Ventilation Report of Bunker Hill and Sullivan Mine Kellogg, Idaho

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VENTILATION REPORT OF BUNKER HILL AND SULLIVAN MINE KELLOGG, IDAHO

*y JOHN W # WARREN

: A. Thesis . Submitted to the Department of Mining in Partial Fulfillment of tnft Requirements foi t]i6 Degree cf Engineer of Mines

MONTANA SCHOOL OF MINES Butte, Montana June, I95O

UMI Number: EP33364

All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent on the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion.

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CONTESTS

Introduction

1

Preface

1

Location

1

Geology

2

Mining Methods

2

Acknowledgements

3

Scope of Survey

3

Restrictions and Limitations

3

Ventilation

3

Description of Present Ventilation Scheme

5

Natural Draft

6

Temperature Variables

7

Importance of Positive Ventilation

8

Ventilation Survey Detail

S

Ventilation Balance

S

Workers' Requirements.

9

Seasonal Change Effect

9

Components

10

Recirculation

10

Volume Relationship

10

Temperatures - Ground Gradient

11 12

Ventilation Maps

12

Fans

13

Foundations for Recommendations

1^

Airway Characteristics

1^

Smooth Lining

16

Mechanical Ventilation

IS

Heat Extraction

19

Llechanical Refrigeration

21

Natural Refrigeration

23

Ideal Ventilation Scheme

2&

Increasing Mechanical Ventilation

29

Recommendations

30

Discussion of Recommendations

3^

Complete Set of Ventilation Maps

31

Study of Milo Creek

31

Study of Atmospheric Conditions

3^

Acquisition of lecessary Ventilation Equipment

32

Memtiership to Industrial Hygiene Foundation

33

Auxiliary Ventilation for All Dead Ends

3^"

Adoption of Complete Dust Control Program

3^

Complete Industrial Hygiene Library

3^

Microprojector Method for Dust Quantitation

^1

New Exhaust Airway

^1

General Notes

^2

Conclusion

^2

V E N T I L A T I O N

R E P O R T

0 F B U N K E R

H I L L

AND

3 U L L I Y A N

KELLOGG,

MINE

IDAHO

by John W# Warren

I N T R O D U C T I O N PREFACE

With the acceptance of an invitation extended "by the management of the Bunker Hill and Sullivan Mining and Concentrating Company, the writer, assistant chief ventilation engineer, Anaconda Copper Mining Company, Butte, Montana, made a ventilation survey of the Bunker Hill and Sullivan .Mine, Kellogg, Idaho, April k to 10, 1 9 ^ . The writer in aporeciation of the many courtesies received is responsible for, and is available, if necessary, for further discussion on the material contained herein.

LOCATION The Bunker Hill and Sullivan mines are situated in the western

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part of the Coeur d'Alene district at Kellogg, Shoshone,County, Idaho. The mine has the distinction of continuous operation during the twentieth century to date,

GEOLOGY A heavily faulted zone of Algonkian quartzites disrupted by later faults contain the ore bodies of the Bunker Hill and Sullivan Mine* Metamorphism in the area is attributed to the underlying intrusives, no connection between these intrusives and the deposition of the ore has been shown. There is a great irregularity of ore occurrence and the outlines of the ore bodies on adjacent levels do not conform.

MINING METHODS

A modified square set method is used in the stoping area. Wide use is made of long caps with auxiliary posts subsequently installed. Timbering gives every evidence of good planning and constant supervision. Due to ground conditions filling is carried exceptionally close with marked success in some areas. The writer has witnessed filling to the back on the hanging wall side of the mining floor.

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A C K N O W L E D G E M E N T S

The writer was extended every courtesy by the management and personnel of the Bunker Hill and Sullivan Mining and Concentrating Company for which he is extremely grateful. The cooperation, courtesy, thought fulness and assistance of the following men is appreciated and the author's gratitude is extended specifically to; Mr. B. K. Haffner, General Manager, for his many courtesies, his foresight, and extending to the writer the opportunity to broaden his own knowledge, Mr. Stanley McDougall, Mine Superintendent, for his assistance, wise counsel and cooperation which was so willingly and intelligently given. Without his help this survey and report would not have "been possible. Mr, Roy S. Hooper, Assistant Mine Superintendent, for his full and helpful cooperation. Mr. U. E. Brown, Chief Mining Engineer, for any and all information desired by the writer. Because of the enormous size of the mine and the writer's limited time this was of very valuable assistance and is greatly appreciated, Mr. Joe Williams, Safety Engineer, who accompanied the writer on all of his underground trips to furnish information on the mine, to act as guide, and to give general valuable assistance. The invaluable assistance of Mr. Williams is hereby gratefully acknowledged. Mr. A. 0. Stevenson, Chief Mechanical Engineer, for his patience and time in the discussion of engineering phases of mine ventilation and for his foresight in anticipated future problems.

S C O P E

OF

S U R V E Y

RESTRICTIONS AND LIMITATIONS

As a result of the short time element, the enormous size of the mine and the lack of sufficient and specific equipment the ventilation survey of the Bunker Hill and Sullivan mine is incomplete, however the writer hereby states that sufficient data was obtained to warrant any and all pertinent statements contained herein. With the existance of the foregoing conditions augmented by the assumption that management is more intensely interested at this time in results than an elaborate report of minute detail.

VENTILATION

Mine ventilation may be said to be the science of producing desirable atmos pheric conditions within all underground openings. Ventilation is generally looked upon as everybody1 s business and consequently no one's responsibility. It is probably because of the aforementioned reason that a well planned but intermittently supervised ventilation scheme becomes inefficient due to lack of supervision in a few seemingly incidental but nevertheless restraining and vital details upon which an efficient ventilation system so often depends. The ventilation system at the Bunker Hill and Sullivan Mine reflects good planning, foresight, supervision and application of engineering principles. It is the writer's opinion that with the

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present ventilation scheme and equipment the ultimate in underground air distribution has been reached from a practical and economical standpoint. It will "be the partial purpose of this report to discuss the present system in detail.

BRIEF DESCRIPTION OF PRESENT VENTILATION SCHEME

The initial intake airways are through old workings which are somewhat inaccessible

and are located above the

Reed tunnel elev-

ation. From this point the air courses downward through the Becker stops area with other inacessible parallels to and through the New and Van raises which were primarily driven for ventilation purposes. These raises are supplemented by other inaccessible parallel downcasts further to the east. The entire downcast volume is boosted through a Jeffrey SH-60 Aerodyne fan in Kellogg Tunnel #9 level from the bottom of the Van raise to #2 incline shaft which serves as the intake airway from its collar at Kellogg Tunnel #9 level to #19 level at which elevation the air is drawn from the shaft and boosted through a Jeffery S-60 fan located in a by-pass near #1 shaft. The air courses northwest through the #19 level to the #19 winze wheee the major part iB downcasted to the #21 level at which elevation it again resumes its northwest course to the May raise vicinity where a split is coursed downcast to the # 23 level and the remaining component is coursed upcast through productive stoping areas to the #1S, #17, and #16 levels which in conjunction with the exhaust on #23 level form four parallel airways which carry the discharge air and terminate in and make up the total upcast com-» ponent in #1 incline shaft.

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The upcast in #1 Shaft is drawn from the shaft at #10 level and boosted upcast by a Jeffrey g-72 fan through an incline air raise to the Kellogg tunnel #9 level where after a short horizontal travel in the connecting airway it oourses upcast through the Dull raise where the major part xof the upcast travels horizontally on #5 level to whatever available

openings the flow may

find to serve as airways to atmosphere. 13,000 C.F.M, is coursed on #5 level to the Cherry incline raise or shaft to be upcasted and exhausted to atmosphere* A near balance is now maintained with four underground booster fans and their respective resistance circuits so that only a small amount os short circuit exists in Kellogg tunnel #9 level between the collars of #2 intake shaft and #1 exhaust shaft. The interconnection between the two incline shaft collars on Kellogg tunnel #9 level is free of air stopping control and existing flow conditions indicate only a very slight pressure differential. There is however, a slight downcast in #1 shaft from the collar to #10 level which originates from two sources. One source is a small component from the Van raise system which passes the collar of #2 shaft and the other component from the portal side of Kellogg tunnel #9 level.

NATURAL DRAFT

In a mine where no mechanical ventilation exists and the air undergoes a temperature change as well as a vapor content change air circulation will exist due to natural draft which is

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a pressure differential the resultant of a difference in the densities of two air columns in the mine. These air densities are primarily dependent on the relative temperatures. The natural draft pressure in the Bunker Hill and Sullivan mine from the #9 to the #19 level is shown in the following calculation; #2 shaft average air density a O.O722 #/cu.ft. #1 shaft average air density « 0.0695 #/cu.ft. Difference in air density a 0.0027 #/cu.ft. Difference in weight of air columns == 2,000 x 0.0C27 « 5.IK) #/square foot 5.^0 = 5.2

1.0^" H2O Pressure differential

The natural draft pressure does not materially change throughcut the year since the temperatures of the air in the inlet and outlet shafts do not vary appreciably.

TEMPERATURE VARIABLES

The temperature of mine air is affected most directly by underground water temperature, The temperature of the surrounding rock and by the oxidation of ore and timber with other minor causes such as; surface atmospheric temperatures, friction due to air movement in airways, heat from machinery, blasting and exhalation of workmen.

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I M P O R T A N C E

OF

P O S I T I V E

V E N T I L A T I O N

In mine ventilation one of the most impostant considerations is its relationshipto the protection and prevention of mine fire. Positive ventilation will cause the entire operating staff to become familiar with the general scheme since they are not confused with untimely changes in weak air flows and reversals due to minor changes. The essential feature of positive ventilation is the control of air flow and this can only be accomplished by mechanical means. The key to adequate and efficient ventilation is proper design of airways, correct equipment and constant, intelligent supervision. Weak air movement 03? poor ventilation tends to vitiate the air and recent experiments have indicated a definite change in the ionic content of the air within occupied areas, resulting in a decrease of both positive and negative ions. The precise effevt on human health and comfort is still to be determined.

V E N T I L A T I O N

S U R V E Y

D E T A I L

As previously stated the survey is lacking in detail nevertheless relevant data was secured to substantiate the statements cons tained in this report.

VENTILATION BALANCE

The volume being circulated through the primary airways in

the Bunker Hill and Sullivan Mine is approximately 50,000 C.F.M. The effective volume delivered toward the main stoping area at depth is less than ^5,000 C.F.M.

Workers1 Requirements

The ordinary individual seldom breathes more than 50 liters of air per minute. The oxygen content of the air should be held above 20 per cent and the carbon dioxide content or other contaminants should not be allowed to rise to a point where the atmosphere would become disagreeable or toxic. The mining law commonly specifies from 100 to 200 cubic feet of air per man per minute. It naturally follows that not only this quantity of air but any additional volume necessary to sufficiently dilute dust concentrations and produce desirable atmospheric conditions should be coursed through the various airways and working places of the mine.

Seasonal Change Effect

In contrast to a 100° temperature differential between a hot day in midsummer and a cold day in winter no appreciable chage in temperature is noted in the ore extraction areas on the lower levels. The near constant temperature is due to the neutralized low temperature ground gradient and mine drainage water of corresponding low temperature in the long airways in the shallow depth workings of the mine now serving as the intake airway.

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Components

In general, the main air flow courses through a single airway throughout the major length of the ventilation system.

The

excessive length of airway and lack of parallel ducts results in a relatively small volume of air being coursed through the mine at an exceptionally high resistance.

Recirculation

Some recirculation occurs as leakage through stoppings such as doors in the crosscuts on the various levels between #2 incline or intake shaft and #1 incline or discharge shaft.

A strong leak

occurred through the air lock on Kellogg tunnel #9 level.

These

leaks detract from, rather than add to good mine ventilation, since a volume of polluted air at high temperatures is circulated through a major part of the primary ventilation system.

Volume Relationship

The volumes circulated should be a function of the requirements for the specific working areas.

Volumes circulated should

not be dependent entirely on temperature conditions, but should be viewed from an industrial hygiene standpoint as well.

Considera-

tion should be given dust concentrations especially where the free silica (Si02) content is high.

Large air volumes dilute not only

dust concentrations but smoke densities as well and act as the

vehicle by which these concentrations are rapidly removed from the mine. Where the temperature of the surrounding rock is in excess of that of the air stream, it is desirable to have as high an air velocity as is economically possible since the surface temperature of the rock is cooled more rapidly and its heat is dissipated at such a rate that the final temperature of the air at the working faces is of lower magnitude than if the air velocities were of lower nature. The cooling power of air increases whith the air velocity and where atmospheric temperatures are above those of the comfort chart and the air is saturated or nearly so, higher air velocities are extremely desirable.

TEMPERATURES

Temperatures in the mine during the survey covered in this report ranged from a minimum of 40° saturated recorded on the Reed tunnel level in shallow depth of the mine and surrounded by openings which have been open to air flow a considerable period of time.

The maximum temperature was recorded in the back of the

White or #2 Raise about 25 feet above the #23 level station. This raise is in a heavily crushed fault zone and has recently undergone a slough.

The temperature here was 39° saturated and represents

a good ground temperature of the area. The temperatures in the active stoping areas such as the Emery, Webber, and Truman veins on the three lower levels approximates 20 F and saturated conditions exist throughout these areas.

Ground Gradient

Ground water issuing from cracks in the rock is an ideal indicator of the rock temperature at the respective elevation especially where areas have recently been exposed. On the #21 level, ground water was recorded at SO°F, and on the #23 level, ground water was recorded at 2>3°F. From indications, it is the writer's opinion that the ground gradient at successive levels in depth may reach an increase of as much as 1^°F per 100 feet of elevation. Underground air will, in general, if the movement is weak or stagnant essentially adjust its own temperature to that of the surrounding rock, though dripping water will more quickly give its temperature to surrounding air than will the surrounding rock. However, the passing of large quantities of air will tend ultimately to change the rook temperature to a shallow depth to the temperature of the moving air.

VENTILATION MAPS

Ventilation maps containing up-to-date information are an important aid in maintaining good mine ventilation.

Attempts to

record ventilation data without the use of symbols usually result in crowded data or loss of data. An appropriate legend is presented as Figure 1.

The maps aid in showing the respective areas in

which workmen are concentrated and assist in coursing sufficient quantities of air to these areas to maintain the quality of the atmosphere within desirable limits.

1 cif=.£MO &r S Y M B O L S

JMTILATION

/I/'r CjDC&S'T'' JrO/H

^i/e/

s4//~ CpO -^z_ ^* !^T"

/n

/hcAe3

ofyvnncc-fioa ^e"r o i l i n g Lubricator"

I" M u e l l e r Valve

Mueller

-^ Air' l i n e

entire muck pile is homogeneously wetted as each successive blast from the respective round hole is thrown back.

The blast to give

maximum effectiveness should never exceed 30 feet from the face. This type of water mist blast is applicable to all types of horizontal headings.

Complete Industrial Hygiene Library

A desirable reference for mine ventilation, dust and industrial hygiene is presented herewith. 1.

Analytical Chemistry of Industrial Poisons, Hazards, And Solvents, by M. B. Jacobs. Interscience Publishers, Inc. New York, N. Y.

2.

Manual of Industrial Health Hazards, by Joseph B. Ficklen. Service to Industry, Box 133 v.'est Hartford, Connecticut

3.

Analysis of Water and Sewage, by Theroux, Eldridge, and Mallmann. McGraw - Hill Book Co. Inc. New York, H. Y.

4.

The Microscope, by S. H. Gage. Comstock Publishing Co. Ithaca, N. Y.

5.

Handbook of Chemical Microscopy, by Chamont and Mason. John '.Viiey and Sons, Inc. New York, N. Y.

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6.

Resistance of Metal Mine Airways, "by G. E. McElroy and A. S. Richardson. Bureau of Mines Bulletin #261 U. S. Government Printing Office Washington D. C.

7.

Engineering Factors In the Ventilation of Metal Mines, by G. E. McElroy. Bureau of Mines Bulletin #3&5 U. S. Government Printing Office Washington D. 0.

&.

Review of Literature on Effects of Breathing Dusts with Special Reference to Silicosis, by D. Harrington and Sara J. Davenport. Bureau of Mines Bulletin #4-00 U. S. Government Printing Office Washington D. C.

9.

The Determination and Control of Industrial Dust, Public Health Bulletin #217. U. S. Treasury Department U. S. Government Printing Office Washington D. C.

10.

Industrial Dust, by Drinker and Hatch. McGraw - Hill Book Co. Mew York, N. Y.

11.

Ventilation of Mines, by waiter S. weeks. McGraw - Hill Book Co. New York, H. Y.

12.

Psychrometric Tables, by C. F. Marvin. U. S. Government Printing Office Washington D. C.

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13.

Comparative Tests of Instruments for Determining Atmospheric Dusts. public Health Bulletin #144 U. S. Government Printing Office Washington D. C.

14.

Economic Design of Mine Airways, by A. S. Richardson. Transactions of American Institute of Mining and Metallurgical Engineers, February 1926.

15.

Microprojection Method fox Counting Impinger Dust Samples. U. S. Bureau of Mines Report on Investigations #3373*

16.

A Technique for Use of the Midget Impinger Method. U. S. Bureau of Mines Information Circular #7026.

17.

Bureau of Mines Midget Impinger. U. S. Bureau of Mines Information Circular #7076.

IS.

List of Respiratory Protective Devices, Approved by the Bureau of Mines. U. S. Bureau of Mines Information Circular #7237.

19.

Selection, Use and Maintenance of Respiratory protective Devices. U. S. Bureau of Mines Information Circular #7236.

20. Dust Hazards and Their Control in Mining. U. S. Bureau of Mines Information Circular #695^-

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Llicroprojector Method For Dust Quantitation

The microprojection method is recommended because of the ease with which determinations can be made.

It facilitates quan-

titation with considerable saving in eye strain.

A print of the

detail of the microprojector used by the writer's parent company is on hand at the Bunker Hill property.

New Exhaust Airway

It has been the main purpose of this report to establish the fundamentals which when considered detract from, rather than add to, any reasonable possibility of improving underground atmospheric environment by straight mechanical ventilation means alone. It is therefore apparent that under the present high mine resistance characteristic, a new exhaust airway is warranted.

The

design should be to carry a total exhaust component of 100,000 C.F.M, .

Depending on whether a shaft or strictly an airway is

considered, the writer will gladly furnish an economic design for a given contemplated linear length and type of airway desired. The possibilities of supplementing natural refrigeration with mechanical ventilation are favorable, essentially for ultimate future use.

Depending upon management's proposed plans and

decisions, the writer will furnish any and all information available on these proposals.

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GENERAL NOTES

It is suggested that a complete analyses of the mine drainage water he made at various elevations for the summer and winter periods.

The mine drainage water has considerable

potential cooling power at some locations which could be used as a cooling medium in air-conditioning hoist rooms and pump stations.

These units must be of the open-sprayv multi-stage

type, due to the corrosive nature of the water. Air analyses are suggested in working areas where air movement is weak or stagnant.

CONCLUSION

,The undersigned is very grateful for having had both the opportunity to witness such a modern and well-conducted mining operation as well as the broadening of his own knowledge. The writer hopes that his recommendations will be carried out and he sincerely believes that if so done, it will result in an economic installation, which in turn will result in desirable underground atmospheric environment for ultimate future mining operations.

Respectfully submitted,

]

MJ

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