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^. STEAM SHOVEL MINING ilililplilliliilllliillllll^^^ yke Qraw^OJillBook (h Ine. PUBLISHERS OF BOOKS F O P_^ Coal Age '=' Electric Railway Journal Electrical World '=' Engineering News-Record American Machinist "^Ingenieria Internacional Engineerings Mining Journal '^ Power Chemical 6 Metallurgical Engineering Electrical Merchandising STEAM SHOA EL MINING INCLUDING A CONSIDERATION OF ELECTRIC SHOVELS AND OTHER POWER EXCAVATORS IN OPEN-PIT MINING BY ROBERT MARSH, Jr. FiKST Edition McGRAW-HILL BOOK COMPANY, Inc. NEW YORK: 239 WEST 39TH STREET LONDON: 6 & 8 BOUVERIE ST., E. C. 4 1920 i$ "ill CoPYRKiHT, 1920, BY THE McGraw-Hill Book Company, Inc. •IHK MAPLK THESS YORK; PA S)eelicateel to POPE YEATMAN to whom for his constant encouragement and example the author is deeply indebted. t»REFACE The purpose of this vokime is to present in a collected and condensed form the general information covering the development and study of such mining problems as may best be solved by the appUcation of open-pit methods involving the use of modern power-excavators. It is assumed that the reader has a general idea of mining practice. Compared with the broad old science of mining, the apphcation of the power-shovel is relatively new, and perhaps for that reason, information concerning its use is not so widely known. The majority of those in charge of such operations are practical men httle given to writing. Many have been drawn from in- dustrial and constructive engineering fields rather than from mining, and some are at times inclined to guard the details of successful methods which have been gained only after long experience. It is therefore the purpose here to analyze, compare and criticise such information on the subject as the writer has accumulated through reading, travel and operation of open-pit work, with the aim of making this information as helpful as possible to the profession of which the writer is happy to belong. It will be noted that emphasis is laid only on such power-shovel work as pertains to mining, rather than to include the broad field of general excavation work, though in many cases the operations are conducted in much the same way. Mining operations are however of a destructive character and much less attention need usually be paid to the aftermath of the excavations or to the final disposal of the debris. The direct object is the winning of the ore, efficiently and cheaply, not the construction of an engineering monument of utility. The prices of steam-shovels and other machinery and supplies, given in this book, are based on 1915-1917 quotations and are believed to be more useful than present day prices, which are regarded as unstable. Firms contemplating purchases should sohcit from manufacturers their latest quotations, but for comparative purposes the prices given in the text are believed to be safest. Vlll PREFACE I wish to make the fullest acknowledgment for the assistance that has been received in gathering this information. It has come from pit and shovel men, from their foremen and super- intendents, from the builders of the machinery and equipment, from engineering periodicals and books, and from those engineers with whom I have had the great pleasure and advantage of as- sociation for the past twelve years. I also wish to express my gratitude and appreciation for the work done by my friend Mr. E. Coppee Thurston in reading and correcting the manu- script and proof sheets. —— CONTENTS Page Preface v CHAPTER I The Power Shovel 1 Introduction to Mining Operations—Early Open-cast Work Transition at Rio Tinto, Spain—Early Application to Mining- Mechanical Development—Invention and Patents—Description of Standard Shovel—Modern Standard Construction—The Rail- road or Standard Type—The Revolving Type—Special Construc- tion—Extra Long Booms and Dipper Sticks—Quarry, Tunnel and Stope Shovels—Wire Rope Shovels—Electric-driven Shovels Electro-hydraulic-driven Shovels—Oil-engine-driven Shovel Competing Machines—General Field—Dredges—Dragline Ex- cavators. CHAPTER II Mechanical Equipment 44 General Conditions Governing a Selection—Shovels—Principal Governing Factors—Pit Working Conditions—Class of Operating Labor—Power—Steam—Electric-alternating Current vs. Direct Current—Compressed Air—Oil Engines—Competing Machines Cost of Shovels—Locomotives—General Governing Conditions —^Direct-connected Steam Type—Determination of Tractive Force—Factor of Adhesion—Resistance Due to Grades—^Re- sistance Due to Rolling Friction—Resistance Due to Curves Hauling Capacity—Horse Power—Fuel and Water Consumption Usual Sizes for Open-pit Mining—Cost of Locomotives—Geared Types—Compressed Air Locomotives—General Considerations Cost of Installation and Operation of Air Haulage—Electric Loco- motives—Trolley System—Centrally Controlled Systems—The Woodford System—Cars—^Stripping Cars—Platform Type Gondola Type—Dumping Type—Air and Hand Operated—Ore Cars—Hopper-bottom and Gondolas—Track—General Pit Track —Definitions and Rules—Alignment—Curves—Maintenance Materials and Equipment—General Requirements—Rail Fastenings and Accessories—Ties—Frogs and Switches—Protec- tive Devices—Drills—Churn Drills—Tripod Drills—Drills for Block-holing—Miscellaneous Equipment—-Pumps—Illumination for Night Work—Telephones and Signals—^Locomotive Crane—Re- pair Car—Employees' Car—Coaling Car—Powder Cars—General ix ——— X CONTENTS Page Utility Cars—Wagons and Trucks—Shops—Machine Shop Blacksmith and Forge—Engine and Car Shops—Electrician's Shop—Carpenter . Shop—Foundry—Sampling, Assaying and Engineering—Balance in Equipment—Life of Equipment—Coarse Crushers—Ore Dryers. CHAPTER III Methods of Attack 115 General Problems—Bench Work—Height of Banks—Width of Benches—Pit Slopes—Slides—Casting Over—Thorough Cut—First Cut Location—Course Staking—Pit Layouts—Spirals—Switch- backs—Tees and Wyes—Tunnels and Shafts—Inclined Planes Milling System. CHAPTER IV Drilling and Blasting 135 Hand Drills—Machine-drills—Churn-drills—Use and Examples in Blasting—Spacing of Holes—Systems of Shooting—Breaking Oversize Material—Various Explosives Used—Calculation of Charges—Detonators—Tamping—Safety Rules—Gopher Holes —Use and Examples in Blasting—Storing and Thawing Explosives —Care in Use of Explosives. CHAPTER V Disposal op Material 167 Transportation—Trackage Arrangements—Delays—Distribution of Equipment —Routing of Overburden—Distribution of Crews Use of Salt Solution—Economy in Using Large Cars—Estimating Cost to New Dump—Pit Haulage on Mesabi and Elsewhere Dumps—General Problem—Hillside and Escarpment Dumps Mesabi Dumps—Trestle Dumps—Slush Dumps—Swamp and Lake Dumps—^Dumps on Caved Ground—Copper Mine Dumps Height of Dumps—Hydraulicking. CHAPTER VI The Determination of A Power Shovel Mine 180 Preliminary Data Required—Maps and Sections—^Local Costs and Conditions—Initial Time and Capital Required—Other General Considerations—Sound Conclusion on Method to be Recommended —Illustrative Example of the Solution of a Problem—Hypothesis Engineering Calculations—Consideration of Shovel Methods Consideration of Underground Methods—Top-slicing—Shrinkage —Stope Method—Block-caving—Branch-raise System—Esti- mated Grade of Ore which can be Worked and Yield a Profit Consideration of Profits from Lower Grade Material—Comparative Resume of Estimated Profits Derivable—Conclusion and Remarks —Special I'robleiiis. CONTENTS xi CHAPTER VII Page Cost of Shovel Work 216 Introduction—Wage Scales—Examples of Cost—Nevada Con. Copper Co. —Utah Copper Co. —Chino Copper Co.—Chile Copper Co.—Mesabi Iron Ores—Miscellaneous Work—Anthracite Strip- ping—Yukon Gold Co. —Panama Canal—Keeping of Cost Records —Graphic Records—OfFce Ta})ulations—Annual Reports. CHAPTER VIII Administration 240 Introduction—Ratio of Output—Example—Lowest Grade of Ore that Should be Worked—Amount of Prepaid Stripping—Engineer- ingj Work—Labor. Index •. 251 STEAM SHOVEL MINING CHAPTER I THE POWER SHOVEL INTRODUCTION TO MINING OPERATIONS Early Open-Cast Work.—Since the earliest time recorded, mining has been carried on from open-pits or "glory-holes." In some places the ore-bodies could be removed directly from the surface, but more often it was necessary to remove valueless material from the top before much of the ore could be won, and later, as depth was gained, valueless material had to be removed from the side slopes. Before the invention of excavating machinery, this work was slowly performed by human labor. In those early times much of the work was done by slaves, and all classes of human labor was indeed cheap in comparison with present labor. Without the assistance of perfected excavating machinery it would now be unprofitable to work many ore deposits which are to-day being profitably exploited, and many others would yield only a small part of the profit they now yield. Transition at Rio Tinto, Spain.—One of the oldest and most interesting examples of open-cast work is found at Rio Tinto, Province of Andalusia, southern Spain. This district was known as Tarshish in the Bible and as Tartessus in classic days, and to it is attributed the silver and much of the gold which formed the mainstay of the wealth of Tyre. Thus its history dates from the remotest antiquity, when it was worked by the Phoenicians, and later by the Romans. These ore deposits are essentially great lenticular bodies of copper-bearing iron pyrites, but their upper portions were so enriched by decomposition that they yielded good returns in silver and gold, and in enriched copper ores which were smelted in little furnaces. Great heaps of old slag found about the mines testify to the large amount of ore extracted and the excel- lence of the metallurgy, the labor of which must have covered 1 STEAM SHOVEL MINING a long period. Part of this work was in the form of open-casts, as they are termed, and part was underground galleries. After a time of inactivity these mines were again exploited by the Spaniards, but they had a rather checkered career until 1872 when those at Rio Tinto were sold to London and - THE POWER SHOVEL 3 Bremen capitalists. The new owners continued to work tlu; open-casts with hand-labor, but with the cost of production steadily increasing.

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