermal conductivity and low resistivity – a combination of qualities that no other type of copper can offer – results in its being specified for use in the most demanding electrical and electronic applications. • Joinable without embrittlement – because this copper contains exceptionally low levels of oxygen in any form, it can be used where welding, brazing or soldering are called for, without risk of embrittlement or porosity occurring in the area of the joint. It is also frequently specified where bright annealing is required. • Consistent and reliable formability – it shows greater qualities of ductility, flows more readily during fabrication, withstands strain better, and has a lower rate of work hardening and greater impact and fatigue strength than any type of pure copper.

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• Low temperature applications – Cryogenic grade OFHC copper is a specially selected grade 1 OFHC copper with a resistivity ratio of 300 to 1. It currently finds its use as a stabiliser for superconductors. Resistivity ratio is defined as the resistivity of an annealed copper at room temperature (20 °C or 293 K) divided by its resistivity at the temperature of liquid helium (4.2 K). As even very small amounts of certain impurities have a very marked effect upon resistivity, cryogenic grade is the very purest quality of OFHC copper.

5.5.5 Copper alloys based upon OFHC copper For OFHC coppers with phosphorus added, very specific amounts of phosphorus are added to oxygen-free high conductivity copper, not to neutralise oxygen, but to provide certain desirable characteristics. For example, the phosphorus can be added as a suppressant of electrical conductivity whilst retaining the other advantages of the highest purity copper. This type of alloy is used for casting top quality plating anodes for which at present no specification has been issued. Other examples of this grade are the following: • Exceptionally low phosphorus OFHC copper ‘OF-XLP’, UNS no. 10300 is 99.95% minimum copper plus silver plus phosphorus with 10/50 parts per million (0.001–0.005%) phosphorus. • Low phosphorus OFHC copper ‘OF-LP’, UNS no. 10800 is 99.95% minimum copper plus silver plus phosphorus with 50/120 parts per million (0.005–0.012%) phosphorus. • Silver-bearing OFHC coppers – UNS no. C 10400 is 8–12 troy ounces per short ton of silver (0.027–0.041%) – UNS no. C 10500 is 10–15 troy ounces per short ton of silver (0.034–0.052%) – UNS no. C 10700 is 25–30 troy ounces per short ton of silver (0.086–0.103%). The advantages of adding silver to OFHC copper are that after cold working the material has good resistance to creep (or continuous and progressive deformation under stress) at elevated

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temperatures and a high softening temperature, as well as enjoying the general qualities of OFHC copper. • Free-machining OFHC copper alloys – UNS no. C 14700 with sulphur and often phosphorus is 99.9% minimum copper plus silver plus sulphur plus phosphorus. – UNS no. C 14500 with tellurium and phosphorus is 99.9% minimum copper plus silver plus tellurium plus phosphorus. The percentages of sulphur, tellurium and phosphorus will vary marginally from producer to producer, although most consumers require alloying elements to be sulphur or tellurium at about 0.5% (5000 parts per million) and phosphorus at generally between 0.002 and 0.012% (20 and 120 parts per million). In these alloys the sulphur or tellurium form copper sulphide or copper telluride particles, which, being uniformly distributed through the material create chippings instead of shavings during the process of machining, thus facilitating the removal of waste metal. • OFHC alloys where exceptional strength is needed – a range of special alloys have been developed using zirconium and chromium, which reach their maximum properties through solution heat treatment, cold working and ageing (see Chapter 7). The advantage of using such alloys is that they combine a relatively high electrical conductivity with ductility and strength at high temperatures. – UNS no. C 15000 with 0.1–0.2% zirconium (1000–2000ppm) – UNS no. C 18200 with 0.6–1.2% chromium (6000–12000ppm) – UNS no. C 18400 with 0.4–1.2% chromium (4000–12000ppm) – UNS no. C 18500 with 0.4–1.0% chromium (4000–10000ppm). Alloys with 2.0–5.0% titanium (20000–50000ppm) and OFHC-nickel-titanium alloys are produced where a nonsparking metal is needed, for instance in coal mining equipment. There are currently no specifications produced for these types of alloy. • OFHC alloys where high corrosion resistance is needed – a range of cupro-nickel based alloys have been produced to cover this special requirement: – UNS no. C 70400 with nickel plus cobalt 4.8–6.2%, iron 1.3–1.7% and manganese 0.3–0.8%. – UNS no. C 70600 with nickel plus cobalt 9.0–11.0%, iron 0.1–0.8%.

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– UNS no. C 71000 with nickel plus cobalt 19.0–23.0%. – UNS no. C 71500 with nickel plus cobalt 23.0–29.0%, iron 0.4–1.0%.

5.6 Alloys where copper is the base metal The object of alloying copper with one or more other elements is to provide specific additional qualities to those exhibited by pure copper, or to enhance an existing one. Properties of the main alloying constituents are given in Chapter 6. Currently there are over 500 different alloys of copper in commercial use, most of them in what may be broadly termed the general engineering field. Obviously it is not possible within the confines of this book to give details of every one, but since they tend to fall into six broad categories, the more important alloys will be mentioned under the following headings: • Brasses – alloys of copper and zinc, and occasionally with other elements • Bronzes and gunmetals – true bronzes are alloys of copper and tin, but additional elements are frequently present such as zinc, phosphorus, nickel and lead. Bronzes containing zinc are called gunmetals • Aluminium bronzes – alloys of copper with up to 14% of aluminium and often other elements such as iron, nickel and manganese • Cupro-nickels – copper and nickel combine readily to produce a wide range of alloys • Nickel silvers – alloys of copper, nickel and zinc • Other alloys – usually produced to provide specific, very special qualities not available in the more general range of alloys.

5.6.1 Brasses As explained earlier, brasses fall into three main categories: • Alpha (cold working) brasses – containing up to 36% zinc. These are usually binary alloys (i.e. consisting of only copper and zinc) and are malleable and ductile, providing good cold working qualities (in pressing or forming).

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• Alpha/beta (hot working) brasses – containing between 36 and 42% zinc. These are harder and stronger and have to be fabricated by hot rolling, extruding, stamping, casting and diecasting. Other elements such as lead, tin, aluminium, iron and manganese are often added to these alloys. • Beta brasses – containing between 42 and 50% zinc. These are very hard, cannot be cold worked, but at elevated temperatures become plastic. They are generally worked by forging, drawing or hot extrusion. A binary alloy containing more than about 50% zinc is too brittle to be of any practical use. These general categories of brass each contain many different specifications, some of the more important grades of which are: • Cap copper – with 2–5% zinc, so called because of its use in the fabrication of percussion caps for ammunition. • Gilding metal – with 5–15% zinc, widely used for the manufacture of costume jewellery and decorative items. In the USA 90/10 alloy is known as commercial bronze, 87.5/12.5 alloy as jewellery bronze and 85/15 alloy as red brass. • Dutch, German brass or low brass (USA) – containing around 20% zinc, because of its golden colour, is used to manufacture ornaments and is rolled or hammered into thin foil as a substitute for gold leaf. • Cartridge brass – with about 30% zinc, gives good ductility and strength and is used particularly for producing wire, tubing and pressed and deep drawn items like shell and cartridge cases. • Yellow brass or muntz metal – an alpha/beta brass with around 40% zinc, is the most widely used brass alloy, being particularly favoured in the production of sheet and strip. These are the main grades of binary brass alloys. They are also produced with the addition of lead – being then known as leaded brasses – and occasionally with small amounts of other constituents such as phosphorus, arsenic, nickel, aluminium or antimony. The most important of the leaded brasses are: • Stamping brass – typically 58% copper, 40% zinc, 2% lead (although the lead can vary from 1 to 2.5%). Lead acts as a lubricant in drilling, milling, stamping or forging operations.

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• Free-turning brasses – typically 57% copper, 40% zinc, 3% lead (but lead may run within the range of 2–4.5%). The lead lying at grain boundaries improves the machinability of the alloy by making the turnings into brittle chippings rather than the spirals that would be generated by unleaded material, thus avoiding the problem of turnings clogging the working parts. Another range of brasses are copper-zinc alloys with small additions of tin and occasionally lead. These are sometimes called tin brasses, the most important of which are: • Naval brasses (sometimes known as admiralty brass) – typically 60% copper, 39% zinc, 1% tin. These are basically 60/40 brasses with 0.5–1.5% tin added to improve corrosion resistance. These alloys are mainly used for condenser plates, marine fittings, propeller shafts, valve stems and welding rods. A further group of complex alloys based upon 60% copper and 40% zinc are: • High tensile brasses – containing small amounts of iron, manganese and aluminium which give increased hardness and strength but reduced ductility. They are sometimes incorrectly termed manganese bronzes.

5.6.2 Bronzes Bronzes are the oldest alloy known to mankind and, strictly speaking, are a binary copper-tin alloy. However, more complex alloys are often produced by the addition of elements such as zinc, phosphorus, nickel and lead. The term bronze has now come to signify a type of alloy and some so-called bronzes contain no tin at all (like silicon bronze and aluminium bronze). Some of the more important alloys among the full range of bronzes are: • Bell metal – typically with 20% tin and a little zinc to act as a deoxidising agent to produce a sound casting. These alloys have been used for centuries to cast bells. They are also sand cast to produce slide valves and bearings that are designed to carry a heavy loading.

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• Coin bronzes – these are usually very high in copper with a little tin and the remainder zinc. Current British copper coins assay 97% copper, 0.5% tin and 2.5% zinc. • Phosphor bronze – is the name given to any bronze that has been deoxidised by the addition of phosphorus. Phosphor bronzes represent a wide and very useful range of high copper bronzes, with tin contents up to 18%, phosphorus between 0.1 and 1% and often additions of other elements such as lead, nickel or zinc. They provide strength, resilience, corrosion resistance and are non-magnetic. They are used for springs, electrical contacts, a wide range of bearings and bushes, turbine blades and gears. Lead has a particularly important role in the production of bronze bearings, where it acts as a lubricant while the thermal conductivity of the copper helps to avoid overheating. A recently developed alloy for aero-engines contains about 30% lead and 5% of other elements like zinc or nickel. • Gunmetals – are a group of copper-tin-zinc casting alloys often with additional lead. Tin ranges up to 10 per cent, as does zinc, while • Leaded Gunmetals – carry up to around 5% lead. Originally used for casting bronze ornaments and guns, the strength and corrosion resistance of these alloys gives them uses for bearings, steam-pipe fittings and marine castings. The best known and most used alloys are ‘85/5/5/5’ (85% copper, 5% each tin, zinc and lead) and admiralty gunmetal (88/10/2 with no lead, or its US equivalent 88/8/4).

5.6.3 Aluminium bronzes Aluminium bronzes, basically consisting of high copper/ aluminium alloys, are not strictly speaking bronzes, because very few specifications actually include tin. The aluminium content ranges up to about 15%, but above that figure the alloys become exceedingly brittle. The addition of comparatively small amounts of iron, nickel, silicon, tin, manganese or zinc provides a wide range of very useful alloys whose most important characteristics are strength (10% aluminium bronze is as strong as mild steel), resistance to corrosion, the ductility to be cold worked (in alloys with below 8% aluminium), and the capacity to be hot

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worked, sand cast and gravity die cast (in alloys containing 8–15% aluminium). They find many applications, for example in selector forks for automobiles, valve gear inserts, moulding dies, ornaments, architectural fittings and imitation gold articles. In chemical engineering they find uses in corrosive environments and in marine engineering in condenser tubing and ships’ propellers.

5.6.4 Cupro-nickels Cupro-nickels are a valuable series of copper-nickel alloys which provide high ductility and good resistance to corrosion and fouling by marine organisms. The 90/10 alloy is used for ships’ condenser tubes and other equipment in contact with seawater, while large quantities are currently being employed in desalination plants, marine fish farming and cladding for ships’ hulls to improve fuel efficiency by eliminating underwater fouling. The 80/20 alloy is readily workable and is employed for cold pressings, stampings and ornamental castings. The 75/25 alloy is widely used as so-called ‘silver’ coinage. The commonest alloy is the 70/30 quality which finds its way into condenser tubing and other general engineering applications calling for good corrosion resistance. The addition of iron, cobalt and/or manganese makes it a special alloy for use in particularly difficult conditions such as occur when seawater is mixed with sand. Binary alloys containing 50–60% copper have applications which take advantage of their high electrical resistance. A 65/30 alloy with around 5% iron, called Everbrite, is used for turbine blades, while a 60/20 alloy with 20% iron, called Cunife, produces a ductile permanent magnet alloy. A range of copper-nickel-cobalt alloys, called Cunicos are also used to make permanent magnets.

5.6.5 Nickel silvers Nickel silver is a name applied to a wide series of copper-nickelzinc alloys with copper contents of between about 45 and 75%, a nickel content of between 10 and 25% with zinc making up the remainder. They possess an attractive colour and good corrosion resistance and mechanical properties. The best quality silver-plated tableware, known as EPNS (electroplated nickel silver), is made from an alloy containing 20% nickel. Other alloys are used for marine fitments, architectural and ornamental metalwork, and food handling equipment.

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5.6.6 Other alloys In Chapter 6 the many useful qualities of copper will be outlined; one of its most important characteristics is its propensity to combine with other elements. This has resulted in the discovery of a great number of alloys, many of which fall outside the categories mentioned above. It is not possible to mention here more than a representative sample of these alloys, all of which have been produced to provide specific and often very special qualities. Among them are the beryllium-copper alloys which, as precipitation-hardened alloys, become as much as three times as hard as mild steel and so are among the strongest of all non-ferrous metals. They have good corrosion resistance as well as retaining high electrical conductivity. They are mostly used for springs, special wires and non-magnetic applications. Other exceptionally strong materials are provided by a series of copper alloys with 1.5–4.0% silicon and about 1% manganese, with the strength of mild steel and good corrosion resistance. They are known as Everdur alloys and are used for pumps and tubing for chemical and food processing plants. High strength at elevated temperatures combined with good ductility is provided by the chromium and zirconium-copper alloys, while titanium-copper gives the non-sparking characteristics so important for equipment in coal mines. A small amount of sulphur or tellurium (0.5%) can be added to copper to make a free-machining rod without any great loss of electrical conductivity, a characteristic used to produce parts for welding torches, motors, electrical connectors and switch gear. The addition of small amounts of silver raises copper’s softening temperature and its resistance to creep (the tendency for metals to deform under stress or increasing temperature). Another class of alloys is important because of their resistance to the passage of electricity, which does not change with variations in temperature (one example contains 85% copper, 13% manganese and 2% aluminium). They are used for underfloor heating and as resistances to control the speed of electric motors.

5.7 Alloys where copper is not the main constituent There are a great number of examples where copper’s unique characteristics are used in the production of alloys, but where it is

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not the major constituent. Most of the main non-ferrous metals utilise copper in one or more of their series of alloys as do steel and the precious metals. However, the tonnages of copper going into such applications are usually quite small, except in the case of some aluminium and nickel alloys. In particular there is the famous ‘monel’ alloy with 65% nickel and 32% copper and additional iron, manganese and often aluminium. This and other high nickel and nickel-copper alloys are used where good mechanical properties and corrosion resistance are required in particularly hostile environments such as pump shafts and power boat propeller shafts. Although copper is not an especially strong metal in its purest form, when added to aluminium it produces strong age-hardening alloys both in the range of general casting and wrought alloys and in the more specialised alloys used by the automotive and aircraft industries. RR58 alloy (later reclassified as 2618A) containing 2.5% copper, 1.5% magnesium, 1.2% iron, 1.0% nickel and the remainder aluminium, was used for the fuselage covering of Concorde. Although the percentage of copper in the aluminium alloys is much lower than in most of the nickel alloys, the tonnage used is probably higher. Copper also features in a wide range of what are called brazing solders, used for joining metals and alloys together. Common brazing of ‘spelter’ solders consists of zinc and copper in equal amounts, while silver solders contain silver in the range 10–80%, copper 16–50% and zinc 38–45%. Gold is also added to silver solders when gold articles are to be joined. Some tin-lead solders have additions of up to 10% copper to strengthen the matrix (or internal framework) of the crystals and in some cases this helps to form intermetallic compounds, which improve the strength and hardness of what are basically weak alloys. There is also a wide range of copper-based master alloys (sometimes termed hardener or foundry alloys). These are used to avoid excessive melting losses when introducing additional elements into molten copper during alloying operations in foundries. They range from 90% copper with 10% alloying element, down to a 50/50 alloy. They can also be obtained as ternary (three metal) alloys such as copper-ironaluminium or copper-iron-manganese. Copper in very small amounts (0.05% or 500ppm) is also included in the specifications of many structural steels to improve corrosion resistance. For the same reason between 1.5 and 2.0% of copper is also introduced into some types of cast iron for roofing.

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Copper plays a role as a hardening agent when gold and silver are fabricated into jewellery, medals, medallions, hollow ware, plates, dishes and other decorative items. Sterling silver is 92.5% pure silver with the remainder normally copper plus a little cadmium. At the other extreme, an exotic but minute outlet for copper that has recently been invented is a copper-containing ceramic for use in superconductors.

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6 Qualities of copper and its alloys

6.1

Good electrical and thermal conductivity

6.2

Capacity to produce useful alloys

6.3

Attractive appearance

6.4

Physical and mechanical properties 6.4.1

Ductility and malleability

6.4.2

Tensile strength

6.4.3

Susceptibility to heat treatment

6.4.4

Machinability of some alloys

6.4.5

Durability

6.4.6

Corrosion resistance

6.4.7

Easily joinable

6.4.8

Retention of qualities at high temperatures

6.4.9

Cryogenic qualities

6.4.10 Good electrodeposition characteristics 6.4.11 Low magnetic permeability 6.4.12 Capacity to be readily cast and fabricated 6.4.13 Harmonic vibrations 6.5

Other useful qualities 6.5.1 Readily recyclable scrap 6.5.2 Copper salts 6.5.3 Other

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Its many qualities have ensured that copper has been continuously in demand over the thousands of years since its discovery, with ever more applications for it and its alloys being found. It is an indispensable element in modern society through its role in the generation and distribution of electricity, telecommunications, electronics, building and building services, transport, general engineering and many other aspects of life. The most important characteristics that make copper so valuable and versatile are: • Its ability to conduct electricity and heat extremely well; • Its capacity to combine with a wide range of other elements to produce useful alloys; • Its attractive appearance; • Its physical and mechanical properties: – ductility and malleability – strength (particularly when alloyed) – its susceptibility to various forms of heat treatment – the machinability of some alloys – durability, i.e. resistance to fatigue, abrasion and wear – resistance to corrosion – it is easily joined – it retains its qualities well at elevated temperatures – its cryogenic (low temperature) characteristics – a capacity to be readily electrodeposited – it is non-magnetic – the ability to be readily fabricated and to produce sound castings – it provides harmonic vibrations especially in certain brass alloys; • It is easily recycled; • It produces useful salts.

6.1 Good electrical and thermal conductivity Electrical conductivity is a measure of the capacity to allow the passage of electricity through a substance. Electrical resistivity is the reciprocal (opposite) of conductivity, that is, the resistance to electrical flow. Thermal conductivity is a measure of the amount of heat that can pass through a substance in a given time. As can be seen from Table 6.1 pure

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Table 6.1 Comparison of electric and thermal conductivity for different metals (copper = 100)

Silver Copper Gold Aluminium Zinc Iron Lead

Electrical conductivity

Thermal conductivity

106 100 72 62 29 18 8

108 100 76 56 29 17 9

copper has the ability to conduct electricity and heat per unit volume better than any other metal except silver, which is only marginally superior to copper in this respect but is very much more expensive (at the time of writing silver costs nearly one hundred times as much as copper). In its purest commercially produced forms – oxygen-free high conductivity (OFMC) copper, top quality cathode and electrolytic tough pitch copper – the metal has a conductivity of 101.0% IACS (International Annealed Copper Standard) at 68 °F (20 °C). Cold working slightly reduces the conductivity of pure copper. Alloying also lowers conductivity, although in varying degrees according to the elements in the alloy. At low temperatures copper does not become a superconductor, but it does show a marked increase in conductivity as the temperature falls towards absolute zero (-273 °C). Its very useful electrical properties provide copper with many of its applications, in the fields of power generation and transmission, electronics, electroplating and telecommunications, e.g. in wiring and cables, switch-gear, transformers, dynamos, motors etc. Good thermal conductivity gives it uses in domestic hot water tubing and cylinders, solar heating apparatus, heat sinks and many other related applications.

6.2 Capacity to produce useful alloys An alloy is defined as a substance possessing metallic properties and composed of two or more elements of which at least one must be a metal. Over 500 useful alloys have been produced in which copper is a

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constituent and in a great majority of cases the main one. The addition of one element to pure copper as the base metal will produce what is termed a binary alloy, while the addition of two, three or four other elements are called ternary, quaternary and quinary alloys, respectively. The object of producing a copper alloy is either to provide an additional specific quality to those exhibited by pure copper, or to enhance an existing one. But the addition to pure copper of even small amounts of almost any other elements that will be accepted into solid solution will decrease ductility and, with the exception of silver, will reduce thermal and electrical conductivity. The major alloying elements in copper-based alloys provide a wide range and combination of different qualities. These are summarised below. Zinc is a base metal in its own right and provides the major alloying element in brasses, which are the largest and most important group of copper alloys. Zinc also plays a part in many bronzes, nickel silvers and gunmetals. The specific qualities that zinc imparts to copper are added strength, hardness and improved resistance to corrosion. Electrical conductivity falls sharply with the introduction of zinc. Tin is another base metal that plays an important role as the major alloying constituent in bronzes and phosphor bronzes and a part in gunmetals and bell metals. Although pure tin is soft, in a copper-based alloy it imparts high strength and improved resistance to corrosion (including that arising from seawater) – hence its use in ancient bronze weapons and cannons. Nickel – copper and nickel are what is termed completely miscible which means that in their molten form they can mix perfectly and on freezing form a solid solution that is homogeneous across the whole range of their alloys (from high copper to high nickel). In copper-nickels, nickel provides good ductility, greater strength and a high degree of resistance to corrosion – hence their use for marine condenser tubing in de-salination plants. Lead in comparatively small amounts improves the machinability of brasses and other alloys by making their turnings into brittle chippings (called swarf) rather than the spirals that are generated by nonleaded material, and which tend to get caught up in the moving parts of the machine. Additions of lead also act as a lubricant, improving the drilling, milling and forging qualities of alloys, especially where shapes or items are being stamped out of sheet or strip. However, the addition of lead reduces electrical conducticity.

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Tellurium in small amounts, like lead, imparts ease of machining, but also increases the strength and corrosion resistance of the alloy, while still retaining good electrical conductivity. Sulphur, like tellurium, improves machinability, strength and corrosion resistance, without unduly affecting conductivity. It is for all practical purposes interchangeable with tellurium; some consumers prefer one, and some the other. Cadmium adds great strength to copper, especially when work hardened. It improves wear resistance and reduces electrical conductivity less than any other alloying element introduced to impart strength; hence its major use is for overhead conductor wire (known as trolley or catenary wire) for the electrification of railways, tramways and similar applications. It also retains its strength at elevated temperatures better than pure copper. Considerable tonnages of 1% cadmium/copper have been used when railway networks have been electrified – in Britain it is said to have been 2500 t for every 100 miles of track. However, the casting of the alloy has been discontinued in a number of countries, since it is regarded as a health hazard. Chromium in small amounts provides a precipitation hardening alloy giving great strength with good electrical and thermal conductivity. Silver is expensive but finds a use in alloys because it raises the softening temperature of pure copper and gives improved creep resistance without reducing electrical or thermal conductivity at all. Silicon improves the strength of pure copper, giving added resistance to acid corrosion and improved weldability and springiness. Phosphorus is used in copper-based alloys as a deoxidising agent. In practice it ties up the oxygen in solution, lowering conductivity but providing additional strength, greater hardness and better corrosion resistance than pure copper. Aluminium, in up to about 14% composition as an alloying element, greatly strengthens and hardens pure copper, making alloys as strong as mild steel and imparting very good corrosion resisting properties – hence the use of aluminium bronzes for ships’ propellers in which iron, nickel and sometimes manganese are added to the alloying constituents. Iron appears in small amounts in a number of alloys, such as high tensile brasses, copper-nickels and aluminium bronzes, as a general strengthening constituent. Rather surprisingly in the latter two ranges of alloys, the addition of 5–10% of iron greatly improves the resistance to

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seawater corrosion. In a 60/20 copper-nickel, 20% of iron produces a ductile permanent magnet alloy (called Cunife). Cobalt finds an application in a range of copper-nickels (called Cunico alloys) used in the production of permanent magnets. Beryllium if alloyed in small quantities with copper, heat treated and precipitation hardened (see Chapter 5, section 5.6.6) produces a material with three times the strength of mild steel and is among the strongest of all non-ferrous metal alloys. It retains good electrical conductivity even when exposed in the long term to elevated temperatures, has good formability and corrosion resistance and is non-magnetic. It therefore finds useful applications in electronics, mining equipment and magnets but has the disadvantage that beryllium itself is a toxic substance and requires very careful handling as far as health and safety are concerned during production, fabrication and recycling. Manganese toughens and strengthens the alloys in which it appears and improves corrosion resistance. Some copper-based alloys containing manganese and aluminium so reduce electrical conductivity that they become strongly resistant to the passage of electricity. This quality does not change with temperature variations and so it finds applications in underfloor heating and in resistances controlling the speed of electrical motors. Zirconium provides high strength at elevated temperatures while not unduly depressing conductivity. Arsenic in small quantities improves the corrosion resistance of pure copper. Bismuth is one of the few metals that does not make any useful alloys with copper. It is often found in conjunction with copper ores and has to be removed in the refining process, otherwise it collects at the grain boundaries in copper and its alloys, making them too brittle to be of practical use.

6.3 Attractive appearance Apart from gold, copper is the only metal to have an attractive colour in its native form. The colour of freshly cast copper is a bright pink. The more familiar warm red colour is in fact due to the formation of a thin coating of copper oxide on the surface of the metal on exposure to air; a drop of acid applied to this attractive red surface reveals the

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bright pink of pure copper beneath. The red coloration tends to deepen with time. Exposure to even mild air pollution (but especially to salty sea air) induces a coating of bright green copper carbonate – known as verdigris. The verdigris not only protects the underlying copper but also provides a decorative colour feature, hence the use of copper sheeting for architectural purposes such as the covering of roofs and domes or exterior cladding on the walls of buildings. Copper and its alloys provide a remarkable range of beautiful colours from the pink and rich red of pure copper, through the paler reds of the high copper brasses (such as the cap coppers) through the golds, ochres, yellows and bronzes of the other brasses and bronzes, to the silvers of the nickel silvers and the whites and greys of some cupronickels. It is no wonder that down the ages, copper has been highly prized for its beauty and widely used for decorative, artistic and architectural purposes.

6.4 Physical and mechanical properties Copper and its alloys also exhibit a remarkable combination of physical and mechanical properties including those described below.

6.4.1 Ductility and malleability Ductility and malleability enable a metal or alloy to undergo cold, visible, plastic deformation under tension without fracturing or separation. An example is extension by drawing, the technique used in the fabrication of brass cartridge cases. Ductility is measured by the percentage of elongation under stress. Malleability refers to the ability of material to take deformation by hammering, forging or rolling without fracturing. Copper exhibits these two properties to the degree that it does, because its crystals have a face-centred structure, so that when stress of one sort or another causes deformation, the metallic bonds within the individual crystals can be broken and reformed without fracturing the whole structure (see Chapter 5, section 5.1). Copper’s good ductility and malleability is passed on, in varying degrees, to most of its alloys, which makes them also capable of being readily cold rolled into strip, sheet and foil, drawn into wire, beaten, spun, forged and extruded, drawn or pressed

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into complex shapes. This versatility is illustrated by the fact that pure copper can be rolled as strip to a thickness of less than 0.25mm, as foil to less than 0.02 mm, while it can be drawn into wire of such fineness that it is difficult to discern it clearly with the naked eye.

6.4.2 Tensile strength Tensile strength is measured by the ability of a metal to withstand the stress of being elongated by being pulled down or drawn. Under the SI nomenclature (Système International d’Unités) this quality is measured in newtons per square millimetre, a unit which has replaced the former measurements of tons per square inch and kilograms per square millimetre. The USA still retains the pounds force per square inch measurement. Pure copper is the strongest of the base metals and in a cold drawn state (measured as 434N/mm2) it is nearly as strong as hot rolled mill steel. Copper alloys are generally stronger than the pure metal with chromium-copper, zirconium-copper, and beryllium-copper being among the strongest. The hardness of any copper or copper alloy is established by using Brinell, Rockwell or Vickers hardness testing procedures.

6.4.3 Susceptibility to heat treatment Copper and its alloys can readily be subjected to a variety of heat treatment processes, which are either a necessary part of fabricating operations, like the various types of annealing (see Chapter 4, section 4.2), or they are used to impart or enhance particular characteristics to the finished semi-wrought product. As most cold-worked copper softens at around 200 °C, annealing during the process of fabrication (known as process annealing) is a comparatively straightforward matter. Among other operations that can be applied to some copper alloys are solution heat treatment (which for a time dissolves some hard intermetallic compounds allowing further fabrication work to be carried out on the alloy). This is often followed by age-hardening (a natural process whereby in time the hard intermetallic compounds come out of solution again to make the alloy much stronger). Quenching is another process whereby the heated alloy is rapidly

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cooled to harden. Also, at the end of each stage of fabrication, copper and its alloys are capable of being cleaned or finished by bright dipping (in zinc or cadmium salts or other mediums to provide a bright finish), pickling (in acid to give a dull finish), polishing, plating and lacquering.

6.4.4 Machinability of some alloys Ease of machining is imparted by the addition of tellurium, sulphur or lead to pure copper or lead to brasses or other alloys (see Chapter 4, section 4.2.8).

6.4.5 Durability Durability is exemplified by resistance to fatigue, abrasion and wear. Copper and some of its alloys exhibit good durability under testing conditions such as repeated motion (at temperatures ranging from high to very low), repeated bending or under the impact of friction. It is, of course, the basic ductility of copper that imparts this reliability to its products in action. Some phosphor bronzes, nickel silvers and silicon bronzes are used in the manufacture of special types of springs, while the addition of elements like silver, beryllium or zirconium improve wear resistance at high temperatures. Copper’s durability is illustrated by the discovery of artefacts created from the pure metal over 6000 years ago.

6.4.6 Corrosion resistance In air, pure copper quickly forms a protective film of surface oxidation which not only imparts its beautiful red patina, but provides some protection against mild forms of corrosion. As mentioned before, over a period, copper exposed to normal degrees of air pollution will develop a coating of bright green verdigris (copper carbonate) which provides a higher degree of corrosion protection. The addition of zinc or tin improves copper’s basic corrosion resistance, but to provide protection against seawater or chemicals it has to be alloyed with metals like nickel, zirconium, aluminium, beryllium or silicon. Only precious metals, stainless steel, titanium and its alloys, some nickel alloys (such as monel) and the copper alloys just mentioned are less susceptible to corrosive attack than pure copper.

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6.4.7 Easily joinable Copper and its alloys can readily be joined by soldering, brazing, welding, riveting, folding and bonding (see Chapter 4, section 4.3). The ability to solder readily is of great importance for the usage of copper and its alloys in the fields of electrical power generation and distribution, telecommunications, electronics, automotive radiators and a wide range of applications for tubes, pipes and fittings. The ability to bond effectively to other materials like steel or glass is important in the production of bimetallic and finned tubing for heat exchangers and air conditioners, as well as specialised applications like the manufacture of klystrons (electronic tubes or valves).

6.4.8 Retention of qualities at high temperatures Pure copper can be used satisfactorily for many years working at temperatures above 100 °C in electric motors and similar applications. Alloying with silver increases the safe working temperature without affecting electrical conductivity. Alloys such as chromium or beryllium/copper can be used at far higher temperatures.

6.4.9 Cryogenic qualities Cryogenic qualities refer to copper’s ability to retain and improve its qualities at very low temperatures. At very low temperatures pure copper does not actually become a superconductor but its conductivity rises sharply as the temperature falls towards absolute zero (-273 °C, or zero kelvin). Moreover at low temperatures copper and its alloys do not become brittle. For special hi-tech applications like stabilising superconducting magnets, particle accelerators or NMR (nuclear magnetic resonance) imaging and spectrography, a cryogenic grade of very pure OFHC copper is used (see Chapter 4, section 4.3). This provides a unique combination of qualities: high electrical and thermal conductivity, high resistivity ratio,1 high heat capacity, good mechanical strength at cryogenic temperatures, good ductility and uniformity of qualities. 1

Resistivity ratio is defined as the resistivity (i.e. the resistance to the flow of electricity) of an annealed copper at room temperature (20 °C or 293 kelvin), divided by its resistivity at the temperature of liquid helium (4.2 kelvin). Cryogenic grade copper normally has a resistivity ratio of around 300 to one. Absolute zero on the kelvin scale is the same as the zero on the perfect gas thermometer, i.e. -273 °C.

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6.4.10

Good electrodeposition characteristics

The ability of copper to be evenly and densely deposited by means of electrolysis is important not only at the refining stage but in many of its applications. For example in the field of electronics the electrical flow path in microchips and PCBs (printed circuit boards) is created by electronically depositing a thin coating of pure copper in the appropriate areas. Any break in these minute threads of copper would create faults which would be difficult and costly to locate in what are often very complex machines such as computers. Therefore a dense and even deposition of the copper is vital. Although the amount of metal used in each item may be minute, the total weight of copper used in all such electronic applications is of growing significance. Oxygen-free copper with specific amounts of added phosphorus is the main type of platers’ cast anode used in electronic applications. Less demanding uses will generally operate with anodes made from cheaper ETP (electrolytic tough pitch) copper with added phosphorus, for instance in decorative plating where copper is deposited as a base for nickel or chromium being plated onto zinc, steel, or plastic stampings or die castings. This technique is used in making a very wide range of items in the automotive industry, in the fields of household hardware and white goods, as well as many other applications. Copper plating of coinage is a growing application.

6.4.11

Low magnetic permeability

Copper and all its alloys that do not contain significant amounts of iron or nickel are non-magnetic. They therefore find special applications for tools and machinery in places like coal mines, where non-sparking qualities are of obvious importance and in sensitive instruments where being non-magnetic is vital.

6.4.12

Capacity to be readily cast and fabricated

As has already been explained (Chapter 4), copper and its alloys are capable of being soundly cast in a variety of ways. This capacity to produce intricate and sound castings and stampings has been utilised down the ages in the production of bells, cannon, jewellery, statuary, ornamental doors and many other works of art, coins and medals. Today

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thousands of different items are cast or stamped in copper and its alloys from tiny machine parts to massive ships’ propellers.

6.4.13

Harmonic vibrations

Copper and some of its alloys, especially certain brasses, have the ability to reproduce true sound under controlled conditions – hence their use down the ages for musical instruments, bells and chimes. Copper, brasses or bell metal (bronze containing 20% or more tin) are used whenever the pitch of harmonic vibration needs to be carefully controlled, so that a particular sound may be truly reproduced.

6.5 Other useful qualities 6.5.1 Readily recyclable scrap The ancient Egyptians used the Ankh sign (a circle with a cross below it) to indicate copper in their hieroglyphic form of writing. It was also the symbol for eternal life, which is indeed one of the characteristics of copper. It is rarely destroyed in consumption. Minor chemical uses are about the only cases where recovery is not feasible. Nearly all copper moves into applications which have a limited life span. When the machine part, cable, fitment etc. is worn out or made obsolete by innovation, its copper or alloy parts are valuable enough to be stripped out and recycled through the smelting, refining and fabricating processes of the copper industry (see Chapter 3, section 3.6). Today somewhere in the region of one-third of all copper and alloy semi-wrought products is made from secondary material, i.e. recycled scrap, residues, ashes and slags. The fact that copper and its alloys can be readily and economically recovered, sorted and recycled is an important characteristic of the metal, since it often reduces product costs, helping to maintain the overall competitiveness of the metal and holds the threat of substitute materials at bay.

6.5.2 Copper salts Virtually the only end uses of copper that preclude scrap recovery are its applications in the chemical field, where it often starts in the form of copper shot (porous balls of copper produced by pouring molten

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copper into warm water). The greatest quantity is used to make copper sulphate, which is the basis for a range of fungicides and seed dressings, as well as sprays and powders to combat animal diseases and infestations. Copper sulphate (of which over 250000 tonnes is consumed annually) also appears as a supplement in fertilisers and animal feeds. In water it inhibits algae growth as well as being an important molluscicide (killing the dangerous bilharzia-bearing snails of Africa and the species of fluke that cause liver rot in sheep). Other copper chemicals find uses as wood preservatives (copper-chrome-arsenic compounds) and in gold refining (copper cyanide). (See Chapter 7, section 7.6.7.)

6.5.3 Other Copper as a trace element is essential to the health of plants, animals and human beings; too little of it in their constitution can lead to deficiency diseases. Copper is also an effective biocide. It controls organisms, such as Legionella in circulating water systems, and the use of brass or copper door knobs and finger plates can reduce the spread of nosocomial infections, like the common cold. Copper-nickel cladding is used to restrict marine biofouling on ships’ hulls and off-shore structures, particularly in the oil industry.

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7 End uses of copper and its alloys

7.1

Electrical engineering applications 7.1.1 Generation and transmission of electricity 7.1.2 Communications 7.1.3 Electronics 7.1.4 Other electrical uses

7.2

Engineering applications 7.2.1 General and mechanical engineering applications 7.2.2 Marine engineering 7.2.3 Chemical engineering, food and drink processing and other

special applications 7.2.4 Other engineering applications 7.3

Applications in construction and building services

7.4

Applications in domestic goods

7.5

Applications in transport

7.6

Other applications 7.6.1 Coinage 7.6.2 Works of art 7.6.3 Custom jewellery and medals 7.6.4 Hardware 7.6.5 Instruments 7.6.6 Hardener or master alloys 7.6.7 Copper salts

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Copper is one of the most useful of all the metals. Pure copper and its vast array of alloys have an enormous number of applications arising from the unique combination of properties they provide, which have been set out in some detail in Chapter 6. It is often difficult to allocate specific applications of copper and its alloys to a particular category. For instance, while a copper cable obviously falls under the heading of electrical applications, where it is used in a house, office or factory it might equally be shown under the category of construction and building services. Again, cadmium-copper catenary wire (for overhead power transmission on railways, tramways, etc.) can equally be designated under the heading of electrical engineering or transportation. Also, fabricators and manufacturers are sometimes reticent about the volume of copper consumed in specific functions. A precise global division of copper consumed among the various applications is therefore not possible, but Table 7.1 showing its usage among major consuming areas in the West in recent years gives some indication of the distribution of copper between the various uses to which it is put. It also indicates the different conditions obtaining in the various regions. Power generation and distribution is by far the biggest element in the Asian countries recorded (and also, no doubt, in China, now the second biggest consuming country after the USA), where many systems are being extended. In Europe and the USA, however, the biggest area of consumption is construction, where in addition to extensive wiring, the water and heating systems are also likely to be made of copper. Because copper and its many alloys play such a vital part in the manufacture of important components for thousands of industrial and domestic products, it would require another substantial book simply to list and describe each application individually. However, it seems that the best way to present a reasonably clear, yet compact, picture of this multitude of applications would be to break the general categories down into their chief component parts, and to give a brief description of typical products from each section. In this way it is possible to give some indication of the extent to which copper and its alloys serve the needs of our civilisation.

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Table 7.1 Applications Category

Principal applications

Europe (%)

USA (%)

Asia* (%)

Weighted average (%)

Electrical & electronic products

Power cables and generators, transformers, electromagnets, switch gear, motors, telephone wire, semiconductors.

37.5

25

50

36

Construction

Electrical wiring, central heating tubes, cylinders and boilers, air-conditioning, plumbing, roofing, sprinkler systems, flashing and architectural metal work.

39.5

43

15

35

Transport

Vehicle wiring, radiators, heaters, and other components, shipbuilding, rail and aerospace.

7.5

12

15

12

Industrial machinery and equipment

Heat exchangers, condensers, gears, bearings, chemical engineering plant, pressure vessels, vats and metres.

9

11

9

9

Consumer and general products

Electrical appliances, computers, coins, chemicals, ordnance, utensils, ornaments and other consumer goods.

6.5

9

11

8

Source: Base Metals Handbook, Woodhead Publishing Ltd, 2001, from ICSG. * India, Indonesia, Japan, Malaysia, Philippines, Singapore and Thailand.

7.1 Electrical engineering applications Most, but by no means all, pure copper used for electrical purposes is fabricated first into copper wire and then becomes incorporated into various types of cables and covered wires for the transmission of electricity. According to Copper Development Association figures (based on the year 1990), the uses to which the 6 500000 t of copper wire produced throughout the World was put, were: • 36% went to the construction industry as building wire (for the transmission of electricity within domestic, commercial and industrial buildings).

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• 22% went into various sizes of power cables for the transmission of electricity from power stations to the buildings where it is used. • 18% went into winding wires for many types and sizes of electric motors and generators. • 17% went into telecommunications cables. • 4% went into wiring for automobiles. • 3% went to other uses. Whilst copper wire is the most important semi-wrought product used in the transmission of electrical power, other fabricated products in pure copper, such as busbars, commutator pieces, strip, tape and sheet, also play a part in the bigger picture.

7.1.1 Generation and transmission of electricity This represents the single largest application for pure copper. By their very nature, uses in this category call for high conductivity copper of 99.9% minimum purity with an electrical conductivity of 100–101% IACS (the International Annealed Copper Specification, see Chapter 5 pages 3, 9 and 11), as well as utilising the very good thermal conductivity of copper. Substantial tonnages of copper in the shape of winding wires and tapes, commutator segments, rotor rings and sections are used in electrical generators (or dynamos), turbines, resistors, transformers, switch gear and electric motors of all sizes. However, by far the largest amount of copper is used for the transmission of electricity. Although, owing to the much greater weight of copper, aluminium has replaced copper for overhead power cables (which are straddling the countryside strung on pylons), for most other forms of transmission, copper appears to be unassailable technically, because of its vastly superior ability to conduct both electricity and heat. To transmit electrical power to wherever it is needed, a wide variety of copper cables have been developed. These range from a simple insulated pair of wires to operate a door bell, through small plastic-covered cables for domestic wiring, up to massive multicored high voltage cables containing hundreds of wires with the capacity to transmit tens of megawatts of electrical power. To fabricate any of these power cables involves several operations among which are stranding (the twisting together of a number of wires),

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insulating of individual cores with cotton, plastics, paper or fabric, filling and laying up (in which individual insulated cores are wound together and the interior of the cable is packed with paper, plastics or textile fillers to present a circular cross-section), greasing with a heavy oil to prevent water damage and sheathing (encasing the whole cable in copper strip, lead, aluminium or steel wires to give maximum possible protection). Very high voltage mains cables often need to be filled with pressurised oil or nitrogen gas to prevent ionisation occurring in any voids within the structure that would lead to a breakdown of the insulation. A good example of modern high voltage technology is the submarine cable linking the British and French electricity networks across the English Channel. A copper conductor of 9000 mm2 (about 14 square inches) in cross-sectional area consists of three layers of shaped copper segments, helically laid around a single rod 10 mm (0.39 inches) in diameter. The overall diameter of the cable including insulation and armouring is 104.2 mm (4 inches) and it weighs 33.8 kg/m (22 pounds per foot). Within factories electricity is often transmitted not just by cables but by means of busbar, thick strips of copper into which heavy machinery, such as cranes, can tap for motive power. Copper parts of electrical machines such as generators, resistors or transformers often come under mechanical and heat stress. For working temperatures up to 150 °C high conductivity copper is normally adequate. For operating environments above that temperature, involving commutator segments, winding wires and similar components, silverbearing high conductivity copper is used. Where high stress is experienced at temperatures above 100 °C – as often occurs in rotor rings and rotor bars – a chromium-copper alloy would be called for.

7.1.2 Communications Copper also plays a major role in telecommunications equipment, in telegraphy, telephones, radio and television; in the transmission of voice and data by laser signals via fibre optics networks; in repeater stations for conventional and fibre optics cables; in communication of data between computers connected by wire, microwave or satellite communication circuits; and in radar installations. Despite the inroads made by fibre optics into areas traditionally served by copper-based telecommunications cables, substantial tonnages of copper go into a wide variety of

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telephone cables linking subscribers to their local exchanges, into equipment at those exchanges, such as switchboards, and into the equipment to link exchanges. For most applications high conductivity copper is perfectly adequate, but hi-tech devices are increasingly calling for oxygen-free high conductivity (OFHC) copper and its very special alloys. It is doubtful whether the introduction of mobile phones has significantly reduced the number of conventional telephones being installed, since the two are used in different circumstances, and, in any event, mobile phones also require copper.

7.1.3 Electronics In the field of electronics the biggest usage of copper is in the production of printed circuit boards (PCBs) and microchips for all types of computer and related equipment. Each item may contain only a minute amount of copper, but given the exceptionally large volumes produced worldwide, it adds up to a very appreciable usage of copper. With the development of miniaturisation in the field of electronics, it has become necessary to electrodeposit the copper flow path for the now minuscule electrical circuits on a microchip or PCB. This calls for the use of OFHC copper plating anodes containing a precise admixture of phosphorus – 400–700 parts per million (0.04–0.07%) – (see Chapter 5 page 12). A break in any circuit owing to porosity caused by the presence of free oxygen in the copper could easily result in the malfunction of an expensive electronic device. Other copper alloys are also widely used in computer parts such as heat sinks, terminal blocks and posts, pins, studs, plugs, connectors and, of course, wiring. Contact tips are made from silver-coated copper, gold-plated brass, nickel silver or sintered tungsten-copper.

7.1.4 Other electrical uses There are many other electrical applications for copper; indeed they are found in connection with most of the other general categories – for example in the construction industry, all forms of transport, in military, naval and air force hardware, in domestic, commercial and industrial goods and equipment, and so on. The use of plating anodes in microtechnological applications has been mentioned above. Ordinary high conductivity copper anodes

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(with and without added phosphorus) are also widely used to deposit copper either as a decorative plating on its own or as a necessary base for a further metallic application such as chromium, silver or nickel. Other applications of copper within the general electrical category range from the specialised use of OFHC material in high power electronic valves (known as klystrons or electronic tubes); to components for semi-conductors used in solid state devices; to complex machines used in scientific experiments (such as linear accelerators); to superconducting magnets for medical diagnostic and spectrographic machines (using nuclear magnetic resonance, NMR); right down to the extruded brass connector segments in the ordinary electrical plug used in millions of homes.

7.2 Engineering applications For the purposes of this survey, the use of copper and its alloys in engineering may (perhaps arbitrarily) be divided into four main categories: • General and mechanical engineering, including components for machines and machine tools for the production of general goods • Marine engineering • Chemical engineering (including petrochemicals), uses in the foodstuffs processing industry and similar special applications • Other uses. Plainly the alloys that are called for by each of these categories will be determined by the conditions in which the bearings, castings, pumps, tubes, valves and other components will have to operate, the need for resistance to corrosion, pollution and even radiation, the mechanical and temperature stresses to which they will be subjected, the type of lubrication involved and any other special circumstances arising in particular processes. Full details on these matters are available in the technical literature produced by institutions like the Copper Development Association and from major fabricators of semi-wrought products. As far as this survey is concerned, a less detailed approach will have to be adopted that can only hope to give a general impression of the enormous range of engineering products that are made from copper and its alloys.

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7.2.1 General and mechanical engineering applications In general and mechanical engineering applications there tend to be less demanding conditions in service, so that a great range of pressure-tight and general engineering castings are produced from gunmetal or duplex brasses (copper-zinc alloys with a microstructure composed of two phases, i.e. the alpha/beta brasses containing between 36 and 42% zinc, see Chapter 5 pages 2, 14 and 15). Typical applications would be plumbing and gas fittings. However, special components machined from die castings such as housings, racks, light duty gears, brackets and similar small parts are usually made from silicon brass, leaded brass or more exceptionally aluminium bronze. Where heavier duty castings are required for, say, gears, wormwheels, loaded rotating nuts or similar applications, tin bronzes and phosphor bronzes would be used. Leaded bronze castings are called for where water and steam fittings have to operate at up to 275 °C. Bearings fall into four main categories: externally lubricated, oil-impregnated porous types, bearings with built-in solid lubrication, and those with roller elements in them. Where they are likely to suffer heavier wear in service, they will be made from a stronger alloy, such as phosphor bronze which is typically used in bushes, wormwheels and cages for ball and roller bearings. Where high sliding velocities are encountered such as in crankshaft or little end bearings and bushes, leaded phosphor bronze or aluminium bronze would be used (the latter alloy being utilised where even greater strength or reliability is also required as in bearings for heavy earth moving machinery, or for ballraces on fire fighting equipment). Beryllium-copper bearings are often used for gearbox linkage bearings. Leaded copper and graphited porous bronze also find uses as bearing metals. Components produced by hot stamping and high-speed machining such as housings, valve bodies, bolts, nuts and water fittings, are made from hot stamping or free-turning brasses. Pressed, cupped and bent parts such as lamp caps, fuse caps, cartridge cases and containers, are produced from single-phase brasses (particularly 70/30 quality), phosphor bronze, gilding metals and nickel silver. Components produced by extrusion and high-speed machining are made from freeturning brasses, free-machining coppers and some special brasses. Such components include parts for industrial and domestic appliances, wiring accessories, switch gear, fuse gear, water and gas fittings,

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instruments, fasteners, door and window furniture, hand rails, architectural metal work and a multitude of other applications. The general engineering industry produces a vast array of items, some of which find their ultimate application in the other general categories that are being used in this survey. Examples of these would be pipes and tubing (such as those for the distribution of water, town gas, lubricants, fuels, less corrosive liquids and low pressure steam) with their fittings, bends, taps, light duty valves and pumps, housings, and racks which could be classified under applications for the construction industry. Other familiar components are found in most households and would be classified under domestic applications, items such as light fittings, cupped ends for domestic fuses, containers, nuts, bolts, screws and similar fastenings, pins, needles and drawing pins, keys, locks, hinges, and hundreds more familiar items that are often taken for granted (like the brass eyelet holes in boots and shoes) without giving a thought to what they are made of. Indeed all the major items of equipment used in the home also contain copper wire and copper alloy parts. Specialised applications for copper castings (including those in chromium and beryllium alloys and dispersion strengthened copper) include water-cooled hot-blast equipment for blast furnaces and converters, such as valves, tuyeres (air blowers) and oxygen lance nozzles; spot welding electrodes and their holders; and mould liners for the continuous casting of copper and steel. Beryllium copper and aluminium bronze are used to make non-sparking tools for the mining, oil and gas industries. A wide range of springs for many engineering purposes are fabricated from phosphor bronze, nickel silver, brass and beryllium copper. Heavy duty industrial pressure vessels and components are often copper lined, while in corrosive situations cupro-nickel cladding would sometimes be used. For even more stringent conditions, castings, bearings and housings are made from aluminium bronze and high tensile brasses, for instance to give improved wear resistance to turbine and supercharger blades, valve spindles, gear wheels, selector forks, heavy rolling mill slipper pads and other mechanical parts. Heavier duty bearings are often made from graphited porous bronze, while leaded bronzes are used where high sliding velocities are encountered. Heavily loaded gears, worm wheels, rotating and spindle nuts are often made from straight tin bronzes or phosphor bronzes. Industrial heat exchangers such as steam

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condensers, radiators, oil coolers and evaporators use pure copper, 70/30 brass, special brasses or cupro-nickel for tubing, tube plates and outer shells according to the conditions in which they operate. Many types of smaller bore tube also find their way into heat exchangers and air-conditioning equipment, often adorned with various styles and sizes of fins. Pipes with spirally corrugated or longitudinally fluted surfaces are also used.

7.2.2 Marine engineering In marine engineering there is a need for alloys that provide a high resistance to the corrosive effects of seawater and to marine biofouling. This obviously involves many types of equipment on board ships, on marine structures such as oil rigs, piers and fish farms, as well as in dockyards and industrial processes using seawater, such as desalination plants or power stations. The cupro-nickel alloys, and naval and admiralty brasses, aluminium bronzes, high tensile brasses, gunmetals and phosphor and tin bronzes are the main types of copper alloys used for major components in marine engineering. However, that is not to say that less complex and expensive brasses and bronzes are not utilised for chains, hooks, nuts, bolts, minor fitments, instruments, small pipework and many other ‘top-side’ items used in a marine environment (including ships’ bells). Typical larger scale applications in this field are the massive castings of marine propellers in nickel-aluminium bronze. Propeller shaft brackets and rudders may be made in this alloy or high tensile brasses, which are also used for smaller propellers. However, where contamination by silt or mud is encountered, or for underwater fastenings, nickelaluminium bronze, or aluminium-silicon bronze alloys are usually called for. In some cases rudders are made from steel with cupro-nickel cladding. For the most stringent applications of all, seawater pumps, together with their shafts and fittings have to be made from aluminium bronze (sometimes the pump bodies are cast in single pieces weighing several tonnes). In most cases the bodies will be cast in gunmetal with only the impeller in an aluminium bronze alloy or in monel (a nickelcopper alloy). In sea valves, the discs and seats are usually of cast nickelaluminium bronze or monel, while the stems will be in those alloys, phosphor bronze or 70/30 cupro-nickel. Where copper alloy pipework is involved, gunmetal valves are most commonly used. Steam condensers,

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oil coolers and other heat exchangers operating with seawater mostly use cupro-nickel or aluminium bronze for tubes, pipework and fittings with tube plates of rolled naval brass or an aluminium bronze with iron. High quality marine pipework or pipelines are usually made from 90/10 cupro-nickel or aluminium bronze. Emergency deluge fire extinguishing systems for marine oil rigs use 90/10 cupro-nickel or high tensile brass for pipework and some fittings, while other components may be made from gunmetal. Large quantities of cupro-nickel and aluminium brass tubing and cladding are used in the construction of desalination plants – for pipework, water boxes, elbows and flash chambers. A typical large flash distillation plant (say in the Persian Gulf), may contain over 500 t of these alloys (compared with 650 t of structural steel and 75 t of stainless steel). Ships’ hulls and many offshore structures are protected from marine biofouling by cladding in cupro-nickel. Marine ladders and safety rails are often made from the same alloy, as are the cages used in fish farming where both corrosion and biological encrustation are a problem.

7.2.3 Chemical engineering, food and drink processing and other special applications In chemical engineering and food and drink processing, even more corrosive conditions are often encountered including highly acidic or alkaline environments and extremes of atmospheric pollution. Pressure vessels, vats, kettles, boiling pans and stills, with their pipework and fittings, pump casings and rotors, valves, nuts and bolts and other components, generally have to be made in aluminium bronze, silicon bronze, phosphor bronze or cupro-nickel. Sometimes these alloys are used in the form of cladding for steel or concrete structures in the chemical industry. Evaporators, refrigerators, fractionating columns and heating coils use copper, aluminium brass, admiralty brass, cupro-nickel, naval brass or aluminium bronze for tubing, plates and other fittings according to their working conditions. Piping for non-aggressive liquors is normally made from pure copper with brass fittings, while for brines and similar solutions aluminium brasses or cupro-nickels are called for. Copper alloys can cope with some highly corrosive solutions. Gunmetals, tin bronzes and aluminium bronzes will be used in most situations where sulphuric, phosphoric and hydrofluoric acids and alkaline salts are involved. However,

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no copper-based alloys can be used for handling wet hydrogen sulphide, ammoniacal compounds or nitric acid. Only aluminium bronze can be used in contact with hydrochloric acid. Therefore chemical reaction vessels, pickling vats, crates, chains and suspension hooks are often made from or lined with this alloy. Because aluminium bronze also resists hydrofluoric acid, it is used for the nozzles which spray the acid to ‘frost’ electric light bulbs as well as for the trays which collect the acid from the process. Superheated steam and dry industrial gases (like oxygen, nitrogen, carbon dioxide, dry sulphur dioxide, halogens and town gas) can be handled by valves and fittings made from gunmetals and aluminium bronze. The paper making industry uses copper and a number of its alloys. These include aluminium bronze for cooling pipes, evaporator tubes, beater bars and rollers (some of which are also made from bronze or gunmetal). The massive ‘Fourdrinier’ wire screens are made from a mesh of brass and phosphor bronze wire, as are other gauzes and scouring pads. In addition many components in the plunger, vacuum and centrifugal pumps and vacuum boxes are made from gunmetal and other copper alloys. Again the special conditions in the oil, gas and petroleum industry call for all the strength, corrosion resistance and heat conductivity that are such important qualities of many copper alloys. In addition a substantial proportion of oil and gas at the time of writing is produced offshore and even more is transported by sea, with all the problems and solutions outlined in section 7.2.2. In the food processing industry special care has to be taken to prevent copper coming into direct contact with the products. This is because even a slight take-up of copper, whilst being medicinally beneficial, can affect taste and colour and hasten the onset of rancidity. Therefore copper alloy castings that could come into contact with the product have to be coated with tin or nickel. Nevertheless the industry uses copper evaporators for concentrating sugar, milk, coffee, tannin, lactic acid, gelatine and many other products. Copper distillation columns are employed to produce industrial alcohol, fatty acids and essential oils. Copper sheet has traditionally been used to form the attractively shaped stills used for the distilling of whisky and other spirits. Copper piping is also used for the condensing coils. Copper plays an even larger role in the brewing industry. Copper sheet often lines mash tuns and

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fermenting vessels, and the brewing coppers are most appropriately nearly always made from ‘the red metal’. The slotted false bottoms of brewery mash tuns are made of bronze or brass. The coiled tubes (called attemperators) through which cold water or brine are circulated to regulate the temperature of fermenting vessels are made of copper, as are the tubular condensing coils.

7.2.4 Other engineering applications The nuclear power industry uses copper in electric motors used in remote control operations within the core of the reactor, in heat exchanger and condenser components outside it and in the normal power station equipment for the production and transmission of electrical power. OFHC copper is required for the thermonuclear fusion containment magnets used in the advanced experimental machine at the JET (Joint European Torus) project at Culham near Oxford (UK) and the Axicell MFTF-B machine at the Lawrence Livermore National Laboratory in the USA. The doughnut shaped ‘tokamak’ in which the white hot plasma has to be suspended in a powerful magnet field is currently made from cupro-nickel. By 2020 or so the possibility of the commercial production of electric power by nuclear fusion should have been fully explored, and, if it proves viable, another quite important application for oxygen-free high conductivity copper and cupro-nickel will have appeared. Another emerging use is in the field of cryogenics (extremely low temperature physics) and the development of superconducting magnets. At temperatures close to absolute zero, certain metals and alloys lose all resistance to the flow of electricity, that is they become superconductors. However, the transition from the resistive to the superconductive state is reversible. Superconducting magnets are vulnerable to the development of relatively ‘hot spots’, which have to be shunted away to the liquid helium coolant by an alternative path provided by cryogenic grade OFHC copper embedded in the superconducting material. Superconducting magnets are currently used mainly in NMR imaging and spectography machines, in high energy physics research machines such as particle accelerators, in the nuclear fusion experiments mentioned above, and in magnetic levitation and propulsion systems. Already OFHC copper is being used for valves handling liquefied gases,

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and it is expected that many more practical uses will emerge from this fast developing area of scientific research.

7.3 Applications in construction and building services As mentioned in section 7.1 the largest amount of copper wire finds its way into what is termed building wire (including small cables), which are used for the transmission of electricity for power, lighting and heating within domestic, commercial and industrial buildings. Another major use in the building industry is in copper plumbing tube, for hot and cold water installations, delivery of town gas and in wet central heating systems, with all the fittings, bends, taps, valves, pumps, housings and accessories involved. The ordinary fittings are normally made from straight brasses (with special dezincification brass alloys used where impurities in the water supply will attack binary brasses), while pumps, valves and other components will use gunmetal castings. Hot water cylinders are fabricated from phosphorus deoxidised non-arsenical copper sheet, as are components of most back boilers operating behind solid fuel open fireplaces. Copper or alloy tubing (often integrally finned or of the fin and tube varieties) is also used in the evaporators and condensers for heat exchangers of all types, particularly those found in most types of domestic heat generating equipment such as boilers, instantaneous hot water heaters or heat pumps. Some immersion heaters are manufactured with copper sheathing round the heating element. Underfloor wet central heating systems utilise copper tubing, while resistance wires made from nickel silver, cupro-nickel or an alloy of copper, manganese and aluminium (an example would be an 85/13/2 alloy) are used in electrical underfloor heating. Solar heating panels also utilise the good heat conductivity of copper sheet and tube. Brass and copper components are used in the fittings and fixings of sprinkler systems and in some smoke warning devices. Copper, brasses, gilding metals and nickel silvers are effective biocides and their use in high quality door and window fittings, balustrades, hand rails, finger plates and similar architectural metal work and interior decorations can, as mentioned earlier, reduce the spread of nosocomial infections, such as the common cold. Indeed the use of copper tubing for the transmission of drinking water is being increasingly recommended as a control against the

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spread of the Legionella virus. In addition brass and other copper alloys are used in the manufacture of locks, keys, hinges and springs as well as many other small items such as nuts, bolts and screws, that play an important part in the processes of building and construction. Architecturally, copper finds a use in roofing, gutters, downpipes and wall cladding, which if left unprotected in time develop a bright green coating of verdigris (or copper carbonate) which is both visually attractive and provides a greater degree of corrosion resistance than the red patina that forms on pure copper. Copper is sometimes used for damp-proof courses, while roof supports, ties, reinforcing bars and other masonry fittings and fitments are often made from aluminium or phosphor bronze, especially where polluted atmospheres are encountered, such as around flues and chimneys. Architecturally decorative items may also be formed in brasses, gilding metal, nickel silver or bronze, with manganese bronze being occasionally chosen for its chocolate brown colour and corrosion resistance. One very special application in this category was the specification of high tensile brass for the window frames in the rebuilding of Coventry Cathedral.

7.4 Applications in domestic goods Many items that can justifiably be placed under the heading of domestic goods will already have been mentioned as electrical or constructional applications. There are inevitable overlaps, however the uses of copper and its alloys are categorised. Virtually all household appliances contain copper wire for the transmission of electrical power, and often utilise components fabricated from a wide range of copper alloys, as well as copper tubing in various forms. Many examples are to be found in what are termed domestic white goods such as refrigerators, washing machines and dryers, air-conditioning devices, vacuum cleaners, electric fires and radiators; in kitchen equipment like food mixers, toasters, washing up machines, electric and microwave ovens; in leisure items such as television sets, radios, video and tape recorders, record players or sewing machines; in home computers and their ancillary appliances, answerphones and other communications equipment. Other domestic items which may use copper, pewter, brass, bronze or gunmetal are decorative artefacts such as candlesticks, ornaments,

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vases, jugs, kettles, mugs and cups. Brass is also to be found in many of the fitments, switches and plugs for domestic lighting, in furniture fittings, as well as the pins, needles, hooks, screws, buttons, padlocks and so many other small items we take for granted about the house – until a need arises. Nickel silver is widely used for cutlery, ornaments and catering equipment in the kitchen, as well as for decorative features for areas such as walls or door frames. The best quality of silver-plated tableware (hallmarked as EPNS, electroplated nickel silver) is made from a copper alloy containing 20% nickel and 17% zinc. Sheffield plate (a silver sheath fused onto a copper core) is still widely produced for ornaments and tableware, being considerably cheaper than the same articles manufactured in solid silver. Many of the working parts of clocks and watches are stamped out of ‘clock brasses’.

7.5 Applications in transport Transport deserves to be treated on its own, despite the fact that many of its applications might seem to fall within categories that have already been covered, such as electrical engineering, electronics or marine engineering. However, transportation, in the widest sense, plays such a vital part in modern civilisation that it would be misleading not to include it in this survey of the main applications of copper and its alloys. With the end of the era of steam locomotion, the amount of copper used by railways fell. However, the subsequent move to electrify many mainlines increased the demand for hard-drawn cadmium/copper catenary wire (generally containing 1% cadmium) to carry the overhead electric power. In Britain about 2500 t of this wire is required for every 100 miles of track that is electrified. It is also used for tramways, trolleybuses and transit systems now being built to modernise transport networks in many cities across the world. Copper also plays a vital part in ensuring safety on modern high-speed railways – for signalling and communications networks which include increasing amounts of electronic equipment. An exciting possibility for the future is an ‘off-rail’ magnetic levitation and propulsion technique being developed in Japan, that has already been tested at very high speeds. In this project, superconducting magnets provide levitation, propulsion and guidance, utilising magnetic repulsion between coils on the vehicle and on the

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guide rail to maintain levitation, and magnetic interaction between onboard coils and others along the track to provide propulsion and correct any deviation. This could become an important extension to rail transport and, if it does develop as expected, it would constitute a major new usage for copper, particularly for the OFHC quality. It is estimated that at the time of writing the average private automobile contains around 60 pounds (27 kg) of copper and its alloys. This is mostly in the form of electric wiring, gaskets and components for the cooling system, hydraulics and starter motors, as well as other small machined parts. Extruded copper alloy ‘H’-section is sometimes used to produce the frames for automotive windscreens. Also, for items subject to very heavy wear and corrosion, such as valve spindles and seatings, gearbox selector forks and synchromesh rings as well as some gears and bushes, aluminium bronze, phosphor bronze or high tensile brass would be specified. Beryllium copper is often used for gearbox linkage bearings. It is even rumoured that the copper radiator might be staging a comeback for special applications. With the decline in the amount of bright trim on cars, less copper is used as a base for chromium plated fixtures and accessories. However, comparatively small but increasing amounts of copper are being used in car radios, audio systems and in the electronics required to operate the rising number of computerised control mechanisms being introduced into cars and lorries. The increasing use of salt on frosty roads has led to the introduction of cupro-nickel for some vulnerable components on more expensive vehicles to counter potential corrosion problems. The final emergence of a viable electric car for general use could increase the demand for copper and its alloys in the automotive industry; but this still seems to be some way off. The applications of copper and its more corrosion-resistant alloys in the shipping industry have already been covered in some detail under the heading of marine engineering. Copper also plays a major role in the numerous electronic devices employed both within ships, and in the tracking and safety systems operating both aboard and ashore. The shipping industry makes full use of telecommunication equipment for telegraphy, telephony, radio, television, satellite communication circuits and of course radar installations, all of which involve the use of copper and some of its alloys. The largest single application of copper alloys, as mentioned before, is for propellers, bearings, drive shafts, condensers and pumps. It has been estimated by the Copper Development Association that in all modern ships – large and small, built both for

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naval or merchant marine purposes – between 2 and 3% of the deadweight consists of copper and copper alloys. Likewise, the aerospace industry utilises a vast array of electronic and telecommunications equipment, especially in connection with the extremely important matters of international air traffic control, autopiloting equipment, navigational aids and devices to meet difficult circumstances such as blind landings. Copper wire plays a vital part in the monitoring and control of many functions operating within the aircraft, as well as for the transmission of electrical power and light. Copper alloys, some of which have been specially developed for applications in the aerospace industry, play an important role in hydraulic service systems, brake assemblies and oil coolers for jet engines. Copper also plays a part as a constituent in a range of aluminium alloys widely used in the manufacture of aircraft. For instance, alloy 2618A (containing 2.5% copper as well as magnesium, iron and nickel) is used to cover the fuselage of Concorde, while the Airbus incorporates four copper-containing aluminium alloys for both surface cladding and structural members. At the time of writing, in space travel and exploration, the role of copper is largely limited to microelectronics.

7.6 Other applications 7.6.1 Coinage Of the diverse applications that make up this category, coinage is probably the largest user of copper at the time of writing. A nation’s coinage is usually stamped from a coin bronze or cupro-nickel blank at an appropriate national institution – in the case of Britain, The Royal Mint (which was sited for centuries next to the Tower of London). The current £1 coin is made from an alloy containing 70% copper, 24.5% zinc and 5.5% nickel, that provides a reassuringly golden colour to the piece. The so-called silver coinage consists of a straight 75/25 cupro-nickel alloy. However, with the depreciation of the value of currencies over time, and a rising trend in the prices of the constituent metals, a problem has arisen. The intrinsic value of the metal contained in certain coins has risen close to and in some cases has actually exceeded the nominal value embossed on them. This already applies to a number of so-called copper coins (in Britain these contain 95.5% copper, 3% tin and 1.5%

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zinc). Whilst it is a serious criminal offence to melt down, clip or deface ‘coin of the realm’, moves have had to be put in train to replace the old ‘copper’ coins by copper-plated steel coins of the same weight. The US Treasury has had to do the same for its smaller coins. On the face of it, this could mean that, in time, the use of copper in coinage could be phased out except for comparatively small amounts used in electroplating other metals. However, all is not yet lost, since serious problems over the forging of bank notes and the cost of replacing them frequently, has raised the possibility of issuing higher value coinage. Because the acceptability of a currency ultimately depends upon trust, confidence and familiarity, copper may still have a role to play until the so-called ‘money-free’ economy finally emerges. However, a rogue-proof electronic credit and clearing system has still to be perfected.

7.6.2 Works of art Works of art such as statuary, medallions or ornamental doors have traditionally been cast in straight bronze, while bells usually contain 20– 25% tin and a little zinc to act as a deoxidising agent.

7.6.3 Custom jewellery and medals Custom jewellery and medals are fabricated from copper, gilding metal, or other brasses and bronzes.

7.6.4 Hardware Hardware such as sporting and military ammunition have percussion caps stamped from cap copper (usually 97% copper and 3% zinc) and cartridge cases of all sizes from small arms up to artillery shells are pressed and deep drawn from 70/30 cartridge brass. The fuse mechanisms for shells are produced from leaded stamping brasses. Copper also has a part to play in military night-sights.

7.6.5 Instruments Brass and other copper alloys have long been favoured for scientific instruments and weights and measures where accuracy, sensitivity and low magnetic permeability is important. Brass is also widely used in

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End uses of copper and its alloys

commercial instruments, for example to provide the gears and plates in petrol pump meters. The harmonic vibrations of musical instruments can be controlled to provide a consistent beauty of tone if they are made from copper, brass or bell bronze. Hence the use of brass for the instruments in one of the main sections of an orchestra and the use of brass or copper for military bugles.

7.6.6 Hardener or master alloys When made from copper, hardener or master alloys are produced in specialist foundries and consist of an alloy of copper and precise amounts of one or more alloying elements, usually 50% copper and 50% of the other element. They are used in general foundry work to produce commercial alloys to closer compositional limits than are attainable if pure metals alone are fed into the furnace. Hardener alloys also reduce melting losses, which is important where the alloying element is particularly expensive. Copper also appears as an alloying element in hardener alloys based on other metals such as aluminium.

7.6.7 Copper salts The last but by no means least of the other uses of copper covers its non-metallic compounds: • Hydrous copper sulphate (CuSO4, 5 H2O) is by far the most important of these. At the time of writing around 200000 t is produced a year, which at 25% metallic copper, indicates an annual usage of 50000 t of copper. It is produced mainly from scrap copper, copper shot or from leaching residual copper from mine dumps using dilute sulphuric acid. It finds an astonishingly wide range of uses as: – A general agricultural fungicide. It is the basis for the famous Bordeaux and Burgundy mixtures originally used in vineyards; – A corrective for copper deficiency in the soil or in animals; – A growth stimulant for fattening pigs and chickens; – A molluscicide for countering snail-borne liver fluke and bilharzia (in Africa); – In public health and medicine, e.g. as an insecticide for use against mosquito larvae;

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• • • • • • • •

– In the chemical industry, in preparation of catalysts and the purification of gases; – In colouring glass, ceramics, cement and plaster; – In dyestuffs and tanning; – As an electrolyte in copper refining and plating; – In paint manufacture (anti-fouling paints), in the petroleum, rubber and textiles industries. Copper acetate is used in pigments and as a catalyst for ageing rubber. Copper oxide features as a fungicide, a seed dressing and in antifouling paints. Cupric oxide finds use as a colouring agent. Cupric chloride and Cuprous chloride are mainly used in the petroleum industry in catalytic oxidation. Copper oxychloride is an important agricultural fungicide. Cupric nitrate finds uses in ceramics, dyeing and fireworks. Copper cyanide is mainly used for electroplating copper. Copper soaps, copper napthenates and anhydrous copper sulphate find uses in rot-proofing agents and wood preservatives.

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8 Structure of the market

8.1

The market in exploration and development licences

8.2

The market for copper concentrates 8.2.1 Custom concentrate terms

8.3

The market for blister and anode

8.4

The market in refined copper 8.4.1 Refined copper terms

8.5

The market in copper and alloy semi-wrought products

8.6

The market in copper and alloy scrap and copper-containing ashes, slags and residues

8.7

The trade in copper warrants

© Woodhead Publishing Ltd

The chain of events by which elemental copper moves from its discovery and mining, into the processes of purification and fabrication, to its ultimate use as part of a finished product, and finally, at the end of the useful life of that product, to the recycling of the copper content through the medium of scrap recovery has already been described. International trade takes place at many points in this cycle and a number of distinct market segments can readily be identified within this overall picture. However, before considering these matters in detail, it is useful to look at the general pattern of international trade in copper as it can be gauged from a study of the statistics arranged by broad geographical regions for the production and consumption of the metal at various stages of its purification and fabrication. This indicates clearly a major characteristic of copper, that it is generally found in commercially exploitable quantities in comparatively few areas of the world, and that the places where today much of the smelting and refining and most of the fabrication take place are usually far from the large centres of consumption. Only in a few areas, such as central China and in Europe, can it be said that copper is being mined reasonably close to major consumption areas, with ‘close’ being within 500 miles. Therefore the metal in all its stages of purification, fabrication, use and recovery from scrap is a commodity that is often transported very great distances across the world and in the process is often traded. This simple fact illuminates the important role played by transportation, particularly the shipping industry (with its constantly moving freight and charter rates) and by all the ancillary services, such as those provided by the warehousing companies and assayers. Also, throughout this great cycle the treatment, movement and storage of copper calls for considerable financial resources to be available. One thousand tonnes of copper cathode at the time of writing costs around $1.5 million. This ‘financial imperative’ applies not only during the stages of mine development and actual production, purification and fabrication of the metal, but also to the financing of the metal’s progress between each of these stages, as well as during the process of trading and stockholding. In this the free terminal markets play a vital part and of course behind it all lie the services of the World’s banking system. Table 8.1 shows the World mining, smelting, refining and consumption of copper by geographical areas in 2000. (The statistics by country from which it has been compiled are taken from Tables 2.2, 3.1 and 8.5, and ICSG.)

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Table 8.1 World production and consumption of copper in 2000 (thousands of tonnes) Area

Production Mine

North America (inc. Mexico) South America Africa Asia Western Europe Eastern Europe (inc. Russia) Oceania Total

Consumption Smelter

Refined

Refined

2 465 5 335 468 1 320 231 2 332 1 032

1 888 2 012 410 2 728 1 222 3 017 393

2 756 3 321 368 2 751 1 921 3 209 487

3 769 518 131 4 074 4 053 2 449 174

13 183

11 670

14 813

15 168

The position of each area is summarised below: • North America (including Mexico). In relation to its huge consumption (the USA has topped 3 million t per annum) the area is reasonably self sufficient, although overall it is a net importer of copper. However, this statement conceals considerable trading both within and outside the area. The mines of western Canada send substantial shipments of concentrates to Japan and south-east Asia, while the refineries of eastern Canada supply cathodes and refinery shapes to the fabricators of the USA mid-west and eastern seaboard as well as to Western Europe. Also, both the USA and Canada import substantial quantities of concentrates and blister copper, mainly from South America. The region is not only the second largest producer of mined, smelted and refined copper, it is also the third largest consuming area, with the USA the largest single national market in the world (see Table 8.2). • South America is the biggest producing area and the biggest exporter of concentrates, blister and refined copper. Cathode exports have grown sharply as more large solvent extractionelectrowinning (SX-EW) plants come into operation. The region is at present a relatively small consumer of copper. • Africa was once the World’s biggest exporter of copper metal, although the Copper Belt’s production is now a shadow of its former self. Apart from South Africa, which absorbs most of its own copper production, it is a very small consuming area.

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Table 8.2 Copper concentrate production and trade in 2000 (thousands of tonnes of copper contained) Concentrate production

Western Europe Finland Germany Norway Portugal Spain Sweden Former Yugoslavia

11

Net imports

137 205

76 23 78 42

263 41 19

Total

230

665

Africa Botswana Congo Morocco Namibia South Africa Zambia Zimbabwe

23 33 7 5 148 184 1

Total

401

1

34 1005 135 1

176

Asia India Indonesia Iran Japan Oman Philippines South Korea Turkey Total

32

76

838

1

8

42 13

Total

1852

55

South America Argentina Brazil Chile Peru

145 31 3230 427

Total

3833

37

2503

269

544 811 278

269

1633

126 1780 65

0 185 1460 367

1971

2012

159

159

411

850

1348 69 105 353

634 909 309

12 33 0 14 140 205 7

256 174 155 1332 33 160 371 22

813

2051

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76

1

70

Primary smelter production

152 238 0 0 290 106 52

7

1277

North America Canada USA Mexico

Net exports

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Table 8.2 Continued Concentrate production

Net imports

Net exports

Primary smelter production

Oceania Australia Papua New Guinea

732 203

255 188

393 0

Total

935

443

393

Other countries Bulgaria Poland Romania Slovakia Kazakhstan Russia Uzbekistan China Mongolia North Korea

76 454 21 1 430 525 65 569 125 12

20 6

161 461 5 0 392 535 75 1000 0 10

Total

2278

Other countries/in transit World Total

12 7 5 31 453 126 508

152

2639

330 10806

3769

25 3769

10455

Source: International Copper Study Group (ICSG), World Metal Statistics (WMS).

• Asia is a mixed bag. It has major importing countries with few indigenous copper resources, notably Japan, South Korea, India and the increasingly sophisticated economies of south-east Asia. Indonesia has become a major producer and it and the Philippines are important middle-ranking exporters of primary copper, mostly to countries within the area, while Iran and Turkey export to Europe. China at present consumes its own production and is a major importer of copper in all forms. Asia is the biggest and fastest growing copper-consuming region. • Western Europe is primarily an importing region taking in concentrates, blister copper and refined metal from many places, but mainly from South America, Africa and Canada, to feed the second largest copper-consuming area in the world. It is a small producer of mined copper. • Eastern Europe (including Russia). In Russia, output and in particular consumption have been hard hit as political upheaval

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Structure of the market

has been followed by economic chaos. As a result it has become a major exporter of metal to Western Europe, as has Poland, although here the economy, and therefore domestic consumption, is in a better state. • Oceania (Australia and Papua New Guinea) is predominantly a producing region, exporting copper to Japan, south-east Asia and Europe, with a fast-growing output in Australia. To sum up, the largest volumes of established trade in primary copper take place across the Pacific and Atlantic oceans – from the western seaboard of North and South America and from Oceania to Japan and south-east Asia; and from Chile and Peru, Oceania and Africa to Europe. Canada’s exports to the eastern USA must also be mentioned. Less well established, because they tend to fluctuate unpredictably, are the considerable movements of copper (mostly in the form of cathode) out of Russia and the very substantial purchases by the Chinese since around 1990. Having looked at the broader picture of the international trade in copper from the standpoint of the available statistics, it is now appropriate to consider the individual market segments.

8.1 The market in exploration and development licences Exploration and development licence markets are small but important markets that cover an essential aspect of the process by which viable mining prospects are discovered and developed (see Chapter 3 pages 1 to 5). Although some copper deposits are discovered by prospecting teams sent out by large natural resources or mining companies, who are quite capable of evaluating, developing and operating any interesting ore-bodies they may discover, other prospects are found by much smaller companies which do not command the financial resources to take matters beyond the initial stages of the evaluation process. This is where the complex and highly specialised markets in copper exploration and development licences and mineral development rights come into play. They tend to be located in places like Toronto, Vancouver and Melbourne, that is, in major producing areas where governments or giant mining companies are not the predominant agents involved directly in the discovery and exploitation of

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mineral deposits, and where large tracts of potentially interesting country have not been enclosed (in the legal sense) by the allocation of exclusive exploration permits.

8.2 The market for copper concentrates Of the 10.84 million t of copper in concentrate mined in 2000, 6.5 million t or 60% of it was smelted in its country of origin; the bulk of it was treated in integrated smelters, that is, plants owned by the same company as the mine, and the rest, mainly from smaller mines, was sold to smelters in the country, usually not far distant. The remaining 40%, amounting to some 4.34 million t copper contained, was shipped out of its country of origin to be smelted probably thousands of miles away, normally in a ‘custom’ smelter, one which buys the concentrates from the mine, treats them and sells the resulting metal (see Table 8.3). It would seem logical to smelt and refine copper concentrates as close to the mine site as possible in order to avoid transport costs and to have the metal in usable form as quickly as possible. Shipping copper in concentrate form is a particularly unattractive proposition, at least in theory, since only 30% of the material shipped, or even less, is likely to be of any value. Transporting raw materials in bulk on land is invariably expensive and may present environmental problems. There are also political and economic arguments (particularly the former) for processing raw materials as far as possible in the country of origin in order to create employment, add value and in developing countries to assist in industrialisation; in the case of foreign-owned mines, this is also to avoid the accusation that foreigners drain a country of its natural resources without any regard for its economic well being. The sight of ore being shipped out of a poor country to be processed in a rich one can be emotive. However, in spite of the persuasive arguments in favour of smelting on the mine site, or at least in the country of origin, at the time of writing it is comparatively rare for a new smelter to be built and even rarer for it to be integrated with a mine; only one new smelter has been built in a producing country in recent years, Gresik in Indonesia, and it is technically custom (i.e. independent of the mine as opposed to integrated) being only 25% owned by Freeport, Ertsberg’s owners. None of the major new or recently expanded mines such as Collahuasi, Los Pelambres or Escondida (the last being the largest copper mine in the

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Structure of the market

Table 8.3 Reported trade in copper concentrates in 2000 (thousands of tonnes of copper contained) Exports

Imports

Germany Portugal Spain Sweden Morocco South Africa Indonesia Papua New Guinea Philippines Turkey Canada USA Mexico Argentina Chile Peru Australia Bulgaria Poland Russia Mongolia

8 76 6 7 7 1 813 188 25 51 480 175 79 126 1780 95 255 29 6 8 126

Finland Germany Spain Sweden Former Yugoslavia Zambia India Japan Oman South Korea Philippines Turkey Canada USA Mexico Peru Brazil Bulgaria Romania Russia Slovakia Kazakhstan China Other countries/in transit

137 213 269 48 19 1 176 1348 69 353 130 14 211 217 92 30 159 9 12 39 7 5 453 330

World Total

4341

World Total

4341

Source: ICSG, WMS.

World) have chosen to build a smelter. While copper concentrate production rose by 107% during the six years to 2000, exports of concentrates rose by nearly 160%. The principal factor determining where a mine’s concentrates are to be treated is inevitably economic and the first consideration is the size of the mine; the economies of scale are such that it is most unlikely that at the time of writing an integrated smelter would be considered for a copper throughput of less than 100000 t per annum at the very least. Only exceptional circumstances, such as the existence of uranium in the ore, as in Olympic Dam, would justify the construction of a smaller plant. Another justification for an integrated smelter and refinery would be the proximity of a good market for the finished metal, but as

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discussed earlier, most copper is mined in developing countries with as yet only limited demands. The classic is Chile, with an annual mine production running at over 4.6 million t and metal consumption of about 83000 t, while in Canada, with consumption not far behind mine production, the distance between the British Columbian mines in the far west and the fabricating plants in the east is such that the former look at concentrate markets in Asia rather than the metal market at home. In both cases, and also in other countries where production far outstrips domestic demand, the mine output will inevitably be exported, if not in concentrate form, then as metal; the choice will ultimately depend on which is more economical. The basic reason for the growth in the tonnage of concentrates being custom smelted is the fact that the cost of building and running an integrated smelter, even for a very large mine, is unlikely to be justified when compared to the cost of having the concentrates smelted elsewhere, assuming always that the mine has reasonable access either to smelting capacity in its own country or to a suitable port. Shipping copper in concentrate form is not necessarily more expensive than as metal; indeed, it may sometimes be cheaper to charter (or even own) a relatively small bulk carrier to carry concentrates than to ship the copper content as metal as a part cargo on liner terms. The copper concentrates are usually shipped in so-called handy size bulk carriers of between 10000 and 25000 t DWT (dead weight), the size being limited by the smelters’ ports. Although freight rates can fluctuate considerably, they are generally at a level that allows concentrates to be shipped to almost any reasonably accessible port in the world, from Finland to Japan. Although they fluctuate widely according to market conditions, custom smelting charges (which are described in more detail below) on average have proved to be sufficiently low, even when transport costs are taken into account, to justify the scale of a mine’s production in the form of concentrate rather than metal. The basic reason for this is the existence of a sufficient and relatively cheap pool of smelting capacity which is not dedicated to any particular mine and so is available to those mines which do not have their own smelters. Custom smelters, usually situated in or near areas of high metal demand, have been in existence for many years (for example, the Swansea smelters in the last century) a good contemporary example is the Norddeutsche smelter in Germany, a country with no copper mine production but a very large consumption. Their numbers have been

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added to over the years by plants which were originally integrated with mines whose production has since declined or actually ceased, leaving the smelter to look elsewhere for an increasing proportion, and sometimes all, of its feed. The prime example of this is the Japanese smelting industry, originally established to smelt their domestic mine output that has long since virtually disappeared. While the life of a mine is inevitably limited, that of a smelter can be prolonged indefinitely if it is accessible to the concentrates of other mines. Not only do smelters survive, but they also grow. It has been regularly demonstrated that the capacity of a smelter can often be increased at relatively little cost, usually by ‘debottlenecking’. Often, if the capacity of one or more parts of a smelter is increased, the remaining sections of the plant are able to accommodate the increased throughput without themselves having to be expanded, thus creating very low cost additional capacity. Many existing smelters have been modernised, often to comply with stricter environmental regulations, and the opportunity has been taken to expand the plant’s capacity at the same time. In addition, older smelters are already largely amortised, thus reducing their costs. The sharp growth in SX-EW production has done much to reduce the pressure on smelting capacity, in spite of strongly increasing mine output; of the 3.7 million t of additional mine output between 1994 and 2000, not far from half was SX-EW production. One other factor which, combined with the policy of the Japanese smelters in the past, did much to establish the global pattern of the trade in concentrates, is tariff protection. A number of countries have had (and some still have) tariffs on imported copper metal, which has the effect of increasing their domestic selling price for refined copper. Such a tariff, therefore, enables smelters in the country to offer lower charges to sellers of concentrates because of the differential between the international price for refined copper (usually the London Metal Exchange, LME, price) on which the valuation of the concentrates is based and the price at which their metal is sold in the home market, which will also be based on the LME price but with the tariff added. At various times Japan, Brazil, South Korea, Spain and India have had tariffs on refined copper imports, and these have all encouraged the export of concentrates to these countries because of the lower charges which in consequence they have been able to offer, but by far the most important of these to the concentrate trade has been Japan. In view of its pivotal role in the trade for many years and its

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influence on countries, it is worth looking briefly at the post war development of Japan’s copper industry. At the end of the Second World War, Japan’s copper industry, like the rest of its economy, was in ruins, and in 1951 a tariff on refined copper of 10% was introduced with the intention of protecting its domestic copper mines. By the 1980s the tariff authorised by the General Agreement on Tariffs and Trade (GATT) was yen 21/kg, although in practice only yen 15/kg was applied (equivalent to around 5% of the LME price expressed in yen). Japanese mine production, however, which had been 120000 t in 1970 had dropped to 53000 t by 1980 and 13000 t by 1990 (and since then has all but disappeared) while the country’s demand for refined copper by 1970 had reached 820000 t, 1158000 t by 1980 and peaked in 1991 at over 1.6 million t. The Japanese copper industry, in which mines, smelters, refineries, fabricators and traders are generally closely allied, if not actually related, and in which the smelters have regularly (although not invariably) co-ordinated their buying from mines, early on evolved a policy of seeking to rely on concentrates rather than metal to meet the dramatic increase in their imported copper requirements. There were several reasons. The Japanese have often been anxious to make the imports on which they rely so heavily as secure as possible, and clearly decided that they could more easily control supplies of concentrates than metal. Geographically, supplies of concentrates were more accessible from countries bordering the Pacific, especially Indonesia, the Philippines, Papua New Guinea and North America, while for the major exporters of refined metal (Zambia, Zaire, Canada, Chile and Peru) Europe, the other great copper-importing area, was closer. Also, the Japanese consumers preferred the reliable quality and delivery of their own refineries rather than foreign brands and have always been wary of becoming heavily reliant on imported refined copper. For these reasons the Japanese smelting companies set out to encourage the establishment of new mines, especially around the Pacific, and to discourage the building of integrated smelters. This was done sometimes by participation, by offering finance against long-term concentrate import contracts, and by attractive custom smelting terms. Mines would not necessarily wish to commit all their production to Japan, so more concentrate supplies became available for other countries, but for years the bulk of exported concentrates was shipped to Japan, and even in 2000, after the emergence of China as a big importer and with rising demand in South Korea and Western Europe, it accounts

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for over one-third of all recorded imports, with net imports of 1.348 million t in 2000. The second biggest market with net imports in 2000 of 0.665 million t for custom concentrates is Western Europe, with smelters in Germany, Spain, Sweden, Finland and the former Yugoslavia. Although the opening of the Neves Corvo mine in Portugal in 1988 and the reopening of the Cerro Colorado mine in Spain in 1995 raised European mine production, the former’s production is declining with lower grades and the latter closed on occasion owing to the low copper price; meanwhile small mines in Sweden, Finland and Norway have closed. The Spanish, Swedish and German smelters have expanded their capacity, so Western Europe is likely to need increased supplies of concentrates from elsewhere in the coming years. Although import finance has been provided by Germany and Finland in more recent years, historically the European smelters have tended to treat mines more on an ‘arm’s length basis’ and did not take such steps as the Japanese to nurture supplies. After Western Europe, China is the next biggest net importer (0.453 million t in 2000). The country has only recently come to prominence in the concentrate trade, as its fast-increasing demand has outdistanced its languishing domestic supply, smelter capacity has increased and stricter environmental measures have restricted the secondary production. China’s importing of concentrates has to some extent been hampered by administrative difficulties experienced by some suppliers, making it in the past a less popular destination for exports, but the passage of time and more settled commercial organisations in China should improve this. South Korea (0.353 million t in 2000) comes next; like Japan it has had tariff protection, no domestic concentrate production and a booming demand. It has one refining complex, at Onsan, to which a second smelting plant was added in 1998 bringing its total capacity to 400000 t per annum. This plant, now 50% owned by Nippon, illustrates a development in Japanese smelters’ policy, which is to invest in smelting capacity outside Japan, as well as at home, because the costs abroad are likely to be lower. Imports of concentrates by the USA have fluctuated; basically, it has been reasonably self-sufficient, and with the smelters well inland, transport to them is expensive. Such are the distances involved that it is cheaper for the mines in the north of the USA to send their production to Canadian smelters rather than to a domestic plant in the south west of the country.

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Imports by the Pasar smelter in the Philippines have increased as the domestic mine production (some of which is exported anyhow) has declined. In Brazil the Caraiba smelter’s capacity is expanding, while the country’s small mine output sinks and its metal demand rises. Canada, like the USA, both exports and imports concentrates for geographical reasons; their smelters in the east are more easily supplied by imports from the USA and further afield than from British Columbia, which exports concentrates mainly to Japan and other Asian countries, with little or nothing sent across the country to their own smelters. India has become a significant importer of concentrates, motivated in part by booming domestic consumption, and in part by a substantial tariff on refined imports. Not surprisingly, Chile is by far the biggest exporter of concentrates (as it is also of refined metal), accounting for over 40% (1.780 million t) of all exports in 2000. However, Chile’s pre-eminence in the concentrate exports is relatively recent; in 1988 with concentrate exports of only 224000 t it ranked behind Canada and on a level with Papua New Guinea, and did not reach its pre-eminent position until the 1990s, which saw the opening of major expansion of Escondida, La Candelaria, Collahuasi, and Los Pelambres (the last not until 1999) all without smelters, and all, it is worth noting, with Japanese participation. Indeed, at least in the case of Escondida, development was dependent on Japanese finance given against a long term sales contract covering most of the mine’s initial concentrate production. The next largest exporting country is Indonesia which shipped over 0.8 million t of copper in concentrate in 2000. In 1999 the country’s mine output was raised by the start-up of the Batu Hijau mine (again, part Japanese owned) which should reach 245000 t per annum in due course. However, offsetting Batu Hijau’s start-up in 1999 was the opening of the 200000 t Gresik smelter, owned 75% by Mitsubishi and 25% by Freeport which will reduce Indonesia’s concentrate exports accordingly, although it should be noted that it is, technically, a custom smelter free to buy concentrates anywhere. Canada is the next largest exporter, shipping 480000 t on the west coast in 2000, but also importing 211000 t on the east, while the reopening of the Port Kembla smelter and the expansion of the Mount Isa plant restricted Australian exports to 255000 t in spite of expanding mine production. Papua New Guinea, Argentina, Portugal and Mongolia are also significant exporters, the last, Chile, being China’s principal

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suppliers, while Portugal ships mainly to other European countries. The USA also exported 175000 t, but imported 217000 t.

8.2.1 Custom concentrate terms Nearly all concentrates that are not smelted by the company that mined them are sold outright to the custom smelter, although in a small number of cases they may be ‘toll smelted’; this means that instead of being sold, the concentrates are smelted and refined for a fee, and the recoverable metal content is returned to the mining company. Most concentrates that are custom smelted are sold directly by the mine to the smelter, although a significant proportion is sold through merchants who act as middlemen between producer and consumer. In the copper market, as in the market for countless other commodities, products and services, these merchants perform the important function of absorbing the fluctuations in both supply and demand by buying up uncommitted marginal production and supplying feed requirements which a smelter has not been able to cover from its direct suppliers. They also specialise in dealing in markets with which a mine may experience difficulties; an example has been China, to whom some suppliers have refused to sell except through a merchant. Previously, before the rapprochement between Eastern and Western countries, some merchants specialised in doing business with the East on behalf of companies who had not the experience (or perhaps inclination) to do so. Most concentrates are sold under medium or long term contracts, some of the latter are of ten years’ or more duration; such contracts normally specify the agreed annual tonnage of concentrates, sometimes providing for variations, either at one side’s option or by mutual agreement. The contract will also state the typical chemical specification of the material, with likely ranges, and shipping arrangements including maximum dimensions of vessels if the ore is to be shipped, delivery basis (free on board, cost insurance, freight, ex ship, etc.), passing of title and risk, weighing and assaying procedures, force majeure and other necessary administrative conditions to be found in any commercial sales contract for exports. The crucial parts of the contract, however, once the tonnage and duration have been settled, are the clauses governing the valuation of the copper content and the charges. Outside the United States the copper content of the exported concentrates (and copper in all forms) is normally valued on the basis of the

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LME settlement price (see Chapter 9) daily quotations, averaged over an agreed period. Since it will be some time before the smelter will have treated the concentrates and is able to sell the resulting metal, the period is often the month after month of arrival, or later, and its timing can be crucial. The so-called ‘payable’ copper content is the agreed content resulting from chemical analysis of samples less a deduction of around 3% of the analysed content, in recognition of the fact that during the smelting process a small proportion of the copper content will inevitably be lost. From the agreed value of the contained copper will usually be deducted two principal charges: the ‘smelting charge’ which is levied per tonne of concentrates shipped and the ‘refining charge’ which is levied per pound weight of payable copper content. These charges in theory reflect the costs of the two processes of smelting and refining, although in practice they are negotiated as a package without the actual costs being apportioned. Occasionally the two charges are combined in a single charge per pound weight of copper. A long term contract is also likely to contain a ‘price sharing’ provision whereby if the LME price rises above, or perhaps falls below, a certain level – say 90 cents per pound weight (c/lb) a part of the difference (typically 10%) will go to the smelter; in this way the smelter participates, for both good and ill, in the price level. Precious metals contents, if above a minimum level (say 1g per tonne for gold and 30 g per tonne for silver) are also payable on the basis of market quotations over an agreed pricing period, after a deduction for processing losses and a refining charge. Certain metals and other elements are deleterious and may carry a financial penalty, if over a certain level; those most often penalised are arsenic, antimony, bismuth, zinc, lead and mercury. Finally, the contract will provide for payment; a provisional one, anytime from loading to after discharge, and a final payment or adjustment when all the details, including the applicable price quotations, are available, probably months after arrival at the smelter. All the terms that can affect the sales revenue may, at times, be subject to renegotiation, although often it is only the treatment and refining charges which are changed. Although in the past terms in long term contracts were sometimes fixed for relatively long periods, today it is normal for a contract to provide for renegotiation of terms at least every two years; a system whereby every year the terms for half the tonnage are renegotiated for two years is popular. Medium term contracts, for a duration of say three to six years

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Structure of the market

will also provide for renegotiation. This recognises the fact that the concentrate market is relatively volatile and fluctuates independently of, and sometimes in the opposite direction to, the market for copper metal. This is logical, since the two markets have largely separate dynamics. The concentrate market moves in accordance with the balance between the supply of concentrates by the mines and the demand by smelters, while the metal market ultimately is governed by the balance between the availability of refined metal and the needs of the fabricators. Sometimes a glut in the metal market will result in a shortage in the concentrate market, since low metal prices may force enough mine closures to leave custom concentrates in short supply, resulting in smelters offering lower charges to attract feed; this happened in the mid-1980s. Likewise, when the custom smelter capacity has not kept pace with expanding concentrate production, as in the early 1990s, a socalled ‘smelter bottleneck’ occurs, which bolsters the metal price by delaying the conversion of concentrates into metal. Although enough contracts are renegotiated throughout the year to indicate the market level and spot contracts (single shipments or limited tonnages for early shipment) may be signed at any time, the renegotiation of most concentrate terms worldwide, referred to (not always accurately) as the mating season, starts in October. Inevitably, the crucial negotiations are with the Japanese smelters, who, when they are joint buyers in major long term contracts, are known as the Japanese Smelters Pool. Thus, their ability to present a united front to the mines, who are independent companies negotiating separately, has inevitably been to their advantage, although at least in the past they have tended to avoid forcing excessively high charges on mines for fear of the mines turning to smelting themselves or, in times of very low copper prices, closing. If the influence of the Japanese smelters in the concentrate market is great, so are their needs. In any event, over the years the custom concentrate terms have, on average, kept to a level that has made selling their production as concentrates an attractive proposition to a series of new mines. Although details of all terms agreed are not published, it is estimated that since about 1990 the combined treatment and refining charges in contracts between mines and smelters have averaged somewhere in the region of 25 c/lb payable copper in constant terms, although they have fluctuated above 30 c/lb and below 20 c/lb. Spot terms with merchants have tended to fluctuate more widely, although their average may not be very different.

© Woodhead Publishing Ltd

Chapter 8 / page 15

The international copper industry

8.3 The market for blister and anode The blister and anode market covers the sale of smelter products and the products of the first stage of fire refining to electrolytic refineries. Like the concentrate market, it is a trade in an intermediate product, but it is on a much smaller scale; in 2000 the reported World trade in blister and anode amounted to barely 18% of that in concentrates. Indeed, while the concentrate market has expanded dramatically, the blister market is smaller now than it was in the early 1980s. The main reason for this contraction is the disappearance of exports from Zaire (as it then was), then around 300000 t per year, mainly destined for the Olen refinery in Belgium (a trade which had survived from the days when the country was a Belgian colony). As the Congo’s production disappeared, so did the trade. However, the blister market will always be much smaller than the trade in concentrates because it is much rarer for a smelter to be without an integrated or nearby refinery than for a mine to be without a smelter. In most cases companies wishing to smelt will also wish to refine, since the relatively modest additional investment will give them access to the much larger and more flexible refined metal market, or in some cases provide feed for their own fabricating plants. As can be seen from Table 8.4 the largest exporter in 2000 of blister was, predictably, Chile, shipping to a variety of destinations, followed by Bulgaria, shipping mostly to Belgium. Of the importers, Belgium was the largest, followed by the USA, China and Mexico. Like concentrates, the blister market can move independently from the other copper markets; while supplies depend on the smelters which sell blister, demand depends heavily on the availability of those types of copper scrap which are also refinery feed, since blister and scrap are often interchangeable and so may on occasion compete against each other (although blister is often in demand by refineries because it is of more consistent quality than scrap). Like concentrates, blister is sold under spot or regularly renegotiated contracts. The terms are basically similar to those in a concentrate contract relating to refining; after a very small metal deduction, a refining charge is levied, and also, where applicable, terms are applied for the precious metals content, since they are not recovered until the refining process.

Chapter 8 / page 16

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Structure of the market

Table 8.4 Reported trade in blister and anode copper for 2000 (thousands of tonnes) Exports

Imports

Belgium Finland Italy Spain Other W. Europe Botswana South Africa Japan Turkey Canada USA Mexico Chile Peru Bulgaria China Romania Other countries/ in transit

19 42 10 27 1 24 1 43 4 54 23 22 170 26 146 2 5 165

Austria Belgium France Germany Italy Spain Other W. Europe Japan South Korea Turkey Other Asia Canada Mexico USA Brazil Australia China

5 215 6 32 3 18 1 19 48 10 5 11 82 185 2 17 125

Total

784

Total

784

Source: International Copper Study Group (ICSG), World Metal Statistics (WMS).

8.4 The market in refined copper The largest market segment in the international trade in copper is in refinery production, mainly cathodes. This covers the movement of electrolytic copper in the form of cathodes from refineries to their first stage fabricators or semi-wrought product manufacturers (as they are more properly termed) who melt or alloy the refined copper as the initial step in the process of creating rod, bar, tube, sheet, plate, strip, foil, sections, castings, forgings, powder or shot – the semi-wrought products that are the basic materials from which the copper-containing finished products are ultimately manufactured. (Chapter 4 provides a detailed survey of the various processes involved.) Some cathodes may move initially into warehouses, particularly those registered with free terminal markets, such as the LME or Comex (see below, page 33); but ultimately all will be consumed (see Table 8.5).

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The international copper industry

Table 8.5 Refined copper consumption (thousands of tonnes) 1970 Western Europe Austria Belgium Finland France Germany Greece Italy Netherlands Portugal Spain Sweden Switzerland UK Former Yugoslavia Other

1980

1990

2000

42.6 145.0 34.8 330.7 695.5 11.6 274.0 39.2 12.0 108.2 86.9 48.1 553.7 70.9 10.3

30.8 303.9 57.5 433.4 747.8 24.7 388.0 18.2 18.4 128.0 105.3 13.7 409.2 122.6 7.8

22.0 389.5 87.0 477.6 896.9 53.7 474.8 23.1 24.5 146.1 117.2 3.5 317.2 92.9 9.0

36.0 347.0 115.7 574.0 1309.7 130.0 663.9 49.2 0.1 284.0 186.7 8.0 322.8 25.0 1.0

2463.5

2809.3

3135.0

4053.1

Africa Egypt South Africa Zambia Zimbabwe Other

5.1 35.0 0.3 3.0 4.1

8.8 89.9 2.2 7.5 7.4

4.2 67.6 8.0 13.7 2.5

25.0 76.7 18.0 10.0 1.0

Total

47.5

115.8

96.0

130.7

50.1 820.6 7.5 9.1 13.5

77.2 1158.3 84.0 84.5 33.4 12.0 1.0 0.1 3.6 0.0 4.4 9.8

132.4 1576.5 324.2 264.7 103.1 49.3 40.0 48.5 16.3 49.2 52.2 41.9

265.0 1347.5 861.0 628.2 244.0 70.0 109.6 166.1 35.0 180.0 150.6 16.8

912.8

1468.3

2698.3

4073.8

North America Canada USA Mexico

229.0 1854.3 54.0

208.6 1867.7 117.0

180.6 2150.4 127.2

274.0 3019.4 475.8

Total

2137.3

2193.3

2458.2

3769.2

Total

Asia India Japan South Korea Taiwan Turkey Indonesia Iran Malaysia Philippines Saudi Arabia Thailand Other



Total

Chapter 8 / page 18

12.0

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Structure of the market

Table 8.5 Continued 1970 South America Argentina Brazil Chile Peru Venezuela Other

1980

29.0 69.2 20.6 4.0

1990

2.0

10.8

16.0

48.9 327.6 83.0 40.0 1.2 17.0

Total

124.8

371.3

245.0

517.7

Oceania Australia New Zealand

105.6 0.5

128.4 1.3

120.0 4.7

168.2 6.0

Total

106.1

129.7

124.7

174.2

5792.0

7087.7

8757.2

12718.7

1.2 34.5

7.0 55.0

10.1 32.1

57.0 90.0 23.0 76.0 23.0 985.0

88.6 123.0 22.0 210.8 80.0 1300.0

76.2 130.9 34.0 170.7 24.7 1000.0

0.3 15.0 20.0 1.5



Western World Total Other countries Albania Bulgaria Czech Republic Slovakia German DR Hungary Poland Romania USSR Kazakhstan Russian Federation Uzbekistan Ukraine China North Korea Other





180.0 12.0

52.5 245.9 42.9 19.2



387.2

25.1 128.7 45.2 30.0

2000



512.0 32.5

18.0 247.2 14.7 16.0 180.0 10.0 15.0 1879.2 15.0 17.3

Total

1481.7

2273.6

2 023.2

2 449.2

World Total

7273.7

9361.3

10780.4

15167.9

Source: ICSG, WMS.

The other aspect of this market segment is the trade in refinery shapes – billets, cakes, ingots and ingotbars. These are produced either in casting shops attached to refineries or, as already mentioned, in similar plants operated by the fabricators themselves. Few reliable figures are available specifically for the trade in refinery shapes, but it is relatively small.

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The international copper industry

Reported World exports of refined copper in 2000 amounted to 6.678 million t, 45% of World refinery production (see Table 8.7). The basic reason for this high level of shipment as previously pointed out is that, as with so many commodities, the major areas of consumption are in most cases far from the major areas of production. In part this is due to the different rates at which the different parts of the globe have industrialised; in the year in question, developed countries accounted for 60% of world consumption, but only 42% of refined production. In addition, some developing countries, especially in Asia where demand is growing very fast, have to rely heavily on imports. Of the three major consuming areas, Western Europe, Asia and North America, Western Europe is the biggest importer of metal by some way, in spite of the fact that it produces nearly half of what it consumes, its modest mine production being bolstered by imported concentrates and substantial secondary production (see Table 8.6). Italy, France, Germany and Britain are the biggest importers. The largest external supplier to Western Europe is Chile, followed by Russia, Peru and Kazakhstan. North America is largely supplied by its neighbours Canada and Mexico, with large tonnages also coming from Chile and Peru. In Asia, as previously remarked, Japan is not usually a very major importer of refined copper, having a domestic production exceeded only by Chile and the USA in 2000, and with its consumption still depressed that year, it was a marginal exporter. The biggest importer of metal in Asia by some way is Taiwan, a major consumer without any domestic production. South Korea’s expanded smelter and refinery capacity and the new Gresik complex in Indonesia will considerably increase south east Asia’s refinery output. With a large and fast-growing demand and limited availability of custom concentrates, China’s metal imports (which can fluctuate sharply) are likely to increase in the future. Chile is the principal supplier to Asia, which is hardly surprising in view of the fact that it accounted for nearly 44% of all exports of refined metal (2.55 million t), followed by Russia with 0.641 million t (10%) and Peru with 0.408 million t (6%). In addition to the exporting and importing of refined copper, there is the movement from long-established refineries in consuming regions such as Japan and Western Europe to relatively local customers. In Japan, where vertical integration has proceeded much further than elsewhere, some of the movement is to service fabricators operating within the same conglomerate, for example, those in the highly integrated

Chapter 8 / page 20

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Structure of the market

Table 8.6 Refined copper production, trade and consumption in 2000 (thousands of tonnes) Production Western Europe Austria Belgium Finland France Germany Greece Italy Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Former Yugoslavia Other W. Europe Total

81 423 114

27

26

314 132

26 70 8 329

3 46

39

1922

325

Total

368

© Woodhead Publishing Ltd

573 596 103 603 88

73

29 4 101 227 7

27 6 260 158 156 1437

Net imports

68 159 7

709

Africa Congo Egypt South Africa Zambia Zimbabwe Other

Asia Burma Cyprus India Indonesia Iran Japan Malaysia Oman Philippines Saudi Arabia Singapore South Korea Taiwan Thailand

Net exports

2370

0

30 102 96 166

24 150

24 120 78 21

468

36 347 116 574 1310 130 664 49 0 0 284 187 8 323 25 1 4054 0 25 77 18 10 1

28 200

228

Consumption

392 629 151

131 0 0 265 70 110 1347 166 0 35 180 12 861 628 151

Chapter 8 / page 21

The international copper industry

Table 8.6 Continued Production Turkey Other

Net exports

64

Total

2750

363

North America Canada USA Mexico

551 1794 411

277

Total

2756

277

South America Argentina Brazil Chile Peru Venezuela Other

Net imports

Consumption

117

244 5

1563

4074

962 65

274 3019 476

1027

3769

33 146

49 328 83 40 1 17

179

518

3

168 6

16 185 2668 452

2552 408

3321

2960

Oceania Australia New Zealand

487

323

Total

487

323

3

174

11604

4476

5142

12720

33

21

Total

Western World Total Other countries Bulgaria Czech Republic Slovakia Hungary Poland Romania Kazakhstan Russia Uzbekistan Ukraine China North Korea Other

1371 15 5

1

Total

3209

1296

600

2449

14813

5772

5742

15169

World Total

8 20 486 13 395 816 75

240 1 393 641

571

15 20 2 18 247 15 16 180 10 15 1879 15 17

Source: ICSG, WMS.

Chapter 8 / page 22

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Structure of the market

Table 8.7 Reported trade in refined copper in 2000 (thousands of tonnes) Exports

Imports

Austria Belgium Finland France Germany Norway Spain Sweden United Kingdom Former Yugoslavia Other W. Europe South Africa Zambia Indonesia Japan South Korea Oman Philippines Singapore Canada USA Mexico Brazil Chile Peru Australia Bulgaria Czech Republic Poland Romania Russia Kazakhstan China Other countries

90 199 17 12 94 26 57 12 10 39 4 28 200 135 299 27 24 129 75 289 94 76 14 2552 408 324 21 5 240 13 650 393 116 6

Austria Belgium Finland France Germany Greece Italy Netherlands Spain Sweden Switzerland United Kingdom India Indonesia Japan Malaysia Philippines Saudi Arabia Singapore South Korea Taiwan Thailand Turkey Canada USA Mexico Argentina Brazil New Zealand Czech Republic Hungary Romania Russia China Other countries/ in transit

36 41 10 585 690 104 603 88 31 82 8 339 30 33 203 166 9 79 54 419 629 151 117 12 1056 141 33 160 3 14 20 14 9 687 22

Total

6678

Total

6678

Source: ICSG, WMS.

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Chapter 8 / page 23

The international copper industry

electrical wire and cable industries. However, at present, Japanese refineries, like their European counterparts also sell their cathodes very widely, especially to the south-east Asian area. Cathodes are also a major aspect of the trading operations of the merchant community. As with concentrates, they are prepared to operate in markets that are too complex or risky for producers or consumers to operate in directly. In recent times it has mainly been merchants who have bought substantial quantities of cathodes from Russia and Poland, and sold them on to consumers around the world at prices that undercut the standard producer tariff. They have also been heavily involved in sales to the Chinese and Indian markets.

8.4.1 Refined copper terms Although large tonnages of refined copper are sold on spot or short term contracts covering shipments over a few months, probably most exported metal is sold under annual contracts. These, like those for concentrates, have their ‘mating season’ starting in October, although the behaviour of the participants is rather different, as are the terms. Compared with those for concentrate, refined metal contracts are relatively simple, since outside North America metal-like concentrates are sold on the basis of LME quotations averaged over an agreed period, say the month after arrival, with an agreed premium (sometimes for a higher premium, the buyer will be allowed to opt to price tonnage on the next day’s quotation, up to a certain percentage of the shipment per day). Like smelting and refining charges, this premium fluctuates according to market conditions, although the premium for annual contracts is much more stable than merchant and other spot terms which, dealing as they do with marginal supply and demand, and like their concentrate equivalents, fluctuate more widely. Just as the Japanese are the most powerful single influence in the concentrate market, so the Chileans lead the market for refined metal. Every October Codelco announce their premium for shipments to the main Western European ports for the coming year, and, in due course, report any variations for other destinations, reflecting freight differentials (previously it was ZCCM of Zambia who made the announcement). Generally, the other producers supplying Western Europe follow suit and there is seldom (if ever) much significant variation in the premiums in annual contracts in any given year. While Chile is by far the largest

Chapter 8 / page 24

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Structure of the market

exporter of refined copper, Western Europe is by far the largest importer, its net imports in 2000, and Chile’s exports represented 41 and 44% of global net exports respectively. Europe’s predominance as a destination for exported copper metal is reinforced by its large number of LME warehouses (see Chapter 9, section 9.9) which, especially in times of recession, attract metal that is not immediately needed by consumers, although there are also LME warehouses in the USA and Singapore. In fact, by the end of 2000 the USA and Singapore warehouses had between them attracted nearly two-thirds of all LME stocks; proximity to Chile and the Asian market are important factors in this phenomenon.

8.5 The market in copper and alloy semi-wrought products The copper and alloy semi-wrought market represents the trade whereby semi-wrought products move from wire and cable mills, copper and brass mills and some specialist foundries into the first of a succession of processors and manufacturers from whom the final copper-containing product eventually emerges. The market in semi-wrought (usually, if less accurately, termed semi-fabricated) products is a mature one, in which fierce competition, low margins and high labour and capital costs have resulted in more and more production becoming concentrated into the hands of large groups and multinational corporations. The detailed pattern of World trade in semi-fabricated products (i.e. in sheet, strip, plate, foil, bar, tube, extruded, drawn, cast and forged products, rod and wire) is difficult to establish, as the statistical information, even for production, is far from complete. However, there does appear to be less intercontinental trade than in many of the other market segments. This is because production of semis is generally concentrated near to the customers that are being served, in areas such as Western Europe, the USA and Japan. Another factor that tends to cause semis production to be located close to customers is that the cost of transporting many semis is relatively higher than the cost of moving the same weight of cathode or blister copper. With coiled products such as rod, tubing or strip, a considerable volume of air has literally to be wrapped, protected, even sometimes boxed, to ensure that the material

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arrives undamaged and in pristine condition, and ocean freight rates operate on the basis of volume as well as weight. The trade in semis falls into three categories. First is the movement from the initial fabricator direct to the next processor, manufacturer or assembler. Table 8.8 shows the reported production and net imports and exports of copper and copper alloy semis in 2000. It will be noted that the major importers of concentrates and unwrought copper, Japan and Western Europe, are major exporters of semis. In the case of Europe, much of the exported tonnage from Germany, Belgium and France is absorbed by other European countries, although in 2000 over half a million tonnes net were shipped out of the continent, which, with production of semis standing at over 6 million t, makes Western Europe by far the biggest producing area in the World. The USA’s production of over 4 million t, was on balance absorbed by the home market, which still needed substantial imports, while China, in spite of being the second biggest national producer of semis, was also by far the biggest importer. Most of the trade or movement of semis falls quite naturally into this category because the wide range of sizes, shapes, thicknesses, finishes and detailed specifications called for by the next stages in the production process, makes it mostly a direct trade between semis producers and their consumers. Period contracts are often involved with consignment stocks, with special payment and delivery clauses being negotiated. Where vertical integration has progressed into the finished product end of the copper business (as has occurred widely in the Japanese and to some extent the Western European and US electrical wire and cable industries), semis often move into other parts of the same organisation and therefore are not, strictly speaking, traded. Secondly, there is trading of certain types of semis by merchants (and some producers) as commodities in their own right, both on a local and an international basis. This is particularly true of continuously cast copper rod, the basic raw material for the production of wire and cable, and by far the most important of all the semis, having an annual consumption of probably over 6 million t. The ability to produce this rod in coils of up to 5 t in weight, strapped, protected from tarnishing by a coating of wax and safely strapped in thick shrink-film plastic, has made this an eminently tradable commodity. Moreover the large volume of total demand, allied to the fact that copper rod is generally produced in only two diameters (6 mm and 8 mm), creates a situation that is open for merchants to ply their trade and apply their special skills in developing new

Chapter 8 / page 26

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Structure of the market

Table 8.8 Reported trade in copper and copper alloy semis in 2000 (thousands of tonnes) (NB not all countries’ data are available) Production Net exports Net imports Western Europe Austria Benelux France Germany Greece Italy Portugal Scandinavia Spain Switzerland United Kingdom Other Europe Total Africa South Africa Total

21 484 775 1913 137 1356 377 374 47 494 44 6022

64 243 213 556 115 78 93

1105

47 79 35 109 527

86 86

Asia Japan South Korea Taiwan Thailand Turkey Other Asia Total

2048 1182 1035 N/A 243

273 289 132

4508

750

North America Canada USA Mexico Total

N/A 4082 560 4642

45 45

South America Argentina Brazil Chile Other America Total

N/A 304 57 N/A 361

33 48 3 84

Oceania Australia Total

196 196

98 98

N/A 29 312 N/A 2282 24 2647

9

124

547 13 584

18462

2206

1654

Other countries Czech Republic Hungary Poland Russia China Other Total World Total

67 56 43 110 29 386 415 18

18

24 108 7

Source: ICSG, WMS.

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The international copper industry

outlets, in moving and financing commodities and, if necessary, holding stocks in anticipation of future needs. A proportion of the worldwide production of copper rod is traded in this way, but it is not possible to quantify the amount more precisely from the available statistics. The bulk of production is certainly traded on a direct producer to consumer basis as detailed above. Thirdly, there is the activity of the local stockist who serves the needs of the smaller consumer of semis. The stockist buys in bulk those types of semis that are likely to be in regular demand and holds them until they can be sold in small lots at substantial mark-up. Stockists often provide additional services, such as cutting to size. They will often stock cathodes as well. At present this is the small bits-and-pieces end of the business; however, this category could assume greater commercial importance in future as the process of rationalisation and amalgamation continues to decrease the number of semis producers and increase their individual size and, perhaps, the minimum tonnages they are prepared to sell in one lot.

8.6 The market in copper and alloy scrap and coppercontaining ashes, slags and residues As pointed out in Chapter 3, around one-third of all the copper used derives from secondary material; of the total reported copper scrap consumed in the Western World in 2000 (5.35 million t) 40% was smelter or refinery feed and 60% was direct feed for remelting by fabricators. This implies a massive movement of material and a substantial amount of international trade. It is difficult to quantify precisely the way in which these movements take place because the statistics on scrap recovery and usage are much less extensive than those for refined production (which themselves are not always complete). Many countries, in reporting scrap usage, do not differentiate between the types of scrap (such as process or new scrap and collected or old scrap), or even between copper and other scrap. Some do not include any copper recovered from ashes, slags and residues. However, the lack of comprehensive statistics does not prevent broad generalisations being made about the flow of trade in scrap, following the general categories detailed below. What may be termed new or process scrap is a by-product of the

Chapter 8 / page 28

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Structure of the market

fabricating industries which are mostly centred in the great industrialised areas of the USA, Western Europe and the Far East. It is generally clean, uncontaminated and requires no processing before being melted again in foundries or casting shops. Little is traded, even locally. Most is reused within the fabricating operation that produced it, or returned to the semis manufacturers by their customers. Old or collected scrap comes in many different grades, but all arise from obsolete items such as worn-out machinery, cables, electronic goods, from scrap cars or demolished buildings. Old scrap falls into two distinct categories; pure copper scrap from obsolete cables or heavy industrial plant, such as transformers, turbines or switchgear, and lower grade copper scrap and material made of copper alloys. The first category normally requires no rerefining, but does usually need processing. For example, cables must be stripped of their insulation and grease, sometimes by a burning process, and the resulting wire bundled or pressed into briquettes suitable for feeding into furnaces at brass mills, foundries, ingot makers’ works and casting shops. This processing function is carried out by scrap merchants who sell the bulk of their production (in the sense of it being sorted, graded and processed at their works) to consumers in their area. However, wellestablished grades such as ‘Berry’ (No. 1 burnt copper wire scrap) are widely traded across the World. This code name relates to an internationally recognised specification laid down by the Institute of Scrap Recycling Industries (ISRI) establishing quality criteria for the main grades of scrap used by smelters, refiners and the various other scrap consumers mentioned above. The second category includes many sorts of copper and alloy scrap which will need rerefining and often resmelting to remove impurities and bring the copper content of the metal up to the quality required by consumers. This tends to be passed to primary and secondary smelters and refiners, after being sorted, processed and, where appropriate, bundled by the scrap merchants. The term secondary when used in connection with smelters and refiners means that their main sources of raw material are from scrap and copper-containing ashes, slags and residues. Many primary smelters use a proportion of secondary material to reduce costs but generally only include scrap or residues of a higher quality than the general feed for secondary smelting operations. Some of the old alloy scrap that can be sorted according to its content may go to ingot makers, casting shops or foundries. In this category

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The international copper industry

scrap grades such as ‘Birch’ (No. 2 burnt copper wire scrap), ‘Candy’ (No. 1 heavy copper scrap) and ‘Cliff’ (No. 2 heavy copper scrap) are widely traded internationally as are copper-containing residues (especially if precious metals are also present) and slimes from electrolytic refineries (see Chapter 3). Other traded grades include relay and electronic scrap, copper and brass radiators from automobiles, gunmetal-containing scrap, and mixed lots designated as copper or brass refining material. Relatively little copper-bearing material is actually wasted, not surprisingly considering the price that the purified metal commands. As Table 8.9 shows, the distribution of secondary production is very different from that of primary production; this is hardly surprising, since while the former is determined by nature, the latter largely reflects economic growth, both current and in the past. Generally, secondary refined production is greatest in those areas where demand for copper exceeds primary production and where there is a high generation of old scrap; this usually suggests a fully developed economy. The obvious example is Western Europe, where refined consumption exceeds primary refined production by three million tonnes and where heavy consumption of copper over many years yields plentiful supplies of old scrap. In 2000 Western Europe produced 0.9 million t of secondary refined copper, 42% of the global recorded production. Germany and Belgium are by far the biggest consumers of scrap for their refined production, importing quantities of scrap from neighbouring countries. Elsewhere in the West, not surprisingly the USA, Japan and Canada are the biggest secondary refined producers. In the East, China’s output sometimes exceeds that of the USA, in spite of a very different economic history; China’s demand for copper has risen steeply, far outstripping its mine production, and it has sought to fill the gap as far as possible with scrap (mainly imported) and imported concentrates. With sagging demand for copper and an urgent need for hard currency, Russia has become a major exporter of scrap, largely to Western Europe. The distribution of consumption of direct use scrap is again different, since it reflects current consumption of copper by manufacturers, and also technical factors. On the basis of the available information, which is far from complete, the major consumers are the USA, Japan, Italy and Germany. Merchants play the key role in the specialised business of importing and exporting scrap. They are experts in sorting, grading, segregating and processing scrap as well as already being masters of the necessary

Chapter 8 / page 30

© Woodhead Publishing Ltd

© Woodhead Publishing Ltd 148 0 0 0 43 0 5 5 201

Total

4

Total

Asia Japan India Malaysia Singapore South Korea Taiwan Turkey Other Asia

0 4

900

Total

Africa South Africa Other Africa

81 186 0 472 73 0 34 37 0 3 14 0

Western Europe Austria Benelux France Germany Italy Netherlands Scandinavia Spain Switzerland United Kingdom Former Yugoslavia Other

Tonnage

Chapter 8 / page 31 7

10 0 0 0 9 0 8 3

1

0 1

42

100 44 0 67 100 0 12 12 0 100 31 0

% of total production

Refined production from scrap

768

360

408

33

24 9

1115

20 32 57 234 482 0 57 24 29 132 36 12

Direct use scrap

Table 8.9 Reported world secondary scrap usage in 2000 (thousands of tonnes)

161

77

31

15 38

493

82

45 150

54 46

116

Net exports

304

22

170

80 32

54

53 1

517

27

201 113

62 114

Net imports

Copper and copper alloy scrap

398

88

31 60 34 75

110

59

58 1

1347

90

20 153 203 290 66 132 104 54 62 173

Exports

541

190 32 16 22 204 44 22 11

5

5

1371

8

82 267 87 491 179 78 58 81 17 23

Imports

Structure of the market

Chapter 8 / page 32 0

© Woodhead Publishing Ltd

Source: ICSG, WMS.

2130

704

Total

World Total

0 0 38 307 348 0 0 11

Other countries Czech Republic Hungary Poland Russia China Kazakhstan Ukraine Other

1426

Total

Western World Total

0 0

321

Total

Oceania Australia New Zealand

61 209 35 0 16

Tonnage

14

31

0 0 8 38 25 0 0 18

13

0

0 0

9

13 14 3 0 1

% of total production

Refined production from scrap

Americas Canada United States Mexico Brazil Other Americas

Table 8.9 Continued

3198

3198

1282

66 117

1099

Direct use scrap

1345

245

59 37 55

34 21 20 19

1100

29

29

417

24

342 51

Net exports

898

N/A

898

23

4

19

Net imports

Copper and copper alloy scrap

2759

264

59 37 65

37 21 26 19

2495

36

33 3

655

24

73 486 72

Exports

2204

19

10

6

3

2185

7

4 3

261

92 144 21 4

Imports

The international copper industry

Structure of the market

commercial and pricing skills. It is a difficult trade which most smelters and refiners, and the various producers of scrap are not necessarily in a position to undertake. This segment of the copper trade fulfils a most important function in recycling copper and alloy scrap materials that are essential for the economic operation of the copper industry as a whole. It also makes a major contribution towards the sustainable use of vital but non-renewable resources whose waste products can be environmentally detrimental if dumped. As time goes on and if the technology of copper recovery continues to improve, the percentage of secondary material in total refined production must increase. It is to be hoped that the bureaucratic inanities of the Basel Convention that classes all grades of scrap as waste, will be amended to allow this vital trade in secondary copper materials to flourish at a time when technical innovation is reducing the lifespan of buildings, plant and machinery, as well as power and communication infrastructures. Scrap trading must be expanded, not inhibited, if the proper final stage in the copper production cycle, through the maximum recycling of its waste products, is to be achieved.

8.7 The trade in copper warrants Copper warrant trading arises from the services provided by free terminal markets such as the LME or Comex in New York. A copper warrant is a legally enforceable document giving title to a specific parcel of 25 t of copper, conforming to a standard quality and specification, of a specified registered brand, lying in an official market warehouse in a specified location. Note that at Comex, the Commodity Exchange in New York, a slightly lower specification of copper is traded than in London, in lots of 25 short tons as opposed to the 25 metric tons or tonnes on the LME. Thus all copper transactions on free terminal markets are made in nominal 25 metric or 25 short ton lots. When a LME market purchase, say of 25 tonnes of copper, is due to be delivered (or ‘matures’), the purchaser delivers a cheque for the appropriate amount to his or her broker, and in return receives one warrant of copper. The market rule is that it is in the seller’s option which warrant shall be delivered. Thus the purchaser may need physical copper for a client in Singapore, but receives a warrant for copper lying in Rotterdam. Rather than pay the cost of transporting the metal from

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Rotterdam to Singapore and incurring financing charges as well, the purchaser would ask his or her broker to find a counterparty who will negotiate a swap of warrants – Singapore for Rotterdam. Many brokers, merchants and others using the facilities of the market, will have ‘long positions’ (purchases) maturing on that same day or will be holding and financing warrants (‘having warrants lying in their box’). If there are more Rotterdam than Singapore warrants circulating, they will need to be offered a premium of a certain number of dollars per tonne to induce them to agree to the swap. Thus an active market in the location of warrants is established. In times when demand is strong, premiums for warrants in certain warehouses may soar; in quieter times the required warrants may be obtainable for just a few dollars per tonne. A similar market operates for particular brands of copper in specific locations. However, this aspect of trading may become less prominent in future if advances in refining techniques, and the market authorities’ rigorous monitoring to ensure that the quality of all registered brands is scrupulously maintained, narrowing quality differences between brands and making consumers less likely to prefer some more than others.

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9 International trade in copper

9.1

The early market

9.2

Establishment of the London Metal Exchange

9.3

Development of the LME

9.4

Copper pricing 9.4.1 Copper prices 9.4.2 Terminal market versus producer prices

9.5

Clearing the market

9.6

Hedging

9.7

Options

9.8

Other markets

9.9

LME and Comex warehouses 9.9.1 Globalisation of LME warehouses 9.9.2 Warehouse charges

9.10 LME procedures and requirements 9.10.1 Warrants 9.10.2 Operation of the LME 9.11 Future of the LME

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Having considered various general aspects and particular segments of the international market in copper and its alloys, it is now time to look at the pricing mechanisms through which it operates. This brings us to the theory and practice of free terminal markets and in particular the services that the LME renders to the copper trade throughout the World.

9.1 The early market Like other metals and substances whose use is widespread but whose production is limited to a relatively small number of places, there must have been a trade in copper ever since it was first used. Early trade, no doubt, was usually by barter, in which precious stones and other metals such as gold, silver (and even lead for small quantities) came to be used in addition to other commodities of practical use to the producers. Some 2000 years before the European Union’s attempt to introduce a common currency to Western Europe, the Romans achieved it (admittedly by sometimes harsher methods than those permitted to the EU) and for a time copper would have traded in the Imperial currency before the Dark Ages descended on Europe, trade was disrupted and consumption of the metal declined. By the late eighteenth and early nineteenth centuries when consumption of copper started to rise strongly as the Industrial Revolution gathered pace, Britain, the cradle of this revolution, was also the biggest producer in the World of both tin and copper. She was also the World’s premier trading nation providing some two-thirds of a World production of the latter estimated at 12000 t. She achieved this position before industrialisation started, and it was not for nothing that she was nicknamed (possibly by Napoleon) ‘a nation of shopkeepers’. However, industrialisation greatly increased the demand for metals, which previously had been restricted to meeting the simple demands of an economy with virtually no engines except for mine pumps, hardly any factories in the modern sense, and horse transport. From the end of the eighteenth century steam engines and manufacturing machinery proliferated, by the 1820s railways started to spread across the country, metal ships driven by steam slowly displaced wooden sailing ships, and telegraphs connected by copper wires spanned countries and then oceans across the World. While Britain was to lose her position as the

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largest producer of copper, first to Chile and then to the United States (and tin to the Malay States), for many years she remained the World’s largest consumer of both. As Britain was for a time both the World’s greatest trading nation and its principal manufacturer, it is hardly surprising that important commodity markets should develop in London, not least because there were already banking, insurance and shipping facilities there. The Jerusalem Coffee House was the first location at which merchants dealing internationally with ores and metals are known to have met regularly, but by the middle of the nineteenth century they were meeting daily at 4 pm in a part of the Royal Exchange. The merchants dealt in a variety of metal products, brass, tin and copper ingots, lead sheet etc., usually ex-vessel or in-warehouse. The trade was usually in warrants or other documents of title, and often with assay certificates. Apparently even in the mid-nineteenth century, metals could usually be relied on to be of reasonably uniform quality, and although the standards looked for in those days were much less exact than they are now, descriptions such as ‘good merchantable quality’ were widely used and meant what they said. In 1869 the metal merchants moved to the Lombard Exchange and Newsroom in Lombard Street which had been set up as a meeting place for brokers and merchants of several commodities, with some rudimentary services, but within a few years some of its more important users decided to set up a separate exchange for metals only. This was not only because the Lombard Exchange was becoming excessively crowded; it was also becoming clear that the London market for metals was acquiring an international reputation, owing to the volume of business transacted there, which was being widely reported. It became increasingly obvious to many of its users that it should be made clear that these prices were arrived at fairly and openly, and were not unduly influenced by individual participants. Both the Baltic and the Liverpool Cotton Exchanges had shown that a formally constituted market, properly run, was preferable to an informal and uncontrolled group, a fact that was not lost on some metal traders.

9.2 Establishment of the London Metal Exchange At the end of 1876 a number of leading operators in the market combined to set up the London Metal Exchange company, with an initial

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capital of £1500 and with its own rooms in Lombard Court, and the merchants and brokers first met under it in January 1877. Telegraph information was provided, and telephone facilities, without which no modern broker could imagine operating, were installed in 1880. The Exchange’s first secretary was appointed at the then reasonably generous salary of £150 per annum. Members paid a modest subscription and the separation of the membership into ‘London’ (trading) and ‘country’ foretold the division into ‘ring’ and ‘non-ring’ categories that was to come. However, although the market itself and its trading times (12.30 pm to 1.15 pm and 4.00 pm to 4.30 pm) had been established, the actual trading was still largely unregulated. In addition to copper and tin, which were the most important metals, pig iron was still traded, while the types and grades of lead and zinc (then called spelter) were too varied to allow any degree of regulation. After a brief period of friction between the traders and the board, which included the temporary abandonment of ring trading, by 1881 a committee of market users had been formed, and before long the LME as we know it now in most essentials had been established. Soon trading was restricted to non-ferrous metals (initially copper, tin, lead and zinc) and the quality of the metal traded was standardised, so that traders could concentrate entirely on the price and delivery date. In due course prices came to be based on metal of known and uniform quality for prompt delivery lying in approved warehouses, with delivery on future dates also being traded. Perhaps most important of all, ‘official’ rings and prices were established. Instead of trading all the metals concurrently, trading in each one for exactly five minutes at a time was adopted, of which the second batch of rings (now starting at 12.30 pm) came to be called the ‘official’ rings; the prompt and three months price levels at which the metal was being traded when the bell rang to end the second ring were published as the day’s ‘official prices’, as they are today (although now they have been joined by later quotations). The three months price, equating roughly with the time a sailing ship might take to sail between Chile or the Malay States and London, enabled metal to be sold for future delivery, and was of great use to those wishing to establish the price of metal some time before its delivery; although the time at sea has now shrunk to a few weeks, the three months price quotation has remained. For many years, the home of the Exchange remained too; in 1882 it moved into new premises in Whittington Avenue, where it was to remain for nearly a century until lack of space forced it to seek a new

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home in Plantation House, and in 1995 it moved again to its present premises in Leadenhall Street.

9.3 Development of the LME From the early 1880s the LME prospered. Its location helped; it was in by far the most important commercial centre in the World, surrounded by other necessary financial and commercial facilities, and boosted by a high domestic demand for the metals. While Britain’s production of tin was soon to decline, and its copper production had already almost disappeared, its consumption of both, as well as lead and in due course zinc, remained huge by the standards of the late nineteenth century. Britain also continued to be the World’s premier trading nation with the largest merchant fleet, a position retained from the days before the Industrial Revolution started in the previous century. During the twentieth century Britain’s position both as a manufacturing and trading nation declined, but the city of London has continued to thrive as a centre of financial and commercial services. The LME has also continued to thrive, if anything boosted by the fact that, with Britain’s decline in the order of consumption of the major base metals (it was only the 12th largest consumer of copper in 2000), it has been relatively less influenced by the domestic market and thus more able to reflect international conditions. Another strength of the market, although one not readily apparent to the ordinary visitor, who will be bemused by the incomprehensible shouts and gestures of the operatives, is its essential simplicity. Sellers shouting the hoped-for price and potential buyers shouting back their bids is a scene that has been repeated in countless markets for literally thousands of years, and may be found in many markets, both formal and informal, to this day. Unlike other markets, the LME is aided by the limit to the rings of five minutes, and trading is concentrated, particularly just before the close of the official ring, because many traders need to buy or sell as close to the official price as possible. Trading continues in all metals in the ring after the official markets for about 15 minutes in the so-called ‘kerb’ market, dating from the days when trading continued on the pavement outside the market. ‘Inter office’ trading continues outside the rings throughout working hours but in spite of the market having every form of electronic communication to aid it, the ancient form of ‘open outcry’ market, which the rings represent, still provides possibly

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the most efficient means of establishing daily prices through the concentrated but highly visible trading of a substantial tonnage of metal in one place and at one time. This is another, and some would argue most important, function of the LME. As well as disposing of any physical surplus and providing a means of forward selling or buying, the market provides universally recognised reference prices for the whole base metals industry. In addition to the turnover on the LME itself, there is a much larger tonnage of metal, including that contained in semi-manufactured goods, refined cathode, semi-refined anode and metal contained in concentrate, which each day is sold and valued on the basis of the day’s LME quotation, but without any concomitant sale taking place on the LME itself. Apart from the United States, where the Comex prices generally (but by no means invariably) apply, the LME quotations are used almost universally for valuing exports and imports and many countries’ domestic prices of copper are also based on them. Although there have been times when the price of copper (and other metals) has been imposed by producers (or in time of war, by governments), in copper at least, apart from in the USA, producer prices have not proved to be durable, and even in America they have tended to follow the market price closely. The market has also provided a means of locking in a price by producers, whereby by selling forward a tonnage on the LME and then buying it back by degrees, as the physical metal is produced and sold, a predetermined price can be achieved. This has been done increasingly by a number of producers, who have sold forward a large proportion of the future production, especially when relatively high costs of production have encouraged them to take advantage of prices that are high enough to show a profit. However, at the time of writing, the copper price has fallen to levels where such operations are unlikely. Occasionally the opposite, forward buying, may be practised, whereby a producer will buy forward a substantial tonnage in the expectation that the price will rise and they will be able to sell the tonnage at a profit, or a consumer may wish to guarantee future supplies at a low price. Selling forward will be done in the expectation that the market price will subsequently fall, or sometimes primarily to ensure that the mine remains profitable for a time, and may be regarded as an insurance against the price falling below the mine’s costs of production, rather than a gamble. Both operations are often undertaken by speculators, large and small, who have no concern with production or consumption

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or indeed copper itself, but will buy or sell anything if the price level suggests it. Irrespective of their motives, speculators are of service to the market, because they improve its liquidity, and if successful, that is, buying when the price is too low and selling when it is too high, they moderate its fluctuations.

9.4 Copper pricing It is, of course, quite possible to set down how the price of copper or any other comparable commodity, should be arrived at in theory. The price should be sufficient to maintain enough economic production to meet the demands of consumers and to ensure the development of additional output both to provide for the growth in demand and for the progressive exhaustion of existing mine capacity. Producers, it may be said, require an adequate price to cover costs and avoid untimely closure, with sufficient incentive to risk the vast sums which opening a mine and refining capacity require. Needless to say, in practice, it is very different. First, consumption, which ultimately governs production, is neither steady nor necessarily able to be forecasted accurately, even in the short term. It is subject both to technical developments which may affect the rate of consumption, and to fluctuations in economic activity, which will vary from one part of the World to another, but which at times may demonstrate a sufficiently widespread cohesion to merit the terms boom or recession. Recession may be very severe and last a number of years; that heralded by the second oil shock in 1979 cast a pall over the industry in the early 1980s. In addition to the widespread recession engendered by oil prices and other exterior factors, its effects were reinforced by other factors that were peculiar to copper. Miniaturisation and substitution hit copper consumption to the extent that in the early and mid-1980s many came to believe that, with the best will in the World, copper consumption would not increase by more than 1% per annum on average, and some foresaw an overall decline in the use of the metal. Even when consumption recovered in the mid-1980s, the price took considerably longer to do likewise because of the huge stocks that had built up during the lean years. One reasonably consistent characteristic of the copper price is that it is unlikely to recover until visible stocks have declined to a manageable level.

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Secondly, production is notoriously bad at keeping in step with demand. This is hardly surprising. Consumption is very difficult to forecast accurately and owing to slow and sometimes inaccurate statistics, even establishing historical levels of consumption has not always been straightforward. As always, it is easier to know the direction you should be going in if you know where you are starting from. Another obvious problem is that increasing production takes time. A new mine is unlikely to take much less than two years to construct, sometimes much more, and even expanding an existing mine will probably take at least a year. To this must be added the time taken in prospecting and for a new mine probably collecting participants and raising finance. Given the inevitable delays in raising production which the process of building or even expanding a mine entails, it is seldom possible to co-ordinate the coming on stream of new production with the changes in the balance of supply and demand, except by luck. High cost mines close when there is a production surplus and the price sinks low. If the slump is serious and lengthy some will not reopen, as their workforces will have scattered and equipment may have been moved elsewhere. More important, a period of low prices is likely to discourage investment in new mine capacity, because it is notoriously difficult to raise finance when there is a recession with falling prices and rising stocks, even though, given the inevitable delay, it may be the ideal time to start building a new mine. In practice, the World’s copper industry is quite likely to find itself with fast increasing production at the time when consumption is flagging and stocks rising and a shortage made much worse by lack of prior investment in mines when consumption recovers. However, the market has demonstrated a reluctance to avoid overproduction. Owners are naturally reluctant to close their mines, even in the face of growing surpluses and even when they are producing at a loss. This reluctance is perfectly understandable when the cost of closing a mine, especially in countries such as the USA and Canada, and the subsequent problems of reopening are taken into account. In addition, mines may have sold much of the output forward at higher prices, so that for a time they are insulated from the current price level. Some mines, such as those in Zambia, are so essential to their country’s supply of foreign exchange that they are likely to continue producing irrespective of the price or their profitability. While a buoyant demand, which was seen in the years following the Second World War and which has also been experienced more recently, will soak up excess production without

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too long a delay, the late 1970s and most of the 1980s, when recession following the oil price rises coincided with a lower intensity of use through substitution and miniaturisation, were a reminder of the difficulties that can assail a commodity market.

9.4.1 Copper prices In the days before prices were widely published by the LME and Comex, they were normally established by negotiation between producer and consumer. In the later eighteenth century prices in Britain seem to have fluctuated usually between £70 and £100/t, and rose towards £200/t during the Napoleonic wars when military demands and increasing use of machinery coincided with lack of imports. However, major (for those days) production in Chile and the USA brought the price down progressively and it fell to only £43/t in 1886. In the following year Pierre Secretan of La Société des Metaux started the first of what was to prove to be a series of attempts to control the price of copper which, after the foundation of the LME, has been worldwide in its application. The ‘Secretan corner’ pushed the price up to £105/t before rising tonnages attracted by the high price finally loosened his control of the market in 1889 and the price fell back sharply. This was but the first of a series of attempts to control the price of copper, but all were to fail eventually and largely for the same reason; while price may be controlled, for a time and up to a point, supplies to the market cannot. Suppliers are too diverse and the attractions of high prices too great to allow the degree of discipline that is required to control a market in the longer term. Only a cartel incorporating nearly all suppliers to the market, both primary and secondary, could impose such unity of action. In copper, with its great numbers of suppliers, this is most unlikely. Thus, at the beginning of the twentieth century the Amalgamated Copper Company, the owners of the Montana mine in the USA among others, brought the price up to over £70/t, but the exercise failed as other mines raised their production. After the First World War, which not surprisingly brought the copper price above £130/t, it fell back to less than half this, and another cartel of Chilean, American, Belgian, Congolese, German and Spanish producers, representing about 95% of World primary production, was formed in 1926. Although they achieved an average price of £84/t in 1929, once again the higher

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price drew in copper from other sources, including much secondary, and the price collapsed. Yet another cartel, the International Copper Cartel founded in 1935, followed much the same path, and during the Second World War the LME was closed and the British government held the price at £61/t. By the time the market reopened the post-war boom and the Korean War had brought the price up to £250/t. The following years saw considerable price fluctuations until in 1961 when a cartel comprising the central African producers (then much more important than they are today) and Chile combined to fix the price, initially at £234/t. This was an unusual cartel in that it succeeded in fixing its price too low. In spite of readjusting its price upwards, the temptation to take on the higher prices being obtained by other producers proved to be too great and by 1966 these countries had returned to the LME. Since then there have been no more attempts to set up producer prices for exports, but squeezes on the market have continued. Most of these have been of little importance but one operator who had a significant effect on the market in the mid-1990s was Yasuo Hamanaka, a dealer in Sumitomo Corporation, who, it seems, pushed up the cash price by large long positions and options. Once again, in due course market forces overcame market manipulation and heavy speculative selling brought the market down by over one-quarter in six days.

9.4.2 Terminal market versus producer prices Market manipulation, at least on such a large scale, is damaging, because for a time the market price is obviously distorted (the support of the tin market by the International Tin Council over a number of years is probably the most serious example among the metals). While the LME price, like any reasonably free market price, cannot pretend to give the metal its appropriate value at any given date (indeed, the current appropriate value cannot possibly be established accurately without a crystal ball) nevertheless, if not seriously interfered with, it will at least track the fortunes of the metal reasonably well over a period and, it may be argued, certainly better than any obvious alternative system of pricing. An example of this is the American system of producer prices which used to follow distinctly different paths to that of the market price, in their case the Comex price; now, however, they follow the market price

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much more closely. In other countries, such as South Africa, where a producer price exists, it is normally based on the LME price. Some would argue that a producer price is preferable to a terminal market price because the latter is arrived at largely by chance, swayed by interests which may be separate from those of the industry and sometimes reflecting heavy buying or selling for hedging or speculative purposes. In the past, as has just been described, the market has on occasions been gripped by strong speculative influences which for a time have driven it to levels well above those it would have achieved otherwise. On the other hand, the alternative, at least for copper, has not proved to be particularly satisfactory. As suggested before, it is almost impossible to fix a producer price that in the longer term is satisfactory both for the producer and the consumer. The circumstances of the industry are continuously changing, although such changes are by no means always apparent at the time; consumption rises at a widely fluctuating rate and sometimes actually falls; the average cost of production is constantly changing; and production regularly exceeds consumption to the point where mines have to be closed. Finally, which producers are to decide the producer price? Different producers need different price levels to cover their costs and while in theory everyone likes high prices, lower cost producers can live with lower prices and still be profitable and may be concerned that the possibility of high price levels may encourage both excessive mine development and substitution by users. In an industry where producers are usually separate from consumers, it is almost impossible to imagine a price level being established that would regularly please both sides of the industry and in any event agreeing on a price that would be acceptable to all producers would be hard enough, if not impossible. Given these problems the need for a free daily universally recognised reference price for exported copper of all forms and a basis for domestic prices is clear. Although it has received (and sometimes deserved) its fair share of criticism, nevertheless since very soon after its inception the LME has been recognised as the most important price basis and so became by far the most widely used. In addition, although its name is the London Metal Exchange, it is not simply a local market. The LME is recognised as being a global rather than a national market, and, unlike Comex, it is not unduly influenced by conditions in its host country. This is particularly so as over the years Britain has become

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progressively less important as a copper-consuming country, while it virtually ceased primary production over a century ago. Although the LME is by no means perfect, producers are happy enough to have one universally recognised price and to be spared the complications and arguments that the existence of more than one potential price basis would entail. As it is, the LME accounts for around 95% of global exchange business in non-ferrous metals and although there are respected national markets, particularly Comex in the US, there are at present no rivals for its international role.

9.5 Clearing the market The LME is somewhat unusual among commodity markets in that it is not cash cleared; that is to say, when a forward purchase or sale on the market shows a book loss or profit owing to price movement, the buyer or seller is not immediately called upon to pay the amount of the loss, nor do they receive any profit made until the due date. Comex, on the other hand, makes or requires such payments on a daily basis. The London Clearing House (LCH) which operates the LME’s clearing system requires bank guarantees from brokers who are clearing members, who in turn may look for bank guarantees from individuals or very small or unknown clients, but these are relatively rare; the LME is essentially a market for companies – mining, processing, manufacturing or investing – which are considered to be credit worthy. A credit level is likely to be agreed with the client before trading on his or her behalf begins. In most cases this will be sufficient to cover the client’s forward positions unless there is a substantial change in the price level while they are outstanding, in which case the broker will call for a margin to reduce their book loss. The LME’s clearing system is operated by the LCH on an offsetting basis, so that positions showing a loss can be offset by those showing a profit. The benefit of this system for a trade user is that the exchange can be used for hedging purchases or sales, which is an operation intended to avoid loss rather than to make a profit, without requiring the ready availability of substantial sums to cover margin calls in the case of adverse price movements. This system has done much over the years to encourage the use of the exchange by the copper industry.

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9.6 Hedging One of the most important uses of the LME is hedging, basically enabling the buyer to lock in the price at which they have bought the metal. While the primary producer need not lock in the sales price, unless the market price is particularly attractive or their financiers or owners require it, a smelter, refiner, or fabricator, who are essentially processors, almost invariably want to lock the purchase and sales prices together, so that they do not run the risk of the profit on the processing of the metal being eroded (or totally consumed) because the LME price has changed in the interval, probably of several months, between their buying the metal and selling the product. Although such companies sometimes deliberately leave their intake, or part of it, unhedged in the expectation that by the time they sell the processed metal the price will have risen above the level at which they bought it, this is essentially a gamble; these companies are processors and should normally expect to make an adequate profit from their charges for processing, rather than rely on price movement. Nearly all operations on the LME, apart from buying or selling metal for cash, involve the differential in price between the cash and the forward prices, named the ‘contango’ if the forward price is the higher and the ‘backwardation’ if lower (there is, to the author’s knowledge, no full explanation for these rather outlandish terms). Normally, copper is in contango in recognition of the cost of holding physical copper – warehouse rent, interest and insurance – for the period involved; the purchaser may either buy copper and hold it for say three months bearing these costs, or buy forward and pay the premium over the cash price. The full contango will not go beyond these costs. The backwardation, on the other hand, can go to any height, at least in theory. It emerges usually when there is, or there appears to be, a shortage of physical metal or there is a continuing purchase pressure on nearby dates. However, a backwardation usually contains the seeds of its own decay, because it encourages those owning otherwise uncommitted refined copper cathodes to place them on warrant in LME warehouses and to lend them to the market at a profit – selling at the higher cash price and repurchasing at the lower forward one. Since there is invariably a differential between the cash and forward prices, the process of hedging will inevitably involve either a cost or a gain, but except in the rare cases of an extreme backwardation, any loss

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from hedging is marginal in relation to the potential loss from adverse price movement. Meanwhile, in the more usual contango market, traders often try to negotiate early pricing periods in their contracts in order to benefit from as long a period of contango as possible, the hedge being closed out when the concentrates or metal are sold on to the buyer. While the processor of the metal, the smelter, refiner or fabricator, can protect themselves from price change by hedging, the end user cannot. Although copper usually represents a relatively small part of the cost of a finished article, such as a car, or even a house, and the manufacturer can quote a price that reflects the cost of copper components in what they are selling, nevertheless price level and price stability are of concern, especially if copper is an important element of the manufacture. Copper represents only a small fraction of the cost of a computer, but a considerable element in an electric power system. Manufacturers are only in favour of copper as long as it is cheaper than any suitable alternative and seriously unstable price is one aspect of the metal which may encourage them to consider alternatives.

9.7 Options Another major use of the market is the granting of options. In their simplest (and oldest) form these allow the grantee or holder of the option, who will have paid a premium or fee to the grantor, the right to sell or buy up to an agreed tonnage at an agreed price (the strike price) throughout the duration of the option. A ‘call’ option allows the holder to call for (i.e. buy) at the option price and a ‘put’ option allows the holder similarly to sell. The cost of the option premium will depend on the relationship of the ‘strike’ price to the current market price; the further the strike price of a put option is above the current price and that of a call option is below it, the cheaper it will be. The more volatile the market price, the higher the premium. Duration will also affect the premium; the shorter it is the cheaper. This simple type of option is of use to producers who fear a decline in the price and by buying put options can guarantee a minimum price for the tonnage so protected, while still benefiting from any higher price that may ensue (less, of course, the options premium). A more refined version of this facility for producers is the so-called Asian put option, which came into prominence in the

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1990s. These options are usually put in place for a number of months and provide for strike prices to be average prices for each month covered. If the average market price for the month is above the strike price that month, the option is abandoned, but if the price is below then it is automatically exercised and the holder of the option receives the difference. The granter of the option is, in effect, being paid a premium by the producer for guaranteeing a certain minimum price for the metal and the higher the strike price the greater the premium. Asian call options are also granted on occasion to end users who need to protect themselves from higher prices. A problem with Asian options emerged in the mid-1990s when a sharp fall in price was accelerated by heavy hedge selling by granters of the options, thus driving the price even further downward. Some financial houses which had taken the risk of these operations lost heavily, leading to major changes in the terms offered to those seeking such options.

9.8 Other markets The only other market for base metals whose prices are quoted widely is Nymex’s Comex division in New York. Founded in 1934 it remains the most important terminal market in the USA, and since the US market for copper is nearly 40% bigger than the next biggest national market (China) this is no mean function. However, Comex is largely restricted to the US domestic market and does not figure much in the international trade in copper in its various forms; the truly international market is the LME. Comex resembles the LME in several ways; it has registered warehouses and published stocks, registered brands, future quotations, etc. and it and the LME are to a degree bound together by arbitrage; if the LME and Comex quotations diverge beyond a certain point it becomes worthwhile buying in one and selling and sometimes actually shipping metal to the other. With LME registered warehouses in the USA, trade in this direction has become easier. Comex also has the added attraction from the speculators’ point of view of paying favourable margins on a daily basis, rather than making the speculator wait until the due date to reap any reward (although the speculator also has to pay if the price goes against him or her). However, it is this very characteristic which makes Comex much less attractive to the trade hedgers, who sell or buy forward

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in order to protect their purchase or sale from adverse price movement and are not necessarily expecting to make any profit out of the operation (although if they are initially selling forward on a contango or buying forward on a backwardation they may do so). The last thing such a trade hedger wants is to pay margin calls on a daily basis, even if they may receive payment instead of paying on occasion. Basically, the LME, while attracting its fair share of speculators (or ‘investors’ to use a more polite term), particularly more recently, is still very largely a market geared to the copper industry rather than the speculator. Of markets in other countries, China has the Shanghai non-ferrous metals market which has an impressive turnover in copper, reflecting the country’s huge and fast-growing consumption and large production; however, in the absence of a proper foreign exchange market this is restricted to being a domestic market.

9.9 LME and Comex warehouses Both the terminal markets have authorised warehouses where metal sold or to be sold on the exchanges is stored. The warehouses, although authorised by the exchanges, are not owned by them. The ordinary companies that do own the warehouses charge fees for storing metal that are largely their own concern, though monitored by the Exchange. The Comex warehouses are all in the USA, although the possibility of establishing them elsewhere has been considered. For nearly a century the LME’s warehouses were all located in Britain, as had been natural enough during the nineteenth and early twentieth centuries when the country was still the greatest consumer of metals in the World, with a huge manufacturing industry and, at least in the case of copper, little or no domestic primary production surviving. As a great importer, Britain also acted as the metals entrepôt for Europe. Much of the copper and other metals destined ultimately for the continent would be landed and first stored in Britain. However, by the 1960s the World, and Britain’s place in it, had changed, its predominance among the industrialised nations had gone and the argument for establishing LME warehouses in other nations had become overwhelming. In 1963 the LME authorised some continental warehouses to store copper and the other metals followed. The development, although some might say tardy, was

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completely logical, for in spite of Britain’s past role as the leading industrial country in the World, the LME had also established itself as an international market, providing both prices, hedging and physical metal to many countries. Progress in establishing LME warehouses on the continent was initially slow, but in due course their numbers increased as they became an essential part of Europe’s trade in metals. In general, the establishment of LME warehouses followed the principle that their first purpose was to be primarily a facility for the consumers of metals rather than a convenience for the producers, although the latter is also certainly true. Most refined metal, at least in the case of copper, is shipped directly from the refinery to the fabricator and under normal circumstances a refinery or merchant would only place metal on warrant in an LME warehouse if a consuming customer could not be found for it. Metal on warrant in an LME warehouse can always be sold on the exchange or lent to the market, by being sold on the LME and the tonnage being simultaneously repurchased for a forward date. In the latter case, if there is a contango, the forward price at which the metal is repurchased will be higher, the difference between the two prices being the contango, which will not significantly exceed the cost of holding the physical metal – warehouse rent and insurance – because were it to be much greater the original owners would prefer to finance it themselves. Thus, although the LME originally functioned (and still does) as a source of supply for consumers when necessary, it is also a repository of unwanted metal in times of surplus, where the metal can be stored safely, is readily available when wanted and can be lent so that finance for it can be provided by some other party if necessary. LME warehouses have also been a valuable instrument in moderating the effect of physical shortages and attempts to corner or squeeze the copper market; shortages or squeezes, by putting pressure on the cash position, are likely to induce a backwardation, which invariably attracts any spare metal into LME warehouses where it can be lent to the market at advantageous conditions for the owner (selling at the higher cash price and repurchasing at the lower forward price), while helping to moderate the price.

9.9.1 Globalisation of LME warehouses In the late twentieth century LME warehouses were established in countries far from Western Europe. This caused considerable debate;

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some countries were initially less than enthusiastic, concerned for existing markets and trading arrangements, and in the case of Japan, high tariffs. However, in due course warehouses were established in Singapore, in Japan (aluminium only) and South Korea. From 1991 warehouses were also established in the USA (but for copper not until 1994), but here serious problems developed. As has been stated before, the general policy of the LME was to establish LME warehouses near consumers rather than producers, on the principle that they are a facility primarily for the former. In the USA, while the major consumers lie in the east and mid-west, the producers are mainly in the west – Utah, Arizona and New Mexico. As LME warehouses were established in Los Angeles and Long Beach, reasonably near the mines but remote from major consumers, and with the LME price naturally at a premium to Comex, American producers were faced with the irresistible temptation to deliver their copper into these conveniently sited warehouses rather than to more distant consumers. The result was greatly inflated warehouse stocks in a part of the country that is relatively remote from major centres of consumption. Metal was also taken from Comex warehouses, put into LME ones and sold at the higher LME price. By the middle of 1999, with total LME stocks climbing towards 800000 t, nearly half were in Long Beach and Los Angeles warehouses. At last the LME decided to limit the tonnage at these locations and gradually it declined. In 2001, with an apparently substantial World production surplus, stocks in USA warehouses have again risen dramatically, but now New Orleans and Baltimore lead the way. This was a salutary lesson in the purpose of an exchange warehouse; ultimately, it should serve the needs of the consumer before those of the producer and it should not become an attractive alternative to shipping to the consumer.

9.9.2 Warehouse charges LME warehouses are not owned by the LME, which has no direct control over their charges. Not surprisingly, the warehouse owners, who fix their own charges for receiving metal, storing it and releasing it, are concerned to keep their warehouses as full as possible, but this perfectly natural ambition has, at times, led to difficulties. Two developments in particular have tended to restrict the freedom of movement of metal from warehouses, which is essential if they are to provide ready

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additional supplies for consumers when needed. Warehousemen, under pressure from merchants, have assisted with the costs of moving metal into warehouses while increasing the cost of moving it out, thus making the holders of warrants less willing to move the metal out of the warehouse. In addition, in some cases metal has been taken into a warehouse on advantageous terms in return for the metal owner’s agreement not to move it out of the warehouse for an agreed period. Neither of these are welcome developments. While the reasonable costs and profit margin of the warehouse owner must, of course, be met, these should not be at the cost of the free movement of the metal, and just as it should be able to be put on warrant when it is not needed for consumption, so it should be able to be taken off warrant when it is.

9.10 9.10.1

LME procedures and requirements Warrants

Only recognised or listed brands of electrolytic cathode copper can now be put on LME warrant. To achieve listing, the producer must undertake to maintain its quality to the standard required by the exchange for Copper Grade A, which currently is BSEN 1978:1998 (cathode grade designation Cu-CATH-1). Its quality must be assessed by LME approved consumers and assayers who will report on its quality and suitability. A warrant represents 25 t (2% more or less) of cathodes of the same brand; each parcel of cathodes, now not exceeding 4 t, must show the brand on the strapping. The warrants, a document of title issued by the warehouse, will show the brand and exact weight. In 1999 SWORD, a secure electronic transfer system for LME warrants, was introduced. All warrants have a barcode and SWORD, as a central database, holds all the details of each warrant. This system enables possession of warrants to be transferred instantaneously, rather than lengthily by hand. While the seller is free to deliver warrants covering metal in whichever LME warehouse they choose, in practice negotiation between buyer and seller, at an agreed premium, will ensure an acceptable brand at an acceptable warehouse can be assured if the metal is to be taken off warrant and shipped to fabricators.

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9.10.2

Operation of the LME

Buying, selling, lending, borrowing and dealing in options continues throughout the day between offices, although for copper always in lots of 25 t. The rings occur four times a day, with the metals being traded in varying orders. The first ring starts at 11.40 am, with the official rings starting with copper at 12.30 pm; it is its trading level at the end of this official ring that establishes the day’s official prices – cash, three months, 15 months and 27 months. The cash price is two working days hence. The afternoon rings start at 3.10 pm. After the rings, between about 1.15 and 1.30 pm and again between 4.35 and 5.00 pm, the kerbs are held at which all the metals are traded together in the ring; these provide opportunities for traders to complete their business. Metal can be traded for every market day up to three months ahead; thereafter there is one due date per week, on Wednesday (in practice the third Wednesday in the month is chosen) until the sixth month, and every third Wednesday in the month thereafter.

9.11

Future of the LME

In general, the LME’s future looks promising, if for no other reason than that producer prices of metals generally no longer represent a threat to the LME price, and its quotations, especially for metal being exported or imported, are universally recognised. This is particularly true of copper, an original LME metal, whose attempts at alternative international pricing have long since (and it is to be hoped, permanently) ceased. Technology is allowing ever more efficient means of trading from separate offices and some doubt the long term need for the rings (as they have for many years). There may, indeed, come a time when this indubitably archaic means of trading is no longer needed, but like any open market it still provides an immediate means of communication which cannot easily be achieved when all the participants are at a distance from each other and the ring can, at times, encompass an atmosphere which will not be replicated by electronics. It may be around for some time yet.

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Index admiralty brasses, 7/9–10 aerospace industry, 7/17 Africa, 8/4–5 Afton, 2/15 air conditioners, 6/9, 7/9, 7/14 Airbus, 7/17 alloys (see also individual alloys), 4/10, 5/1, 5/13–21, 6/2–5, 7/17, 7/19 aluminium, 2/1, 5/14, 5/18–20, 6/4, 6/8, 7/4, 7/7–11, 7/14, 7/16–17, 7/19 Amalgamated Copper Company, 9/8 Amarillo refinery, 2/14 American Society for Testing and Materials (ASTM), 3/23, 4/5, 5/6 ammunition, 5/15 7/18 Andes, 2/7 Anglo American, 2/20 annealing, 4/7–8 Anqing, 2/17 antimony, 2/6, 3/7 Antofagasta Holdings, 2/14 architecture, 5/18 Argentina, 2/10, 8/12 Arizona, 2/7 arsenic, 2/6, 5/6, 5/9, 6/5, 6/12–13 Asarco, 2/14, 2/18 ashes, 3/29, 8/28–33 Asia, 8/4–5, 8/8, 8/20 Asian options, 9/13–14 Atacama Desert, 2/12 Australia, 2/7, 2/12, 2/16–17 automobiles, 7/15–16 Axicell MFTF-B, 7/12 backwardation, 9/12–13, 9/16 Bagdad, 2/14 Baltic Exchange, 9/2 bar, 8/17, 8/25 Batu Hijau, 8/12 bearings, 7/7 Belgium, 8/16, 8/26, 8/30 Bell (mine), 2/15 bells, 1/5, 5/16, 6/10–11, 7/18 ‘Berry’ (No 1 burnt copper wire scrap), 8/29 beryllium, 5/19, 6/5, 6/7, 6/8, 6/9, 7/7–8, 7/16

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BHP, 2/14 billets, 8/19 Bingham Canyon, 2/13–14, 3/8–9 bismuth, 3/7, 5/9, 6/5 blister copper, 3/12, 5/4, 8/16 Bolsover, Thomas, 1/5 Bougainville, 2/6, 2/11 brass, 1/3, 1/5, 3/25–26, 4/9, 5/2, 5/14–16, 6/6, 6/8, 7/5, 7/7–10, 7/12–19, 8/29 Brazil, 8/12 brazing, 4/10, 5/11 British Columbia, 8/8 British Standard Specification (BSS), 5/5 brokers, 9/2 bronze, 3/25, 4/12, 5/14, 5/16–18, 6/6, 6/8, 7/7–12, 7/14, 7/16, 7/19 Bronze Age, 1/1–4 Bulgaria, 8/16 bulk carriers, 8/8 busbar, 7/4 by-products, 3/6–7 cable, 3/26, 7/1, 7/3–4, 8/26 cadmium, 5/6, 6/4, 6/8, 7/1, 7/15 cake, 8/19 Canada, 2/7, 2/13, 2/15–17, 8/2, 8/4–5, 8/8, 8/10–12, 8/20, 8/30, 9/7 ‘candy’ (no. 1 heavy copper scrap), 8/30 cannon, 6/10 Caraiba smelter, 8/12 cartridges, 7/18 casting, 4/2–4, 6/10, 8/17 catenary wire, 7/1 ceramic, 5/21 Cerro Colorado, 2/21 Cerro Verde, 2/19 chalcocite, 2/5 Chalcolithic Period, 1/1 chalcopyrites, 2/5 Chambishi, 2/20 chemical engineering, 7/6, 7/10–12 Chile, 2/7–8, 2/11–14, 3/9, 3/21, 8/5, 8/8, 8/10, 8/12, 8/16, 8/20, 8/24–25, 9/3, 9/8–9 China, 2/11, 2/17–18, 8/1, 8/4–5, 8/10–12, 8/16, 8/20, 8/26, 8/30, 9/14 Chino, 2/14

Index / page i

Index

chromium, 5/6, 5/13, 5/19, 6/4, 6/7, 6/9–10, 6/12, 7/4, 7/8, 7/16 Chuquicamata, 2/13, 3/8 clearing, 9/11 ‘cliff’ (no. 2 copper scrap), 8/30 cobalt, 2/4, 5/13–14, 6/5 Cobriza, 2/19 Codelco, 2/13–14, 8/24 coinage, 6/10, 7/17–18 Collahuasi, 2/14, 8/6, 8/12 Colossus of Rhodes, 1/4 Comex, 3/21, 8/17, 8/33, 9/5, 9/9–11, 9/14–15 Cominco, 2/15 computers, 7/4 concentrate contracts, 8/13 Concorde, 5/20, 7/17 condensers, 5/18, 7/9, 7/13 Congo, Democratic Republic of, 2/8, 2/11–12, 2/21 construction, 7/1–2, 7/5, 7/8, 7/13–14 contango, 9/12–13 Continental, 2/15 converting, 3/12 copper anode, 3/12, 5/5, 5/12, 8/16, 9/5 appearance, 6/5–6 cathode, 3/14–18, 3/21–22, 5/3, 5/6, 8/2, 8/28, 9/5, 9/18 concentrates, 3/10, 8/6–16, 9/5 concentrate terms, 8/13–15 consumption, 7/1, 8/2–5, 8/17–24, 9/6–7, 9/10 cryogenic qualities, 6/9–10 early production, 1/2 mines, 2/7–21 ores, 2/1–6 physical properties, 6/6–11 plating, 1/5 price, 3/5, 9/6–11 production, 2/8–21, 9/7, 9/10 refined, 3/10, 3/14–18, 8/17–25 salts, 6/11, 7/19 sulphate, 6/12, 7/19 Copper Belt, 2/8 Copper Development Association (CDA), 5/5–6, 7/6, 7/16 covellite, 2/5 Coventry Cathedral, 7/4 Cuajone, 2/18–19 cunicos, 5/18 cunife, 5/18

Index / page ii

cuprite, 2/5 cupro-nickel, 5/18, 7/8–9, 7/16–17 cuprum, 1/4 custom smelting, 8/8–13 custom smelting terms, 8/13 cyprium aes, 1/4 Cyprus, 1/4 Cyprus Amax, 2/14 Daye smelter, 2/17 ‘de-bottlenecking’, 8/9 deposits, 2/3–6 Deutsche Normanausschuss (DNA), 5/6 Dexing, 2/17 DIN specifications, 5/6 domestic applications, 7/8 domestic goods, 7/14–15 downpipes, 7/14 drawing, 4/9 drilling, 3/3 dryers, 7/14 dump leaching, 3/18 dynamos, 7/3 El Abra, 2/14 El Paso smelter, 2/14 El Teniente, 3/7 electric car, 7/16 electric fires, 7/14 electrical conductivity, 1/6–7, 5/19, 6/1–2 Electricity, 1/6–7, 7/2–6 electrolysis, 4/11, 6/10 electrolyte, 7/20 electronics, 7/5 EPNS (electroplated nickel silver), 5/18, 7/15 Ernest Henry, 2/16 Ertsberg/Grasberg, 2/15, 8/6 Escondida mine, 2/14, 3/3, 8/6, 8/12 ETP (electrolytic tough pitch) copper, 5/3, 5/9, 6/10 European Union, 9/1 evaporators, 7/13 extrusion, 4/6, 4/9 fabricators, 4/1–12, 7/1, 7/6, 8/17, 8/19 Falconbridge, 2/14, 2/16 fibre optics, 7/4 finance, 3/5–6 Finland, 8/8, 8/11 First Quantum, 2/20 foil, 4/1, 8/17, 8/25

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Index

forging, 4/6, 8/17 forward market, 9/4–6 ‘Fourdrinier’ wire screens, 7/11 France, 8/20, 8/26 Freeport, 2/15, 8/6, 8/12 freight, 8/8 Fujimoro, 2/18 fungicides, 3/24 Furukawa, 2/17 Garfield smelter and refinery, 2/14 Gecamines, 2/21 General Agreement on Trade and Tariffs (GATT), 8/10 general engineering, 7/6–9 generators, 7/3 Germany, 8/11, 8/20, 8/26, 8/30 Gibraltar, 2/15 Glencore, 2/20 Gold, 1/1, 1/3, 2/4, 2/6, 3/6, 5/20, 6/5, 7/5, 9/1 Goldstream, 2/15 Goonumbla, 8/16 Graphite, 4/12 Great Britain, 8/20, 9/1–2, 9/4, 9/15 Gresik, 8/6, 8/12, 8/20 Grupo Mexico, 2/18 Guixi smelter refinery, 2/17 gunmetal, 5/14, 5/17, 7/9–11, 7/13 guns, 1/5 gutters, 7/14 Hamanaka, Yasuo, 9/9 heat exchangers, 7/13 heating, 7/1, 7/13 hedging, 9/11–13 Heyden smelter, 2/14 Highland Valley, 2/15 Hijau, 2/15 Horne smelter, 2/16 hot water cylinders, 7/13 Hudson Bay, 2/16 Huludao refinery, 2/18 Hurley smelter, 2/14 hydraulic pressing, 4/6 hydrochloric acid, 7/10 hydrofluoric acid, 7/10 hydrometallurgy, 3/10, 3/18–21 IACS (international annealed copper specification), 5/11 INCO, 3/13

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India, 8/4, 8/9 Indonesia, 2/10, 2/15, 8/4, 8/10, 8/12, 8/20 Industrial Revolution, 1/5, 9/1 ingots, 8/19, 8/29 Institute of Scrap Recycling Industries (ISRI), 8/29 International Copper Cartel, 9/9 International Copper Study Group (ICSG), 3/14 International Tin Council, 9/9 Iran, 2/7 iron, 2/1, 2/4, 3/11, 5/4–5, 5/20, 6/4, 6/8 Iron Age, 1/1 Iscor, 2/21 Island, 2/15 Italy, 8/20, 8/30 Jackling, Daniel C, 3/9 Japan, 2/7, 2/11, 8/2, 8/4–5, 8/8–12, 8/20, 8/24–26, 8/30 Japanese Smelters Pool, 8/15 Jerusalem Coffee House, 9/2 JET (Joint European Torus), 7/12 Jiangxi Copper Co., 2/17–18 Kamoto, 2/21 Kazakhstan, 8/20 Kerb market, 9/4 Kidd Creek, 2/16 Kirovgrad smelter, 2/20 klystrons, 6/9, 7/6 Konkola division, 2/20 Krasnouralsk smelter, 2/20 Kyshtym refinery, 2/20 La Candelaria, 8/12 La Oroya smelter & refinery, 2/19 La Société des Métaux, 9/8 Lawrence Livermore National Laboratory, 7/12 leaching, 3/18–21, 7/19 lead, 2/4, 3/7, 3/26, 5/6, 5/9, 5/15–17, 6/3, 6/8, 7/4, 7/7, 8/17, 9/1–2, 9/4 Leadenhall St., 9/4 Legionella, 6/12, 7/14 licences, 8/5–6 Liverpool Cotton Exchange, 9/2 LME Warehouses, 8/25, 8/33–34, 9/3, 9/15–18 Lombard Exchange, 9/2 London Clearing House (LCH), 9/11

Index / page iii

Index

London Metal Exchange (LME), 3/21, 8/9–10, 8/14, 8/33–34, 9/2–6, 9/8–18 Los Pelambres, 8/6, 8/12, 8/14 Magma, 2/14 magnesium, 5/6, 5/20 magnetic levitation, 7/15 Malay States, 9/2, 9/3 manganese, 5/19–20, 6/5, 7/13–14 marine biofouling, 6/12 marine engineering (see also ships), 5/18, 7/6, 7/9–10 Marmon Group, 2/19 Mednogorsk smelter, 2/20 merchants, 8/13, 8/30–31, 9/2–3 Mexico, 2/10, 8/2, 8/16, 8/20 Miami smelter, 2/14 microchips, 6/10, 7/5 Minorco, 2/14 Mitsubishi, 3/13, 8/12 Mitsui, 2/14 Molybdenum, 2/6, 3/7 Monchegorsk refinery, 2/20 monel, 7/9 Mongolia, 2/11, 8/12 Montana, 9/8 Morenci, 2/14 MRT, 2/21 Mt Gordon (Gunpowder), 2/16 Mt Isa, 2/16–17, 3/7, 3/13, 8/12 Mufulira division, 2/20 musical instruments, 6/11, 7/19 Nadezhdinsky smelter, 2/20 Napoleon, 9/1 Nchanga division, 2/20 Neves Corvo, 3/7 New York, 9/14 Newmont, 2/15 nickel, 3/7, 3/25, 5/2, 5/13–14, 5/20, 6/3, 6/10, 7/6, 7/9–13 nickel silver, 5/18, 6/8, 6/12, 7/5, 7/8, 7/14–15 Nippon, 2/14, 8/11 Nkana, 2/20 Noranda, 2/16 Norilsk, 2/19–20 North America, 8/2, 8/5, 8/20 Norway, 8/11 Nymex, 9/14

Index / page iv

Oceania, 8/5 OFHC (oxygen-free high conductivity), 4/11, 5/4, 6/10, 7/5–6, 7/12 Ok Tedi, 2/7 Olympic Dam, 2/16–17, 3/7, 8/7 Onsan, 8/11 open pit, 3/8 options, 9/13–14 origins of copper, 2/1–6 Osborne Copper, 2/17 Outokumpu, 3/13 oxide ores, 2/5–6, 3/18 oxygen, 5/2–5, 5/9–13, 6/4, 7/5 Pacific, 2/7, 8/5 Palabora, 2/21 Pantheon, 1/4 Papua New Guinea, 2/6–7, 2/11, 8/5, 8/10, 8/12 Pasar smelter, 8/12 PCB (painted circuit boards), 6/10, 7/5 Pechenganickel smelter, 2/20 Peru, 2/7, 2/10, 2/18, 8/5, 8/10, 8/20 pewter, 7/14 Phelps Dodge, 2/14, 2/18 Philippines, 2/7, 2/11, 8/4, 8/10, 8/12 phosphorus, 5/9–10, 5/12–13, 5/16–17, 6/4, 6/10, 7/5–7, 7/9–10, 7/13–14 piping, 7/9–10 Plantation House, 9/4 plastic, 6/10 plate, 8/25 platinum group metals, 3/6 Poland, 2/11, 8/5 Porphyry, 2/3–4, 2/8, 2/11 Port Kembla smelter, 2/17, 8/12 Portugal, 2/21, 3/7, 8/11–12 powder, 4/1, 4/11–12 Praine, Sir Ronald, 3/3 precious metal terms, 8/14 producer price, 9/9 propellers, 6/11, 7/9 pumps, 7/11, 7/13 pyrometallurgy, 3/10 Pyshma refinery, 2/20 quenching, 6/7–8 radiators, 3/27, 6/9, 7/9, 7/14, 7/16 radio, 7/4, 7/14, 7/16 railways, 7/15–16, 9/1

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Index

refined copper terms, 8/24–25 refinery shapes, 5/3, 5/5, 8/19 refining charge, 8/14 refrigerators, 7/14 residues, 3/27, 3/29, 8/28–33 ‘rings’ (LME), 9/3–4 Rio Algom, 2/15 Rio Tinto, 1/4, 2/14, 2/15 Robinson, 2/15 Rocky Mountains, 2/7 rod, 4/2, 4/4–5, 8/17, 8/26, 8/28 rolling, 4/7–8 Roman Empire, 1/4, 9/1 roofing, 3/24, 7/14 Rotterdam, 8/33–34 Royal Exchange, 9/2 RTB-Bor, 2/21 Russia, 2/8, 2/19–20, 8/4–5, 8/20, 8/30 Sacaton, 2/8 San Manuel smelter and refinery, 2/15 scrap, 3/24–29, 4/2, 4/9, 6/11, 7/19, 8/1, 8/16, 8/28–33 secondary metal – see scrap Secretan, Pierre, 9/8 sections, 8/17 semi-conductors, 7/6 semi-wrought products (semis), 8/25–28 Severonikel smelter, 2/20 Shanghai metals market, 9/15 Shanghai refinery, 2/17 shapes, 3/15, 3/21 sheet, 4/1, 4/8, 5/15, 6/6, 7/11–12, 8/17, 8/25 Sheffield plate, 7/14 shells, 7/18 ships, 7/16–17, 8/1 shot, 3/25, 4/1, 4/12, 7/19, 8/17 Sierrita, 2/14 silicon, 5/19, 6/4, 6/8, 7/9–10 silver, 1/3, 2/4, 2/6, 3/6, 5/3–4, 5/6, 5/9, 5/11–14, 5/20–21, 6/4, 6/8–9, 7/4–5, 9/1 Similco, 2/15 Singapore, 8/25, 8/33–34 slag, 3/27, 8/28–33 slimes, 3/17, 3/27, 5/4 smelters, 3/10–14, 8/6, 8/11, 9/12 smelting charge, 8/14 solar heating, 7/13 solder, 3/26, 4/10–11, 5/20, 6/9

© Woodhead Publishing Ltd

Solomon, 1/4 solvent extraction-electrowinning (SXEW), 2/15, 3/20–21, 5/7, 8/2, 8/9 South Africa, 2/21, 8/2, 9/10 South America, 8/2, 8/5 South Korea, 8/4, 8/9–11, 8/20 Spain, 2/21, 8/9, 8/11 SPCC, 2/18–19 stamping, 4/9 Star Mountains, 2/7 steam engines, 9/1 steel, 3/26, 5/20, 6/8, 6/10, 7/4, 7/9–10 Sterlite, 2/17 stockists, 8/28 Stone Age, 1/1 strip, 4/1, 4/5, 4/7–8, 5/15, 8/17, 8/25 Sudbury, 3/7 sulphide ores, 2/5, 3/10 sulphur, 3/11–12, 3/14, 4/10, 5/4–6, 5/13, 5/19, 6/4, 6/8 sulphuric acid, 3/14, 7/10, 7/19 Sumerians, 1/3 Sumitomo Corp., 2/15, 2/18, 9/9 superconductors, 5/21, 6/9, 7/12–13 superior, 2/8 Sweden, 8/11 SWORD, 9/18 Taiwan, 8/20 tariffs, 8/9 telegraphy, 7/4, 9/1, 9/3 telephones, 7/4–5, 9/3 television, 7/4 tellurium, 4/10, 5/6, 5/9, 5/13, 5/19, 6/4, 6/8 thermal conductivity, 6/1–2 Timmins smelter and refinery, 2/16 Timna, 1/2 tin, 2/4, 5/6, 5/14–17, 6/3, 6/8, 7/7–8, 7/11, 9/2–4, 9/9 Tintaya, 2/19 titanium, 5/13, 6/8 Tongling non-ferrous, 2/17–18 Toquepala, 2/18–19 tramways, 7/15 transformers, 7/3 transport, 7/15–17 trolley-buses, 7/15 tube, 4/1, 4/5–9, 6/9, 7/13–14, 8/17, 8/25 tungsten, 2/4, 7/5 turbines, 7/3

Index / page v

Index

Turkey, 2/7, 8/4 turning, 4/10 Twin Buttes, 2/8 Tyrone, 2/14 underground mines, 3/7–8 uranium, 3/7 USA, 2/7, 2/13–15, 2/17, 3/21, 8/2, 8/11–13, 8/20, 8/25–26, 8/30, 9/5, 9/7–8, 9/14 USSR, 2/11 Veliki Krivelj, 2/21 verdigris, 6/6, 6/8, 7/14 wall cladding, 7/14 warrants, 8/33–34, 9/2, 9/12, 9/16, 9/18 washing machines, 7/14 welding, 4/11 Western Europe, 8/1, 8/5, 8/10, 8/20, 8/24–26, 8/30

Index / page vi

Western Metal, 2/16 Whittington Avenue, 9/3 wire, 3/25–26, 7/3, 7/5, 7/13, 7/15–16, 7/17, 8/25–26 wire rod, 4/1 works of art, 7/18 Xinzing refinery, 2/18 Yangtze river, 2/17 Yugoslavia (former), 2/21, 8/11 Yunnan refinery, 2/18 Zaire (now Congo), 2/8, 8/10, 8/16 Zambia, 2/8, 2/10–11, 2/18, 2/20–21, 3/2, 8/10, 8/24, 9/7 ZCCM, 2/20, 8/24 zinc, 1/3, 2/4, 3/25, 5/1, 5/4, 5/6, 5/13–17, 6/3, 6/8, 6/10, 7/7, 7/15, 7/17–18, 9/3–4 zirconium, 5/6, 5/13, 5/19, 6/5, 6/7, 6/8

© Woodhead Publishing Ltd

Appendices: World’s major copper mines and plants

Appendix 1 Mines and owners Appendix 2 Smelters and owners Appendix 3 Refineries and owners

© Woodhead Publishing Ltd

Appendix 1 Mines and owners Area

Mine operator/ owners

Source

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

Botswana Consolidated Various

Concs.

15

Concs.

7

22

Iscor/Gecamines Gen. des Carrieres/ Gecamines

Concs. Concs.

35 25

60

Morocco Guemassa

BRPM/ONA

Concs.

7

7

Namibla Kombat Otjihase

Ongopolo Ongopolo

Concs. Concs.

10 15

25

Ind. Development Corp. of SA Ltd. Metorex Rio Tinto Various Various

Concs.

12

Concs. Concs. Concs. Concs.

15 110 29 25

Metorex

Concs.

12

Anglo American/ICC Mopani Copper Mines/ZCCM Mopani Copper Mines/ZCCM Anglo American/ZCCM Anglo American/ZCCM Anglo American/ZCCM Mopani Copper Mines

Concs. Concs.

60 40

Concs.

50

Concs. Concs SX-EW Concs.

150 85 70 50

Anglo-American Various

Concs. SX-EW

1 12

530

Various Various

SX-EW Concs.

9 4

13

Africa Botswana Selebi-Phikwe Other mines Congo Kamoto Kolwezi

South Africa Foskor Nigramoep Palabora Platinum mines Small mines Zambia Chibuluma West Konkola 1 & 3 Mindola Mufulira Nchanga Chingola Nchanga TLP Nkana South & Central Nampundwe Small mines Zimbabwe Small mines Small mines Total Africa

© Woodhead Publishing Ltd

190

847

Appendices / page 1

Appendices

Appendix 1 – Continued Area

Mine operator/ owners

Source

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

Ivanhoe/Mining Enterprise No. 1

SX-EW

30

Hindustan Copper

Concs.

12

Hindustan Copper Various

Concs. Concs.

23 6

Newmont/Sumitomo/ Pikaufu Indah Freeport/Rio Tinto

Concs.

282

Concs.

725

National Iranian Copper Co. National Iranian Copper Co.

Concs.

158

SX-EW

15

173

Benguet Philex Mining Mariculum Mining

Concs. Concs. Concs.

2 22 25

49

Arabian Shield

Concs.

9

9

Murgul (Black Sea Copper) Inmet Mining Various

Concs.

25

Concs. Concs.

35 12

Asia Burma Monywa India Khetri/Kolihan/ Chandmari Malanjkhand Other mines Indonesia Batu Hijau Grasberg/ Ertsbarg Iran Sar Cheshmeh/ Birjand Sar Cheshmeh Philippines Lepanto Santo Tomas II Sipalay/Negros Occidental Saudi Arabia Al Masane Turkey Cakmakkaya Cayeli Other mines Total Asia

30

41

1007

72 1381

North and Central America Canada Highland Valley Huckleberry

Highland Valley Copper Imperial Metals/ Japanese consortium

Appendices / page 2

Concs.

190

Concs.

37

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 1 – Continued Area

Mine operator/ owners

Source

Kemess South Kidd Creek Les Mines Selbaie Louvicourt

Northgate Falconbridge Billiton

Concs. Concs. Concs.

30 55 11

Aur Res./Novicourt/ Teck Boliden Westmin Falconbridge

Concs.

52

Concs. Concs.

12 46

Inco Hudson Bay

Concs. Concs.

114 49

Various

Concs.

48

Phelps Dodge Phelps Dodge Kennecott (Rio Tinto) Phelps Dodge Phelps Dodge Montana Res./ Grupo Mexico Phelps Dodge BHP Grupo Mexico

Concs. SX-EW Concs.

110 10 310

Concs. SX-EW Concs.

90 55 50

SX-EW SX-EW Concs.

50 12 70

Concs.

50

SX-EW

340

Concs. SX-EW Concs. SX-EW SX-EW SX-EW SX-EW Concs. SX-EW

100 47 102 18 19 23 75 13 15

Myra Falls Sudbury Area Mines Inco Mines Trout Lake/Flin Flon Small mines USA Bagdad Bagdad Bingham Canyon Chino Chino Continental East Cyprus Miami Miami Leach Mission Complex Morenci Morenci Ray Ray Sierrita Sierrita Silver Bell Tonopah Tyrone Leach Small mines Small mines

Phelps Dodge/ Sumitomo Phelps Dodge/ Sumitomo Grupo Mexico Grupo Mexico Phelps Dodge Phelps Dodge Grupo Mexico Equatorial Mining Phelps Dodge Various Various

© Woodhead Publishing Ltd

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

644

1559

Appendices / page 3

Appendices

Appendix 1 – Continued Area

Mexico Cananea Cananea La Caridad La Caridad San Martin Small mines

Mine operator/ owners

Source

Estimated annual capacity (thousand tonnes)

Grupo Mexico Grupo Mexico Mexicana de Cobre Mexicana de Cobre Industria Minera Mexico Various

Concs. SX-EW Concs. SX-EW Concs.

120 77 170 25 20

Concs.

19

Total North and Central America

Total (thousand tonnes)

431 2634

South America Argentina Bajo el Alumbrera

MIM/North/ Rio Algom

Concs.

178

178

Brazil Jaguarari

Caraiba

Concs.

50

50

Aur Res./CMP/ Enami Codelco Phelps Dodge/ Sumitomo Rio Algom Codelco Codelco Minorco/Falconbridge/ Mitsui/Nippon Minorco/Falconbridge/ Mitsui/ Nippon Codelco/Phelps Dodge Barrick Cia. Min. Disputada de Las Condes Cia. Min. Disputada de Las Condes Codelco Codelco Antofagasta Hldgs. /AMP

SX-EW

22

Concs. Concs.

260 230

SX-EW Concs. SX-EW Concs.

125 503 141 390

SX-EW

58

SX-EW Concs. Concs.

220 15 70

SX-EW

8

Concs. SX-EW SX-EW

350 4 45

Chile Andacollo Andina Candelaria Cerro Colorado Chuquicamata Chuquicamata Collahuasi Collahuasi El Abra El Indio El Soldado El Soldado El Teniente El Teniente El Tesoro

Appendices / page 4

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 1 – Continued Area

Mine operator/ owners

Source

Estimated annual capacity (thousand tonnes)

Escondida

BHP/Rio Tinto/Japan Escondida BHP/Rio Tinto/Japan Escondida Milpo Falconbridge/Noranda Cia. Min. Disputada de Las Condes Cia. Min. Disputada de Las Condes Antofagasta Hldgs./ Nippon/Mitsubishi Mantos Blancos (Minorco) Anglo-American Anglo-American Antofagasta Hldgs.

Concs.

750

SX-EW

145

SX-EW SX-EW Concs.

13 60 180

SX-EW

12

Concs.

370

SX-EW

60

Concs. SX-EW SX-EW SX-EW

45 60 51 75

SX-EW Concs. SX-EW Concs.

250 70 25 16

SX-EW

8

Zaldivar Zaldivar Small mines

Codelco Codelco Codelco Soc. Punta del Cobre Soc. Punta del Cobre Placer Dome Placer Dome Enami and others

Concs. SX-EW Concs.

4 130 85

4850

Colombia Small mines

Various

Concs.

4

4

Billiton, Teck, Noranda, Mitsubishi Phelps Dodge Doe Run SPCC (Grupo Mexico/ Marmon/PD)

Concs.

150

SX-EW Concs. Concs.

75 30 182

Escondida Ivan/Zar Lomas Bayas Los Bronces Los Bronces Los Pelambres Manta Verde Mantos Blancos Mantos Blancos Michilla Quebrada Blanca Radomiro Tomic Salvador Salvador San Jose San Jose

Peru Antamina Cerro Verde I Cobriza Cuajone

© Woodhead Publishing Ltd

Total (thousand tonnes)

Appendices / page 5

Appendices

Appendix 1 – Continued Area

Mine operator/ owners

Source

Cuajone

SPCC (Grupo Mexico/ Marmon/PD) BHP

SX-EW

5

Concs.

80

SPCC (Grupo Mexico/ Marmon/PD) SPCC (Grupo Mexico/ Marmon/PD) Various

Concs.

110

SX-EW

62

Concs.

27

Tintaya/ Chabucas Toquepala Toquepala Small mines

Estimated annual capacity (thousand tonnes)

Total South America

Total (thousand tonnes)

721 5803

Western Europe Cyprus Skouriotissa

Oxiana Res./ Hellenic

SX-EW

10

10

Inmet

Concs.

11

11

Somincor Beralt Tin & Wolfram

Concs. Concs.

84 1

85

Spain Almagrera

Navan Res.

Concs.

5

5

Sweden Aitik Boliden Mines

Boliden Boliden

Concs. Concs.

68 10

78

Former Yugoslavia Cerovo RTB Bor Majdanpek RTB Bor Veliki Krivelj RTB Bor

Concs. Concs. Concs.

10 65 35

Finland Pyhasalmi Portugal Neves Corvo Panasqueira

Total Western Europe

110 299

Oceania Australia Cadia Hill Cobar Eloise Ernest Henry

Newcrest Mining Glencore Int. Almag Res. MIM

Appendices / page 6

Concs. Concs. Concs. Concs.

25 30 20 95

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 1 – Continued Area

Mine operator/ owners

Source

North Parkes Gunpowder/ Mt Gordon Mount Isa Mount Lyell Nifty Olympic Dam Olympic Dam Osborne Reward Starra (Selwyn) Small mines Small mines

Rio Tinto/Sumitomo Western Metals

Concs. SX-EW

60 50

MIM Sterlite Industries Straits Res. Western Mining Western Mining Placer Pacific Sterlite Selwyn Mines Various Various

Concs. Concs. SX-EW Concs. SX-EW Concs. Concs. Concs. Concs. SX-EW

180 25 25 220 8 50 20 15 19 16

858

Concs.

210

210

Papua New Guinea Ok Tedi BHP/Inmet/PNG Gvt.

Estimated annual capacity (thousand tonnes)

Total Oceania

Total (thousand tonnes)

1068

Total Western World

12032

Other countries Bulgaria Asarel Medet Elatsite Small mines

VA Copper Elatsite Copper Co. Various

Concs. Concs. Concs.

53 40 12

105

Macedonia Small mines

Various

Concs.

12

12

KGHM KGHM

Concs. Concs.

85 140

KGHM

Concs.

245

Romanian Gvt.

Concs.

5

Romanian Gvt.

Concs.

12

Deva Mining

Concs.

10

Poland Lubin PolkowiceSieroscowice Rudna Romania Balan/Ursului/ Fundu M Moldova/ Florimunda Rosia Poieni

© Woodhead Publishing Ltd

470

27

Appendices / page 7

Appendices

Appendix 1 – Continued Area

Mine operator/ owners

Source

Aleksandrinskaya Mining Gai Combine UGMK Norilsk Uralelectromed Bashkirsky Uchalinsky Mining Various

Concs.

15

Concs. Concs. Concs. Concs. Concs. Concs. Concs.

15 60 400 30 23 27 51

621

Armenian Gvt. Kadzharan Mining/ Zangezur

Concs. Concs.

2 13

15

Georgia Madneuli

Georgian Gvt.

Concs.

9

9

Kazakhstan Dzhezkazgan Irtysh/Belnusov Itauz Kounrad/Sayak Shemonaikhinsky Zhezkent Other mines

Samsung Samsung Samsung Samsung Samsung Samsung Various

Concs. Concs. Concs. Concs. Concs. Concs. Concs.

230 25 40 40 40 110 30

515

Erdenet Mining & Concentrating Erdenet Mining & Concentrating

Concs.

140

SX-EW

5

145

Almalyk mining

Concs.

100

100

Baiyin Non-Ferrous Metals Jiangxi Daye Iron Jiangxi Dongchuan Bureau of Mines

Concs.

15

Concs. Concs. Concs. Concs.

20 20 130 20

Russia Aleksandrinsky Dombarovsky Gai Norilsk Mills Safyanoskaya Sibayskaya Uchalinsky Other mines Armenia Agarak/Kapan Kadzharan

Mongolia Erdenet Erdenet Uzbekistan Almalyk China Baiyin Chengmenshan Daye Dexing Dongchuan

Appendices / page 8

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 1 – Continued Area

Mine operator/ owners

Source

Jinquan

Jinquan Non-Ferrous Metals Zhongtiaoshan NonFerrous Metals Tonglushan Copper CCLZ Yunnan Copper Chinese Gvt. Chinese Gvt. Jiangxi

Concs.

20

Concs.

35

Concs. Concs. Concs. Concs. Concs. Concs.

12 48 60 15 18

Various Various

SX-EW Concs.

35 179

627

North Korean Gvt.

Concs.

15

15

Tongkuangyu Tonglushan Various Mines Yimen Yongping Yuanqu Yushan/ Dongxiang SX-EW mines Small mines North Korea Komdok

Estimated annual capacity (thousand tonnes)

Total other countries

Total (thousand tonnes)

2661

Total World

14693

Appendix 2 Smelters and owners Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

Botswana Consolidated

Concs.

26

26

Congo Luilu Shituru

Gecamines Gecamines

Concs. Concs.

30 30

60

Namibia Tsumeb

OMPL

Concs.

50

50

Metorex

Concs.

50

Africa Botswana Selebi-Phikwe

South Africa Nababeep (O’okiep)

© Woodhead Publishing Ltd

Appendices / page 9

Appendices

Appendix 2 – Continued Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Palabora Plantinum plants

Rio Tinto Various

Concs. Concs.

135 16

Avmin First Quantum/ Glencore Anglo American/ ZCCM ZCCM ZCCM

Leach slags Concs.

15 180

ZMDC Various

Zambia Chambishi RLE Mufulira Nchanga TLP Nkana Nkana Cobalt Plant (RLE) Zimbabwe Alaska Small plants

Tailings

70

Concs. Concs.

200 14

Concs. Concs.

25 14

Total Africa

Total (thousand tonnes)

201

479

39 855

Asia India Birla Ghatsila Khetri Sterlite

Indo Gulf Hindustan Copper Hundustan Copper Sterlite Industries

Concs. Concs. Concs. Concs.

120 17 31 120

288

Indonesia Gresik

Mitsubishi/Freeport

Concs.

200

200

National Iranian Copper Ind.

Concs.

160

160

Sumitomo Metal Mining Nippon Mining & Metals Dowa Mining Mitsubishi Materials Corp. Onahama Smelting & Refining Nippon Mining & Metals Hibi Kyodo Smelting

Concs.

300

Concs.

36

Concs. Concs.

96 306

Concs.

348

Concs.

470

Concs.

263

Iran Sar Chesmeh Japan Besshi (Toyo) Hitachi Kosaka Naoshima Onahama Saganoseki Tamano

Appendices / page 10

1819

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 2 – Continued Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

South Korea Onsan I Onsan II

LG/Nippon Mining LG/Nippon Mining

Concs. Concs.

190 220

410

Oman Sohar

Oman Mining

Concs.

35

35

Philippines Isabel

Glencore

Concs.

190

190

Turkey Samsun

KBI

Concs.

42

42

Total Asia

Total (thousand tonnes)

3144

North and Central America Canada Flin Flon Gaspe Horne Kidd Creek Sudbury Sudbury

Hudson Bay Noranda Noranda Falconbridge Inco Falconbridge

Concs. Concs. Concs. Concs. Concs. Concs.

90 135 200 155 135 20

Scrap Concs.

135 320

Hayden Hurley Chino Miami

Chemetco Metal Kennecott (Rio Tinto) Grupo Mexico Phelps Dodge Phelps Dodge

Concs. Concs. Concs.

210 190 180

1035

Mexico La Caridad San Luis Potosi

Mexicana de Cobre IMMSA

Concs. Concs.

400 36

436

USA Alton Garfield

Total North and Central America

735

2206

South America Brazil Camacari Chile Altonorte (La Negra)

Caraiba Metals

Concs.

220

Noranda

Concs.

165

© Woodhead Publishing Ltd

220

Appendices / page 11

Appendices

Appendix 2 – Continued Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Chagres (Disputada) Chuquicamata El Teniente (Caletones) H. Videla Lira Las Ventanas Salvador (Potrerillos)

Cia. Min. Disputada de las Condes Codelco Codelco

Concs.

150

Concs. Concs.

480 430

ENAMI ENAMI Codelco

Concs. Concs. Concs.

75 115 150

1565

SPCC Doe Run

Concs. Concs.

350 80

430

Peru Ilo La Oroya Total South America

Total (thousand tonnes)

2215

Western Europe Austria Brixlegg

Montanwarke Brixlegg

Scrap

85

Scrap

150

Hoboken

La Metallo Chimique Umicore

Scrap

50

200

Finland Harjavalta

Outokumpu

Concs.

160

160

Norddeutsche Affinerie MKM Norddeutsche Affinerie

Concs.

450

Scrap Scrap

96 170

716

Belgium Beerse

Germany Hamburg Hettstedt Lunen

85

Italy Porto Maghera Porto Maghera

SIMAR SIMAR

Scrap Scrap

105 24

129

Spain Berango Huelva

ELMET Atlantic Copper

Scrap Concs.

32 320

352

Appendices / page 12

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 2 – Continued Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Boliden

Concs.

240

240

Former Yugoslavia Bor RTB Bor

Concs.

170

170

Sweden Ronnskar

Total Western Europe

Total (thousand tonnes)

2052

Oceania Australia Mount Isa Olympic Dam Port Kembla

MIM Western Mining Furukawa/Nittetsu/ NisshoI wai/ Itochu

Concs. Concs. Concs.

270 220 120

Total Oceania

610

610

Total Western World

11082

Other countries Armenia Mannes & Vallex

Armenia/US Joint Venture

Concs.

12

12

Bulgaria Eliseina Pirdop

Eliseina Ltd. Umicore

Scrap Concs.

14 185

199

Hungary Csepel

Hungarian Gvt.

Scrap

4

4

Poland Glogow I Glogow II Hutmen Legnica

KGHM KGHM ZHPMN KGHM

Concs. Concs. Scrap Concs.

220 180 9 90

499

Romania Baia Mare Zlatna Zlatna Zlatna

Allied Deals Zlatna Metallurgical Zlatna Metallurgical Zlatna Metallurgical

Concs. Scrap Concs. Concs.

35 10 40 13

98

Slovakia Krompachy

Kovohute Krompachy

Scrap

20

20

© Woodhead Publishing Ltd

Appendices / page 13

Appendices

Appendix 2 – Continued Area

Russia Karabash (Urals) Kirovgrad Krasnouralsk (Urals) Mednogorsk (Urals) Moscow Nadezhdinsky (E. Siberia) Norilsk Pechenganickel (Kola Pen.) Severonikel (Kola Pen.) Sredneuralsky (SUMZ) Kazakhstan Balkashmys Dzhezkazgan Uzbekistan Almalyk China Baiyin Changzhou Chongqing Daye Dongfang Guixi Huludao Jinchang Jinchuan

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Kyshtym Kirovogradsky JSC Krasnouralsk Copper (Svyatogor) Depo-Service

Concs. Scrap Concs.

40 150 70

Concs.

40

Total (thousand tonnes)

Moscow Smelting & Refining Norilsk

Scrap

30

Concs.

100

Norilsk Pechenganickel

Concs. Concs.

400 40

Severonikel

Concs.

60

Glencore

Scrap

110

1040

Samsung Samsung

Concs. Concs.

200 215

415

Almalyk Mining & Metallurgical

Concs.

140

140

Local Gvt. Local Gvt. Nanfeng Medecine Daye Non-Ferrous Metals Dongfang Copper Corp. Jiangxi Copper Corp. Huludao Zinc Corp. Tongling Non-Ferrous/ Sharpline Jinchuan Non-Ferrous

Concs. Concs. Scrap Concs.

65 35 20 150

Concs.

30

Concs. Concs. Concs.

220 60 65

Concs.

35

Appendices / page 14

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 2 – Continued Area

Smelter operator/ owners

Principal raw material

Estimated annual capacity (thousand tonnes)

Jinlong

Concs.

130

Yantai Yunnan Zhong tiaoshan (Yanqu) Small plants

Tongling Non-Ferrous/ Sharpline/Itochu/ Sumitomo Local Gvt. Local Gvt. Zhong tiaoshan Non ferrous Metals Various

Concs. Concs. Concs.

30 150 45

Concs.

74

1109

North Korea Hungnam Nampo

North Korean Gvt. North Korean Gvt.

Concs. Concs.

40 40

80

Total other countries

Total (thousand tonnes)

3616

Total World

14698

Source: ICSG.

Appendix 3 Refineries and owners* Area

Refinery operator/ owners

Process

Principal raw material

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

Congo Shituru

Gecamines

FR

EW copper

100

100

Egypt Cairo

General Metals

FR

Scrap

4

4

South Africa Benoni Palabora

Metal Sales Rio Tinto

FR Scrap Electrolytic Anode

7 140

147

Glencore/First Quantum ZCCM ZCCM

Electrolytic Anode

265

Electrolytic Anode Electrolytic Anode

180 40

Africa

Zambia Mufulira Nkana Nkana

© Woodhead Publishing Ltd

485

Appendices / page 15

Appendices

Appendix 3 – Continued Area

Zimbabwe Alaska

Refinery operator/ owners

Process

Principal raw material

Mhangura

Electrolytic Anode

Estimated annual capacity (thousand tonnes)

15

Total Africa

Total (thousand tonnes)

15 751

Asia India Birla Ghatsila Khetri Sterlite Indonesia Gresik Iran Sar Chesmeh Japan Besshi (Toyo) Hitachi Kosaka Naoshima

Onahama

Saganoseki Tamano South Korea Changhang

Indo Gulf Hindustan Copper Hindustan Copper Sterlite Industries

Electrolytic Anode Electrolytic Anode

120 17

Electrolytic Anode

31

Electrolytic Anode

120

288

Mitsubishi/ Freeport

Electrolytic Anode

200

200

National Iranian Copper Ind.

Electrolytic Anode

150

150

Sumitomo Metal Mining Nippon Mining & Metals Dowa Mining Mitsubishi Materials Corp Onahama Smelting and refining co. Nippon Mining & Metals Hibi Kyodo smelting

Electrolytic Anode

250

Electrolytic Anode

180

Electrolytic Anode Electrolytic Anode

72 225

Electrolytic Anode

258

Electrolytic Anode

270

Electrolytic Anode

218

Electrolytic Scrap

60

LG/Nippon Mining

Appendices / page 16

1473

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 3 – Continued Area

Refinery operator/ owners

Process

Onsan I

LG/Nippon Mining LG/Nippon Mining

Electrolytic Anode

220

Electrolytic Anode

190

470

Oman Sohar

Oman Mining

Electrolytic Anode

33

33

Philippines Isabel

Pasar

Electrolytic Anode

175

175

ER Bakir Bakirson Electrolytic Copper Sarkuysan Electrolytic Copper

Electrolytic Anode Electrolytic Anode

20 22

Electrolytic Anode

100

Onsan II

Turkey Denizli Duzce

Sarkuysan

Principal raw material

Estimated annual capacity (thousand tonnes)

Total Asia

Total (thousand tonnes)

142

2931

North and Central America Canada CCR Sudbury Timmins USA Amarillo El Paso Garfield Indiana Miami Reading Sauget Warrenton White Pine Mexico La Caridad

Noranda Inco Falconbridge

Electrolytic Anode Electrolytic Anode Electrolytic Anode

360 140 147

Grupo Mexico Phelps Dodge Kennecott (Rio Tinto) Essex Group Phelps Dodge Reading Ind. Cerro American Iron & Metal BHP

Electrolytic Anode Electrolytic Anode Electrolytic Anode

450 415 320

FR Electrolytic FR FR FR

Scrap Anode Scrap Scrap Scrap

18 172 70 55 32

Electrolytic Anode

75

Electrolytic Anode

330

Mexicana de Cobre

© Woodhead Publishing Ltd

647

1607

Appendices / page 17

Appendices

Appendix 3 – Continued Area

Refinery operator/ owners

Process

Principal raw material

Refineria Mexico Celaya

Cobre de Mexico Cobre de Mexico

Electrolytic Anode Electrolytic Scrap

Estimated annual capacity (thousand tonnes) 150 30

Total North and Central America

Total (thousand tonnes)

510 2764

South America Brazil Camacari Chile Chuquicamata El Teniente Las Ventanas Salvador (Potrerillos) Peru Ilo La Oroya

Caraiba Metais

Electrolytic Anode

220

220

Codelco Codelco Enami Codelco

Electrolytic FR Electrolytic Electrolytic

Anode Anode Anode Anode

690 170 320 140

1320

SPCC (Grupo Mexico) Doe Run

Electrolytic Anode

240

Electrolytic Anode

80

Total South America

320 1860

Western Europe Austria Brixlegg

Montanwerke Brixlegg

Electrolytic Scrap

72

Electrolytic Scrap

40

Liege Olen

La Metallo Chimique UCA Umicore

FR Scrap Electrolytic Anode

80 330

450

Finland Pori

Outokumpu

Electrolytic Anode

125

125

Norddeutsche Affinerie MKM Norddeutsche Affinerie KME

Electrolytic Anode

385

Electrolytic Anode Electrolytic Anode

63 180

Belgium Beerse

Germany Hamburg Hettstedt Lunen Osnabruck

Appendices / page 18

FR

Scrap

95

72

723

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 3 – Continued Area

Refinery operator/ owners

Process

Principal raw material

Estimated annual capacity (thousand tonnes)

Italy Fornaci di Barga Pieve Vergonte

Europa Metalli Sitindustrie

FR FR

Anode Anode

24 30

54

Spain Barcelona Berango Huelva

La Farga ELMET Atlantic Copper

FR Scrap Electrolytic Anode Electrolytic Anode

20 50 260

330

Sweden Ronnskar

Boliden

Electrolytic Anode

240

240

Former Yugoslavia Bor RTB Bor

Electrolytic Anode

170

Total Western Europe

Total (thousand tonnes)

170 2164

Oceania Australia Olympic Dam Port Kembla

Townsville

Western Mining Furukawa/ Nittetsu/ Nissho Iwai/ Itochu MIM

Electrolytic Anode Electrolytic Anode

220 120

Electrolytic Anode

270

Total Oceania

610 610

Total Western World

11080

Other countries Bulgaria Pirdop

Umicore

Electrolytic Anode

45

45

Poland Glogow I Glogow II Legnica

KGHM KGHM KGHM

Electrolytic Anode Electrolytic Anode Electrolytic Anode

195 195 85

475

Allied Deals Zlatna Metallurgical

Electrolytic Anode Electrolytic Anode

45 40

85

Romania Baia Mare Zlatna

© Woodhead Publishing Ltd

Appendices / page 19

Appendices

Appendix 3 – Continued Area

Slovakia Krompachy Russia Kyshtym Monchegorsk (Kola Pen.) Moscow

Refinery operator/ owners

Process

Principal raw material

Estimated annual capacity (thousand tonnes)

Kovohute Krompachy

Electrolytic Scrap

Uralelectrocopper Severonikel

Electrolytic Anode Electrolytic Cu/Ni Matte Electrolytic Scrap

80 100

330 310 7

857

20

Total (thousand tonnes)

20

Norilsk

Moscow Smelting & Refining Norilsk

Pyshma (Urals) Yuzhuralnickel

Uralelectromed Yuzhuralnickel

Electrolytic Cu/Ni/ Matte Electrolytic Anode Electrolytic Scrap

Kazakhstan Balkash Dzhezkazgan

Samsung Samsung

Electrolytic Anode Electrolytic Anode

175 250

425

Almalyk Mining & Metallurgical

Electrolytic Anode

115

115

Baiyin NonFerrous Local Gvt. Nanfeng Medecine Private Tianjin Copper Plant Daye Non-Ferrous Metals Local Gvt. Jiangxi Copper Corp. Huludao Zinc Corp. Tongling NonFerrous/ Sharpline

Electrolytic Anode

60

Electrolytic Blister FR Scrap

40 20

Electrolytic Scrap Electrolytic Scrap

65 30

Electrolytic Blister

85

Electrolytic Anode Electrolytic Anode

20 250

Electrolytic Anode

80

Electrolytic Anode

50

Uzbekistan Almalyk China Baiyin Changzhou Chongqing Dachang Datong Daye Fuchunjiang Guixi Huludao Jinchang

Appendices / page 20

30

© Woodhead Publishing Ltd

World’s major copper mines and plants

Appendix 3 – Continued Area

Refinery operator/ owners

Process

Jinchuan Jinlong

Local Gvt. Tongling NonFerrous/ Sharpline Local Gvt. Local Gvt. Local Gvt. Taicang Copper Group Taiyuan Copper Group Local Gvt. Shenyang Construction Inv. co. Local Gvt. Local Gvt. Tongling NonFerrous Various

Electrolytic Anode Electrolytic Anode

Luoyang Meizhou Jinyan Shanghai Taicang Taiyuan Wuhu Xinxing

Yantai Yunnan Zhangjiagang Small plants North Korea Nampo Tanchon (Hungnam)

North Korean Gvt. North Korean Gvt.

Total other countries Total World

Electrolytic FR Electrolytic FR

Principal raw material

Estimated annual capacity (thousand tonnes)

Total (thousand tonnes)

50 130

Anode Scrap Anode Anode

50 20 50 20

Electrolytic Anode

30

Electrolytic Blister Electrolytic Anode

45 100

Electrolytic Anode Electrolytic Anode Electrolytic Scrap

30 150 40

Various

112

1527

40 25

65

Various

Electrolytic Anode Electrolytic Anode

3614 14654

*Omitting SX-EW operations Key to abbreviations and terms: FR, fire refining: EW, electrowon: Scrap, includes secondary anode and blister: Anode, includes blister. Source: International Copper Study Group.

© Woodhead Publishing Ltd

Appendices / page 21