GIFT OF Dean Frank H. Probert Mining Dept. HANDBOOK OF MINING DETAILS McGraw-Hill BookCompany Electrical World Ite Engineering ardMining Journal Engineering Record Engineering News Railway Age Gazette American Machinist Signal Engineer AmericauEtigineer Electric Railway Journal Coal Age Metallurgical and Chem ical Engineering P owe r HANDBOOK OF MINING DETAILS COMPILED FROM THE ENGINEERING AND MINING JOURNAL BY THE EDITORIAL STAFF McGRAW-HILL BOOK COMPANY 239 WEST 39TH STREET, NEW YORK 6 BOUVERIE STREET, LONDON, E. C. 1912 SIFT Off FrfANK H MINING DEPI. COPYRIGHT, 1912, BY THE MCGRAW-HILL BOOK COMPANY OT. THE. MAPLE. PRESS- YORK. PA PREFACE This book is a collection of articles that have appeared in the Engineering and Mining Journal during the last two or three years under the general head of "Details of Practical Mining," a department of the Journal that has been appreciated highly by its readers, many of whom have expressed the wish that a collection in book form be made, which has now been done. In the editing of this volume, the work has been chiefly in the selection of the material and its arrangement in chapters. Now and then it has been possible to excise some paragraphs as being unessential and occasionally the phraseology of some articles has been altered a little, the requirements of preparation for the original weekly publication not always having permitted leisurely considera- tion, but in the main the articles now presented in this book are as they were given in the pages of the Engineering and Mining Journal. However, it has been necessary in a few cases to reduce the size of the engravings. In making this collection the limitation of space necessitated the rejection of all material that did not pertain to the subjects selected for the chapters of the book, and even so it was necessary to dismiss some of the longer articles pertaining to them, which approached the character, of essays rather than being the description and discussion of details. Of course a wealth of contributions pertaining to the arts of ore dressing and metallurgy had to be rejected sum- marily. The compilation covers the publications in the Engineering and Mining Journal from Aug. 7, 1909, to July i, 1912. If all of the material that appeared in this department of the Journal during that period of three years had been used it would have been necessary to make a book of several times the size of this. No claim is made that this book is a treatise, exhausting its subject, or any part of it. It is simply a handbook that is a more or less random collection of useful information, being just what passes through the pages of the Engineering and Mining Journal in the course of a few years. No special attempt to round out any subject has been made. Yet it will be found that some subjects are fully treated. With regard to the authority of what is to be found in these pages: The matter in the main is merely descriptive of what is done. Nevertheless, there is frequently the injection of opinion and advice. A great technical journal is directed by its editor and is shaped by its editorial staff, but it is essentially the product of its contributors. It is a co-operative institution and its pages are a symposium of the experiences and views of many professional men. During the 18 months ending with June 30, 1912, there were 460 contributors to the VI PREFACE Engineering and Mining Journal, exclusive of the members of the editorial staff, and its regular coadjutors, and its news correspondents. Many of these con- tributors furnished articles that are now collected in this book. Their articles generally are signed. The unsigned articles are chiefly the work of members of the editorial staff of the Journal who have been sent into the field to study mining practice. The heterogeneous authorship of this book naturally gives rise to some in- consistencies, some differences of opinion and some conflicts in advice. It has seemed to me best to let these stand just as in the original, since they are often merely the reflection of different conditions prevailing in different parts of the country, and if carefully read, absence of unity in this respect will not be mis- leading. W. R. INGALLS. October i, 1912 CONTENTS CHAPTER I PAGE GENERAL NOTES I Checking Men in and out of Mines Mining Records (by Frederick T. Rubidge) Standard Cost Sheets Labor Wasting and Labor Saving (by S. A. Worcester) Labor and Tonnage Charts as Aids in Reducing Costs (by Claude T. Rice) The Automobile in Mining Acetylene Lamps Candle Tests (by Claude T. Rice) Underground Repair Shops Abandoned Shafts and Open Cuts Speaking Tubes in Mines (by Lee L. Wilcox) Improvements in Mine Bunks Portable Houses A Sanitary Underground Latrine Inspection Department of the Goldfield Consoli- dated Goldfield Consolidated Fire Equipment (by Claude T. Rice) The Diamond Hitch (by W. H. Storms) Splicing Wire Rope A Guy Rope Tightener Disposal of Waste Mine Tailings for Filling (by Lucius L. Wittich) Strength of a Mine Dam. CHAPTER II EXPLOSIVES 24 Don'ts in Using Explosives Preparations for Blasting (by M. T. Hoster) Table for Cutting Fuse Blasting in Wet Shafts (by E. M. Weston) Blasting in Wet Ground The Calumet System of Lighting Fuse Prevention of Drilling into Mis- fired Holes (by John T. Fuller) Cartridges for Tamping Use of High Explosives Joplin Scraper and Loading Stick Breaking Ground for Steam Shovels The Necessity for Strong Detonators Priming with Electric Fuse Device for Clearing a Hung-up Chute (by J. Bowie Wilson) Powder Magazines Powder House with Concrete Roof (by Claude T. Rice) Concrete Powder House Powder Storage Underground Thawing Dynamite Thawing Dynamite by Electricity. CHAPTER III ROCK DRILLS 46 Air Hammer Drilling in Sticky Ground (by George E. Addy) A Drill for Soft Ground Design of Drill Bits (by Ward Blackburn) Rand Drill Steel and Bits (by E. M. Weston) Ejecting Sludge from Drill Holes (by E. M. Weston) Improved Chuck for Piston Drills Shaping Chuck Bolts (by H. Lawrence Brown) Improved Drill Post Collar (by Albert Mendelsohn) Drill Post with Removable Screw Jack for Machine Drill Columns Removing Stuck Drills Wrench for Removing Stuck Drills (by Claude T. Rice) Wrinkle for Piston Drill Cleaning Drill Holes (by J. H. Forell) Preventing of Freezing of Air Exhaust Cutting Timber by Small Hammer Drills An Air Moil for Cutting Timber Hitches (by S. H. Hill) Boring Flat Holes with Air Hammer Drills (by Clarence C. Semple) Drilling with Double Screw Columns (by P. B. McDonald) Bundling Drill Steel Handling Drill Steel at Champion Mine Mine Dust Prevention on the Rand (by E. M. Weston) The Dwyer Dust Arrester Water Blast for Allaying Dust. vii viii CONTENTS CHAPTER IV PAGE SHAFT WORK 68 Shaft Sinking at the Pioneer Mine Rapid Shaft Sinking in Butte (by C. J. Stone) Shaft Sinking at Stella Mine, New York Bucket Trolley for Shaft Sinking (by L. E. Ives) A Two-way Shaft Securing Loose Rock by Bolts Necessity for Strong Partitions in Shafts Corner Framing of Shaft Timbers (by W. H. Storms) Method of Extending Shaft Timbers (by D. A. McMillen) Shaft Timbering at the Keystone Mine (by William H. Storms) Rogers Shaft at Iron River, Michigan (by H. L. Botsford) Combination Post and Set Timbering in Shafts (by Claude T. Rice) Timbering Swelling Ground (by George C. McFarlane) Placing Shaft Timbers Supporting Guides or Runners in Shaft Holding Shaft Timbers with Wire Cables Steel Shaft Sets on the Mesabi Range (by F. A. Kennedy) Arrange- ment for Guiding a Drop Shaft Concrete in Inclined Shafts (by Sheldon Smillie) Injection of Grouting behind Shaft Tubbing Grouting in Quicksand Shaft Station in Inclined Foot Wall Shaft (by Claude T. Rice) Large Underground Station in a Coeur d'Alene Mine Concerte Floors for Shaft Stations Skip Pockets Skip Pocket and Station at Leonard Mine, Butte. CHAPTER V DRIVING ADITS AND DRIFTS 101 Fast Drifting Maintaining Grade in Driving Alignment in Driving Placing Holes for Blasting (by P. B. McDonald) Drifting with Stope Drills (by Horace Lunt) Driving Inclined Raises with Stoping Drills (by Arthur O. Christensen) Driving Vertical Raises with Stoping Drills (by Arthur O. Christensen) Staple for Temporary Staging Framing for Tunnel Sets Comparative Strength of Several Styles of Framed Timber Sets (by K. C. Parrish) Reinforced Concrete in a Tunnel A Method of Mining in Heavy Ground (by W. L. Fleming) Driving in Loose Ground (by George J. Young) False Set for Spiling Ground (by James Humes) Drift Timbering for Heavy Ground Finger-pin Timbering in Swelling Ground Joint for Drift Timbers. CHAPTER VI STOPING .,....">' ". ... 121 Stoping with the Slicing System Stoping at Goldiield Consolidated A Modified System of Back Stoping (by J. E. Wilson) Eliminating Shoveling in Square Set Stopes Recovering Ore from Pillars Scaffolding for Drills in Wide Stopes Placing Holes in Breast Stoping (by Harvey S. Brown) A Method of Blasting in Stopes Obtaining Cheap Stope Filling "Sand Filling" Stopes in the Transvaal The Use of Cyanide Tailings for Stope Fillings Mining Dangerous Ground on the Mesabi Range (by B. M. Concklin) Method of Rigging Ladders to Reach Stope Backs Staging for High Set-ups in Stopes Chain Ladders in Waste Chute Notes on Placing and Cutting Stulls Framing of Round Timbers (by Percy E. Barbou~ N Leaning Stope Sets Battery Method of Stull Timbering (by Claude T. Rice, - Timbering Wide Stopes Placing Sills Beneath Square Sets Already in Place Centennial-Eureka Chute Pocket and Gate Steel Ore Chute for Use in High- grade Stopes Bulkheaded Ore Chutes Lining for Ore Chutes Safeguarding Ore Chutes Gate for Ore Bin Chutes (by Algernon Del Mar) Ore Crushing Plant l Underground Underground Grizzlies A Movable Picking Floor A Modified Chinaman Ore Chute Construction A Standard Ore Chute (by S. S. Arentz). CONTENTS ix CHAPTER VII PAGE HEADFRAMES, CHUTES, POCKETS, ETC I49 Gate for Ore Chute Chute Gate at Mammoth Mine, Kennett, Cal. Gate for Lump Ore Bin (by Guy C. Stoltz) A Finger Chute (by A. Livingstone Oke) Steel Arc Chute Gate Cananea Arc Type Gate Skip Loader at the Original Consolidated Measuring Pocket for Skips Skip Loading Chute Whitford-M lls Skip Loading Device (by E. M. Weston) Red Jacket Ore Pockets Measuring Pocket for an Inclined Shaft An Underground Ore Pocket How to Erect Three- leg Shears (by A. Livingstone Oke) Headframe for a Prospect Shaft Headframe for a Winze Hoist An Underground Hoist Details of a Wooden Headframe Overwinding Allowance in Head Gears Tipple Construction in the Birmingham District Cananea Ore Bins (by Claude T. Rice) Tonopah Orehouses Concrete Storage Bin (by Fremont N. Turgeon). CHAPTER VIII HOISTING AND TRANSPORTATION 177 Graphic Solutions of Skip Loads (by F. W. Collins) Vertical Unbalanced Loads Lifted by First Motion Hoist Determining the Rope Speed in Hoisting Determin- ing the Number of Cars Hoisted per Hour Determining the Face of Winding Drums Determining the Amount of Rope Wound on a Drum Power Required to Haul % Cars on Various Pitches Rope Capacity of Drums Flat Rope vs. Round Rope Remarks on Hoisting Ropes Uses for Old Hoisting Cable Gravity Planes at Cheever Mine (by Guy C. Stoltz) Car Stopping Devices on Gravity Inclines Tail Rope Haulage Operated by Skips An Underground Haulage System (by Albert H. Fay) An Underground Hoisting Station (by S. A. Worcester) Catenary Hoisting Cable Double Hoisting Cables Hoisting Cable Run through a Drill Hole Rapid Hoisting with Wire Guide (by Hugh C. Watson) Concrete Chute Bridging a Level A Cheap Mine Road (by S. H. Brockunier) Snatch Blocks Applied to Hoisting (by Stephen L. Goodale) A Simple Form of Lift Cable Drum for Lowering Timber A Portable Winch Combination Timber Hoist and Winch Interchangeable Arrangement for Steam and Electric Hoist A Cone Friction for Mine Hoists Deep Sinking with Gasoline Hoists Steam Hoists for Shallow Mines (by Sven T. Nelson) Sheave Supports for Underground Hoists Arrangement of Sheaves at the Tobin Mine Rope Guard for Idler Rope Idlers for Inclined Shaft Idler for Hoisting Rope in Inclines Device for Prevention of Overwinding Device for Cleaning Flat Wire Cables (By M. J. McGill) Mine Signal Switch- Electric Signals for Underground Tramways (by W. S. Grether) An Electric Signal Device (by P. B. McDonald) Hand Bell Signal Wiring (by Guy C. Stoltz) The Solution of a Cableway Hoist Problem Turning Device for Tramway Track Cables Cable Clamp for Tramway (by Claude T. Rice) Oiling Tramway Track Cables Oiler for Tramway Buckets Anchoring Wire Ropes (by A. Living- stone Oke). CHAPTER IX SKIPS, CAGES, CARS AND BUCKETS ....... 222 Drill-steel Bucket Tram Car for the Prospector (by Guy C. Stoltz) The Mineville Cre Bucket Joplin Bucket Cars Wooden Ore Car A Joplin Car for Boulders (by Claude T. Rice) Tram Car for Stope Filling Tram Car with Automatic Door Side Dump Mine Car (by Claude T. Rice) Cradle for Dumping Mine Cars CONTENTS PAGE Calumet & Hecla Ore Cars Coeur d'Alene Mine Car A Copper Range Man Car Copper Range Ore Skip The Franklin Ore Skip The Franklin lo-ton Skip Skip and Dump Plate for Vertical Shaft (by L. L. Wilcox) Automatic Skip for Inclined Shafts Dumping Skip for Winze (by K. Baumgarten) A Timber Skip Counterbalance for Skips Skip Improvements A Three-deck Man-cage Hiawatha Mine Cage (by H. L. Botsford) A Light Mine Cage (by H. L. Botsford) Harness for Lowering Mule Down a Shaft (by W. F. Boericke) Automatically Discharging Bailers (by W. H. Storms) A Two-ton Water Car (by Guy C. Stoltz) Scraper for Cleaning Stopes A Scheme for Transporting Lumber (by W. F. Du Bois) A Wagon Oil Tank (by Chester Steinem) An Automatic Bucket Tripping Device Safety Dump for Sinking Bucket Self-dumping Bucket for Winze (by Lawrence May) Automatic Bucket Dump Method of Handling Sinking Buckets (by W. B. Baggaley) Type of Skip Dumps in New York Iron Mines (by Guy C. Stoltz) The Orig'nal Consolidated Self-dumping Skip Skip Changing Device at Leonard No. 2 Shaft Crane for Changing Skips Self-acting Tipple Tram Car Tipple (by Guy C. Stoltz) Revolving Tipple Automatic Trip for Ore Cars. CHAPTER X SAFETY APPLIANCES FOR HOISTING AND TRAMMING 273 Hoisting Bucket Hooks A Safety Hook for Hoists Safety Crane Hooks Thimble for Hoisting Cable Safety Crossheads for Hoisting Buckets Safety Crosshead for Bucket Shaft The Bryant Safety Crosshead Safety Catch for Cage (by H. L. Botsford) Skip Chairs at Argonaut Mine Landing Chair for Skips in Inclines Emergency Chairs on Headframe Testing Safety Devices on Mine Cages Cage Landing Chairs (W. F. Boericke) Improved Landing Chair Chairs on the Cage Landing Chair for Cage (by C. L. Se very) Safety Gate for Cages (by R. B. Wallace) A Safety Device for Cages at the Chapin Mine Shaft Gates Anaconda Gates (by F. L. Fisher) Guards at Shaft Stations Mine Track (by Alvin R. Kenner) A New Track Spike Short Guard Rail Fastening (by G. M. Shoe- maker) Mining Track Frog Mine Track Switches Calculating a Crossover Switch Gravity Tram Switch (by B. A. Statz) A Double Gage Turnout An Automatic Switch A Convenient Switch-throwing Device Turntable for Mine Cars A Ball-bearing Turntable. CHAPTER XI PUMPING AND DRAINING 307 A Useful Pump Formula (by A. Livingstone Oke) Un watering Flooded Mines (by D. Lament) The Sinking Pump and Its Troubles (by M. T. Hoster) Unwatering a Mine with Electric Turbine Pumps (by Percy E. B arbour) An Automatic Cut-off for Electric Pumps Pumps for Fire Protection (A. W. Newberry) Repairing a Cracked Pump Cylinder Air Escape on Small Pump Columns Concrete Water Column Expansion Joint for Pipe Lines (by C. L. Edholm) Utilizing Water in Mines Pump Station at Leonard Mine, Butte Notes on the Pohle Air Lift (by W. S. Anderson) Unwatering Shaft by Compressed Air (by Louis Boudoire) Mine Eductors (by Oskar Nagel) Draining a Shaft through a Drill Hole (by Lucius L. Wittich) Draining with Well Points Draining an Ore Chute (by Arthur O. Christensen) Draining Gravity Planes Gate for Controlling Mine Water Stopping the Flow of Water from a Drill Hole. CONTENTS xi CHAPTER XII PAGE VENTILATION AND COMPRESSED Am 331 Ventilation for Transvaal Mines Carbon Dioxide Criterion for Ventilation Lack of Oxygen in Hydraulic Air Wrinkles for Ventilating Mine Workings Ventilation by Suction (by Arthur O. Christensen) Ventilating with Compressed Air Scheme for Ventilating the Working Face An Hydraulic Air Blast Wing Sail for Ventilating Shafts (by A. O. Christensen) Ventilating Slopes in Bisbee (by F. W. Holler) Piping Arrangement for Fan Blower Mine Ventilation through a Drill Hole Ventilation by Drill Holes (by W. F. Boericke) Self Acting Mine Doors A Mine Air Door (by P. L. Woodman) Starting a Ventilating Fan Automatically (by S. A. Worcester and J. H. Dietz) Volumetric Efficiency of Air Compressors (byF. D. Holdsworth) Test- ing Ah- Consumption of Drills Proportions of Air Mains and Branches Compressor Precooler Washing Air for Compressors Air Compressor Lubrication Storing Compressed Air in a Natural Rock Receiver Using a Pump for Compressing Air Reheating Compressed Air with Steam Reheater for Air Hoist Electric Reheaters Placing Air Lines in Shafts A Method of Hanging Air Pipes (by C. T. Rice) Stopping Leaks in Air Receivers Pipe Lines as a Factor hi Rescue Work Water hi the Air Line Freezing of Compressed Air Pipe Lines (by Stacy H. Hill) Electric Heater for Ah* Line Drains (G. C. Bateman). LIST OF ILLUSTRATIONS FIG. PAGE 1. Report Form to be Punched by Shift Boss 2 2. Labor and Tonnage Charts, Highland Boy Mine 9 3. Sanitary Mine Bunk 14 4. Sanitary Latrine Used Underground at Goldneld . . ; .- 15 5. The Diamond Hitch 18 6. Methods of Splicing Wire Rope 20 7. Guy Rope Tightener and Anchorages .................... 21 8. Fuse Table and Cap Crimper Used in Joplin District 28 9. Clay-filled Box with Nails Showing Position of Drill Holes 31 10. Method of Making Tamping Cartridges 33 n. Device for Molding Tamping Cartridges . -. . 34 12. Scraper and Loading Tool Used at Joplin ..'...- 36 13. Cannon for Opening Chutes ; 39 14. Powder House at the Champion Mine 41 15. Powder Thawer 43 16. Powder House at Traders' Mine . . . 44 17. A Pick-pointed Drill for Soft Ground . . . . 46 18. Drill Made of Steel Tubing 46 19. Designs of Drill Bits ......... -. . 49 20. Drill Bits Used on the Rand 51 21. Hollow-steel Bit with Side Opening . 51 22. North Star Boldess Chuck for Piston Drills ........... 52 23. Device for Shaping Chuck Bolts 4 53 24. Drill-post Collar without Bolts . . . . . ....:.....,.... . . 54 25. Drill Column with Removable Screw 55 26. Cast-iron Jack for Drill Column ........ 5 6 27. A Drill-twisting Wrench 57 28. Cotter Wrench for Stuck Drills 57 29. Squirt Gun for Cleaning Drill Holes 5 8 30. Drill Sharpening Plant at Champion Mine 63 31. Pursers' Dust Collector 65 32. Aymard's Dust Collector 65 33. Dwyer Dust-collecting Device 66 34. Water Blast and Draft Inducer for Allaying Dust in Drifts 67 35. Shaft Sinking under Rock Pentice 68 36. Details of Anna Shaft Extension 7 1 37. Plan of Stella Shaft 72 38. Bucket Trolley for Shaft Sinking 73 39. An Unusual Two-way Shaft 74 40. Shaft-timber Ends 7 6 41. Methods of Framing Shaft Timbers 77 42. Framing for Shaft Timbers to Allow for Additional Compartment 7 8 43. Method of Timbering the Keystone Shaft 79 44. Rogers Shaft Below Concrete Portion 80 45. Steel Work in Concrete Portion, Rogers Shaft . . 8l xiii xiv LIST OF ILLUSTRATIONS FIG. PAGE 46. Posts and Square Timbers in an Inclined Shaft 84 47. Shaft Timbering in Swelling Ground . . . . 85 48. Method of Supporting Guides ..... i .., 87 49. Steel Shaft Sets at Whiteside Mine 88 50. Arrangement of Guides for Drop-shaft Sinking 89 51. Sections of Inclined Shaft 91 52. Details of Connection of Concrete Shaft Runners with Wooden Runners of Rock House 92 53. Shaft Tubing Arranged for Injection of Grouting 93 54. Shaft Stations in Inclined Shafts 95 55. General Plan of Timber, Boiler and Hoist Stations, Morning Mine, Mullan, Idaho . . 96 56. Arrangement of Skip Pockets at Bunker Hill Mine . r . .''. . 98 57. Skip Pocket at i8oo-ft. Level of Leonard Mine, Butte, Mont. . . . . "."'- 99 58. Arrangement of Drill Holes in Opencut and Tunnel Work. .... . . . . . . 103 59. Foot Frame for Stoping Drill 105 60. Machine Set Up in Inclined Raise 107 61. Station and Timbering in Vertical Raise . . 108 62. Staging Staple and Manner of Using It no 63. Drift Set for Heavy Ground no 64. Framing for Tunnel Set in 65. Drift Timbering in Running Ground .........*..... 113 66. Section Along Drift Showing Method of Placing Sets . . . .". . . . . * . . . 113 67. Boom Method of Timbering in Drifting Through Heavy Ground 114 68. A False Set for Driving Through Loose and Heavy Ground 115 69. Drift Timbers at Kennedy Mine, Calif 118 70. Bridge Sets with Lagging Over Finger Pins * .' ....... 119 71. An Impracticable Joint 119 72. Scheme of Back Stoping Employed at the Dolores Mine 122 73. Section of Stope Showing Diverting Wing Chutes 123 74. Robbing Ore Pillars 124 75. Stage for Drilling or Sampling in Stopes ...;... 125 76. Arrangement of Holes for Blasting without Removing Drill . . . . . . . . . . 126 77. A System of Mining on Mesabi Range ......... 128 78. Ladder Scaffold for Stopes 129 79. Method of Measuring the Stull 131 80. The Stull in Place 132 81. Details of Square Set with Round Timbers . ; . , 133 82. Leaning Stope Sets Used on Mother Lode . . > 134 83. Battery Stulls in Calumet & Hecla Stopes . .'. , . . . 135 84. End View of Stope 136 85. Timbering Narrow Stopes in Treacherous Ground 137 86. Timbering Arrangement for Removing Back . . . 139 87. Plan fo Bulkheaded Ore Chute 141 88. Gate for Ore Bin Chutes 143 89. Arrangement and Construction of Underground Grizzly 145 90. The Improved "Chinaman" 146 91. Standard Ore Chute in Goldfield Cons. Mines 147 92. Standard Ore Chute Used at Nevada-Douglas Mines 148 93. Chute Gate at Mammoth Copper Mine 149 94. Air-hoist Gate for Coarse Ore 150 LIST OF ILLUSTRATIONS XV FIG. P AGB 95. Finger Chute for Filling Wheelbarrows 151 96. Steel Arc Chute at Pittsburg-Silver Peak Mine 152 97. Elevation of Cananea Bins, Showing Arc Gate 153 98. Details of Metal Part of Arc-type Gate for Chutes ' 154 99. Skip Loading Arrangement for Original Cons. Mining Co 155 100. Skip Loading Arrangement at Scranton Mine, Hibbing, Minn 156 101. Gate for Skip Loading Chute 157 102. The Whitford-Mills Skip-loading Device 158 103. Details of a Steel Ore Pocket in Red Jacket Shaft 160 104. Skip-loading Device at Osceola Mine 161 105. Underground Ore Pocket 162 106. Plan and Elevation of Three-leg Sheaves 163 107. Prospect Headframe at Sand Grass Shaft 164 108. Ore Bin and Headframe for a Winze Hoist 165 109. Arrangement of an Underground Hoist 166 no. The Clermont Headframe, Goldfield Cons. Mines Co 168 in. Constructional Details of Tipple Used in Birmingham District 169 112. Structural Details of the Cananea Ore Bins 171 113. New Orehouses of Tonopah Mining Co 172 114. Sections of Tonopah-Belmont Or ehouse 174 115. Elevations of Tonopah-Belmont Orehouse 175 116. Concrete Storage Bin , 176 117. Graphic Determination of Pull on a Skip Bail 177 118. Chart for Finding the Proper-sized Engine when the Unbalanced Load and the Steam Pressure are Known 178 119. Chart for Determining the Rope Speed in Hoisting 179 120. Chart to Determine Number of Cars Hoisted per Hour 180 121. Chart for Determining the Face of a Grooved Drum 180 122. Chart to Determine the Face, When the Drum is Not Grooved 181 123. Chart to Determine the Face, If the Drum is Conical 181 124. Chart for Determining the Amount of Rope Wound on Drum 182 125. Calculation of Power Required to Haul Cars on Various Pitches 183 126. Some German Car-stopping Devices 188 127. Winze Hoist Station in a Colorado Mine . I9 1 128. Snatch Block Applied to Mine Hoisting 195 129. Sketch Showing Piston Arrangement for Coal Lift 196 130. Device for Lowering Timbers in Iron Mines 197 131. Timber Hoist at Hematite Mine, Ishpeming, Mich. 198 132. Interchangeable Arrangement for Steam or Electric Hoist ..'..' 199 133. A Hoist Friction with Cork Insets -201 134. Continuous Diagram from an Automatic Cutoff Hoisting Engine 203 135. Sheave Support in Shifting Ground - 205 136. Arrangement of Hoisting Plant at the Tobin Mine 206 137. Idler for Skip Rope in Shafts -207 138. Idler Wheels for Hoisting Ropes 207 139. Idler for Hoisting Ropes Used at Champion Mine 208 140. Device to Prevent Overwinding 209 141. Cleaning Device for Flat Wire Cables 211 142. Signal Switch at Baltic Mine, Michigan . . 211 143. Spring Switch for Electric Mine Signal 2I2 xvi LIST OF ILLUSTRATIONS FIG. PAGE 144. German Signaling Device . 213 145. Arrangement of Signal-bell Wiring at Port Henry, N. Y 214 146. Details of the Ruttle Clamp for Tramway Cables 217 147. Nonleaking Oiler for Tramway Buckets 219 148. Wire-rope Anchorage 220 149. Bucket for Drill Steel - 222 150. Bucket and Tram Platform 223 151. Iron-ore Bucket Used by Port Henry Iron Ore Co 224 152. Bucket Cars Used in the Joplin District 225 153. Sulphur, Mining and Railroad Co.'s Ore Car .226 154. Car for Tramming Boulders, as Made at Joplin 227 155. Trimountain Car for Stope Filling 228 156. Side-dump Car Used at North Star Mine, Grass Valley, Calif 229 157. Mine-car Dumping Cradle 230 158. Two-door Car for Tramming Boulders 232 159. Ore-car Used in Main Tunnel of Morning Mine, Ida 233 160. Man- Car for an Incline Shaft 234 161. Details of the Skip Used at the Champion Mine 236 162. The lo-ton Skip for the Franklin Mine -. - 238 163. Skip and Dump Plate Used in a Minnesota Iron Mine 239 164. A Skip for Flat-dipping Shaft 240 165. Automatic Dumping Skip for Winze . 241 166. Skip at Adams Mine 242 167. Hiawatha Cage with Skip Attached , 244 168. Safety Catch Used on the Hiawatha Mine Cage .. . 245 169. Structural Details of a Light Mine Cage . < 246 170. Harness for Lowering Mules 248 171. Automatic Discharging Bailers 249 172. Water Skip Used at Mineville, N. Y. . . - 250 173. A Lake Superior Stope-floor Scraper . 251 174. A Lumber "Lizard" 252 175. Tanks for Wagons for Hauling Fuel Oil 253 176. Automatic Bucket Trip . . . 254 177. Arrangement Used at Kennedy Mine for Dumping Sinking Bucket 255 178. Self -dumping Bucket Used at Bully Hill Mine .256 179. Automatic Dumping Bucket 258 180. Surface Arrangement for Handling Sinking Buckets by Compressed Air 260 181. Types of Skip Dumps . . 261, 262 182. Self-dumping Skip at Original Mine, Butte, Mont 264 183. Arrangement for Interchanging Skips and Cages on Leonard No, 2 Headframe, Butte 266 184. Arrangement of Track for Tipple 268 185. Automatic Tipple with Support 268 186. Constructional Details of Cars and Tipples 269 187. Tipple Used by Witherbee, Sherman & Co., Mineville, N Y .'270 188. Revolving Tipple for Ore Cars ..271 189. Car with Automatic Trip 271 190. Snap and Pig-tail Bucket Hooks Used in Joplin Mines 273 191. Swivel Hook for Hoisting 273 192. A Self-locking Hoist Hook 274 193. Types of Safety Crane Hooks 275 LIST OF ILLUSTRATIONS xvii FlG - PAGE 194. A New Safety Crane Hook 276 195. Details of Hoisting-cable Thimble 277 196. Safety Crosshead Used at a Cobalt Mine 278 197. Safety Crosshead for Hoisting with Buckets 279 198. Crosshead Used on Sinking Bucket in Morning Mine 279 199. Bryant Safety Crosshead 280 200. Device for Lowering Bucket Independently of Cage 282 201. A Lake Superior Type of Mine Cage . . . . 284 202. Skip Chairs Used in Argonaut Mine, Jackson, Calif 286 203. Buffer Bars for Incline Skipways 287 204. Tripping Device Used in Testing Safety Appliances on Cages 288 205. Landing Chairs in Shaft 289 206. Landing Chair Used at Flat River, Mo. ........ 290 207. Cage Chairs . . 291 208. Cage Fitted with Landing Chairs 292 209. A Folding Safety Cage ............ 293 210. Safety Device for Cages ........... -. 294 211. Operation of Shaft Gates . 294 212. Station Gates in a Butte Mine . . . 4 . . 295 213. A Simple Iron Shaft Guard .................. 296 214. Extending Track without Using Short Rails . . . 297 215. Method of Fastening a Guard Rail 298 216. Track and Frog 299 217. One- and Two-way Mine Switches 300 218. Calculating a Crossover Switch 301 219. Switch for Gravity Tram 301 220. Double-gate Turnout Used on Mine Tracks 302 221. Gravity Switch for Ore Cars . 303 222. The Petersen Switch 303 223. Turntable Used in Highland Boy Mine 304 224. Turntable Used in Some Michigan Copper Mines 305 225. Valve and Column Pipe of Sinking Pump 312 226. Arrangement of Automatic Cut-off 314 227. Pump Connected to Airlines for Fire Service 316 228. Timber Set in Pump Station, Leonard Mine, Butte, Mont 318 229. Air-lift for Unwatering Shaft 321 230. Types of Mine Eductors 322 231. Drainage Scheme from Station to Suction Pipe 326 232. Method of Cutting Timbers 326 233. Draining a Gravity Plane with Sewer Pipe 327 234. Cast-iron Gate for Mine Drifts 328 235. Drill Hole and Fittings 330 236. Jet for Ventilating by Compressed Air 333 237. Water and Air-line Connections for Spray 335 238. Convenient Air Blast 336 239. Sail for Shaft Ventilating 33 6 240. Pipe Arrangement on Fan Blower Used on Comstock 337 241. Stove-pipe Ventilator for Drill Holes 339 242. Self-acting Mine Doors for Double Track Drift or Tunnel 340 243. Details of Mine Air-door and Catches 34 1 xviii LIST OF ILLUSTRATIONS FIG. PAGE 244. Automatic Starter for Ventilating Fan , 342 245. Air Tank and Connections. . f 347 246. A Precooler for Air Compressors 350 247. Concrete Box for Washing Air . . , . ... . ^. . . . *. . . 351 248. Piping from Pump to Tanks ....*.*. 352 249. Electric Reheater Used at Bully Hill, Calif 354 250. Old Pipe Supports for Air Mains . .... . 356 251. Taper Bolt for Stopping Leaks 357 252. Ejector Valve for Air Line 358 253. Piping for Ejecting Valve 359 2 54. Electric Heater Used on Cobalt Air Mains 360 I GENERAL NOTES Economics of Management Convenience and Protection of Employes and Equipment Knots and Ties Miscellaneous Notes ECONOMICS OF MANAGEMENT Checking Men In and Out of Mines. At the Newport mine, Ironwood, Mich., where over 1000 men are employed, each man is given a brass tag with a number. Each morning as he goes to work he must appear at the time- keeper's office and present his brass tag, receiving in exchange a small card- board check upon which is the date, his name, number and occupation. He keeps this check during the day and returns it at night with the timekeeper's notation on it showing the number of hours worked and the job or contract number, to w r hich his time is charged that day. The brass check is returned to him when he presents his cardboard check. The time records are made up from these cards. The system entails much labor but no more than in almost any factory employing a like number of men. In order to divide the work of issuing these checks at the office windows, there are three aisles leading to three office windows; one for the surface men, one for the numbers ranging from 400 to 1000 and a third for numbers above 1000. Mining Records (By Frederick T. Rubidge). The collection of mining data is not always an easy matter and it not infrequently happens that men who are good mine foremen and shift bosses have little education and cannot write legibly, especially by the light of candle and with the palm of the hand as a desk. The writing of the reports gives an excuse for a half hour's leisure, and it is customary for them to retire to some convenient place in order to make out those required of them, and this usually at the end of the shift when their men should be watched and the holes are being charged for blasting. When thus writing up his report from memory the shift boss often forgets just how many men he had in this or that working place, and satisfies himself by putting figures down which will total properly. And when this report is received either by the foreman or at the main office it is scarcely intelligible, due to the combination of errors, smut and poor writing. In endeavoring to overcome the difficulties mentioned, I have successfully replaced the pencil with the punch, the results being (i) a more accurate report, for the reason that the punching is done at the working place and without inconvenience, ($) a more legible report, being both clean and neat, HANDBOOK OF MINING DETAILS m ?4glditioit to being entirely printed, (3) and a report in which, the duplicate 'is aVgbbd as w t5ie original. Incidentally the men take kindly to the innovation. Figure i is a reproduction of the shift-boss report. The forms as furnished to the shift bosses were bound into booklets of 50 leaves, alternately white and light green in color, and with light fiber covers. The stopes were numbered according to the coordinate system. The coordinate numbers were also used, in connection with the level, compass point, or foot- and hanging-wall (F. W. and H. W.) to designate the location of raises and drifts, punching also the word RA ISE or DRIF T as the case might be. M D stands for mine development and D W for dead work as opposed to mining proper. Under DRILLS, B H stands for block-hole drill, H D for hammer drill, and P for piston drill. JAN. SEP. DRILLS NO NO. 2 XTRA FUSE CAPS LAG'NG HOTT SETT. T.M CARS FEB. OCT. 100 100 200 1001200 100'200 300 300 300 APR. DEC. 400 400 MAY 3 500 500 600 1910 DAY 1912 KCT. FIG. I. REPORT FORM TO BE PUNCHED BY SHIFT BOSS. No. i, No. 2 and XTRA refer to grades of powder. Other abbreviations are as follows: S T, stopers; D R, drill runners; H, drill helpers (or timbermen's helper if TIM is punched, indicating that it is the timber boss' report) ; T R, trammers; T M, timbermen; GRA, grading; M, mucking; TRIM, trimming; PIL'R, when punched in conjunction with a stope number is understood to be the pillar adjacent to that stope on the north. The numbers under the different classes of labor and under drills indicate shifts. For the labor it would be better to use hours instead of shifts as being more accurate but in this instance it would have made the form too large for convenient handling and punching. For each working place a white and green sheet is punched one operation serving for both. The punched sheets remain in the book until the end of the shift when they are torn out and left at the mine office. The green ones are retained there, filed in pigeon holes corresponding to the working places, and the white ones are sent to the main office. Each shift boss has a different punch mark. Any necessary corrections can be made by the mine foreman who has an individual punch mark. GENERAL NOTES 3 At the end of the month the totals for each working place are made up at the main office, according to these reports, the stoping being separated from the drifting and raising. The necessary data regarding the tonnages are furnished by the surveyor and checked with the hoisting records. The surveyor also fills out the location, dimensions, inclination, etc., of the various working places. Powder is recorded in sticks but the explosives unit is necessarily the dollar. After the figures are completed copies are sent to the foremen for remarks, giving them the opportunity to explain any unusual increase in labor or explosives. If their remarks agree with the facts they are noted on the final copies which are distributed to all in authority. The punch form has also been used to advantage in recording electric haulage, hoisting and pumping records, and it is probable that it would be useful in milling and smelting. Standard Cost Sheets. The standardization committee of the Institution of Mining and Metallurgy on mine accounts and cost sheets, has made the following recommendations 1 in regard to the standardization of working accounts and cost sheets. These recommendations have been adopted by the council, which advises their use wherever conditions will permit. The committee recommended that for the sake of convenient comparison, both in working accounts and cost sheets, all expenditure should be classified under the following main heads: (i) Development. (2) Extraction of ore (i.e., mining). (3) Sorting at surface, preliminary crushing and transport. (4) Re- duction costs (i.e., ore treatment). (5) Administration charges and general charges at mine. (6) Realization charges on products. (7) Taxes and royal- ties of all kinds, shown separately. (8) Head-office charges. The subdivision of these main heads into subheads must necessarily depend somewhat upon the conditions, but the advantages of adhering as closely as possible to one form, and departing from it only where necessary, are manifest. The following were suggested as desirable subdivisions: (1) Development costs need only appear in the general cost sheet in one total, but a detailed sheet should be prepared showing the total expenditure and cost per foot in shaft sinking, driving, crosscutting, raising, winzing and plat (or station) cutting separately, as well as the proportions of these expenditures which are for labor and for materials respectively. (2) Extraction of ore may be usefully divided into: (a) Stoping or break- ing of ore, including under subheads: compressed-air and rock-drill costs, labor and supplies, shoveling, etc. (6) Timbering, filling excavations and sorting of ore in stopes (if any), (c) Hoisting, (d) Pumping. Where the cost of pump- ing is exceptionally heavy, it may be convenient to make this item a main head. The same remark applies to the removal of the overburden when a deposit requires to be stripped, (e) Underground tramming. (/) Sampling, assaying and surveying, (g) General underground maintenance. It is sug- gested that these subdivisions of the main head should be set out in detail in Bull. No. 76, I. M. M. 4 HANDBOOK OF MINING DETAILS the general cost sheet, because mining is at once the principal item of working cost and offers the greatest scope for economies. (4) Reduction costs should be subdivided according to the treatment undergone by the ore, e.g., crushing, amalgamation, concentration, fine grind- ing, cyaniding sands, slimes treatment, roasting, smelting, converting, leaching, precipitation, etc. ; for each of which a detail sheet should be prepared in such form as circumstances may dictate. (5) Administration may be divided into salaries (general resident manager and clerical staff on the spot), stationery and office general expenses, traveling expenses, insurance and legal expenses, accidents, medical, sanitary and hospital expenses, stabling and sundry transport, etc. (8) Head-office charges, besides ordinary central-office expenses, will include a great variety of items, such as agency expenses, directors', consulting engineers' and auditors' fees, bank charges, etc., also interest on debentures (if any). The individual items under (5) and (8) are likely at times to merge one into the other. Labor Wasting and Labor Saving (By S. A. Worcester). The persistent use of such antiquated devices as hand-trammed cars and barrows, shovels, forks, scrapers, rakes and hand-feeding operations of various kinds in large plants operated with ample capital is difficult to understand. The army of laborers necessary is always ready for a strike whenever the agitator appears, and the operation of the plant is therefore largely subject to the caprice of this element. Lack of intelligence is a most fruitful source of annoyance and of accident to the laborer and the plant. The attitude of managers toward improvements finds, unfortunately, much support in the antiquated designs that are regularly being offered and erected by machinery builders and consulting engineers. An instance of this was the recent erection of several concentrating mills in which the concentrates are shoveled and wheeled from the table boxes, and, after drying or draining, are again shoveled and wheeled to box cars or wagons. One loo-ton mill, recently designed by a well-known engineer, requires five men per day shift and four men per night shift; another i5o-ton mill doing exactly similar work, but using modern devices economically arranged, employs but three men per day shift and two men per night shift. In the old-line mills referred to, one man per shift is usually employed as crusher feeder, whereas many well-known plants eliminate this attendance by using either a simple automatic feeder or a crusher hopper large enough to receive the mine run. Such simple and practical devices as shaking launders, conveyors, etc., for moving concentrates, are in use in a number of mills and are familiar to every progressive designer, so that there is no justification for shoveling and wheeling. Many cyanide plants employ one or more men per shift filling sand tanks by tramming a car from a sand bin to the tanks. Automatic appliances that GENERAL NOTES 5 would save their cost in a brief period of continuous operation were available for this work when these mills were built. Well-designed excavator and con- veyor systems for handling tailings and sands were proved successful a number of years ago, and the shovel and tram car are obsolete. Many managers and some engineers contend that automatic machinery involves necessarily a large outlay, and is, therefore, prohibited except for long- running operations. While it is no doubt true that the probable life of the plant must determine the outlay within reasonable limits, yet there are many instances of labor-wasting plants which have cost more than completely auto- matic arrangements would have cost. Automatic devices are not necessarily cumbersome and complicated. Highly economical results can often be accom- plished by simple and inexpensive apparatus, if the designer has the object fully in mind. Mills are frequently designed so that a large sample has to be reduced or cut down daily by hand. A large sample is then taken to the assay office and recrushed and ground, the rejection being returned to the mill. In nearly all cases a laboratory crusher with proper automatic sampling apparatus can be so placed by the designer that the sample made in the mill is ready for grinding, and small enough for convenient handling, all rejections being returned by the automatic splitter to the mill. The work thus done is likely to be more accurate than hand work and the labor saved is well worth considering. In mining operations the same disregard for economy of labor is evident. Nothing is more common than ore bins so designed that they can neither be filled to nearly the full capacity nor emptied entirely without using a shovel or scraper. Hoisting cages are still being frequently installed in metal-mine shafts, involving higher labor and power costs, greater first outlay and main- tenance, greater dead weight and smaller capacity by far than the skip, which is an old and thoroughly proved appliance. In view of the present state of the art, nothing but ignorance, in most cases, can explain this blunder. The employment of cages, with a number of laborers on each shift tramming small-capacity cars from cage to ore house or waste dump, is one of the most common labor- and power-wasting arrangements now in use. One skip-hoist- ing plant of my design displaced four laborers per shift, a net saving of $24 per day, by replacing cages with skips dumping into a motor car which delivers the ore to the ore house. This car is operated by a motorman. At two other plants, where the motor car is at all times visible from the engine room, the car is operated by the engineer, using a controller placed at the hoist. At two plants, where circumstances favor such an arrangement, the skip empties its load into a chute leading direct to the ore house and having deflecting doors which direct the ore to any desired bin. At smaller hoisting plants, using the bucket, there are now several different styles of automatic bucket dumpers in use, which in many cases save one man's labor per shift. These dumpers can be placed at the top of the headframe so 6 HANDBOOK OF MINING DETAILS as to dump the ore directly into the ore house, thereby saving the wages of a top trammer. In spite of the evident economy of these simple devices, mining operators are still frequently erecting labor wasters at actually a greater out- lay than would be required for uptodate rigs. The ancient hook-and-ring arrangement for dumping buckets is still being frequently erected in places where the inexpensive automatic device would save one man's wages per shift. One favorite argument against placing the ore house close to the shaft, in order to save tramming, is that the headframe must usually be made higher for this arrangement. It is also a popular belief among hoisting engineers that the more nearly vertical rope pull of the headframe has an undesirable effect on the hoist. I am positive that a careful analysis of conditions will fully dispel this belief. Mine operators seem to have an aversion toward head- frames of any considerable height, and when an extension can be no longer avoided it is made about half as much as it should be to give ample head room. As a rule it is far better economy to gain head room for ore-handling operations by a headframe of sufficient height, than to tram a car from the shaft over a dump or trestle to a point where sufficient elevation exists. An almost invariable mistake in the design of ore houses and bins is the prac- tice of placing the grizzly or spout which delivers ore to the bin at so low a height that the bin can be only partly filled when the rising ore chokes the spout. Then no further filling can be done until the ore is shoveled away toward the sides and corners of the bin. The spout must be so placed as to form a rock cone whose sides slope naturally from the top edges of the bin to the end of the spout, in order to fill the bin to its capacity without shoveling. The moss-covered error of insufficient slope in bin bottoms and chutes still prevails, and it is probable that fully 50% of all wooden bins built by small operators in the Rocky mountains have bottoms so flat that they cannot be emptied without using the shovel. Horizontal bin bottoms are still being built occasionally, although careful consideration of the working of this bin will nearly always place it in deserved disfavor. The practice of arranging bins from which ore is to be hauled by wagon, so that every pound of ore has to be shoveled into the wagon, is indefensible. Where the hauling is to be done by contractors and no lower price can be gained by using bin gates with ample height for saving shoveling, there is still the advantage that having a convenient arrangement insures better service than when all the ore must be shoveled. Teamsters' unions sometimes limit the number of loads per day per man or team, but in case of any delay the mine having spouts and gates is more likely to get its full number of loads hauled than the one without such conveniences. In many places ore bins for loading railroad cars are still erected with spouts So low that much scraping is necessary to empty the bins, and much shoveling necessary to trim the load. If the bins and spouts are properly designed gondola cars can be loaded rapidly without the use of either shovel or scraper. GENERAL NOTES 7 By using portable diverting spouts, box cars can be loaded and the load nicely trimmed without any shoveling. For loading fine ore, slimes and concentrates into box cars, a short portable conveyor operated by a small motor will carry the ore from the bin spout to the ends of the car and trim the load without wheeling or shoveling. If designing engineers will adopt as a cardinal principle the elimination, as completely as possible, of all manual labor and particularly of shoveling and hand-tramming, there will be materially less encouragement and support for managers who persist in labor- wasting methods, and if the managers will exhibit, in the adaptation of modern appliances to their work, a minute fraction of the ingenuity and dogged persistence with which they at present defend and adhere to their evidently obsolete equipment, labor problems will be speedily solved and net profits increased. Labor and Tonnage Chart as Aids in Reducing Costs (By Claude T. Rice). To get the mining costs as low as is compatible with good mining it is essential' to instill a healthy rivalry among the men and let them know that the mine superintendent, and every one in authority on the job, knows how much work they are doing. A great aid in accomplishing this at the Highland Boy mine is the posting of labor and tonnage charts where the bosses and men can see them. The tonnage chart shows the tonnage mined by each shift, the combined tonnage of the two shifts and the tonnage sent out over the tramway (at the Highland Boy, the ore is shipped in that way from the mine), the total number of machine drills at work in the mine, the number of machines working in ore and the number working in waste. On the labor chart, the total number of men employed at the mine, the number underground, the tons mined per man employed at the mine and per man working underground are shown. The charts are drawn on cross-section paper ruled 10 squares to the inch and a negative made from a tracing ruled with cross-section lines. From the negative a print with white background and blue lines is obtained. The scale and the headings, as well as the days of the month, are put on the original tracing cloth so that the final prints are all ready for use. The data for the last day of the preceding month are shown as the start of each curve. The days of the month are plotted as the abscissas and the other data as the ordinates, the horizontal scale being a day to the inch, while the vertical scale varies with the different curves. The various curves are drawn in with different-colored crayons so that there is no trouble in following them. The tonnage curves are drawn to a vertical scale of 100 tons to the inch, as at the Highland Boy mine the tonnage does not fluctuate more than 200 tons per day and this scale is ample to show with sufficient emphasis the varia- tions in the tonnage mined from day to day. The shift tonnages are plotted from the tonnage reported by the respective shift bosses who estimate this from the number of cars dumped in the tramway bins. The tramway tonnage is 8 HANDBOOK OF MINING DETAILS reckoned from the number of buckets sent out over the line and the average weight of a loaded bucket as determined over a long period of time by checking it against the weighed ore shipped to the smeltery. The tramway curve is therefore the more accurate curve. The curves reported by the shift bosses give checks on how full the cars are loaded underground, so by comparing the curves of the tonnages mined by each shift, it is possible to see which is, in all probability, failing to load the cars properly. At the Highland Boy mine, the saving effected by correcting the practice of underloading cars, through the use of these curves has been greater than the cost of keeping them. Below the tonnage curves, and on the same chart are plotted the machine curves. The vertical scale used on these is five machines to the inch. This scale is sufficient to give emphasis to the variations in the number of machines at work which is usually only about twenty-five. As one of the curves shows the total number of machines running on ore and another the number working on waste, and as most of the machines on development work would be working in waste, an indication is given as to whether the development work is being kept uptodate or whether it is being shirked so as to make a tonnage showing. It might be well to show the number of machines working in ore and the number on development instead of in waste; as such a curve would be more important than the waste curves unless the filling were being broken underground. The vertical scale used on the curves representing the number of men working about the mine is 10 men to the inch. It might be well at mines where the square-set method of mining is used or where stull timbering is done, to show how many men are working at timbering, for the job with the greatest possibilities for loafing is that of timbering. It always pays to keep close track of the timbermen. On the labor chart it might also be well to plot a curve showing the number of sets or stulls put in each day so as to keep still closer track of the work of the timbermen. On the tons-per-man curves a vertical scale of half a ton to the inch is used so as to show plainly the variations. The importance of this is evident. The drop in the labor curves shows clearly which day of the month is pay day, even if it is not marked. The tons-per-man curves also show that the best workers are not the drinking men, although this increase in the tons mined per man is due partly to the fact that less development work is done on pay day. At a mine where the stopes are being filled it would also be advisable to plot a curve, on the tonnage chart, showing the number of tons or cars of waste filling that is being dumped into the stopes. This would give a check on the progress in the filling of the stopes and the tendency to let that important element in the mining lag behind in the scramble after ore would be reduced. The importance of these curves representing graphically the several steps in the operation of the mine is evident. They afford, in a manner that spurs the men on to do better work, a means of keeping close check on 60 % of GENERAL NOTES the total expenditures in the mining of the ore. The curves have been in use at the Highland Boy mine nearly a year and have been found of great aid to those in charge. Their introduction was due to Ivan DeLashmutt, engineer at the mine. The set of curves shown in Fig. 2 are taken from the charts showing the details ^'.?.>'l 284 Tonnage 10 1 12 13 '-?,'. "' x ^N i_^. ^/ 5? ^& -si". 3 s^r 8 9 10 11 12 13 14 15 16 17 18 19 20 21 2 rticalScie:. V 3**' LI v^ As X ----- .,-': FIG. 2. LABOR AND TONNAGE CHARTS SHOWING RECORD FOR TYPICAL MONTH AT HIGHLAND BOY MINE. of the work for a fairly typical month. The work in keeping these charts uptodate is small. Charts 22 in. wide and 34 in. long are used. The Automobile in Mining. The automobile is doing much to solve the transportation problem in Mohave county, Ariz. A large auto-truck, put into use by the Dixie Queen mine recently, has been thoroughly tried out in the 25- 10 HANDBOOK OF MINING DETAILS mile haul between the mine and Chloride and has given excellent service. Loads as high as four tons have been successfully hauled to the mine in less than half the time required by teams. [Throughout the Western desert regions the automobile has proved an important factor in the development of the mining industry. The outlying, and formerly inaccessible, districts have been brought into easy communication with the centers of population, thus stimulating and facilitating operations. The use of automobile trucks has also become extensive in the mining industry all over the world. EDITOR.] CONVENIENCE AND PROTECTION OF EMPLOYES AND EQUIPMENT Acetylene Lamps. The Republic Iron Co. has been using acetylene lamps in its mines for about one year. When the lamps were first introduced, they were sold to the miners at the same price as the ordinary lamps in which "sunshine" was used. After all the men had been supplied, the additional lamps were charged out at 75 cents each, which is the actual cost. With ordi- nary care one lamp will last six months. The require 1/2 Ib. of carbide per day. That quantity is given to the miner at the beginning of each shift, at which time he returns an empty can which is filled during the day and thus is ready for the next morning. Each lamp burns about two hours before it is necessary to recharge. The lamp is small and light, and is worn on the hat, the same as the ordinary oil lamp. The great advantage in the use of these lamps is cleanliness. There is no oil and no soot. They also give a better light and do not foul the air to such an extent as some other illumi- nants. The acutal cost of using acetylene lamps is about one-fourth that of candles, and one-half that of "sunshine" or oil. Some superintendents have tried to introduce the acetylene lamp but have failed; some of the excuses are that the miner does not like the lamp; that it is too much bother to charge it with carbide twice a day underground, and that the lamps get out of order too easily. The lamp as usually constructed is too frail for rough usage. The reflector causes some trouble, and the thread which connects the carbide chamber with the water compartment wears out easily. These are mechanical difficulties that the manufacturers can readily overcome. With proper care the lamp, as constructed, will last a year. The Penn Iron Mining Co. has been using Baldwin acetylene lamps about two years at its mines near Vulcan and Republic, Mich. After a thorough trial, the lamps have proved to be cheaper than either candles or sunshine. They are much cleaner than candles or oil, give a better light and burn better in poor air. Candle Tests (By Claude T. Rice). Candle tests are run frequently at mines, but generally candles of the same make are tried the Granite candle, a soft one, against the hard wax candles, the Goodwin or the Schneider. There GENERAL NOTES II are several factors affecting the life of a candle, the most important being the condition of the air. Air currents, poor ventilation, and hot workings cause candles to burn dimly and unevenly, so all the material is not consumed. The size of the candle has an important bearing upon the cost per man, and often a cent per man can be saved by changing the weight. The accompanying table, made from the results of a test at a fairly well ven- tilated mine of about the average temperature for a deep mine, is interesting as showing the merits of some new candles or rather candles that are not so well known to western miners, while it also brings out the importance of the weight of the candle used. Since the tests were made the cost of candles has been reduced at this mine to 3.203 cents per man, using i2-oz. "Sunlight" candles. CANDLE TESTS Make of candle . . Standard oil Peiry (hard Perry (hard Perry (hard Werks (hard Schnei- ders "gran- ite" wax) wax) wax) wax) (hard wax) Weight, ounces 12 14 12 J-5 14 14. Length of test, days Number of men working per day 31 34Sl i5i 306 J 7 322* 26 3 o6f 2 3 366 2 9 380 Price per box at mine $? AC $4 64 $4 08 $4.36 $c .0^7 $4.0^6 Candles used per man per day. Cost per man per day. . 4.35 $0 062 3.06 $0.071 3-94 $0.067 3.58 $0.065 3-30 $0.0607 3-7 $0.0778 CANDLE TESTS (Continued) Make of candle Good- wins (hard wax) Standard oil, No. i hard Sunlight (soft candle) Sunlight Sunlight Weight, ounces 14 12 13 13 12 Length of test, days 14 16 3 3 1 3 Number of men working per day Price per box at mine 388| $C . 1C 383f $4.35 429! $2 .0^ 375* $2 .93 377i 7 ^ Candles used per man per day. Cost per man per day 3-5 $0.749 3-7 $0.064 3-44 $0.0421 3-546 $0.0433 3-538 $0.0403 12 HANDBOOK OF MINING DETAILS Underground Repair Shops. At the middle working-level stations of the shafts of the Tonopah Mining Co., and also in the Goldfield Consolidated mines, repair shops are maintained for fixing all air drills underground. A machinist is employed on day shift to make these repairs, and no machines are sent to surface unless there are some unusual repairs to be made. At the Tonopah mines the shop is equipped with a drill press which is especially useful in boring out broken stud bolts on the air chests, the only other power- driven machine being a grinding wheel. Power is supplied by a i-h.p. electric motor. Abandoned Shafts and Open Cuts. Abandoned shafts and open cuts should be kept securely covered or fenced to prevent accidents due to persons falling into them. This, however, is not always a simple matter, due to the fact that vandals steal the material with which the openings are covered or fenced. Only recently in South Africa an old shaft was covered with timbers too heavy to move, and they were actually chopped in pieces in order that they might be carried away. In another case a wire netting had been placed around an open pit and someone had deliberately taken the wire down and stolen it. In practically every mining camp there are abandoned shafts that are not covered or even marked. Too much care cannot be taken to make these places safe. In the vicinity of Nome, Alaska, there are dozens of open shafts on the tundra, with nothing to mark their situation save the small pile of dirt that has been taken out. During the winter the snow drifts over these, completely covering them, thus making an excellent trap for the cross-country traveler. Speaking Tubes in Mines. Speaking tubes are used for communicating from one part of the mine to another in the Allouez mine in the Michigan copper country. They can be used up to distances of 1000 ft., beyond which the service is not satisfactory. In the Allouez mine the tubes are i i/ 2-in. pipes. A tee is inserted in the line wherever it is desired to establish a point from which communications can be sent. The mouthpiece is made by screwing a short nipple into the tee. The nipple is closed by a wooden plug, attached to a string or chain hung from the pipe to prevent loss. The nipples are kept closed when not in use. To call a station a knocker, consisting of a 2-in. nipple that encircles the i i/2-in. pipe above the tee, is used. Lifting and dropping the knocker on the tee causes a sound that is clearly transmitted by the pipe. For greater distances than 800 ft., 2-in. pipe should be used. Safety Appliances in Mines (By Lee L. Wilcox). It is the purpose of this article to describe the various safety devices used at the mines of the Republic Iron & Steel Co. They naturally divide themselves into two class3s; those tending to prevent accidents and minimize the dangers to which workmen are subjected, and those which relieve suffering and lessen the attendant dangers after an accident has occurred. The first class, being preventive, has occupied most of the time and has included every phase of work about the mines. It was started by the appoint- GENERAL NOTES 13 ment of a committee from among the mining captains and mechanics, whose duty it is to make regular monthly inspection trips, to report on the condition of the various mines and to recommend means for improving the conditions where in their judgment it seemed necessary. This committee performs its work faithfully and efficiently, and the result has been the extensive adoption of safety appliances. This can be best described by citing some of the devices employed. In the shops all pulleys, belts, gears, and such equipment are enclosed with strong wire-cloth guards. Line shafts and jack shafts are provided with overhead walks for the oilers and repair men. Hoisting engines, compressors, and other machines are protected by substantial handrails wherever moving parts may endanger the employees. In the matter of underground protection the company is very particular. All openings, such as shafts or raises, are thoroughly protected by gates, railings or bars, making it practically impossible for a man to step into them accident- ally. In addition to this ore chutes are equipped with grates, and ladderways are provided with permanent platforms at intervals of about 12 ft., through which are left openings only large enough to allow a man to pass. Ladderways in hoisting shafts and air shafts are electric lighted wherever possible, and no one is allowed to carry a lighted candle in them, thus insuring protection against fire. The shafts are equipped with sprinkling devices for use in case of fire. These are made by running a 2-in. pipe the entire depth of the shaft. To this pipeline are connected, at lo-ft. intervals, pipes which extend horizontally around the shaft and which are drilled with 1/4 holes at intervals of 4 in. The stations and pump-rooms in the mines, where there is little water, are pro- tected in the same manner. The places so protected can be thoroughly sprinkled in a short time. In dealing with the second class of safety appliances, which have to do with conditions after an accident, the company has installed two complete sets of the Draeger rescue apparatus, 1910 type, one pulmotor and the necessary secondary equipment to keep this apparatus in perfect working order. Rescue parties consisting of from four to eight men, who are entirely familiar with the underground workings, have been organized at each mine. These parties are drilled regularly in the use of the apparatus. The drills consist of climbing ladders, using picks and shovels, carrying men and other such work. They are varied from time to time as the instructor may direct. Together with the rescue parties first-aid parties are organized. The company has a physician at these meetings to instruct how to handle injured men and how to apply bandages. Improvements in Mine Bunks. Proper sanitary conditions and comfort for employees should be seriously considered by operators in every line of business. Health and satisfaction among those employed at a mine is practi- 14 HANDBOOK OF MINING DETAILS cally conducive to an increased and steady production. This has been given consideration at the Sunnyside mine, in Eureka gulch, San Juan county, Colo. Here the mine has provided reading rooms, baths and every modern con- venience. The question of sanitary sleeping quarters within limited space has been solved by the installation of a bunk, patented and manufactured by Charles Scheer, of Silverton, Colo. It is made up of piping with appropriate coupling and joints. As shown in Fig. 3 it can be used with any coil spring. It is provided with side rails for the protection of the occupant. The parts are entirely separable and can be readily transported. The healthful atmosphere that prevails in the sleeping quarters at the Sunnyside mine is ample proof that it fulfils the desired object. In one feature alone, the elimination of the bed bug, the installation has repaid the company. FIG. 3. SANITARY MINE BUNK BUILT OF PIPE AND FITTINGS. Portable Houses. One of the continual problems of the prospector and miner is that of his cabin. To a certain extent this is being answered by the builders of portable houses. These range from 7X9 ft. to about 18X30 ft. in floor space, which means from one to six rooms. These houses can be set up or taken down without any tools in three hours, or less, are weather proof, and the material is also guaranteed against mildew or rot. They are usually screened, and completely proof against insects, a matter of importance in tropical or mosquito-infested districts. The weight of the houses per square foot of floor area varies from about 4.4 Ib. in the smallest size down to 3.2 Ib. in the larger sizes, while the prices range from about 80 cents per square foot of floor area for the smallest down to about 65 cents per square foot for the largest size. From the above data a miner knowing about the size of house he desires, can closely approximate its weight and cost. A Sanitary Underground Latrine. The latrine, the details of which are shown in Fig. 4, is in use at the Goldfield Consolidated mines, and after a test of several months has been found to be absolutely sanitary. Moreover, as the GENERAL NOTES 15 box closes tight, there is no odor of lime scenting up the whole level, as is the case when open boxes are used. The latrine is constructed of No. 10 sheet iron and can easily be made by any blacksmith. The top and bottom are riveted to the body, which is 26 in. high and 16 in. in diameter. The top is made by flanging over a form, as this is the easiest way when there are several to be made. This form is made from a plate of 3/4-in. iron, and the inside edge of the ring is turned in a lathe to an easy curve. The outer edge of the sheet forming the top piece of the box is flanged 2 in., so as to stiffen the sides. The Locking Ecceutrltf FIG. 4. SANITARY LATRINE USED UNDERGROUND AT GOLDFEELD. bottom piece is also flanged over the same form. A flange for a 2 i/2-in. pipe is riveted to the cylindrical body at the bottom, into which a pipe is screwed for an outlet. The outlet is closed with a screw plug, as a valve would be in the way and liable to be broken off when the latrine is taken to the surface to be emptied. A hole is drilled through the screw plug, and a pin put in it so it can be removed without touching it with the hands. Near the top, on the oppo- site side from the discharge, a flange is riveted for a 3/4-in. pipe, also closed by a plug. A short piece of pipe extends from the inside of the flange, ending in an elbow that is fastened to a short nipple pointing down to the bottom of the box. The cover piece is a circular plate of i/2-in. iron in which a groove is cut about 3/8 in. deep to hold a ring of i/2-in. engine packing, to make a tight joint between the cover and the seat of the latrine when the cover is locked in 16 HANDBOOK OF MINING DETAILS place. The cover is hinged to the body of the latrine, and is locked in place by means of a bar, fastened at one end of the body by a link so that when the latrine is in use underground it hangs straight down by the side, entirely out of the way. On the other end in the top of the locking bar is a notch over which slips a link fastened to the opposite side. A small eccentric with a short lever arm is carried on a bar for locking the device. After using the latrine, a little lime is thrown in and then the cover closed down, but not locked, as the weight of the lid is enough to keep the box fairly air-tight. The latrine is placed in a small room partitioned off for the purpose. Before removing the latrine the top is locked in place. It is then loaded on a truck and hoisted to the surface. There the discharge plug is removed by means of a wrench, and connection made between the washing-out jet at the top of the latrine and the water line at a pressure of about 120 Ib. per square inch. The seat is also washed by a hose. Inspection Department of the Goldfield Consolidated. The inspec- tion department of this company is in charge of the fire-fighting corps. Its members devote the entire 8-hour day to inspecting the mine workings, hoisting engines, hoisting ropes, cages and passages and ladders used by men. The miner who neglects keeping his working place safe is discharged. Records of all accidents are kept, the cause being specified after an investigation. The men are impressed with the importance of attending to minor injuries, especially cuts, in order to avoid septicemic infection. Since the organization of the department in May, 1910, there have been but two fatal accidents. The records show that the majority of the accidents were due to falls of roof, and falls down ladderways and chutes. Most of the ladderway falls were caused by the miners having one hand employed in carrying tools. The miners are encouraged in every way to report dangerous conditions, and are commended for their interest even though an investigation shows the report to be not well founded. Goldfield Consolidated Fire Equipment (By Claude T. Rice). Since the fire in April, 1910, did such serious damage to the Goldfield Consolidated mill, the company has spent much money in installing a comprehensive fire- fighting equipment. As the square-set method of timbering is used, it is necessary to keep a supply of timber at the sawmill. This timber is protected by several hydraulic monitors, mounted on platforms, high enough for the operator to get a good view of the yard, in a manner similar to that adopted at most of the big sawmills on the Pacific coast. The monitor used, made by A. J. Morse & Son, is much cheaper and less elaborate than most monitors put on the market; it costs only $15, while others sell for about $150. It has a 2-in. inlet and i-in. discharge pipe. It discharges about 350 gallons per minute at a pres- sure of 80 Ib. at the orifice, and has a range of about 1 50 ft. At the shaft and buildings there are hydrants with lines of 2-in. hose coiled nearby. At each mine and at the mill are fire stations, where are kept hose carts, ladders, a 4o-gallon chemical barge, picks and fire lanterns, all sealed in GENERAL NOTES 17 place to prevent tampering. All hydrants are kept sealed and are inspected about once a week, for if the water were turned off at one of these places, it might take several minutes to discover the difficulty, during which time the fire would be making headway. As the floor and much of the interior construction of the mill are of wood, 1 6 connections for hose are provided. Under the ore bins, where there is a possibility of a fire starting and gaining headway before being discovered, a sprinkler fire-extinguishing apparatus is installed. The main water line is carried on the trestles of the railroad that connects the mines with the mill, and there are numerous hydrants for hose connections at each trestle. The reservoir feeding this system is on top of Columbia mountain, and has a capacity of 146,0x30 gallons. There is a pump supplying the reservoir at the rate of 120 gallons per minute from a tank holding 30,000 gallons. The tank is replenished at the rate of 100 gallons per minute. In the fire-prevention equipment there are 11,500 ft. of 5~in. pipe, 5000 ft. of 4-in. pipe and 10,000 ft. of 2 1/2- and i -in. pipe, a total of 26,000 feet. Comparatively speaking, the amount of water available for underground fires is small. In contending against such fires, reliance would have to be placed upon bulkheads, so placed as to keep the fire within a restricted area. The mines are inspected after each shift for the discovery of incipient fires. At each mine there are two Drager helmets. KNOTS AND TIES The Diamond Hitch (By W. H. Storms). There are many things that prospectors should know in addition to a knowledge of minerals and formations and how to hit a drill, and one of the most useful of the others is how to " throw the diamond hitch." The diamond hitch is used to secure a pack on the back of an animal in such manner that the rope at the top of the pack forms a diamond, and is the most satisfactory way to fasten a pack that has been devised. The first essential is a good pack saddle, to which are attached back and breast straps to keep the load from shifting on steep hills. The next essential is a strong rope. A 5/8-in. manila is good, but a rawhide lariat is better if it is not too new and stiff. First secure the pack saddle on the animal, and be sure that it is secure, for pack animals soon become tricky and will swell up by holding their breath while the saddle is being cinched. To beat this draw the straps tight and pretend to make them fast, watching the animal, and when the breath is exhaled, quickly take up the slack. When the pack saddle is securely cinched the various articles of the pack may be placed on the back of the animal, being held in place by preliminary lashing, good enough to hold temporarily. After all is in place you are ready for the diamond hitch. This requires two men, one on each side of the animal. i8 HANDBOOK OF MINING DETAILS He on the left is the thrower; he on the right of the animal, the cincher. The thrower first ties one end of the pack rope securely to a ring attached to a broad leathern cinch, as at A in Fig. 5. The other end of this cinch is equipped with a hook B. Having made the rope fast, the thrower, holding the rope and ring end of the cinch in his left hand, tosses the hook end of the cinch under the animal's belly, where it is caught by the cincher with his left hand. The latter now stands ready to use his right hand when his partner throws him the loop C over the back of the animal. The loop is quickly caught in the hook, and the thrower adjusts the rope so as best to secure the various articles of the pack, Cinch Head Tail -Cinch FIG. 5. THE DIAMOND HITCH. while following the lines shown in the sketch. The cincher now draws the long end of the rope tight, and throws the loose end forward over the back of the animal to the thrower, and together they adjust the rope to the pack, while keeping the loose end taut. A turn is taken beneath the rope at D, and it is then carried forward and around the lower corner of the pack at E, and back- ward along the lower side of it toward F, where it is taken upward to the top and a second turn taken at G. From there it is passed around the back and upper comer at H, down to 7 and around that corner, and forward along the lower right-hand side of the pack to /, upward and around the corner at K and looped under at L; thence forward and downward to M, and along the lower GENERAL NOTES 19 left-hand side, where a turn can be taken in the crossing rope at JV, and the loose end secured in the diamond at the top of the pack. Throughout this entire performance the rope must be kept as tight as pos- sible, and the end secured so it will not slip. The diamond hitch is quickly undone, once the end is loosened, for there is no portion of it that binds, or works into hard knots. Splicing Wire Rope. Wire rope is susceptible of almost perfect splicing and the operation is so simple, states F. L. Johnson in Power, that it may be learned in an hour by any mechanic who is at all skillful in the use of ordinary tools. For all kinds of transmission rope the long splice is used and should not be less than 16 ft. in length for i/2-in. rope and increasing to 30 ft. for the larger sizes. Where the splicing must be done in position, rope blocks are used to draw the wire taut, as in Fig. i, care being taken to make fast far enough from the ends to leave plenty of room for the splice and the men who make it. If possible, it is better to hold the rope taut, mark the splice on both ends, by securely winding with No. 20 annealed-iron wire, throw it off the sheaves and make the splice on the floor or staging, as may be most convenient. The strands of both ends are unlaid, back to the points wound with wire, the hemp core cut off and the ends of the rope brought together with the strands inter- laced, as shown in Fig. 2. Any strand, as a, Fig. 3, is now unlaid and closely followed by the corresponding strand i of the other end of the rope which is pressed closely into the groove left by the unlaid strand. The unwinding of one strand and the inwinding of the other are continued until all but about 1 2 in. of strand i is laid in, when a is cut off at the same length and both strands securely tied with cord. Strands 4 and d are next treated in the same way and the pro- cess is repeated with each pair of strands until all are laid and cut, the projecting ends being tied as shown in Fig. 4 to prevent unwinding. When this has been done the splice is bent and worked in all directions until the tension in all the strands is equal and the rope as flexible there as elsewhere. If this is not done and there is more tension in some of the strands than in others when a stress is put on the rope, these strands will pull into the rope, making a bad looking and weak splice. Next, the open or free ends of the 12 strands are carefully trimmed and wound with fine wire. Two rope-and-stick clamps, Fig. 5, are now secured to the rope, one on each side of an end crossing, as in Fig. 8, for the purpose of untwisting the rope to allow tucking the strand ends into the middle of the rope. There are two ways of tucking in these ends. They are first straightened with a mallet; the long ends of the rope-clamp handles are twisted in opposite directions, separating the strands and exposing the hemp core, which is cut off and pulled out between the points to which the tucked-in strands will reach and the ends forced into the place formerly occupied by the core. This is most easily done with the aid of a marlin spike, which is passed over the strand that is to be tucked and under two strands of the rope, Fig. 6, and moved along the rope spirally following the lay and forcing the free end, as shown in 2O HANDBOOK OF MINING DETAILS Fig. 7, into the core space. In the other method the strands are more widely separated by untwisting the rope with the clamps, Fig. 9, slipping the free end between the strands and correcting slight kinks by the use of a mallet. The order in which the ends are tucked in is immaterial. Some operators prefer to FIG. 6. METHODS OF SPLICING WIRE ROPE. tuck all the ends pointing in one direction before any of those pointing the opposite way, while others finish each pair of ends in series. If the foregoing directions are intelligently followed the splice will be uniform with the rest of the rope, of nearly equal strength throughout, and after a few hours' use it will be GENERAL NOTES 21 almost impossible to detect the splice. Four-strand hemp ropes can be spliced in the same way, this splice being known among riggers as the long splice. Ji-in. Pipe 4-in. long Details of Guy Rope Tightener 18-h J d 7-tn. >] f^ H-in. Round Iron 4-ftr H Iron Parts of Concrete Anchorage FIG. 7. GUY-ROPE TIGHTENER AND ANCHORAGES. A Guy-rope Tightener. In Fig. 7 are shown the details of a guy-rope tightening device which is used in the southwestern Missouri zinc district. The tightening device resembles a buckle in construction. It is made of i/2-in. 22 HANDBOOK OF MINING DETAILS wrought iron, with a piece of pipe over the broad end of the buckle-shaped link so as to allow the tongue to rotate readily without much friction. This tightener is fastened to the anchor of 5/8-in. wrought iron after the guy rope has been secured to the tongue of the tightener. By using the tongue as a lever, the guy line is wound around the broad end of the buckle until the proper tension has been obtained. Then the tongue is locked by hooking its end over the buckle part of the tightener. The iron parts for a concrete anchorage in which a pipe cross piece is used are also shown. MISCELLANEOUS NOTES . Disposal of Waste. In the stripping of the large ore deposits on the Mes- abi range, the disposal of the overburden is one of the large problems that has to be solved. In most cases this waste material is hauled from i to 2 miles in side-dump cars and emptied over the side of a dump, 50 to 100 ft. high. The shifting of the standard-gage track to keep up with the growth of the dump is a matter of considerable expense. In nearly all cases this shifting is accom- plished by hand labor. At one or two mines it is done with the wrecking car by simply attaching four chains to 3o-ft. sections of track, lifting them bodily and setting them over the required distance. At one mine a track shifter is being tried. Where there is ample room and no danger of damage suits arising, the latest device is to use water to wash the material from the railroad tracks. The necessary requirements are a high bank upon which to build a 15- or 2o-ft. trestle, and a deep gulch in which to deposit the dirt. A substan- tial trestle is constructed and this is filled up to the ties with dirt from the dump cars. Just beneath the ties and on the outside row of posts is placed a 6-in. water pipe with i/2-in. holes in one side, 18 in. apart. These holes all open out from the track. The bottom of the trestle is buried sufficiently deep to hold it in place and there is little danger of its washing out. The material is dumped over the side of the trestle from the cars and the water plays upon it, washing it down the slope to the low ground. In this way the angle of repose for the dirt will be 10 or 15 instead of approximately 40. In the case under consideration the track is about 7 5 ft. above the side of a small lake. This flat alluvial fan will extend out a long distance and add largely to the capacity of the dump. In this way a solid track can be maintained and it need only be moved once in many months, whereas, in the usual scheme it is necessary to shift the track almost daily. The shifting operation is expensive and in addition the track is always in bad condition. Mine Tailings for Filling (By Lucius L. Wittich). While the use of mine tailings as railroad ballast is not new, the method employed by the St. Louis & San Francisco R. R. Co., west of Joplin, Mo., is, I believe, novel. The tailings were introduced into abandoned and dangerous zinc and lead workings directly beneath the railroad right-of-way through four 8-in. drill holes put GENERAL NOTES 23 down from the surface to penetrate the drifts, 140 ft. beneath. Hopper-shaped excavations were made at the top of each drill hole, the holes having been sunk between the rails of the track about 20 ft. apart. More than 16,000 cu. yd. of mine gravel were used in filling the old drifts, the greatest volume put through a single hole having been in excess of 9000 cu. yd. That the tailings might be equitably distributed and made compact, streams of water from two 2-in. pumps were poured into the hoppers, the water carrying the tailings through the drill holes and spreading them through the drifts. As a precautionary measure, to prevent the tailings spreading over too wide an area, the ground of the old workings, at certain points where it connected with other drifts, was shot down and these barriers acted as walls which stopped the promiscuous distribution of the waste chat, but which were porous enough to permit the big volume of water escaping into other drifts, from which it was pumped again through the pumps that had been stationed in the mine. Strength of a Mine Dam. The total pressure exerted by water on a dam is found by multiplying the wetted area of the face of the dam, expressed in square feet, by 62 1/2, the weight in pounds of i cu. ft. of water, and this prod- uct by the vertical height of the surface of the water above the center of gravity of the wetted area, says Coal Age. To calculate the required thickness of a dam, let /= Thickness of dam (in.); r= Shorter radius of dam (in.); w= Width of opening or span (in.); p= Pressure of water at dam (Ib. per square inch); S= Compressive strength of material (Ib. per square inch). For an arched dam The shorter radius of the dam should be from one-fourth to one-third greater than the clear span or width of opening. For practical reasons, it would not be advisable to build a dam less than 20 in. thick. II EXPLOSIVES Blasting and Handling of Dynamite Storage of Explosives Frozen Dynamite. BLASTING AND HANDLING OF EXPLOSIVES "Don'ts" in Using Explosives. The following "Don'ts" were embodied in a lecture on explosives, delivered recently by A. E. Anderson before the mining men of Telluride, Colo. While many of them are by no means new, occasional repetition is not undesirable; if properly observed, fewer dispatches headed "Blown up While Thawing Frozen Dynamite," etc., would be seen. Don't forget the nature of explosives, but remember that with proper care they can be handled with comparative safety. Don't smoke while handling explosives, and don't handle explosives near an open light. Don't shoot into explosives with a rifle or pistol, either in or out of a magazine. Don't leave explosives in a field or any place where cattle can get at them. Cattle like the taste of the soda and saltpeter in explosives, but the other ingredients would probably make them sick or kill them. Don't handle or store explosives in or near a residence. Don't leave explosives in a wet or damp place. They should be kept in a suitable, dry place, under lock and key, and where children or irresponsible persons cannot get at them. Don't explode a charge to chamber a bore hole and then immediately re- load it, as the bore hole will be hot and the second charge may explode prematurely. Don't do tamping with iron or steel bars or tools. Use only a wooden tamp- ing stick with no metal parts. Don't force a primer into a bore hole. Don't explode a charge before everyone is well beyond the danger zone and protected from flying debris. Protect the supply of explosives also from danger from this source. Don't hurry in seeking an explanation for the failure of a charge to explode. Don't drill, bore or pick out a charge which has failed to explode. Drill and charge another bore hole at least 2 ft. from the missed one. 24 EXPLOSIVES 25 Don't use two kinds of explosives in the same bore hole except where one is used as a primer to detonate the other, as where dynamite is used to detonate Judson powder. The quicker explosive may open cracks in the rock and permit the slower to blow out through these cracks, doing little or no work. Don't use blasting powder, permissible explosives or high explosives in the same bore hole in coal mines. Don't use frozen or chilled explosives. Most dynamite, except Red Cross, freezes at a temperature between 45 F. and 50 F. Don't thaw dynamite on heated stoves, rocks, sand, bricks or metal or in an oven, and don't thaw dynamite in front of, near or over a steam boiler or fire of any kind. Don't take dynamite into or near a blacksmith shop or near a forge on open work. Don't put dynamite on shelves or anything else directly over steam or hot water pipes or other heated metal surface. Don't cut or break a dynamite cartridge while it is frozen, and don't rub a cartridge of dynamite in the hands to complete thawing. Don't heat a thawing house with pipes containing steam under pressure. Don't place a hot- water thawer over a fire, and never put dynamite into hot water or allow it to come in contact with steam. Don't allow thawed dynamite to remain exposed to low temperature before using it. If it freezes again before it is used it must be thawed again. Don't allow priming, the placing of a blasting cap or electric fuse in dyna- mite, to be done in a thawing house or magazine. Don't prime dynamite cartridges or charge or connect bore holes for elec- tric firing during the immediate approach or progress of a thunder storm. Don't carry blasting caps or electric fuses in wearing clothes. Don't tap or otherwise investigate a blasting cap or electric fuse. Don't attempt to take blasting caps from the box by inserting a wire, nail or other sharp instrument. Don't try to withdraw the wires from an electric fuse. Don't fasten a blasting cap to the fuse with the teeth or by flattening it with a knife ; use a cap crimper. Don't keep electric fuses, blasting machines or blasting caps in a damp place. Don't attempt to use electric fuses with the regular insulation in un- usually wet work. For this purpose secure special waterproof fuses. Don't worry along with old, broken leading wire or connecting wire. A new supply won't cost much and will pay for itself many times over. Don't handle fuse carelessly in cold weather, for when cold it is stiff and breaks easily. Don't store or transport blasting caps or electric fuses with high explosives. 26 HANDBOOK OF MINING DETAILS Don't store fuse in a hot place, as this may dry it out so that uncoiling will break it. Don't "lace" fuse through dynamite cartridges. This practice is fre- quently responsible for the burning of the charge. Don't operate blasting machines half-heartedly. They are built to be ope- rated with full force. They must be kept clean and dry. Don't cut the fuse short to save time. It is dangerous economy. Don't expect explosives to do good work if it is attempted to explode them with a detonator of insufficient strength. Preparations for Blasting (By M. T. Hoster). In almost every one of the various mines and mining districts of the country some peculiarity in the pro- cedure of the miner in firing his round of holes may be observed. The necessary operations are discussed under the subheads following, and the best practice outlined. Cutting the Fuse. Fuse should never be less than 5 ft. in length and often 6 or 7 ft., depending on the number of holes, whether in a shaft, raise, drift or stope. It should always be cut straight across (not slanting) with a sharp knife or cleaver, for if the fuse is not so cut, some of the powder may fall out or the pointed end may bend over and seal the powder from the fulminate when the fuse is pushed into the cap. Crimping. Crimping the cap on the fuse is usually done with a crimper, the teeth or a knife. Crimping caps with a knife or the teeth is not only dan- gerous but ineffective and is often responsible for expensive misfires. With the thin-jawed crimper, the cap is grooved on the fuse, the great disadvantage of this being that such a sharp groove may often squeeze the shell into the fuse so closely that the powder train is choked or cut, causing a missed hole. Two or more such grooves may be lightly pressed on each cap, but water may leak in as the cap does not fit the fuse closely. The broad-jawed, or California crimper is far better, as the metal is not grooved and still fits the fuse closely. With the California crimper, the cap should be pressed several times, revolving the fuse and cap slowly each time the jaws open, squeezing lightly at first and stronger as the cap contracts about the fuse. This crimp gives a water-tight fit. Many missed holes are unquestion- ably due to imperfect crimping; hence this operation should be left to a reliable man and not merely to the miner. The Primer. At times, one will see a miner loading his holes by tamping in a stick or two of powder, then inserting the fuse and tamping in more powder, the fuse lying between the wall of the hole and the powder. This is inefficient. A primer should always be prepared beforehand. The best two methods of making a primer are: (i) Open up one end of the cartridge, extract a small amount of powder, press a hole into the center of the stick of powder and insert the fuse. Then twist the paper cartridge about the fuse and tie it tightly with cord. For wet holes the space at the top of the cartridge is often filled with EXPLOSIVES 27 grease. (2) Simply stick a hole into the cartridge and insert the fuse. This method does not require as much time and is not as good as the first, but will give satisfactory results. This primer must be handled with care to prevent the fuse from coming out and should always be inserted into the hole fuse-end first, which necessitates a bend in the fuse and there is a possibility of this nicking the fuse and causing a misfire. Greasing. For wet holes the fuse is often greased with axle grease or crude oil. Some miners rub grease into the entire fuse, but this is not necessary, as any good fuse will withstand water for a few hours at least. If grease is used at all it should be rubbed on the fuse only where it enters the cap so as to prevent water from soaking into the cap at that point. Loading the Holes. For dry holes, all of the paper cartridges, excepting the primer cartridge, should be slit with a knife before placing in the hole. The object of this is to give the powder a chance to spread out when tamped and so fill the entire hole. For wet holes it is best to slit the first two cartridges only, as the water will fill up any space not taken up by the remaining powder. The most effective place to have the powder is at the bottom of the hole, hence the object of slitting at least the first two sticks. In loading a hole with, for example, five sticks of powder, put in the first two sticks, tamping each solidly into place. Then put in the primer, tamping but lightly, and finally the last two sticks of powder, which should be pressed in well. Some miners say to load the primer last, but this hardly seems advisable. Never load the primer first, and always use a wooden tamping stick. Tamping with Clay or Mud. In some districts soft clay or mud is tamped into the hole after the powder has been loaded but whether there is any good resulting from this tamping is doubtful. It is often advantageous to force a little earthy matter into a hole in order to prevent the sparks of some nearby hole from igniting the powder or to prevent the powder in a dry hole from falling out, but otherwise the force of the explosion can hardly be affected by this tamping. If a hole is tamped at all it should never be filled to the collar, as this makes it difficult to discover a missed hole. Splitting and Spitting the Fuse. Each fuse to be spit should be cut open at or near the end so as to expose sufficient fuse powder for igniting. The three general ways in which this may be done are: Slice the last inch of the fuse in half; cut a slit in the side of the fuse; fork open the end of the fuse. The first is a poor way, as the powder exposed may all fall out before it is time to spit. The second method is much used as there is the least chance of the powder falling out and it requires little time. The chief disadvantage to this method is that when spitting, the fire may travel away from instead of toward the cap, and the miner, being in a hurry, may not notice this. The last method is undoubtedly the best, for although some of the fuse powder may fall out, enough will always be left where the arms of the fork meet. For very wet places the second method has an advantage over the third in that the powder is not as likely to become wet. 28 HANDBOOK OF MINING DETAILS The old and still much used method of spitting by use of candles or miners' lamps is slow, inefficient for a large number of holes, and dangerous. Spitting one fuse by candle, the second fuse from the first, the third from the second, etc., is good but can be used only when the holes are close together. The advan- tage of this method is that, when through spitting, the miner is certain that all the fuse was spit properly. A more common, and far better, scheme is to use an extra piece of fuse about 18 in. long, which is slit or notched along one side, the notches being about i in. apart. When ready, light one end of this fuse, and as the fire travels along the fuse it will spit out at each notch in succession. As the fire spits from the first notch, ignite the first fuse, with the second notch the second fuse, etc., the advantages being that there is the same interval between the lighting of each fuse and the method is rapid, safe and easy. Table for Cutting Fuse. The accompanying drawing, Fig. 8, shows the design of a table for conveniently cutting fuse. It is used at the Blackberry and FIG. 8. FUSE TABLE AND CAP CRIMPER USED IN JOPLIN DISTRICT. Montana mines, near Joplin, Mo. The coil of fuse is carried on a conical spin- dle at the end of the table, and from this spindle the fuse is unwound as it is measured. The fuse is held between a series of two 6o-d. nails driven into two cleats of iX2-in. wood that are screwed to the table. The cutting is done 6 in. ahead of the first pair of nails, so that there are no long, loose ends in the way. On the table are marks which are used in measuring the several lengths of fuse usually required. In cutting the fuse, the loose end from the coil is run through the first pair of nails, taken around the turning nails, passed through the last pair of nails that hold the loose end when the fuse is being cut, and the end is pulled along to the mark indicating the length desired. Then with the fuse cutters the fuse is cut off at the other end, and another piece of fuse measured until all the fuses have been cut, the different pieces being left securely held between the nails until the miner is ready to cap them. To aid in the cutting, the fuse cutters, which are ordinary crimpers, are made with a spring riveted to one of the handles, so as to EXPLOSIVES 29 keep the jaws apart. This increases the speed of cutting the fuse somewhat, and makes the use of the crimpers more convenient. Blasting in Wet Shafts (By E. M. Weston). It frequently happens, espe- cially when shaft sinking with machines is in progress in wet shafts, that the pumps have to be withdrawn before blasting. This may mean that the water has risen to a height of several feet above the bottom of the shaft before the holes can be fired. If fuses are used they should be well greased just where the detonator has been placed on one end and inserted in the primer. It is true economy to use two fuses and two detonators in the leading or cut holes of the round thereby lessening any risk of the whole round being hung up by misfires. All fuses should be of the same length, from 6 to 12 ft., depending upon the number of holes to be fired. In large shafts on the Rand i2-ft. fuses are used. As soon as the holes are charged the ends of the fuses are tied to a small plank or a wedge that has been used to rig the base for the machines, 6 in. or more of the end of the fuses projecting above the plank and as the water rises all fuse ends float. The miners work in pairs lighting the fuses from the back of the shaft toward the bucket or skip in the center. " Cheesa sticks," as they are called locally are made by splitting blasting gelatine and wrapping it around pine sticks about 18 in. long. In a wet shaft the fumes given off, though poisonous, are rapidly absorbed by the water and the use of such sticks in shaft sinking is justified. One miner carries the lighted stick and the other cuts each of the back rows of fuses about i in. from its end and rapidly bends it back, while the other miner applies the stick before the composition becomes damp. When the fuse is seen to spit the next one of the row is lighted. If the fuse does not take fire after the first cut has been made, another cut is made, and no fuse is left until it is seen to spit. The next rows are dealt with in the same way, except that the fuses are cut several inches further down so that each row nearer the center of shaft will explode before those first lighted. If considered more convenient the reverse order of lighting may be adopted, but the advantage of lighting the back rows first is that the men are near the bucket when all the fuses have been lighted; they are not obliged to walk over lighted fuses to reach the bucket. In this way fuses can be lighted with cer- tainty even in the wettest shafts and it is worth while at mines where lower-grade explosives are used to have some blasting gelatine on hand with which to make these lighting sticks, as gelignite and dynamite are too granular and brittle for the purpose. Substitutes for "cheesa sticks" made of chemical combinations and designed to give off no carbon monoxide or nitrous oxide are being intro- duced with more or less success for general mine work on the Rand. I have not however, heard that they have been used successfully in wet-shaft sinking. Blasting in Wet Ground. Where a blast is to be fired in wet ground, soap or tallow should be smeared over the safety fuse at the place where it enters the blasting cap in order to keep the charge in the latter perfectly dry. Oil 3 HANDBOOK OF MINING DETAILS or grease should never be used for this purpose as they are likely to soak into the fuse and destroy the efficiency of the powder which it contains. The Calumet System of Lighting Fuse There are many different ways of lighting blasting fuse, but one of the best, when there are not too many to be lighted, is the method used in mines of the Calumet & Hecla company at Lake Superior. This method consists in taking the end of the fuse sticking out of the hole and plastering it to the wall with a piece of moist clay, a spot being chosen so that in case there is a draft the candle used to light the fuse will be sheltered from the air current. A snuff of a candle about an inch long and having a wick about 1/2 in. in length is then placed in the clay so that the flame will reach the fuse. The candle snuff is then lighted and allowed to burn for about 1/2 minute, or long enough for the tar in the fuse covering to begin to bubble out. The candle is then blown out and the fuse to the next hole is prepared in a similar manner. This fuse is heated, the candle in turn is put out and the procedure is repeated until all the fuses are ready. Then the miner relights the snuffs and hurries away. As it takes a minute or so for the candle snuffs to burn through the fuse far enough to reach the powder train, the miner has ample time to -get to safety, while there can be no failure of the fuse to light and there is no necessity for the miner to linger at the breast or face after the holes are spr", as sometimes a miner must do when the powder has become dislodged from a split fuse, and it becomes necessary to cut it again. Many miners lose their lives by lingering in just this mariner. The fuses can be cut so that the holes will explode in any order desired, just as when the fuse is lighted in some other manner. The time required for the flame to burn through the wrapping seldom varies enough to cause the holes to explode out of the order desired. There is a limit to the number of holes that can be fired by one man in this way. It is perfectly safe for a man to light as many as 10 fuses in this manner, but as there is a certain time consumed in relighting the snuffs, it is debatable whether it is not safer to use some other method when more than that number of holes has to be fired by one man. The method is good for firing shots in wet ground, provided that the snuffs can be protected from the drip of the water. When that cannot be done the same principle of firing burning through the covering to light the powder train in the fuse can be utilized by putting the fuses, several in a bunch, on piles of oily waste and lighting the waste. However, when spitting his shots in the ordinary manner, a miner has had to recut the fuses, he. should never, as a last resort, hold the fuse in the flame of his light in the hope that by setting fire to the end of the fuse he can avoid a misfire, for if he has to run before the powder train catches, the covering may smolder for many minutes before the powder is reached. The miner, thinking that the fuse did not ignite, returns to the face. In this way many men are in- jured in blasting. The snuff method of firing the holes avoids all such dangers, as the flame of the snuff soon burns through the covering to the powder. The EXPLOSIVES important point in the Calumet system of firing is that there can be nothing that will cause the miner to linger at the face after once he has started to light his shots. Prevention of Drilling into Misfired Holes (By John T. Fuller). A common cause of accident in shaft sinking is drilling into a misfired hole or striking a pick into a misfire while mucking. Such accidents are due frequently to lack of information as to the exact situation of the holes of the blasted round. There are several ways of lessening the danger. One is to have each shift charge and blast the holes drilled by the preceding shift. This second shift then mucks out and drills the holes for the next shift to blast. A second way is to have each shift drill, blast and muck its own round, leaving the shaft clean j-- End View Side View FIG. 9. CLAY-FELLED BOX WITH NAILS, SHOWING POSITION OF DRILL HOLES. for the next shift. Both of these methods, however, involve more or less of an upset of the usual order of doing things. The usual order is to have the shift coming on muck the rock broken by the preceding shift, then drill and blast a round of holes, leaving the muck in turn for the succeeding shift. In a large shaft, sunk under my direction, the device herein described was used to aid in locating the holes drilled by the previous shift. A box was made of the same shape as the shaft and built to a convenient scale, as shown in Fig. 9. It was about 4 in. deep, and along the edges saw cuts about i in. deep were made, 32 HANDBOOK OF MINING DETAILS the distance between each representing i ft. of length or width of shaft. A substantial cover with hooks to fasten it securely shut was also provided. This box was filled with moist clay, leveled off even with the edges and lines scribed across the surface of the clay by a pocket knife and a straight-edge, using the saw cuts as guides. The box of clay thus represented the shaft bottom, sub- divided into i -ft. squares. When the miner went down to charge the holes he carried this box with him; also a pocketful of 2o-d. wire nails. Before charging a hole, he would thrust his tamping stick to the bottom, which enabled him to gage the direction of the hole. He would then thrust a wire nail into his clay model as closely as possible to the direction and position of the hole in the shaft bottom. The squares greatly aided properly locating the holes in the model. Thus, when the miner had completed charging and had lighted the round, he returned to the surface with an almost exact reproduction of the layout of holes. The box, with its record, was turned over to the miner in charge of the suc- ceeding shift, with such other information as could be gathered from listening for, and counting the reports, etc. When the men went down to muck out after the smoke had cleared, they took the box with them, using it as a guide in directing the mucking and in locating any possible misfires after the shaft had been cleaned out and before work was started on the new round of holes. It was then a simple matter to withdraw the nails, smooth over the clay and pre- pare the box for the next record. Not a single accident due to drilling or mucking into misfired holes occurred in this shaft, although it was about 30X8 ft. and was sunk to the looo-ft. level. Cartridges for Tamping. The importance of tamping dynamite in drill holes, especially the lower grades, is rapidly becoming recognized in the mining practice of the United States. In many instances the powder companies furnish paper cartridges at small cost for incasing the tamping, and in some mines such casings are used. This, however, is not common practice. The general practice is to use fine material from the vein for tamping. This is far better than using no tamping at all, but the sharp pieces of rock that such material usually contains are likely to cut the fuse. In the copper mines of Lake Supe- rior, the miners engaged in drilling and breaking work by contract, and pay for the powder they use. They have an excellent method of making tamping cartridges. The tamping is clay sent down from the surface that is moist- ened and mixed with fines from the lode, so that the mass is coherent when tightly packed. The casing is made from ordinary newspaper, according to two methods, in one of which the newspaper is sealed with candle grease, while in the other no sealing is used. By either method a good cartridge is obtained, but the better method is that in which the paper of the casing is sealed with candle grease. In both methods the newspaper, in single thicknesses, is wrapped tightly around a piece of old shovel-handle. When candle grease is used, the paper of the car- tridge ends in a straight line running lengthwise with the piece of shovel-handle, EXPLOSIVES 33 about which it has been wrapped five or six times. The outside edge of the paper is sealed by dropping candle grease on it and pressing the paper together while the grease is hot. About i or i i / 2 in. of paper extends below the piece of shovel-handle. This is folded up and sealed back on itself by hammering it on a piece of wood after some candle grease has been dropped on it. The shovel handle is then removed, the cartridge filled with tamping, and the other end sealed in a similar way after the tamping has been compacted by tapping the bottom end of the cartridge lightly on a board. Fig. 10 shows the method of making the cartridge. In the other system no candle grease or other sealing Square Roll Bias Roll Folding in Th (Candle Grease Seal) (NoSealing Required) Ends FIG. 10. METHOD OF MAKING TAMPING CARTRIDGES. substance is used. The cartridge is not so strong; yet is plenty good enough for the purpose. More paper has to be used, as the piece of newspaper is wrapped about the shovel -handle 8 or 10 times. The lower end of the cartridge is sealed by folding the paper back upon itself and hammering it vigorously on a piece of board so as to mat it together. The seal is not good, but the cartridge can be removed, tamping put into it and compacted by tapping the bottom on a board. Then the top end is sealed by folding it in several times on itself and compact- ing the paper of the end by pounding it against a board. Such cartridges are strong enough to stand any ordinary usage in loading holes. Another device is illustrated in Fig. 1 1. It is made by threading one end of a 9-in. piece of brass tubing of suitable diameter. The bore of the tube is fitted with a plunger tapped to take a lo-in. rod about 1/4 in. diameter. The other end of the rod is threaded and attached to a handle by two flat nuts as shown. 3 34 HANDBOOK OF MINING DETAILS The threaded end of the brass tube is closed by a cap through which the plunger rod passes as shown in the sketch. A hole 1/4 in. diameter is drilled in the side of the brass tube i in. below the cap. This tube, a small planed board, a few newspapers, and a batch of moist, fine dirt are all that is required to make neat cartridges that will give no trouble in tamping a drill hole. The newspapers are cut into strips 10 in. wide by 8 in. long. The plunger of the molding tube is withdrawn to the cap end and the bore is packed with moist dirt, the i/4-in. hole at the cap end permitting the air to escape. When the bore has been filled the tube is stood upright upon the planed board and the plunger is pressed down to compact the dirt into a cylinder; the tube is then laid upon its side and the cylinder removed from the tube by pushing on the plunger handle, so that the ejected cylinder of dirt lies upon a piece of the newspaper laid smoothly upon the planed board. To complete the cartridge it is only necessary to roll it up in the paper and fold over the ends. These tamping cartridges should be carefully placed side by side in an empty powder box as soon as made, and FIG. II. DEVICE POR MOLDING TAMPING CARTRIDGES. when needed, the box of cartridges is carried to the place where blasting is to be done. As all the cartridges are of uniform size no trouble will be experi- enced in placing them in the drill holes if the tube is of the proper diameter for the size of hole in which the cartridges are to be used. In the diamond mines at Kimberley, South Africa, according to John T. Fuller, tamping cartridges are made by native boys delegated for this purpose. The cartridges are made of cylinders of mud covered with the paraffin paper in which the bundles of dynamite sticks are originally wrapped. Use of High Explosives. At a great many mines and quarries a prejudice exists among the miners against the use of dynamite of a higher grade than 40%, this regardless of the hardness of the rock mined. In mining a moderately hard and easily fractured material 40% explosive gives good results, and has the advantage of being comparatively safe. However, even 40% dynamite is not a substance with which anybody can afford to be careless. If a man is careful and uses ordinary intelligence in handling dyna- mite, 60, 80, or even 95 % blasting gelatin can be handled with a reasonable degree of security. In many of the mines of the West where ore with a hard, tough quartz gangue is encountered, 60 and even 80 % dynamite has EXPLOSIVES 35 proved far more satisfactory than the lower grade material, giving a broken product which can be easily shoveled in the cars without previous cobbing or popping. In several instances, nitroglycerin and even guncotton have been used with success. The pyrrhotite ore encountered in the mines of the Tennessee Copper Co. is extremely hard and tough in many places. In the Eureka open-cut mine, where the ore is very tough and cemented with a blue quartz gangue, the company is experimenting with 95% blasting gelatin manufactured by the Du Pont Powder Co. As far as can be seen from the work already done, this explosive is giving excellent results. Owing to the prejudice of the miners against high explosives, it was introduced at first without telling the miners of its grade. Now, however, after the men have become accustomed to using it, they feel no more fear of it, seemingly, than they do of the ordinary 40 or 60% grade dyna- mite. It has been found to shatter the rock much more than a lower grade pow- der, and about eight or nine sticks of the gelatin will do as much work or break down as much rock as nearly double that many sticks of 40 % dynamite. In the underground workings, objection is made to the use of gelatin even where the men are not afraid of it, as they find it will not stay in upcast holes. In tamping it acts like so much rubber and unless some paper is stuffed in the mouth of the hole it is, very likely to roll out, this of course being a source of danger. The decision as to the grade of dynamite to be used should depend upon the results obtained. In a locality where labor is expensive, it may be more eco- nomic to use high-grade explosive on account of the labor saved from blocking or sledging the ore shot down, whereas, with similar ore, in another region where cheap labor is available it may prove cheaper to use a lower grade of dynamite and break the large blocks of ore by hand. Each superintendent must deter- mine the grade of explosive best adapted to his conditions. Joplin Scraper and Loading Stick. The ore in the Joplin mines is a min- eralization of stratified beds. The roof is good and in stoping a system of drill- ing is used, in which a bench is taken up by a series of flat holes after the ore next the roof has been blasted out in a heading. In this bench work some of the deepest drilling in underground metal mining in the United States is done. Holes 1 8 ft. deep are not uncommon, i6-ft. holes are common, and 12- and 14- ft. holes are typical practice in the bench portion, which is called the stope. To break the heavy burdens, it is necessary to chamber the bottom of the flat holes, and because of the rapid wearing of the bits, it is often necessary to blast the hole for gage, so that one bit may follow another. This springing of the hole is called "squibbing." The squibbing makes the bore of the hole ragged, therefore difficult to load. This and the occurrence of cavities in the ore, through which some of the holes pass, makes "railroading" of the powder to the bottom of the hole ahead of the loading stick impossible. A pointed tamping stick is therefore used. Some sticks are pointed with a piece of copper HANDBOOK OF MINING DETAILS wire; others with a copper nail. The ground is flinty, so that the use of a steel wire nail in the tamping stick would almost surely be attended by sparking. A copper nail is sometimes used, but this is not considered good practice by the powder companies. The best practice is to use a tamping stick with a wooden point. In some of the sticks a point is made by sharpening the tamping stick itself, but it is preferable to insert a round piece of hardwood in an auger hole in the end of the stick and to sharpen this inserted piece of wood. The stick of powder is impaled on the point, so that it can be made to pass any irregularities in the bore and deposited at the bottom of the hole. This is important, especially in squibbing, as part of the hole may be lost if the squibbing- dynamite is not at the bottom of the hole when fired. The other end of the stick is used in tamping. WooctPin - FIG. 12. SCRAPER AND LOADING TOOL USED AT JOPLIN. On account of the crumbling of the ore, scraping out the deep holes is a difficult operation, and it is, therefore, important that the machine man be able to keep the spoon of the scraper in its proper position in respect to the bottom of the hole. Instead of using round iron for making the scraper, a piece of 3/8Xi/2-in. steel is used for the shorter, and 5/8Xi/2-in. for the longer scrapers. The spoon is made about 5 in. long, with a nose nearly the diameter of the steel used in the hole. When the wide side of the scraper rod is horizon- tal, the nose of the scraper is turned either up or down in the hole. It is, therefore, possible to pull the scraper with its load out of a hole, while with a round handle, it is not uncommon to lose the load. The advantage of a handle EXPLOSIVES 37 of rectangular section is evident. Drawings of the scraper and loading tool used at Joplin are shown in Fig. 12. Breaking Ground for Steam Shovels. Two systems of blasting the ground to be excavated by steam shovels are used in the Mesabi district, Minn. The overburden to be blasted is glacial drift, while the ore is soft hematite. Where the bench to be broken does not exceed 20 or 25 ft. in height, the usual method is to drill holes 15 to 18 ft. from the edge and about 15 ft. apart, extending along the entire bench to be broken. A handle bar is fastened to the drill steel and two men operate the drill by means of this handle. The drill is lifted about 2 ft. and dropped by its own weight. The men walk around in a circle 3 ft. in diam- eter and in this way turn the drill. When the hole is the required depth (about 20 ft.) one or two sticks of 7/8-in. powder are lowered and discharged to spring the hole. The hole is again opened and 5 to 15 sticks of dynamite are placed in the bottom of the hole and discharged to spring the hole further, so that it will contain 10 to 15 kegs of black powder. When loading the hole with black powder, a stick of dynamite, in which two caps and fuses are inserted, or an electric fuse attached, is lowered in the hole and powder is filled around it. After the powder is in place, the hole is firmly tamped with sand. Each hole is discharged separately. During cold winter weather only one hole is discharged at a time, and the loosened material is moved before it has an opportunity to freeze. In the summer often 15 or 20 holes will be fired, one after the other, yielding enough loose material to last the steam shovel several days. The other system of loading, called "gophering," is used when the ground is so dry or sandy that the vertical hole cannot be kept open, or when the bench is too high to drill from the top. In this method holes are drilled in from the side. The total depth is 20 to 25 ft. A pointed i i/4-in. drill bar is used. After it has been driven a few feet with hammers, the bar is withdrawn, and sticks of 7/8-in. dynamite are placed end to end in the hole and discharged. This loosens the ground and the dirt is then taken out by means of a long-handled shovel. In this way a hole 10 or 12 in. in diameter is opened. The hole is inclined at an angle of 15 to 20. The lower end of the hole is sprung with 8 or 10 sticks of 7/8-in. powder and cleaned out. Ten to 15 kegs of black powder are then used. The black powder is fed into the hole by means of a box 3 X3 X 15 in., nailed to a 22-ft. pole. Another method of loading is by means of a V-shaped trough made of 3/4X4-in. boards. The powder is poured into the upper end, and the trough given a backward and forward motion, and in this way the powder soon finds its way to the bottom of the hole. Two men can usually put in two of these holes per shift. If the ground is loose enough to work with the shovel, it is not necessary to spring the hole before the bottom is reached. When boulders are encountered, they are broken by discharging dynamite on their face. In the case of a boulder too large to break in this way, it is often necessary to start another hole. The Necessity for Strong Detonators. In detonating high explosives, the 38 HANDBOOK OF MINING DETAILS stronger or sharper the initial shock the quicker and more thorough is the detona- tion of the charge. If the detonation is slow and incomplete a greater quantity of explosive is required to do the same work, and large volumes of poisonous gas are evolved a matter of serious consequence in underground work. Quick and complete detonation results in a minimum of flame, a point of first impor- tance with those explosives intended for use in the presence of inflammable gas or coal dust. Electric fuses or blasting caps too weak to detonate a charge of high explosives frequently generate sufficient heat to ignite it. The effect of a detonator on a charge of high explosives in a bore hole is by no means infinite, but decreases with distance. It is, therefore, easy to understand the necessity for using detonators sufficiently strong for the effect of the detonator to extend as far as possible through the charge. It should not, however, be understood that the detonator should be placed in the center of the charge, for numerous tests have shown that the greatest effect of a detonator is straight away from its loaded end, and in a line with its long axis, i.e., a detonator will explode a cartridge of dyna- mite farther away from it, if it is lying with the loaded end pointed toward the cartridge, than it will if it is lying parallel to the cartridge. It may be impossible to explain this, but it is known to be a fact. In deep bore holes loaded with long charges, it is well to place caps in cartridges of explosives at intervals of at least 5 ft. throughout the charge, so that the effect of the explosive material which they contain will extend the entire length of the charge. Priming With Electric Fuse. To prime a high-explosive cartridge for electric blasting the fuse cap should be inserted into the center of one end of the cartridge and pointed directly toward the opposite end. The two lead wires should then be brought together up one side of the cartridge and tied in place with string at points an inch or two from either end of the cartridge. The common practice of inserting the cap diagonally into the side of a cartridge and then looping the wires about the cartridge in several half hitches is to be con- demned. In looping the wires, the insulation is likely to be broken, causing short circuiting or leakage of current in wet work; the wires may even be broken. The common practice, when the cap is pointed diagonally toward the end of the cartridge, is to place the cartridge so that the end of the cap will be nearest the outside or top of the charge. Any pull on the lead wires tends to swing the cap in a position more at right angles to the long axis of the cartridge. Thus the end of the cap may easily be swung entirely out of the explosive. In blasting, the principal part of the detonating charge should be placed in the center of the cartridge of explosive, and not to one side or entirely outside, against the paper. A great many missed shots are doubtless caused by improper priming. Device for Clearing a Hung-up Chute (By J. Bowie Wilson). All under- ground managers have at some time been worried by ore chutes choking and hanging up out of reach of the trammer's bar. When the material consists of fine clayey stuff the only remedy is practically to dig it out. If the material consists of rock, even if it contains a proportion of clay, and the block is due to EXPLOSIVES 39 the large pieces keying together and arching over in the chute, the following method of clearing the chute will be found better and certainly safer than attempt- ing to shoot down the pass by tying pieces of dynamite to a tamping stick. This scheme is used at the Mount Morgan mine in Queensland, and consists in firing a wooden plug from a small cannon placed in the bottom of the chute. The cannon is made from a length of steel shafting, the center being bored out in a lathe and a touch-hole drilled large enough to take the ordinary fuse in use at the mine. The end of the shafting is turned down to fit into a hole in the top of a short length of 9 Xp-in. hardwood timber of such shape that when the device is laid on the floor of the chute and resting against the chute door, the cannon will point up the center of the raise. Fig. 13 shows the construction of the cannon. It is charged with ordinary black blasting powder and a plug of hard- wood timber is tapped home in its mouth. A fuse is then inserted into the Wooden Plug Floor of Chute FIG. 13. CANNON FOR OPENING CHUTES. touch-hole to explode the powder. In action the cannon is a big popgun, and on the powder exploding, the wooden plug hits the keyed material with a good, sudden blow. If the shot is successful the material falls upon the gun and its carriage, but these, being of a simple design, are in no way hurt and can be recovered. A knock against the side of the truck suffices to clear the cannon of anv material and it is thrown down in the tunnel beside the chute until required again. If the chute is not freed by the first shot it will generally be found to open after several. A great advantage of this method is that the men are in no danger when using it. 40 HANDBOOK OF MINING DETAILS STORAGE OF EXPLOSIVES Powder Magazines. The mining law of the Transvaal is strict with respect to the construction and management of magazines for explosives. Some of the provisions are the following: Care shall be taken that explosives magazines are erected only at such places where there is a suitable depth of soil or sand. In no case shall an explosives magazine be erected upon rocky ground. In the construction and erection of the magazines only the lightest and most suitable material avail- able shall be used for walls and roofs. Solid arched roofs are particularly prohibited. The magazine shall be at least 6 ft. 6 in. in the clear from floor to ceiling, and shall comprise at least two compartments, one called the lobby, which is acces- sible from the outside, and used for the reception and delivery of explosives; the other called the storage room, which is accessible only from the lobby and is used for the storage of explosives. The outer door to the lobby must open outward, and be faced with sheet iron about 1/4 in. thick, and fitted with a good lock, for which purpose a padlock will not be deemed to be sufficient. The compartments of a magazine shall be properly ventilated by cowled ventilators in the roof, or properly protected ventilating channels in the gables. The highest temperature allowed in the storage room shall not exceed 95 F. The ceiling of a magazine shall be of wood, and its inner sides shall be wood- lined, the lining to be at least 3 in. distant from the walls and the intervening space filled with some uninflammable non-heat-conducting material. The floor shall be of wood, of sufficient strength, and shall be well ventilated beneath; it shall also be provided with a proper drain for insuring the dryness of the maga- zine. Roofs of galvanized iron shall have wood lining immediately against the iron. All nails, fastenings, locks, keys and fittings inside the magazine shall be made of wood, brass or copper. The magazine shall be fitted with a reliable lightning conductor, supported on a vertical post standing clear of the building, but not more than 18 in. from one of the walls, and rising at least 6 ft. above the highest point of the magazine. This lightning conductor shall be carried to a properly laid earth plate. A surface or sub-surface magazine shall be surrounded by an outer earth wall, and the bottom of the inner slope of the same shall not be less than 3 ft. from the sides of the building. This earth wall shall have a natural slope on either side, and be 3 ft. wide at the top, and as high as the highest point of the roof. The approach to the precincts of the magazine, through the outer earth wall, shall have a strongly built gate, which shall be kept locked. The entrance to the magazine shall be either in a broken line, or the door shall be protected by an outer protecting earth wall entirely shielding the entrance. A reliable self-registering thermometer shall be kept in the storage room of every explosives magazine. At least one pair of magazine shoes shall be kept EXPLOSIVES in the lobby of every magazine, and no person shall enter the storage room of any magazine except when wearing such shoes or when barefooted. Powder House with Concrete Roof (By Claude T. Rice). A powder house with a concrete roof, such as is used by the Copper Range company's mines in Michigan, is shown in Fig. 14. In designing the roof the weight of 150 Ib. per cubic foot of concrete and 31 Ib. pressure per square foot for wind, snow and other loads were taken, and the ordinary force diagram for designing I" ll Ij i! it 1 -}*** [Is 9 .IP ; y' r ' i J ^X * i! ii 2?^ /** r/ Detail of Arch Centers FIG. 14. POWDER HOUSE AT THE CHAMPION MINE. arches used in proportioning the thickness. The concrete was mixed in the proportions i : 2 : 4 to i : 3 : 5. No waterproofing mixture was added, but instead the whole roof was covered with a thin, smooth layer of i : i cement. The concrete is reinforced with rods of i/2-in. iron at 24-in. centers. The side walls are of masonry built of waste rock from the mine, and are tied together at the top crosswise by three i-in. rods. A small ventilating hole is left in the end walls near the top. The building is not for the thawing of the dynamite, but merely for its safe storage at the surface. 42 HANDBOOK OF MINING DETAILS Concrete Powder House. At the properties of one large Eastern mining company the powder houses are about 6X12 ft., built entirely of concrete. The door and door frame are wood, but covered with sheet iron. The floor is cemented. These houses are used for the storage of only a few boxes of powder for immediate use at the mine. There are a number of these buildings, and each shipment of powder is distributed among them. This avoids the storage of large quantities at one place. However, the design of these magazines is not one that is to be recommended. Powder Storage Underground. At the Leonard mine, Chisholm, Minn., only one box of powder is taken underground for each working face. This powder is kept under lock and key in a box, 2 X2 X4 ft. In this box is also kept one box of candles and whatever fuse and caps are necessary for each face. The day shift and the night shift each have a key to the box. These boxes are so distributed that they are not less than 75 ft. apart and at a safe distance from the working face. This distribution of powder prevents any serious explo- sions, such as may occur when many boxes are kept in one magazine. [However, it is not good practice to keep caps and fuse and powder in the same box. EDITOR.] FROZEN DYNAMITE The nitroglycerin in dynamite freezes at 42 to 46 F., and when frozen is insensible to detonation but explodes readily by friction or by breaking or cut- ting the cartridge. It should be thawed by putting it in a watertight case and immersing in warm water, or by laying it in a warm room. It should not be thawed by putting the sticks in warm water, as a certain amount of the' nitroglycerin is lost through its coming out of the cartridge and sinking to the bottom. This water may perchance be heated again, in which case the collected nitroglycerin is likely to explode. It should also be noted that in case any water does contain nitroglycerin mingled with it, that the water should be poured out carefully and not thrown out violently on the ground. It is also dangerous to hold a stick of frozen dynamite over a hot object, as one drop of the nitro- glycerin may ooze out, fall, explode and set off the stick. It is hardly necessary to state that it is imprudent to thaw dynamite by carrying it down one's boot leg or inside one's shirt. There are only two safe ways and those are the ones given above, and those should not be pursued too enthusiastically. Make haste slowly. Thawing Dynamite. A dynamite thawer, described by R. E. Tilden, of Winnemucca, Nev., is effective, safe, and has the advantage that the smallest mine can afford one; its cost is nothing. To thaw the dynamite use a large bottle, fill with warm water, then place the cartridges around the bottle in layers, wrapping them in place with a woolen rag or cloth, tied by a string. The size of bottle selected should be governed by the amount of powder to be thawed for EXPLOSIVES 43 use in one place in the mine and by the time that will elapse, after being taken underground, until the powder is used. The bottles may be conveniently car- ried in pails. Powder taken into the mine in the morning will be thawed and remain so until evening. A simple, economical and perfectly safe method of thawing dynamite is that which has been used for over a year at the Van Roi mine, near Silverton, Slocan district, B. C. Douglas Lay, superintendent of the mine, describes this as being merely an adaptation of the widely known principle of heating by hot-water coils. The thawing house is a building occupying a floor space of about 8 X 10 f t. Placed in it is the water-supply tank a barrel kept full, or nearly full, of water, which is heated by means of pipes passing to a coil in a stove in another building about 300 ft. distant from the thawing house, and at a considerably FIG. 15. THAWER FOR DYNAMITE. lower level. The pipes from the barrel, which connect with the stove coil, are placed in a box buried in the ground, to insure insulation. In the thawing house there is a box 5 ft. long, 2 ft. wide, and 2 ft. deep, with a lid. A large pipe coil, connected with the hot- water column, is in the bottom of the box; it is covered with sawdust, and the sticks of dynamite are placed in the box. The sawdust serves to absorb any exuded nitroglycerin, and is renewed frequently. The building containing the heating stove and coil is erected near the entrance to one of the mine adits and is used as a dry room by the miners. As already 44 HANDBOOK OF "MINING DETAILS mentioned, it is remote from the thawing house, so that the latter would be absolutely safe, even if, from any cause, the former should catch fire. In Fig. 15 is shown a type of thawer used by the Oliver Mining Co., Hibbing, Mich., which has given excellent satisfaction. It is made of galvanized iron, about 10X10X16 in. high. Twelve 2 i/4-in. tubes are soldered in, giving the appearance of a tubular boiler. Six inches from the bottom is a water-tight partition, above which is water to cover the tubes. The ends of the tubes are open for the insertion of the sticks of dynamite. Two or three short pieces of candles placed below furnish heat for warming the water, unless hot water is available. A metal cover is placed over the box. The candles are thoroughly inclosed beneath and obtain an ample supply of air through three ventilation holes on each side. At the Traders' mine, Iron Mountain, Mich., a small house has been con- structed in which to thaw all the powder used in the mine. The building is 10X12 ft, built of 12 Xi2-in. timbers placed close together and is on alow piece of ground sheltered by a high bank. Exhaust steam from the boiler house is FIG. 1 6. THAWING HOUSE AT TRADERS MINE. used for heating the building. It enters through a 3-in. pipe above the tray upon which the powder is placed, and then passes down and into a cylinder 12 in. in diameter and 5 ft. long which is beneath the tray. Fig. 16 shows the arrangement. The tray itself is made of i/2-in. iron bars placed about 1/2 in. apart. It is 3 X6 ft. and affords ample room for four or five boxes of powder. This has been in use 14 years. Only one day's supply of powder is kept in this building. The fuse and caps are in another building 50 ft. away. The main powder storage house, where carload shipments are kept, is 1/4 mile distant. Thawing Dynamite by Electricity. A method of thawing dynamite used by the Vermont Copper Co. consists in heating the thawing box by electricity. The box referred to is about 16X40X36 in., and stands on edge. It is made of wood with a number of trays that will slide in and out. Each tray is made of small strips of wood, and it is upon these trays that the powder is placed. Doors are made as nearly air-tight as possible. The lower 8 in. of the box has wire coils through which the current is passed, and the heat from the coils warms the EXPLOSIVES 45 box. Above the coils is a thin sheet of galvanized iron, to prevent any powder or nitroglycerin from coming in contact with them. The sheet iron is covered with asbestos sheet. The box is usually thoroughly heated before placing the dynamite on the trays, and then the current is turned off. The thawer is placed in some remote part of the mine, at the end of a drift which can be closed from draft, and is thoroughly inclosed in a small house. Ill ROCK DRILLS Bits and Drill Parts Pointers on Operation Economics of Practice. BITS AND DRILL PARTS Air-hammer Drilling in Sticky Ground (By George E. Addy). The sticking of a drill steel in soft, clayey ground may be overcome by welding a piece of ribbed drill steel, A in Fig. 17, to a bull pick B. The drill so made can be driven with a hammer drill. If a set of three drills is made, the shorter steels having the larger points, a hole 3 ft. deep can be drilled. These pick-pointed drills will be found to be time savers as compared with the usual types of drills, or with driving a bull pick with a hammer. FIG. 17. A PICK-POINTED DRILL FOR SOFT GROUND. A Drill for Soft Ground. The vanadium deposits of San Miguel county, Colo., occur in sandstone which is generally soft and often moist. It is difficult to drill this sandstone because the moist sand sticks in the holes. To obviate this the miners use a hand drill made of steel tubing, in which saw teeth are cut on the end, set out for clearance as shown in Fig. 18. With this drill, upper holes are regularly drilled, the cuttings coming out of the bit through the hollow center. The device is satisfactory within the limits for drilling shallow holes in soft wet ground. FIG. l8. DRILL MADE OF STEEL TUBING. Design of Drill Bits (By Ward Blackburn). The efficiency of a rock- drilling plant is determined by the amount of power delivered to the bit and converted into cutting power. No matter how efficient the compressing plant and the rock drills, or how careful the drill operator, if the bit is dull or of incorrect shape, the rock is not cut, good energy is wasted, and money and time are lost, in reaming the bore hole or in pulverizing the rock, and the real object of the work is defeated. ROCK DRILLS 47 At most mines little attention is paid to the drill bits by anyone except the blacksmith. The drill runner is satisfied if the bits run out a change and hold gage well for the next bit to follow. The fewer changes, the better he likes it. The same is true of the blacksmith. The longer a bit is in service the less frequently must it be sharpened. The bit is designed for use as long as possible without resharpening and the cutting properties take second place. In designing a good bit both cutting and staying properties should be con- sidered, but the day of hand-sharpening and of chuck bolts is rapidly passing, and now the efficiency sacrificed to staying properties is determined largely by the cost of transportation and handling of bits and permissible loss of gage. It is not influenced to the same extent as formerly by the labor of sharpening or trouble of changing bits. The cost of transportation and handling of bits amounts to a considerable item which increases as the lasting qualities of the bit are replaced by cutting qualities, so that it often governs the extent to which the design may be changed. Light, compact mechanical sharpeners can now be obtained at a reasonable price, and as these machines reduce the cost of sharpening to a low figure and enable the blacksmith to make several hundred bits per day, shop considerations offer no serious reason for retaining merely staying qualities in the design of the bit. Nearly all rock drills can be provided with a wedge chuck, or some means of holding the bit behind chuck keys so that bits can be changed in a fraction of a minute. This largely overcomes the objection to short bits. In several mines the cost of transportation and handling of bits is greatly reduced by installing the power sharpener with oil or coke furnaces underground. Allowable loss of gage is an important factor, for the greater the loss the larger must be the diameter of the shorter bits to insure a certain diameter of hole at a fixed depth. This larger diameter means a loss of power, so this point can never be lost sight of in determining the bit to be used. Operators who believe the gage should be retained irrespective of the amount of power used, run the edges of the wings of the bit back about i in. in a line parallel to the axis, making the bit a reaming tool. If this is done, as soon as the cutting edges wear a little the shoulders begin to bind and stick against the sides of the hole, and it must be reamed out to a size which will allow the bit to move for- ward. When such a bit is removed from the hole it will show greater wear on the edges of the wings than on the cutting edges. As the bit is apparently as hard 1/2 in. back, as on the cutting edge it is reasonable to suppose that there has been as much work done in wearing the steel of the wings as in wearing an equal amount at the cutting edge, that is, if the reaming edges show more wear than the cutting edges, it is to be supposed that they have done at least as much work as the latter. In other words, as much if not more power has been ex- pended in reaming the hole as in cutting it; half the power has been used in cutting an area of say 7 sq. in., that of a 3-in. circle, and half the power has been used in reaming an area of a little more than 1/2 sq. in., the area of the i/i6-in. 48 HANDBOOK OF MINING DETAILS rings reamed out. Furthermore, the rock drill is designed to cut rock by means of a blow. It is not a reaming machine, and as soon as a bit is cutting or reaming the side of the hole it is retarding the action of the drill. This strains the rotation and has a tendency to twist and break the bit. Power expended in reaming is power lost. From this it is apparent that because of the rapid loss of power and the wear and tear on the rock drill, little of the efficiency of the bit should be sacrificed to the reaming qualities. It is sometimes claimed that unless the bit has reaming edges, the hole will become rifled. This was true to some extent when the bits were forged by hand, but it was due to the difficulty of getting each corner or wing equidistant from the center of the bit. With most power sharpeners this difficulty is removed, and with the correctly formed bits there is little trouble from rifling. While it is true that one bit cannot be selected as a standard for any and all classes of rock, still the power-sharpener manufacturers, especially those who have gone into the study of drill bits, are gradually working toward a few standard types. The consensus of opinion is that under average conditions, a good bit for power-drilling work should embody the following points: (1) It must take full advantage of the chipping and fracturing of the rock. In a bore hole there is a certain depth to which rock will fracture when struck by a sharp tool. If the tool is driven deeper than this it will not fracture the rock ; it will crush it. If the cutting edge of the bit is blunt it will not get full advantage of the fracture, and considerable of the force will be expended in crushing or pulverizing. The bit acts as a wedge. (2) The wings of the bits should be as thin as is consistent with standing-up quality to allow for the ejection of the cuttings. If the wings are left heavy there is little space for the escape of cuttings and consequently they are held in front of the bit and continually churned and ground, the bit does not easily reach solid rock and the blow loses a large proportion of its cutting power before it reaches the rock. (3) The bit must be perfectly free in the hole at all times; because of the tendency of the rock to fracture, the drill hole will be a trifle larger than the cut- ting edge. If the bit is so designed that the cutting edge is its greatest diameter and will practically remain so until dull, it will always remain free in the hole. (4) The bit must allow equal wear on all corners. If the bit is not sym- metrical, that is if the ends of all the cutting edges are not the same distance from the center of the bit, the longest end will cut a groove in the side of the bore hole and a rifled hole will result. Furthermore, the wear is unequal and the extra strains in the steel often break it. The rotation of the drill is impeded and the parts subjected to excessive wear. (5) The bit must be dressed in a manner consistent with the treatment of good steel. It must not be overheated, or worked while too hot. Light rapid blows should be used in forging. The bit must be tempered properly. The proper temper should be determined by experiment and rigidly adhered to. The ROCK DRILLS 49 bit should be allowed to cool thoroughly after forging and should then be re- heated for tempering. It should never be sharpened and tempered on the same heat. In Fig. 19 are shown bits designed to fill these requirements. An angle of about 90 for the cutting edge is generally accepted as the correct angle. If the angle is greater the bit has a tendency to crush rather than fracture the rock, and as a rule the bit cuts slowly. An angle less than 90 gives a bit which will cut fast, but it has a tendency to break off and wear rapidly. There is also a tendency for it to enter the rock, especially soft rock, past the point of fracture, and expend energy in crushing or wedging out the rock. The "mudding" powers are greatly diminished. The thickness of the wings may range from 3/4 in. on a large steel, to 3/8 in. or even less on a stoper and hammer-drill bit. The wing must not be so thin that it breaks off, still, the less stock necessary the better the clearance for the cuttings. CORRECTLY MADE BITS. INCORRECTLY MADE BITS. FIG. 19. DESIGNS OF DRILL BITS. The third point is probably the hardest to comply with. When the bits shown in Fig. 19 are first placed in the hole the cutting edge is the largest diameter, and as it may be safely assumed that the rock will fracture 1/16 in. beyond the bit, the latter must be free in the hole. The wings of the bit taper in the ratio of one to four, or one to five, and as the cutting edge wears, a shoulder or reaming edge forms on the wing. When it wears between 1/16 and 1/8 in. from each wing, a shoulder i / 4 to 5 / 8 in. forms and there is a point between these where the cutting edge is fracturing the rock in the side of the hole to a diameter equal to the diameter of the bit through the shoulders. In other words, the shoulders of the bit are just touching the sides of the hole. If the bits run past this point, the cutting edge will not cut the hole to a diameter large enough to admit the bit and the shoulders immediately become reaming surfaces. The taper of i : 4 or i : 5 is determined upon as a medium. If less taper is used, say 1:7, the shoulders become more prominent and the cutting edge has less allowable wearing surface before the bit binds in the hole causing the shoulders to become reaming surfaces. If the wings have a greater taper, say 1:2, the wear is excessive, and the loss of gage prohibitive. The sharp taper 4 50 HANDBOOK OF MINING DETAILS leaves the ends of the cutting edge in a weakened condition and they easily break up and chip off. The necessity for having the drill bit concentric is obvious. In hand sharp- ening and even with some power sharpeners it is not uncommon to find one of the ends of the cutting edges protruding 1/32 to 1/16 in. beyond the others. Some sharpener manufacturers have effectively overcome this difficulty by entirely inclosing the bit under a heavy pressure while it is being forged. When this is done there can be no question as to the corners falling within a circle. The tempering and manner of heating and treating the bit is generally left to the discretion of the blacksmith. This is a mistake, as a little attention and study given the subject by the manager or superintendent will often result in marked improvements. Many kinds of steel now on the market, and the scien- tific methods of treatment are entirely new to the average smith. A word should be said about mechanical sharpeners. These machines have been greatly improved in the last few years, and now extremely light, simple designs of remarkably high capacity and efficiency are within the reach of all. The bits dressed in the sharpener are always perfect in form and gage and everything considered, will give from 25 to 50% greater efficiency than if sharpened by hand. In addition to the increased speed of drilling there is a noticeable saving in the wear and breakage of machine parts and the bit itself lasts longer and wears much better. When installing a power sharpener one should not lose sight of its main advantage, increasing the efficiency of the drill bit. It should be installed with the idea that because of the marked reduction in the cost and time of sharpening one can afford to furnish the drill with better steel more often. It is impossible to make a hard and fast rule as to when a power machine should be installed, but it is certain that a sharpener will effect a material reduction in cost per steel dressed, lessen the machine repair parts required, save steel and steel breakage, and greatly increase the drilling speed of machines. Rand Drill Steel and Bits (By E. M. Weston). Tests have recently been made by Robert Allen at the Robinson Deep mine to determine the most suitable steel for making drills for use in the Rand mines. Many varieties of steel have been tested in the following way. From 40 to 60 drills made from each brand of steel were sharpened by hand, weighed, measured by a microm- eter gage, then sent to the mine where they were used in 2 3/4-in. machines to drill the hardest rock. The depth of holes drilled and time taken were noted. The drills were then sent to the surface where they were again weighed and measured and the quality of the steel compared by the loss in gage. It is difficult to convince the Rand miners that the proper heating and tempering of the steel has an important bearing on the efficiency of the drills, so it was neces- sary to recommend steel of such carbon content as would permit of direct plunging in the type of tank giving a limited depth of immersion for cross bits. The bits as finally adopted, are shown in Fig. 20. They are used in 2 1/2- and 2 3/4-in. ROCK DRILLS 51 machines. The starting bit is used to drill 15 in. of hole, the second 21 in., and the third and fourth 24 in. each. With higher air pressure I believe that the third and fourth bits should be made of i-in. steel, as even with 70 Ib. air pres- sure a 2 3/4-in. machine will bend some of the 7/8-in. drills. A carbon content of from 0.7 to 0.75% is the highest that will permit of steel being satisfactorily welded and which will temper without cracking on direct plunging. Starter. Second. FIG. 2O. DRILL BITS USED ON THE RAND. Ejecting Sludge from Drill Holes (By E. M. Weston). A method of ejecting mud and cuttings from a drill hole has been devised by Mr. Tippet, an Australian, that may result in making it possible to use a one-man drill in the mines of the Rand. He conceived the idea of withdrawing the sludge through, instead of forcing water down hollow steel. He intended to bring the sludge right through the machine by means of a suction device which was to be worked FIG. 21. HOLLOW-STEEL BIT WITH SIDE OPENING. by the exhaust air. While using a rose bit, he noted that when the suction was not operating, the drillings were being vigorously ejected. The sludge evidently entered the hollow in the steel with considerable velocity on the down stroke, the inertia of which was not entirely overcome during the period of the return stroke. All that is necessary to take advantage of this effect is to employ hollow 52 HANDBOOK OF MINING DETAILS steel and forge a collar near the shank, then to drill a transverse hole to connect with the central channel at a point just below the chuck. Steel of this construc- tion has been found to hold its gage remarkably well. The steel used with piston drills is i i/4-in. diameter, through which passes a 3/4-in. channel. The central channel becomes filled with sludge but does not choke with pieces of rock (granite) even when as large as a ten-cent piece. Fig. 21 shows the trans- verse and longitudinal passages of the improved drill steel. Improved Chuck for Piston Drills. In the North Star mines, at Grass Valley, Calif., a special type of chuck designed by Messrs. Paynter and Bastian, employees of the company, is used on the piston-machine drills. The peculiarity Cross Section on Line w-Jfr Gib and Key, but not Bushing Key, shown. Cross Section on Line w-n Gibs and Keys not shown . FIG. 22. NORTH STAR BOLTLESS CHUCK FOR PISTON DRILLS. of the chuck is that it includes no bolts, and hence does not require the use of a wrench for tightening the grip upon the drill shank. The working drawing, Fig. 22, shows the details of the chuck and clamping arrangement. The chuck is drilled as usual to receive the shank of the drill steel. A slot, above and parallel to the shank of the steel, is cut in the chuck to receive a gib A that bears against the shank of the drill. Below the drill socket and perpendicular to the axis of the chuck two holes are cut to receive bushing keys X and Y, that bear against either end of the lower part of the drill shank and take up wear from the chuck. A strap or band C fits around the chuck and over a tapered key B that bears on the gib A . The key B is tapered away from the end of the chuck so that as every impact of the drill against rock drives it further under the strap C, the gib is forced more tightly against the drill shank. There is, hence, no tendency of the drill to become loose in the chuck. On the other hand, it is held more securely at each stroke. The key B is made with a heavy head at either end. To fasten the drill in the chuck the key is driven tight by a blow ROCK DRILLS 53 upon the head at the larger end. A blow on the other end of the key serves to loosen it and allows the drill to be removed. This type of chuck has been used for several years in the North Star mines and has proved entirely satisfactory. Its advantage over the ordinary type where bolts have to be drawn tight every few minutes should be evident. The construction embodies no particular difficulties. Shaping Chuck Bolts (By H. Lawrence Brown). The accompanying sketch, Fig. 23, shows a device for making chuck bolts for machine drills. It consists of the plate B, made of i-in. iron, bolted to a work bench by 3/4-in. countersunk bolts A. To the plate are riveted the pieces C and D, of i-in. O-A ; O n ' T AO 3 D O a 3 / c o \t O-A o AO f FIG. 23. DEVICE FOR SHAPING CHUCK BOLTS. material, with a curve in the piece C corresponding with the bend desired in the chuck bolt. The levers F are about 2 ft. long and are offset as shown at E, where the thread on the bolt begins, in order not to injure the threads while the bolt is being shaped. The threaded bolt is heated and placed between C and D, while the levers are open. Closing the levers to the posi- tion shown bends the bolt to the proper shape. Improved Drill Post Collar (By Albert Mendelsohn). An improved post collar now being used in some of the copper mines of Lake Superior is shown in Fig. 24. It does away entirely with the two bolts of the collar at present in general use, and can be loosened or tightened by a single blow of the miner's wrench. It consists of a cast-steel band A of diameter slightly greater than that of the post. A tool-steel gib B fits into a slot in the band, and directly over the gib a wedge-shaped key C of the same material is driven. The inner face of the gib is shaped to an arc of the same radius as the post and when 54 HANDBOOK OF MINING DETAILS the wedge is struck on its wide end the gib is forced tightly against the post. An advantage of this collar over the one at present in general use is that time and work are saved, because there are no bolts to tighten and loosen. This time may not amount to much on a two-man machine, but with the introduction of the one-man " butterfly" drill and the attention to details necessary in running it, any device that will save two or three minutes per hole drilled is of importance. At present the miner using a one-man machine has to adjust nine bolts; the elimination of two is, therefore, no small item. Another advantage, and one which is of importance on one-man machines, is the fact that this improved FIG. 24. DRILL-POST COLLAR WITHOUT BOLTS. collar can be rapidly loosened and tightened, and if necessary with one hand. In raising the machine on the post, if the post is wet or the machine too far in on the arm, the arm will not catch on the post. This means that the machine and arm must be held in the elevated position while the collar is loosened, slid up the post under the arm and tightened. In any case, speed is desirable under these conditions, and with a one-man machine it is imperative. Inci- dentally, it might be mentioned that these collars were used with the two one-man machines with which four men recently drove 285 ft. of 6Xy-ft. drift in one month; exceptional drifting for the copper country. Drill Post with Removable Screw. In the Copper Range, Hancock and Quincy mines single-screw posts, the jack screws of which are removable, are used whenever a single-screw post is required in making a cross-bar setup with a machine. The details of the screw are shown in Fig. 25. The device has even been used in shaft sinking and is said to have proved as satisfactory for that ROCK DRILLS 55 work as an ordinary post, while it possesses the advantage that owing to the fact that the screw feeds ahead instead of the jacking nut, as is the case in the ordinary single-screw post, the screw can be stuck into a hole in the wall, and the bar jacked without any trouble arising from projections from the wall inter- fering with jacking. The separate screw and nut also possess the advantage that such a single-screw jack can be used with several different lengths of bars. The nut of the jacking device is octagonal in shape with four steel-bushed holes in its sides for receiving the jacking bar, and one end of the nut is made big enough to go over the end of the post as a collar. The screw has a blunt end that goes against the ground, while in it is a keyway that goes over three I Two threads per inch. Hardened steel bashing. S-KejB to prevent screw from turning %-la.stud3 screwed in and ailed to form key for screw. Head shrank in Soft steel bashing shrunk it FIG. 25. DETAILS OF DRILL COLUMN WITH REMOVABLE SCREW. lugs in the end of the post so as to keep the screw from twisting with respect to the post as the jacking nut is turned. The post has at one end the ordinary toothed head shrunk on it, while at the other there is a soft-steel bushing or guide shrunk in for the screw. Through this end of the bar three holes are drilled and tapped for y/S-in. studs. These studs are screwed in tightly and then filed flat to serve as the keys to go into the keyway in the jacking screw, as well as to hold in the guide bushing. The barrel of the post is a piece of ordinary 4-in. gas pipe. Jack for Machine Drill Columns. Machine-drill jacks become quite heavy as the length of the column increases, especially when a column with two jack screws is used. In the Michigan copper country, machines have to be set up with columns as long as 13 ft. It therefore becomes important to make them as light as possible, especially now that one-man machines are being introduced. In driving drifts it is often desirable to have two lengths of column; in such a case the Osceola type of machine column, in which the jack proper is in one piece and the post in another that can be lifted out of its socket in the jack, is convenient. When the post has to be moved, the weight to be lifted is divided in two as the two parts are moved separately. At the Osceola and the Calumet & Hecla mines, the post consists of an ordinary 4-in. gas pipe for 56 HANDBOOK OF MINING DETAILS both two-man and one-man machines, with a light cast-iron cap fastened to the upper end. In the bottom of this pipe a notch is cut to fit over the lug in the bottom of the socket hole of the jack. Fig. 26 shows the design of this screw part, which is cast in one piece with socket holes, into which the nuts of the jack screws are fastened. The lug on the bottom of the post socket is now cast square, but in the future it is probable that it will be cast with a V-section, so that FIG. 26. CAST-IRON- JACK FOR A DRILL COLUMN. the notches in the bottom end of the post can be cut to fit tight, for often at present these notches in the post are cut too wide, allowing the post to turn slightly when the machine is started and throwing the hole slightly out of align- ment. Such a machine jack can be made cheaply, as there is no machine work on the casting, while its use is a great advantage where a two-post jack is re- quired for one-man drills. POINTERS ON OPERATION Removing Stuck Drills. In drilling deep holes by hand with 15- or 20-ft. steel, the steel often sticks; or, in some cases, a drill is actually driven in soft ground as one would drive a stake, and then it becomes necessary to resort to some means to remove it. This may be done easily by taking a piece of steel i 1/4 or i 1/2 in. thick, 6 in. square, with a hole in the center about twice the size of the drill. This is placed over the head of the drill and two steel wedges driven in, to fasten the piece of steel on the drill, thus forming a good shoulder against which to hammer. A few blows on this will soon loosen the drill. It is much more effective than a chain and lever, or pulley block. Wrench for Removing Stuck Drills (By Claude T. Rice). A miner often loses an hour or two through the sticking of a drill in a deep hole. The ROCK DRILLS 57 fault is usually the miner's. A small quantity of sticky drillings will wedge a drill so that, unless there is a good wrench for twisting it out through the drillings, it cannot be removed, and a new hole must be drilled. Cruciform steel has less tendency to stick in damp holes than octagonal or hexagonal steel, as the ribs act like a conveyor to eject the drilling, provided that the hole is not too flat and the drillings are not too sticky. E. M. Weston has advised the use FIG. 27. A DRILL-TWISTING WRENCH. of drill steel with a rolled screw to overcome this difficulty and on the Fort Wayne electric drill, bits with twisted shanks are used. Similar steel was used a few years ago with good results in piston drills in certain of the New York iron mines. Twisted drill steel does not stick in a hole, I understand, but it is expensive and probably not so satisfactory as octagonal or cruciform steel. The most satisfactory wrench that I have seen for twisting drill steel from a hole is that in use in the Calumet & Hecla mines and shown in Fig. 27. It is made of 3/4-in. iron and consists of a frame to which one of the toothed jaws is FIG. 28. COTTER WRENCH FOR STUCK DRILLS. fastened ; the other slides loosely in the slot of the frame, being prevented from slipping out by shoulders. Back of the loose jaw is a key, prevented from falling out by a pin through its small end. This, driven downward by a hammer, forces the teeth of the jaws into the drill steel so as to grip securely. The ex- tension of the frame forms a handle 18 in. long, but in case this is not long enough, a piece of pipe can be slipped over it. The wrench is simply and 58 HANDBOOK OF MINING DETAILS strongly made, so that it can be hammered, twisted, and jerked without injury. It has been in use for several years at the Calumet & Hecla mines and has proved satisfactory. In Fig. 28 is shown the design of the wrench that is used at the Mohawk mine in Michigan to aid in loosening drills that become jammed in bore holes. The wrench is quite similar to the one that is used at the Calumet & Hecla mines. The grip on the drill is obtained by driving in a key or cotter that grips the drill between itself and the jaw of the wrench. The wrench is much heavier, and does not seem to be quite as handy as the one used at the Calumet & Hecla mines. In working the drill out a chain is fastened to the drill, thence it is passed around the machine post. One man pulls on the chain while the other twists the drill with the wrench. Wrinkle for Piston Drill. It is frequently necessary for a machine-man to release his hold on the crank to throw water into a hole or attend to the many little details that are constantly requiring his attention, and a freely feeding drill will crank itself back too rapidly to permit its being left. Miners often hang a wrench on the crank or lean a piece of steel against it or twist the hose around it. The last two expedients are unhandy and inconvenient; any weight hung on the crank will slip off unless the drill is inclined steeply downward. A hole drilled through the crank at the base of the handle, through which a wire may be slipped to hold the weight will expedite the miner's work consider- ably and do away with the temptation to allow the feed to work stiffly. A couple of 7/8- or i-in. nuts bound closely to the crank in this manner will not slip around or get tangled with the crosshead. Cleaning Drill Holes (By J. H. Forell). In drilling upward slanting back holes in dry ground, the drillings are often removed by a squirt gun, an improved Ed. Iron Thread 244Q, j i^-iti. Sq. \VeldedShoulder Iii. Hole FIG. 29. SQUIRT GUN FOR CLEANING DRILL HOLES. form of which is shown in Fig. 29. A piece of i-in. black pipe, 20 to 24 in. long, is threaded at one end. A cap, slightly cone-shaped at one end, is turned on a lathe and threaded at the large end to fit the i-in. pipe; the small end is tapped to receive a i/4-in. pipe 16 to 24 in. long. The outer end of the i/4-in. pipe is threaded internally to hold a plug through which passes a i/i6-in. hole. The i/4-in. pipe is curved to enable the operator to introduce it into the hole without danger of being struck by the chuck of the machine. The plunger is made of 3/8-in. round iron and is packed with cotton candle- wicking held between two shoulders of i/4-in. square iron about 4 in. apart. The advantage ROCK DRILLS 59 of this squirt gun is in the long, narrow pipe, which can be introduced into the hole a foot or more, giving a greater pressure at the cutting end of the hole, whereas, with the old-style gun the greatest pressure was near the collar. Preventing Freezing of Air Exhaust. Alcohol is used to prevent freezing at the exhaust of the air-operated shot drills in use at the site of the new station in New York of the New York Central railroad. This company has had to do an enormous amount of core drilling within the last 15 years, and in this work several types of drills have been used. One of the most interesting outcomes of the work is the freezing-prevention appliance that can be readily adapted for use on any small air-operated machine where trouble is experienced from freezing at the exhaust. Alcohol is admitted to a vertical part of the air- supply pipe and close to the machine. The device used for feeding the alcohol is attached to the feed pipe as is a lubricator. It consists of a piece of i i / 2-in. pipe about 12 in. long, fitted with bushings at the top to take a piece of i/2-in. pipe 6 in. long. The small pipe is closed by a valve. The other end of the i i /2-in. pipe is fitted with bushings to take a 3-in. piece of i/2-in. pipe, to which a valve and an elbow are attached and into the elbow another short piece of i/2-in. pipe is screwed. The threaded end of the last-mentioned pipe is screwed into a hole tapped into the air pipe so that when screwed tight the i i/2-in. pipe is parallel to the air pipe. By opening the top valve, the i i/2-in. pipe can be filled with alcohol. That valve is then closed, and, when the machine is operating, the lower valve is opened just enough to permit drops to pass slowly. The admixture of alcohol vapor in the air effectually prevents freezing at the exhaust. The i i/2-in. pipe, which has a capacity of about i pint, is usually filled with alcohol twice per shift. Cutting Timber by Small Hammer Drills. Small hammer drills are used with a chisel bit in the Hecla mine at Burke, Ida., for cutting oft" the crushed ends of timbers. In the stopes the greatest pressure is from the squeeze of the walls, and as the ends of the stulls and caps become splintered and crushed, it is necessary to cut them off and put in new blocking. It is often difficult to get at the crushed timbers, and, even when accessible, it is not an easy job to chisel or saw the wet and twisted fibers by hand. The cutting of the wood is rendered quite easy with the drills, and by using sufficiently long bits, almost any desired place can be reached. The drills and chisels may also be used to great advantage for chiseling wall plates when an extra shaft compartment must be added, or in cutting off posts to ease up drift sets in heavy ground. In a number of mines, the blocking on drift caps is shot out when it is neces- sary to ease up on the sets; this work can much more safely and surely be accomplished with the drill. An Air Moil for Cutting Timber Hitches (By S. H. Hill). In the Lake Superior district it has been customary to cut the hitches required in timbering by hand, usually with a moil. However, since a great number of first-class air hammer drills have come upon the market the use of an air moil for this 60 HANDBOOK OF MINING DETAILS work has met with favor upon the grounds of economy and speed. The air moil can, of course, only be used in headings that are piped for air. A reducer can be used on the end of the pipe and air for the hand tool taken from the nipple used for heading machines. However, this necessitates doing the hitch cutting or squaring when the heading machines are not in use or while one of them has been purposely stopped. The introduction of a manifold on the end of air pipe, having one opening especially for the hand tool is more satisfactory. There is also a possibility of using the air moil in sampling breasts, etc. Boring Flat Holes with Air Hammer Drills (By Clarence C. Semple). In the smaller mines of the Cripple Creek district, air-hammer drills are used to bore flat holes, some of which are almost horizontal. The cuttings are removed from the hole by a blowpipe, an instrument designed for the purpose by H. E. Harris, the local agent for the Waugh drill. The blowpipe consists of a brass tube 1/8 in. in diameter and as long as the deepest hole drilled. One end of the tube is attached to a short piece of i/2-in. hose by a 1/2- to i/8-in. bushing and a hose coupling; the other end of the hose is fitted with a coupling, and nipple connecting with a i/2-in. valve. The air hose from the mains con- nect with the air inlet of the drill by a tee, to the third branch of which the blowpipe hose and valve is attached. Cruciform steel is used and the blowpipe tube is extended into the hole between two of the lugs of the steel, where it turns easily with the steel without catching on the walls of the hole as the drill is rotated. The quantity or air necessary to blow the cuttings from the hole is regulated by the valve of the i/2-in. hose. The blowpipe makes a dusty working face if the ground is dry, so the miners usually wear respirators or throw a little water into the hole with a can. It is also possible to connect the blowpipe by a second i/2-in. hose and a three-way valve, with a water supply so that water can be introduced into the hole to allay the dust, and air then used only to blow out the mud, the three-way valve being used to control the flow of water or air. [The adaptation of air-hammer drills to use in raises and drifts is brought out in articles in Chapters IV and V. EDITOR.] ECONOMICS OF PRACTICE Drilling with Double Screw Columns (By P. B. McDonald). A single- screw column or bar, rigged horizontally, is of course invaluable for supporting a machine drill over a pile of muck in a drift; in some cases, it is more easily handled, due to its length coinciding more closely with the width of the work- ing than the double-screw column with the height. Operators often purchase single-screw columns for occasional work and the miners get into the habit of using them generally around the mine because they permit of more time being wasted in clearing away muck. Under ordinary circumstances better results can be obtained if the muck is ROCK DRILLS 61 cleaned out promptly, and the drilling done on double-screw columns rigged vertically with an arm. Due to the extra movement permitted by the arm, the holes can be placed with greater accuracy and convenience. When men can conveniently place holes where their judgment directs, there is less chance of the cut failing to break. For the same reason it may be possible to break the cut with one or two holes less than would be required with the horizontal bar, which does not allow much leeway in the movement of the drill. When a horizontal bar is used, the setup has sometimes to be made a few inches too far back; if the sides of the drift are uneven, or the miners misjudge the distance from the face a few inches. This results in shortening the length of the hole that can be cut with any one drill. Holes shortened four inches, make a loss of 7% on the time spent in rigging, blasting, changing drills, etc., which operations consume approximately 50% of the miner's time, making a net loss of 3 1/2% on the total work on the cut. This case is especially marked with drill machines having too short a feed screw, as many of them have. The face of the drift is usually uneven, and the horizontal bar has to be rigged far enough back to allow room for a " starter" on the farthest projecting surface. Holes drilled at an angle from a horizontal bar, such as cutting-in holes, will not penetrate so far in the line of the drift as the other holes, making an uneven space when the round is blasted. Of course, this can be corrected by shortening the straight hole, or by using an extra drill on the angle holes, but both of these operations mean a loss of time. In general, a cut drilled from a single-screw column will be shorter than one drilled from a double-screw column, so that the time sepnt in rigging, changing drills and blasting is not utilized to the best advantage. It is always necessary to rig the horizontal bar twice, the second occasion being for the purpose of drilling the bottom holes. This consumes from 10 to 30 minutes. With the double-screw column it is often possible to drill an entire cut from one rigging. The rigging of the double-screw column vertically is usually accomplished in less time than is required to rig a single-screw bar horizontally, especially where much blocking has to be done, because the blocks that rest on the top will slide out from between the single-screw bar and the side of the drift. Such details may affect the day's work of a single miner but a small amount per day, but the aggregate difference in work done by a force of men in a year is large. Bundling Drill Steel. At the Hamilton shaft of the Chapin mine, where a small number of men are at work as contract miners, the steel is delivered at the surface from the shop. As the miners come out for their dinner, each drill gang selects its drills for the next shift. These are all bundled together and tied with a wire. While the men are out at noon, the steel is lowered and sent to a common distributing center near where the men are working. 62 HANDBOOK OF MINING DETAILS The majority of the work is by contract, and each contractor's tools are numbered. This saves the trouble of sorting the steel underground where the light is usually none too good. It also facilitates the distribution of the steel. The steel is furnished by the company while the powder, fuse and other tools are charged directly to the miner. At the Ludington shaft where most of the work is now being done, one man is employed whose only work is to look after, collect, and deliver the drill steel to the miner. Handling Drill Steel at Champion Mine. The best way of handling drill steel at a mine where there are several working shafts is often a serious question. There are several places at some mines where the steel is sharpened on being brought to the surface. At the larger mines it is generally better to sharpen the steel at some central place. The reason that the smaller mines favor the sharpening of the steel at each shaft is that the cost of gathering the steel is great unless the quantity is large. This problem of gathering and handling the steel has been solved in a simple manner at the Champion mine of the Copper Range company in Michigan. At this mine there are four working shafts from each of which steel is gathered. Shaft B sends up about 325 drills, shaft C 250, shaft D 200, and shaft E 180 drills per day. The drills are sent up loose on the cages, and at the surface are loaded directly into tank-steel boxes that are carried in the bed of a wagon in summer or sleigh in winter. These boxes are made in three pieces, a bottom and two hinged sides to which rings are fastened for receiving the hoops of the chains used to lift the boxes out of the wagon. While in the wagon the sides of the boxes are held up by the sides of the wagon or sleigh. In loading these drills they are sorted according to size so that they can be sharpened at the shop without any needless increase in the handling. Each shaft has its own wagon or sleigh. When it has been loaded with dull drills the team which does the hauling for the shafts comes for the wagon in the morning and hauls it to the blacksmith-shop with its load of drills. While the team goes after another load from another shaft, the drills are unloaded by means of an air lift .attached to a trolley that travels on an I-beam carried in the frame of the shop. Picking the boxes up with their load of drills at A, in Fig. 30 by hooking chains into the rings on their sides, the 2 i/ 2-ton air-lift B traveling on the overhead trolley takes its load to rack C in back of the heating furnace and on the same side as the drill sharpener so that the drills can be readily placed in the furnace. There the chains are unhooked from the box and the sides allowed to fall flat on the drill rack C. When all of the drills have been taken from the box during the progress of sharpening, the box is lifted with the air lift and taken over to rack D where it is put down between some pegs that will hold up its sides. As fast as the drills are sharpened they are sent over to the other side of ROCK DRILLS 63 the heating furnace to be tempered. On the tempering side is a cooling rack where the drills are held for the proper color to come and then are plunged into the cooling tank which is at the side of rack D. From the cooling tanks the drills are put in the boxes resting on rack D, being placed in the boxes of the mine to which the drills belong. As soon as all the drills for one shaft have Drill Sharpening Machine Tempering Trough FIG. 30. DRILL SHARPENING PLANT AT CHAMPION MINE. been tempered, the boxes are picked up by the traveling air lift, taken back and loaded into the wagon that is standing under the loading place. Then the drills are hauled back to the shaft, where the boys sort out the drills belonging to each machine by the numbers that are cut in their shanks and load them on the cage, those for one machine pointing up, those for the next machine on that level down, thus each machine gets back as many drills as were sent up. In this way the handling of the drills is reduced to a minimum, and yet all the 64 HANDBOOK OF MINING DETAILS advantages of central sharpening are retained for scattered shafts. The only investment other than would be required ordinarily is the providing of a wagon costing $50 or $60 to serve each shaft. The hauling is done by one of the teams that is maintained to do general hauling about the mine. This system of hand- ling the steel has been in use for a long time at the Champion mine and is satisfactory. Mine Dust Prevention on the Rand (By E. M. Weston). There are two types of dust arresters in use on the Rand, one being merely an arrangement to trap the dust in a wet sack and the other adopting the old suction principle. That designed by Doctor Aymard belongs to the first class and the other is known as Pursers'. The government, the mine owners and to a certain extent the miners have begun to realize the terrible loss to the community and to the industry in the destruction of the skilled-laborer supply and the life, moral nature and efficiency of the miners that is caused by unhealthy conditions in mining. Of these the worst effects as regards health have been caused by the gases produced by explosives and more particularly by the dust produced by blasting, by rock drilling in upper holes and by shoveling. With regard to dust from drilling uppers with either piston or hammer drills, most miners refuse to use a water jet to kill the dust in the hole, but lately I have met a few miners here who are using water jets in raises. The general complaint is that owing to the splash and drip, it is pleasanter to die of phthisis than of rheumatism. Sprays affixed to the machine have never been popular here, as they increase the humidity of the air greatly and do not lay more than 70% of the dust. Leyner drills or any hammer drills working with hollow steel are not in use, though I think the improved Leyner drill using hollow steel bits in one piece may yet find a place here for certain work. When a fair sized mine like the Nourse blunts 27,000 drill bits a week the question of maintenance of hollow steel is a serious one. I can say that at present there is no serious attempt being made on this field to destroy the dust in the hole itself when boring dry holes. Many attempts have been made to design an apparatus that will collect all the dangerous dust at the mouth of the hole. Mr. Remeaux of France has recently done some work on the subject. It is comparatively easy to design a device that will collect the dust, but the trouble is to design something that will not detract from the efficiency of the work and will not hinder the men, or take too long to adjust. Pursers' dust arrester, shown in Fig. 31, consists of a short length of piping of such a size at one end and perhaps split so that it can be driven into the mouth of the hole formed by the starter drill bit. To the outer end is fixed a T-piece with the opening pointing downward and to this opening is fixed a reducing piece and an air cock and small air jet to act as an injector and on the end is a wet bag or a pipe opening under water. The idea being that after the hole is started the pipe is driven in and the air connection made and the suction of air will draw in the dust. There are several disadvan- ROCK DRILLS 65 tages connected with this device: (i) It involves the use of a certain amount of air and, as the ordinary 3/4-in. hose in use does not supply a 3 i/4-in. drill with sufficient air as it is, it thus hinders drilling. (2) It could not be used in a steep hole as the dust would fall past the opening. (3) It involves the use FIG. 31. PURSERS' DUST ARRESTER. of an air hose about the feet of the drill tender, a "spanner boy," where it is sure to get damaged or to be in the way in removing drills from the chuck. The construction of Doctor Aymard's device and its use with hammer and piston drills is shown in Fig. 32. A conical ring, which can be made by riveting sheet iron (or better by a drop forging out of a piece of weldless tubing) is hung by two trunnions in the yoke of wrought iron which is connected with a bar FIG. 32. AYMARD'S DUST COLLECTOR. sliding in a tube which can be clamped in any position by the set screw shown. Over this ring is sewn a bag of jute sacking of the shape shown and with a piston drill the other end of the sack is supported by a loose ring which slides on the drill bit. With a hammer drill the bottom of the bag is tied round the 5 66 HANDBOOK OF MINING DETAILS drill steel. This apparatus requires some small trouble in fixing, but I believe it to be a practical device that might be adopted in many American mines with advantage where the hammer drill has already earned the unenviable name of "widow maker." The miner if he wishes to, can make a good use of this device which costs only i to make, and it will pay miners to install it. The sacking is, of course, kept damp to settle and collect the dust. I have heard it said that the bag is liable to catch the chuck of the machine but this is easily guarded against with care. On the mines of the Rand, the only real objection to the .use of dust arresters with piston drills is that where three drills are employed in one face, there is no room for their use; but on one of the large mines the other day quite a number of these devices were shown that had been wilfully damaged by the miners to avoid using them. The new miners' phthisis compensation act will have one good result as it makes it in the interest of the mine owners to secure as many convictions as possible against their workmen for breaches of the act, as three convictions render a miner ineligible for compensation. The Dwyer Dust Arrester. The Dwyer dust arrester is intended for use with rock-drilling machines that can be so operated that the exhaust air will pass down the tubular steel bit to the bottom of the hole being drilled, to blow the dust and cuttings made by the bit through the annular space between the bit and walls of the hole. The device is a receptacle that permits escape of the air, but retains the cuttings. In the accompanying illustration of the device, FIG. 33. DWYER DUST-COLLECTING DEVICE. Fig. 33, A is a sheet of metal rolled into a cylinder, the edges of which are free to overlap as much as may be necessary to introduce it into the mouth of the hole cut to sufficient depth by a starting bit, to permit introduction of the collar far enough into the hole to obtain a tight fit. To the collar is tied a bag B, which has an opening at C for slipping over the collar. The bag is attached to the collar by an elastic band. At D there is an opening in the bag through which the drill passes. To the neck of the bag at the point D is attached a cord carrying a weight at the end. This cord is wrapped about the neck of the bag to hold it to the drill ; the weight making tying unnecessary. The bag B may be made of some light open fabric through which the air will pass, but which will filter the dust, or heavy material, such as leather, may be used, in which case a large opening E is made in the bag in which a sponge is held, through ROCK DRILLS 67 which the air escapes while the dust is retained. The device was invented by William E. Dwyer, of Leadville, Colo., and is patented. Water Blast for Allaying Dust. The James water blast, illustrated in Fig. 34, was developed in South Africa and now is used in many of the mines on the Rand. In a recent report by the Royal Commission on Mines on New Zealand, this type of dust allayer was recommended for adoption in the mines of that country. The blast is intended especially for allaying dust and absorbing noxious powder fumes immediately after blasting. As shown in Fig. 34, the appliance is simple, consisting of a short piece of 6-in. pipe about 10 ft. long closed at each end by a flange which has been tapped and threaded so that the 6-in. pipe can be installed in any part of the 2-in. compressed-air mains. When FIG. 34. WATER BLAST AND DRAFT INDUCER FOR ALLAYING DUST IN DRIFTS. placed in position the side of the 6-in. pipe is tapped and threaded for a small pipe by which connection is made with a supply of water under low pressure. This may be obtained conveniently by providing a tank or cistern for water storage in some part of the mine above the level in which the water blast is used. Valves in the 2-in. service pipe and in the small water supply pipe are used to control the flow of air and water. While drilling is going on the air valve is left wide open, but the water valve is closed. When ready to blast the miners close the air valve and open the water valve; the 6-in. cylinder is quickly rilled with water. As soon as the blast has been fired the air valve is opened suddenly causing the water contained in the 6-in. pipe to be ejected into the face of the drift in the form of a fine spray. The spray of water is effective for a distance of 30 or 40 ft. back from the face. To promote further ventilation an induction draft pipe as shown in the sketch may be used to deliver air at the face or to withdraw air from it. The water blast not only allays the dust made while blasting, but wets the broken material so thoroughly that little or no dust is raised by shoveling. IV SHAFT WORK Methods in Use Timbering Use of Steel and Concrete Shaft Stations and Skip Pockets Shaft Sinking at the Pioneer Mine. The vertical shaft of the Pioneer mine, Ely, Minn., is being sunk 200 ft. from the i4oo-ft. level. Fig. 35 shows the method followed in this work. The sinking had to be done without inter- fering with the hoisting of ore. A station about 25X60 ft. was cut on the ~T~ 4. -J-l 1 1 fv ] 1 i 1 1 1 1 Hoist ,/> Ran 4-1 H HH|H FIG. 35. SHAFT SINKING UNDER ROCK PENTICE, PIONEER MINE. i4oo-ft. level and an inclined winze started near the center of the station. This winze was extended on about a 45 slope until it intersected the line of the main shaft leaving a rock pentice in the bottom of the shaft just above where the new work was to begin. After the completion of the winze a i-in. cable was anchored in the roof of the station and in the side of the shaft extension, 68 SHAFT WORK 69 as shown. This cable was used as a track upon which a carrier was operated. A small hoist was placed near the farther end of the station, and a i-ton bucket was used for handling the broken rock. The bucket is drawn up by a 3/4-in. cable until the bail strikes the carrier on the stationary cable. The carrier then conveys the bucket to the station where it is emptied into a car and trammed by hand to the shaft and hoisted on the man and timber cage, thus not interfering with the hoisting of the ore. The shaft is 7 1/2X24 ft. and has four compartments. Rapid Shaft Sinking in Butte (By C. J. Stone). The following notes concern more particularly the equipment and the methods employed in sinking the shaft of the Butte- Alex Scott Copper Co. below the i4oo-ft. level, rather than any general description of methods in the Butte district. During April, 1910, an effort was made to attain the greatest possible speed at shaft sinking, consistent with good work and safety to the miners, and as a result 106 ft. was sunk from the i4oo-ft. level in 30 working days. The shaft has but two compartments, each being 4 ft. square in the clear. The rock was all hoisted to the surface in straight-sided buckets 27 in. in diameter by 42 in. deep, swung from the bottom of a skeleton sinking cage of light construction. The sinking cage measures 16 ft. from its bottom to the top of the sinking shoes. A previous sinking campaign had developed serious trouble from the loaded bucket swinging and striking the wall plates of the shaft at times when rapid hoisting was necessary. To eliminate this the bucket is hung from two chains close to the bottom of the cage, only sufficient space being allowed to permit its being detached while at the bottom of the shaft. A ring is welded into the bucket at each side and a finger hook, such as is used on logging chains, is passed through the ring and locked in place by a slip ring. A screw-eye fastens the chain to the cage and furnishes the adjustment. With this device an adjustment can be secured on the chains that will permit only the least amount of swinging of the bucket in the shaft, and hoisting can be done at any speed desired and with perfect safety to the miners below. The chains may be quickly detached to remove the bucket. The working crew consists of four machine miners and one pump man on each shift, and three eight hour shifts constitute the day. One of the miners on each shift acts as a working boss and he is paid 75 cents extra per shift. Two 3 i/8-in. Ingersoll-Rand drills are used under an air pressure of 85 to 90 Ib. at the compressor. The cut holes are drilled from 8 to 9 ft. deep and a wedge bit is used on the finishing drill. The side or back holes are 6 ft. deep. It requires from 1 6 to 19 holes to break the ground, which is for the most part a hard granite with the partings or cleavages running the long way of the shaft. The blasting is rarely perfectly satisfactory. Should the ground be particularly soft and the cleavages favcrable, a blast will probably break to the bottom of the holes. Under ordinary circumstances, however, from 18 in. to 2 ft. will have to be fired again. 70 HANDBOOK OF MINING DETAILS The practice in some large shafts is to blast the cut holes first and after mucking, blast their bottoms until the cut is entirely out, when the remainder of the holes are fired. Experience has shown that better results are obtained if the cut holes are fired with a battery, but the damage to the timbers when sinking in hard rock is so great that the method has not found favor in Butte and the old method of blasting with waterproof fuse maintains. Forty per cent, gelatin dynamite is used. The water is handled with a No. 7 Cameron sinking pump. The air exhaust is passed through a check valve into the water or discharge column. This eliminates the roar of the exhaust in the shaft and makes it possible for either a Knowles or a Cameron sinker to lift water 200 ft. in place of 100 ft., which is the .normal lift of a No. 7 pump. In the sinking of the Alex Scott shaft the flow of water varied from 20 to 30 gallons per minute and no time was lost during the month because of water in the shaft. The hoisting was done as rapidly as possible. During the mucking hours the bucket was brought to the surface from the i5oo-ft. level in from 30 to 45 seconds, according to the engineer. The hoisting engine is of the first motion type, built for high pressure; the cylinders are 12X36 in. and the drum is 5 ft. in diameter. It was built by the Nordberg Manufacturing Company. The timbering is the usual shaft set. The sets are of ioX lo-in. black larch and fir timber, placed 5 ft. between centers and lagged with 2X10- or 3Xn-in. plank. Each set is thoroughly blocked and wedged and absolutely no cutting is allowed. The shaft must be broken sufficiently large to hang the sets free from the walls and the lagging must be placed loose to permit later swelling of the ground. For blasting timbers heavy channel irons are used, the channels being bolted tight to the bottom set before firing. Openings are cut in the channels for the nuts of the hanging bolts. The ends and the centers are protected in this way as well as the wall plates. A marked difference is noted in the physical condition of the timbers by the use of the channel irons in place of the ordinary 5X 10 blasting timbers. The bonus or premium system was employed as one means of securing rapid work. The ordinary speed of shaft sinking below the i2oo-ft. level in Butte is from 65 to 85 ft. per month. As a basis for the bonus, therefore, 75 ft. were taken and the shaft miners and pump men were given each one dollar per foot for every foot that was accomplished above the base during the month. In this instance it amounted to $31 bonus to each man as a reward of merit. The bonus cost per foot amounted to $15, and the entire or actual labor cost for the 106 ft. accomplished, including the bonus, amounted to $36.54 per foot. Should only ordinary speed have been made and the bonus system not employed as an incentive for hard and faithful labor, the cost would have been $45.46 per foot. However, as the actual amount of sinking that otherwise might have been accomplished is an unknown factor, the latter figure is only an assump- tion on the base or average measurement. SHAFT WORK 71 Shaft Sinking at Stella Mine, New York. The drawings in Figs. 36 and 37 show the methods of shaft sinking used by the St. Lawrence Pyrites Co., DeKalb Junction, N. Y. In each case it was desired to sink the shaft and at the same time continue hoisting ore. As there were no levels below the shaft sump, there was no opportunity for extending the shaft by means of a raise from lower levels. The Stella shaft is inclined at an angle of 18; the Anna at 45 At the Anna shaft advantage was taken of an existing crosscut, and a stope in an upper branch to start the new section of the shaft, back of and above Electric Hoist FIG. 36. DETAILS OF ANNA SHAFT EXTENSION. the sump. The hanging wall was taken out sufficiently to allow the construction of a small ore bin, as shown in Fig. 36, and at the same time provide space for the sheave. An electric hoist was installed in the crosscut a little to one side of the shaft. The ore bin is constructed just above the incline shaft so that the ore can be dumped directly into the skip and taken to the surface. A small self- dumping skip is used in the shaft extension and all the material from the shaft is dumped into the ore bin. 7 2 HANDBOOK OF MINING DETAILS The method employed at the Stella shaft is to drift out about 20 or 25 ft. from one side of the main shaft and then sink on the incline at such an angle as to meet the line of the permanent shaft at a distance of 30 to 35 ft. below the working level. One reason for not cutting out the hanging wall, as was done at the Anna, was that the roof was barren. In the Stella, all of the work was done in the main orebody. When the line of the main shaft was reached, this auxiliary shaft was then deflected to as to be a continuation of the desired shaft. The ore from the auxiliary shaft is dumped into the bin and transferred by car to the main shaft. Another advantage of sinking the shafts by these methods is that the sump is maintained in perfect condition and the pumps are able to take care of all of the water so that the work below was comparatively dry. Electric Hoist Main Shaft, ?0 Slop*. FIG. 37. PLAN OF STELLA SHAFT. Bucket Trolley for Shaft Sinking (By L. E. Ives). The problem of maintaining a normal production of ore from a shaft in which sinking is being carried on, is one that constantly confronts the mine superintendent. In Fig. 38 is illustrated a method used in the Michigan copper country, at a number of important mines. The sketch shows a section of an inclined shaft, but does not show details of timbering. A and B represent the two bottom plats from which ore is being mined and hoisted. Below the bottom plat B, and not indicated in the sketch, is a pentice, or bulkhead, which prevents the skip, in case of accident, from descending upon the miners who are engaged in sinking at the working face M. While affording protection to the miners, the pentice at the same time precludes the possibility of loading the muck from the working face, directly into the skip. Again, even were this possible, it is undesirable for the reason that the skip would be taken out of ore-hoisting service for too long periods. The pentice is extended across both skip compartments, but terminates just short of the ladderway. Over the center of the ladderway, and at the proper spacing, holes are drilled in the hanging wall into which iron eye-pins N are inserted and wedged. From these eye-pins, by means of chains G, is supported an I-beam F in such a way that the flat side of the flange is parallel to the hanging wall and about 10 in. or a foot from it. Along this I-beam runs the SHAFT WORK 73 trolley K. The latter is triangular in form, but the angles vary with the dip of the shaft in which it is used. It is so constructed that when the trolley and bucket are being hoisted, or in other words, when the trolley is running along the I-beam, the bucket is suspended vertically beneath the pulley, which is farthest up the shaft along the I-beam. Only one rope E is used and in lowering the bucket L, when the trolley is stopped by a projection, placed for the purpose at the lower end of the I-beam, the rope continues to lower the bucket to the working bottom, as indicated by the dotted lines. Here the rope is unhooked from the bucket, if desired, and the latter may be moved to any part of the FIG. 38. BUCKET TROLLEY FOR SHAFT SINKING. bottom. In hoisting, when the bucket reaches the trolley, the former auto- matically clamps into the latter and with no delay whatever, trolley and bucket together continue to move upward, until the point for dumping is reached. In dumping and loading into the skip two methods are in use. In either case the bucket is dumped into a chute. In one case, however, the contents run immediately into a tram car and this, when filled, is pushed around and dumped into the skip, just as ore would be. In the other case, and this is used pref- erably where only one compartment is being used for hoisting ore, the bucket is dumped into a bin which is built in the unused compartment. The mouth of this bin is so placed that when the latter is full and a skip is available, the gate is opened and the entire contents of the bin are dumped at once into the waiting skip. For hoisting the bucket and trolley an ordinary wire rope is used and a compressed-air hoist H, usually called a puffer, is placed on a platform, built at a point between the two deepest levels. The hoist is operated easily by a boy. C D indicates the top of the skip rail. A Two-way Shaft. We once observed in Colorado a unique method of prospecting a vein, which is not to be generally recommended, but in this case well served its purpose, and conformed to the cardinal principle of pros- pecting, namely, " Follow the ore." A vertical shaft had been started on vein outcropping at A. About 50 ft. down, at B, the vein was found to split. The chances seemed to be that it was going around a horse, the latter appearing 74 HANDBOOK OF MINING DETAILS to be of large size, and both branches of the vein looking equally good. In order to follow them both, the vertical shaft was converted into a two-way shaft as shown in Fig. 39. Hoisting was done regularly from both branches. Skids were laid in branches B C and B D, the buckets sliding down and being dragged up upon them. The upper end of the skids were extended by a movable switch, constructed of two pieces of timber, pivoted at the lower end. In hoisting from B C, the switch was thrown in the position Z Y. When it was desired to hoist from B D, the switch was thrown over to X Z causing the bucket to descend in the desired direction. Of course, it was necessary to place rollers for the cable at X and Y, which are shown in the sketch in an exaggerated form, in order to make the arrangement quite clear. FIG. 39. AN UNUSUAL TWO-WAY SHAFT. Securing Loose Rock by Bolts. In the Camp Bird mine the wall rock is quite hard and in most cases stands well, but in the driving of the main raise extending from the haulage level to the upper workings, through which supplies and men are hoisted, several large slabs of rock began to loosen after the timber- ing of the raise was well under way. Cracks began to open behind these slabs which would have come down in pieces weighing several tons had is been neces- sary to blast them. As this could not be done without considerable danger to the timber in the raise, the slabs were bolted in place in the following manner: A slab was securely spragged in place by temporary stulls running across the raise, so that is could not move or at least without giving ample warning. Single- jack holes were drilled through the slabs, which were themselves quite solid, and into the solid ground behind them for a distance of a foot or more. Then SHAFT WORK 75 the depth of the hole was measured, and an old piece of drill steel, with its head well upset so as to form a strong head like that of a bolt, was cut off to the right length and the lower end split. A narrow steel wedge was then inserted in the split end, which was pushed into the hole, wedge-end first, until the wedge was against the bottom; then, by hammering, the split ends of the drill were spread until the bolt was securely anchored in the wall rock behind the slab of ground, thus holding the slab tightly in place. The sprags were then removed. These slabs had been held by bolts 7 or 8 years when my attention was called to them. Apparently they had not moved a fraction of an inch since they were bolted to the wall behind them. Several bolts were used in each slab placed according to the direction of the crack behind them. The method of securing the bolts in the wall rock is, of course, the same as that of anchoring bolts in concrete when for any reason new bolts have to be used in old foundations. TIMBERING Necessity of Strong Partitions in Shafts. It is usual and proper, in a mine shaft, to separate the compartment reserved for the men from those through which the ore is hoisted to the surface. In some mines it appears to be considered that any sort of timbering is good enough to form the partition, and it would seem as if the temptation to use thin planking which can be nailed in place almost as quickly as it can be sawed, is almost too strong to be resisted. In one such case an accident of a serious nature was only avoided by a mere chance. A skip was being hauled to the surface, containing a number of large pieces of ore. It had been nearly filled, and by some means the top piece became dislodged and fell over the skip into the shaft. In falling it glanced against the timbering of the partition, then went down the shaft, bounding from side to side. As, however, it passed down, its momentum increased, until near the bottom of the shaft, the thin wooden partition was not strong enough to throw it off again, and it crashed through the timber into the compartment reserved for the men. By the merest chance, no one was there at the time. If there had been a workman in the way, he would most assuredly have been killed as the fall was a long one. It is just this sort of thing which a manager of a mine should foresee and prevent as far as possible by making his constructions amply strong, even at increased expense. Corner Framing of Shaft Timbers (By W. H. Storms). There is some diversity in the style of framing timbers for shafts. The difference is found chiefly at the corners, and while each method has its advocates, any of these several methods will answer all purposes under certain conditions, for all are in practical use. The drawings shown in Fig. 40 illustrate the several styles. Only the ends of the wall plates are shown, it being understood that the end plates must be framed in exact conformity with the wall plates. In each case the daps in which the posts must rest are either shown or are provided for. In Fig. i, the dap is shown on both upper and lower sides; in Fig. 2 it shows 7 6 HANDBOOK OF MINING DETAILS only on the under side, the corresponding dap for the upper post being cut in the end plate, which is not shown; in Fig. 3 the edge of the dap is shown both top and bottom, and in Fig. 4 it is shown on both upper and lower sides of the plate. The style of framing shown in Fig. i, was in use at least 60 years ago, and is about the only style of framing shaft timbers illustrated in old works on mining, such, for instance, as Overman's " Metallurgy," published in 1850. There are mines where this peculiar style of timbering is still in use, but it has nothing in particular to recommend it, while the placing of the end plates, unless they are provided with separate hanging bolts, is accomplished with difficulty, which FIG. I FIG. 3. FIG. 2. FIG. 4. FIG. 40. SHAFT TIMBER ENDS. is not the case with any of the other methods here shown. Fig. 2 represents the end of a wall plate halved and provided with a dap on the lower side to accommodate the post of the set below, at that corner, and a corresponding dap must be cut on top of the end plate that will rest upon it. This is a simple and common way of framing timbers for vertical shafts. The method of framing shown in Fig. 3 is similar to that in Fig. 2, the only difference being in the bevel, shown at B. This bevel is for the purpose of reducing the tendency of the timbers to split under heavy side pressure, but ordinarily, where the side pressure is sufficiently great to cause timbers to split when framed as shown in Fig. 2, the bevel will make but little difference. Neither the style illustrated in Fig. 2 nor Fig. 3 is well adapted to shafts which depart more than 1 5 from the vertical. Timbers for inclined shafts are now framed almost universally as shown in Fig. 4. This method is equally adapted to either inclined or vertical shafts. It will be noticed that the so-called dovetail mortise is beveled on one side only, the other side being normal (at a right angle) to the top of the timber. A modification of this is sometimes seen where both sides are cut with a bevel. This has no advantage and is also more troublesome to cut. All the marking in the laying out of shaft timbers can and should be done with the use of SHAFT WORK 77 a templet. This should be made of a good sound piece of wood, for the back, to which should be secured steel plates of the proper size and shape to indicate the various cuts to be made. When a templet is used there are fewer mistakes Detail of End Plate r t = -1 "* i < 7 -j > Detail of r T T Wall Plate L i i FIG. 41. METHODS OF FRAMING TIMBER. made in laying out the work. A man may be an excellent carpenter and yet know nothing whatever of laying out marks for framing shaft timbers. Then too, with the use of the templet all the timbers are framed exactly alike, 78 HANDBOOK OF MINING DETAILS all cuts corresponding in position and size, which is sometimes not the case when the work is laid out with a square, unless the man be a most careful workman. Figure 41 shows the method of framing shaft sets from 8-in. timber which is probably in most common use. It combines the maximum strength with the minimum labor of framing. Angles other than right angles are to be avoided as far as possible. They are hard to fit. To frame this joint, fasten templet to side A of wall and end plates and frame top and bottom faces of tongue and shoulder, squaring from the templet. Also frame daps for posts at center of wall plates and mark top and bottom of dap for the divider. The sides may be framed and squared from these faces when finished. The wedge- shaped gain on divider holds the divider on the bottom set and avoids the deep cut in the wall plate necessary for a tongue. The false set which protects the bottom timbers from the blasts is easier to handle if made of half-round logs without framing. The false wall plates should completely cover the shaft wall plates and be attached by bolts through the holes drilled for the hangers. The false end plates and divider need only reach from one false wall plate to the other and holes should be drilled in the shaft-end plates to accommodate bolts in the same manner as in the wall plates. Extension of Wall x Plate used in Enlarged x - x Shaft. FIG. 42. FRAMING FOR SHAFT TIMBERS TO ALLOW FOR ADDITIONAL COMPARTMENT. Method of Extending Shaft Timbers (By D. A. McMillen). In timber- ing shafts it is often necessary to devise some means of converting an end plate into a divider and extending the wall plate so as to add another compartment. In the ordinary procedure, when adding an extra shaft compartment, it is SHAFT WORK 79 often cheapest to retimber entirely that portion of the shaft which is to be enlarged, as the ordinary wall plate serving for a two-compartment shaft will not do for one of three compartments. If the end plate of the two-compart- ment shaft is framed in the beginning, as shown in Fig. 42 at A and the wall plate on the side to be extended as B, it is comparatively easy to add an extension C to the wall plate and to fit these together, making the timbers B and C act as wall plates, and A as a divider instead of an end plate. The scheme thus simply resolves itself into a matter of cutting the wall plate B-C into two parts that can be afterward fitted together. A block to conform with the shape of D is usually fitted into the open space that is left before the timbers of the extra compartment are added. This system has been adopted in several places in the Globe district and has proved satisfactory. Shaft Timbering at the Keystone Mine (By William H. Storms). The Keystone mine at Amador City, Calif., is one of the largest mines on the famous Mother Lode. It has been extensively developed by a number of JE^E ^K^^Es^ FIG. 43. METHOD OF TIMBERING THE KEYSTONE SHAFT. incline shafts of varying depth, the deepest being the Patton shaft near the north end of the property, which was started by W. H. Patton over 40 years ago, and now has a depth of 1573 ft. This shaft, beginning in the slate country rock, at a depth of about 400 ft., is approached by a fissure which occurs in the hanging-wall side of the shaft and continues in or near it to about the 8oo-ft. level. The ground is very heavy, and has for years been a source of annoyance and expense in keeping the shaft open. Time and again the timbers have 8o HANDBOOK OF MINING DETAILS been reinforced and renewed until, in some of the worst places the shaft is supported by a solid crib work of great timbers. One effect of the heavy down- ward pressure of the swelling ground on the hanging wall side of the shaft has been to force the caps down upon the ends of the dividers, causing the latter to cut deeply into the caps, thereby weakening the timbers and reducing the size of the shaft, hence necessitating frequent repairs. A few months ago a scheme was introduced in the retimbering of the Patton shaft which has been found to give complete satisfaction and which is evidently going to result in the y 2"Planks o a^m"Bolts f lifHoles 12" X 12 "x 18 G" f ]^tf* -1C" : 10" , 3-10-- t-b' 00 v, _j 4>, n > i ir Cage ^f 5-betwee i > i CM Ladder (M ^ P S3 T^^-i X Guides "o and Pipes ^ ? i 4 i T ,4"x4" ' Q v [o * Q | V' x8 " 1 ^jsCounterw'tg \ ^ 6 i b t^ > 12x12" o o II Plan. 91 1 ,2"x 2 'Strip, r^-j - | /.Spiked on. M 1 Ivwy v//, i! !: J i: ; '////, to 1 ^lo- I Cedar Post -" 10"Top I" 0) 1 1'4" Hanger r; Bolts ^ * | Q 2"x 2"Strip A, 'M i- / V V i! i! '////, MM 1 6"C.I.*/^ LJ L-JWashe/ L iSiHA RlPvation. U ^^ FIG. 44. ROGERS SHAFT BELOW CONCRETE PORTION. saving of much time and timber in repairing this shaft. The idea is illustrated in Fig. 43. It is simply the insertion of a heavy head block a between plate b and divider d, as shown. No mortise or dap is cut in the wall plate, and the divider is sawed off square. The plate timbers are 18 in. square, the dividers 12 X 1 8 in., and the head block is 18 in. wide, 24 in. long and 4 in. thick. It is cut as shown, and is slipped in between the wall plate and the top of the divider SHAFT WORK 81 and held in place by driving in shingle wedges. The pressure soon exerts itself, however, and wedges then become superfluous. Rogers Shaft at Iron River, Michigan (By H. L. Botsford). The accompanying sketches, Figs. 44 and 45, illustrate the size and timbering of a new shaft which the Munro Iron Mining Co. is sinking at a property near Iron River, Mich. A concrete drop shaft has been sunk through the overburden by The Foundation Co. of New York. From this point on, the sinking will be continued by the mining company and the shaft will be rectangular in section, Skip Guide l"Bolta Bracket- K So; Bracket u Limit of Shaft in Ledge ^ D I d Is "S3 8"x 16"x H" 6 c. E P < i| -? ?3 f.s Plate X ^: 2 8 'Ship Channel. \ /. J8S J cc Detail here. 6'x 8"Guides \ zza fa oc 3 ^> m ' fcr b 8 *.. 5'2- - S 4 ^ 1 G.-L.-Bracket (Limit of Shaft in Ledge 4-G-Lr-B racket i "IS" Ship Chanr ; on Edge. ,el/ / : T This Distance f/ Varies. = ~\ q* :*<,';?": V? *7vi>^:**v?i!V^ ; ^l out more than 12 "from Concrete. \' 'j ' sj^-ig^! [ When less than 12 "from Concrete, Coacre te. i"Bolt / Depth of Suppoit Guide thus: pj an Timber 12 Sets spaced 8' Centers Vertically. FIG. 45. STEEL WORK IN CONCRETE PORTION OF ROGERS SHAFT. 11X16 ft. 6 in., inside dimensions, with two skip-compartments, a cage- way and a combined pipe- and ladder-way. One end of the latter compartment is arranged to accommodate the counter-weight for the cage. Figure 44 shows a plan and side elevation of the shaft as it will be con- structed below the concrete portion. The skips, which will be operated in balance, are of liberal width to facilitate their loading through the chute at the 6 82 HANDBOOK OF MINING DETAILS bottom of the shaft. In the past it has been found that where the skip is narrow, and blocky ore is hoisted, considerable trouble is experienced by the clogging of the ore in the loading chute; with the width of skip as designed, it is expected that this difficulty will be obviated. The cage compartment is 6X n ft. and will permit the operation of a cage large enough to take a 55-cu. ft. saddle-back tram car, this being the size of the underground car which will be used in the mine. The size of the cage will also permit the hoisting of rock on it, if this is found to be necessary during the ore-shipping season. Another advantage of the large-sized cage is, that cars may be loaded with mine timbers at the timber yard on surface, trammed to the shaft, lowered into the mine, and taken to their destination underground without further handling of the timber. The steelwork which will support the guides in the concreted portion of the shaft, and the bracket for attaching the steel members to the concrete walls is shown in Fig. 45. These sets will be spaced 8 ft. between centers. Bolts which fasten the brackets to the concrete will be split 2 1/2 in. on the bottom end and a wedge inserted before driving them in the holes drilled for them in the concrete wall ; in addition they will be leaded in. While the initial cost of such shaft construction is high, the advantages are many. Water difficulties are overcome to a large extent and stability and alignment are assured. Combination Post and Set Timbering in Shafts (By Claude T. Rice). The ground in the inclined shafts that follow the Calumet & Hecla conglomerate is so heavy that a crew of seven men is kept at work easing the timbers. The manner of supporting the roof when it becomes bad is novel, in that the main part of the top weight is carried on posts while the scalings from the roof are supported by lagging carried on regular shaft sets. When the shaft is first sunk, only the posts, or the "end timbers," as they are called locally, are put in, and the shaft is made 22X9 ft., but after a time the weight begins to come on the roof and the shaft pilla s begin to flake away under the pressure, increasing the width to about 25 ft. by the time that the shaft sets are placed. The posts are put in with foot and head blocks, built up of 6-in. pieces criss-crossed to make a head block 1 8 to 24 in. thick, and a foot block about 12 in. thick. Then when the weight comes on the posts the crushing of these thick head blocks gives the ground a chance to adjust itself to the new conditions bafore the posts are injured. The posts when first put in are about 6 1/2 ft. long, from 2 1/2 to 3 ft. in diameter. Posts of Georgia pine last about two years before they need to be reheaded and will stand three reheadings, each of which lengthens the post's life two years, so that the posts have a life of seven or eight years in these shafts. Some hemlock posts are used, which last about two years before they have to bs replaced. No reheading of the hemlock posts is possible, as they rot too fast for it to pay. A few hard-wood posts have been tried, but lasted scarcely a year, rotting into a mush-like pulp, in an amazing manner. SHAFT WORK 83 The post is reheaded as soon as the head block has been compressed to the limit and before compression of the post itself has begun. Owing to the pieces in the head block being laid so that they take the weight across their fibers instead of along them, the compression is confined entirely to the block until the last, when the wood fiber has become so compacted that it is as firm as the fiber of the posts. This reheading consists of sawing and chiseling out a cut across the top of the post so as to allow the post to be knocked out. About 6 in. is lost in this way at each reheading. Then a new set of foot and head blocks is put in, and the post is good for another two years, being practically as strong as when first put in. When the second set of head blocks has been com- pressed to the limit, the post is again reheaded, but before the post has had to be reheaded, the roof will have begun to scale off partly under the weight and partly because of swelling, caused by oxidation of lime minerals in the hanging wall. Lagging has, therefore, to be put in over the skip compartments, and this lagging is carried on regular sets such as are commonly used in inclined shafts. Owing to the swelling of the foot wall, which gives especial trouble through raising and warping the tracks so that the skips will not stay on them, no sill is used under the posts of the shaft set; instead foot blocks of liberal propor- tions are used. The lagging rests on i4X i4-in. caps of pine. In a shaft having two hoisting compartments, the cap is in two pieces that butt against one another over the manway, which is placed in the center, as shown in Fig. 46. Above the cap proper is carried a false cap of round timber whenever there is sufficient room. This rests on blocks placed on. the cap pieces directly over the posts. Under the cap and between the posts and the cap are squeezing pieces of 6X i4-in. timber, about 24 in. long, with their ends beveled so that they will bend and have less tendency to cut into the caps. The squeezing pieces take most of the crushing in these sets, as by them the pressure is distributed over a larger area on the cap than on the post. In other words, there is a concentrated pressure on the underside of the squeezing pieces, and a distributed pressure on the top side. Consequently, the post cuts up into the underside of the squeezing piece, but the squeezing piece does not in turn cut into the cap. As the weight comes end-on on the fibers of the post, it sustains little injury when it cuts into the squeezing piece. Studdles are put in to brace the timbers, always at the bottom and generally also at the top of the posts. In order to provide room for the circulation of air between the stull, or end-timber posts and the square-timber posts, as the shaft sets are called, a 3~in. block is put in between. This prevents decay starting on the posts where the two would otherwise be in contact. In easing the timbers, the men work on top of the lagging that is carried on the square timbers, and throw the rock that comes from the easing of the roof off at the far sides of the shaft so it can be scraped down to the level and loaded on the sides. Some of it cannot be prevented from falling into the manway HANDBOOK OF MINING DETAILS and is worked down to the level that way. By this arrangement the timber- men are able to work over the skipways without interfering with the hoisting; indeed it is to accomplish this that the square timbers are used. Longitudinal Section of Shaft showing Timbering. 10-in. Round False Cap Cross Section FIG. 46. POSTS AND SQUARE TIMBERS IN AN INCLINED SHAFT. The combination of posts to take the bulk of the top weight with sets to carry the lagging is a most admirable scheme for timbering inclines in heavy ground, for it throws most of the wear and tear on the round posts, which are the cheapest elements in the combination to replace. Moreover, by using the SHAFT WORK 85 squeezing pieces the caps are saved from injury and the life of the square- timber sets is increased. The manway is put in the center of the shaft, so that the men who replace the rope idlers can inspect the track between idlers without entering the skip compartments. The ladder is carried on pieces of timber clamped to the air main, the ladder being bolted to the crosspieces by staples. There is some objection to this arrangement, as if any repairs have to be made on the air- main, the ladder has to be removed. Still there is the advantage that the ladder is kept clear of the ground, so that rocks cannot accumulate under it which is one of the things that has to be guarded against in an inclined shaft. Timbering Swelling Ground (By George C. McFarlane). In swelling ground it is noticeable that the swelling is always at right angles to the foliation, and drifts paralleling the stratification may require double setting, while the crosscuts will stand without timber. I have also noted cases where drifts in the upper workings had stood for years without retimbering, while below the oxidized zone heavy sets were crushed and broken in 2 months. As a rule this swelling ground is not difficult to retimber. Ground that is heavy because the rock is loose and full of slips often comes down in large masses; when a couple FIG. 47. SHAFT TIMBERING IN SWELLING GROUND. of sets break, the fall may bring down adjacent sets. On the other hand, in a drift in swelling ground the timbers may be crushing and binding and when a broken set is knocked out, only three or four wheelbarrow loads of rock will come down. For replacing broken shaft sets in swelling ground I devised the form of timbering shown in Fig. 47. Two sets of 6X lo-in. timbers with a 6Xi2-in. filler between the wall plates are used. One side of the 6X lo-in. piece and both sides of the filler are sawed on a bevel of 1/2 in. as shown. In sawing, the bevel cut is made by placing a bar of flat iron across the bunks of the saw 86 HANDBOOK OF MINING DETAILS carriage in front of the head blocks and canting the stick back on the bar. In placing the sets, the posts must be put in tight, using two or more jacks to bring the plates and filler to a solid bearing at each post. In sinking a new shaft with this kind of timbering the set would be gripped together by hanger bolts until a set of dead logs were placed. As the walls of the shaft swell, the filler is of course forced in between the plates, causing the posts to sink into them. If the plates and filler grip tighter on one side, the set will be crowded toward the slack side as it takes the squeeze. In an hour or so between shifts this can be remedied by jacking in a couple of extra posts on the slack side, and in this way the guides can be kept in good alinement. This form of set allows the walls of the shaft to swell 4 in. without breaking the timbers. Should the swelling force the filler flush with the plates, pieces of lagging can be removed, a few at a time, the wall cut back a few inches and the lagging reset by inserting blocks between it and the wall plates. The posts can then be removed and the filler jacked out with a couple of pipe jacks, the posts reset and the temporary blocking between the lagging and the wall plates removed. One set of posts will have to be chopped out to release the fillers of the first set; after that, many of the posts and part of the lagging can be recovered in shape to use again. Placing Shaft Timber. At the Iron Blossom mine, in the Tintic district, Utah, shaft sets are put together at the bottom of the shaft and then hoisted into position. When a set of timbers is to be put in, the framed pieces are lowered on the cage, temporary guides being used so as to allow the cage to drop below the point to which shaft timbering has advanced. The wall plates are laid upon a 5-ft. board placed across the bottom of the cage. The end plates and dividers are then dropped into place and the sets drawn tightly together. Wooden dowels may be used to secure the framed ends to the wall and the end plates. When the set is put together, the cage is hoisted to the proper point and the rigid set drawn up against the posts by hanging irons from the next set above. By thus making up the shaft set before it is put into position it is claimed that time is saved and more rigid sets are insured. Supporting Guides or Runners in Shaft. The scheme shown in Fig. 48 for the support of shaft guides is used at the Tobin and Dunn mines at Crystal Falls, Mich. The guide itself is 5X8 in., and is fastened to the shaft timbers by two 3/4-in. lag screws. In addition to this a 3X3-in. angle iron is used every 10 or 15 ft. in the shaft. This angle iron is bolted to the runner with two i/2X6-in. bolts and fastened to the shaft timber with two i/2-in. lag screws. The original method was to use only one lag screw in the center of a 5X 6-in. runner. This was found to be entirely too weak, and the screws almost invariably broke at a point where the thread begins. With the present arrange- ment the runners do not work loose, except as the acid waters may corrode the bolts. SHAFT WORK 87 Holding Shaft Timbers with Wire Cables. The Fremont shaft, at the Fremont Consolidated mine ; near Amador City, Calif., has two compartments and dips at an angle of 52. It is 650 ft. deep with a 5o-ft. sump, and is true throughout its depth, being unquestionably the best inclined shaft on the Mother Lode. In sinking this shaft, some heavy ground that caved badly was encountered. It was impossible to get a bearing for the wall plates or caps, and the more the ground was trimmed away to secure a bearing for these timbers, Side Back o o FIG. 48. METHOD OF SUPPORTING SHAFT GUIDES. the worse it caved, until a large cavern was formed above the shaft. In order to timber the shaft through this ground, the expedient of securing the timbers in place with old hoisting cable was tried and proved quite successful. The sets in the caving zone were tied with the cable to those above which had firm bearings in the wall rock. This hanging of the timbers was continued until firm ground that would give sufficient bearing for the timbers was again encoun- tered. Stringers were then placed over the suspended shaft sets and upon them a cribbing built up in the opening; old timbers and waste were stowed in it 88 HANDBOOK OF MINING DETAILS until it was entirely and tightly filled. No trouble has since been experi- enced with the shaft at this point. USES OF STEEL AND CONCRETE Steel Shaft Sets on the Mesabi Range (By F. A. Kennedy). The steel sets used by the Shenango Furnace Co. in its Whiteside mine near Buhl, Minn., are illustrated in Fig. 49. The inside measurements are 6 ft. X 18 ft., 8 in. The wall plates and end pieces are 5-in. H's weighing 18.7 Ib. per foot, with lo-in. I-beams for dividers. The sets are spaced 4 ft. center to center and held together with eight 3 i/2-in. angle studdles. All angles are 3'x 3 x % x 20^ Connecting Angla 1 3H-' x y/i x H x 5 Counseling Angle FIG. 49. STEEL SHAFT SETS AT WHITESIDE MINE. shop riveted to the end pieces and dividers so that little time is lost in putting a set in place. Machine bolts were used with nut locks for bolting the steel together. The shaft was wet and it took but 2 hours' labor at the most to put a set in place. Norway planks were used as slats and are held in place by means of small 2Xi/2X2-in. angles shop riveted to the back of all wall plates and end pieces. Later on it is proposed to replace the slats by concrete. The sketch shows how the first bearing set was placed under the second set. The rails are 33 ft. long, resting on concrete foundations each 10 ft. in length. Another bearing set of i2-in. X i4-ft. I-beams was put in when the rock forma- SHAFT WORK 89 tion was encountered. Bearers like the last named were put in every 60 ft. down the shaft. This is found to be a satisfactory method of sinking. Arrangement for Guiding a Drop Shaft. The sinking of the W. F. 2 shaft at Obernkirchen, South Hanover, Germany, encountered just below the surface an i8-m. zone of watery sand and clay, necessitating the use of drop- shaft methods. The manner in which the shaft was guided in the true vertical direction is of interest, and is illustrated in Fig. 50. The inside diameter of the finished shaft was required to be 4.5 m. ; the con- crete wall of the drop shaft was therefore molded to an inside diameter of 5.5 m., with walls 77 cm. thick. The outside of the wall was coated with cement plaster and then smeared thickly with brown soap, whereby the friction of the shaft against the guides was greatly reduced. It was only necessary to build Vertical Section FIG. 50. ARRANGEMENT OF GUIDES FOR DROP-SHAFT SINKING. the walls 16 cm. above the top of the guides to maintain the weight required to give a steady downward motion. The sinking went on without incident to a depth of 14.5 m., when the wall refused to drop further, even though it was heavily weighted and the top built up to a height of 3.16 m. above the guides. It was ascertained by boring that a further depth of only 7 m. was necessary to reach solid strata, and it seemed possible to gain this distance by forepoling. Before this plan could be put into operation, however, an inrush of material under the sinking shoe made it imperative to adopt a second, interior drop shaft, made of sheet iron. The bottom of the concrete shaft was firmly puddled with clay, and the iron drop shaft, of 4.95 m. inside diameter and 15.8 m. high, was lowered into place. Sinking by this means went on rapidly until solid strata were encountered at a depth of 21.76 m. The shaft was continued into the rock to a further depth of 6 m., leaving 3 m. of the iron wall reaching up inside the concrete wall of the outer shaft. The space between these two walls was then filled 90 HANDBOOK OF MINING DETAILS with cement grouting (equal parts of quick-setting cement and sand) by boring holes through the iron plates and connecting the holes with pipes reaching to the surface. The upper 20 cm. of the space was filled with pitch-pine wedging. The first 5 m. in the solid rock were lined with cast-iron tubbings and a masonry bearing ring, behind which all the spaces were thoroughly grouted. At a depth of 32.6 m. sinking was begun in the ordinary manner, with masonry lining. Concrete in Inclined Shafts (By Sheldon Smillie). When a well organized, well advised mining company commences to sink a shaft, the question of durability of equipment outweighs that of first cost, and for this reason concrete has in some places gradually superseded timber for supporting the walls through the overburden. Its long life in wet shafts and its freedom from the danger of fire especially commend it. For use in vertical shafts through water-bearing ground it has been employed for some time, but only recently has it been applied to metal mining and inclined shafts. In the Lake Superior copper region all new shafts are equipped with concrete collars. Concrete runners under the rails have not yet gained the popularity they deserve, but are coming into use more and more. The collar or cribbing makes an absolutely water-tight joint with bedrock, keeping out all surface water, is free from rot and should a fire occur in either the shaft or in the rock- house above, large iron doors may be closed to make an effectual barrier. Managers have installed concrete runners experimentally and in a critical mood have found absolutely nothing to complain of except that a fast-moving skip makes much noise. It was thought that with rails laid rigidly on the con- crete there would be considerable breakage from crystallization, but this seems not to be the case. In my opinion, if it proved a source of trouble, both the breakage and the noise could be eliminated by inserting a strip of wood between the rail and the concrete. The strip could be replaced without much trouble when rotten, and would furnish little combustible material in event of fire. The only real objection ever made was that if a skip went off the track it would either break the runners or would become so tightly wedged that the runner would have to be broken to get the skip out and valuable time would be lost making forms and allowing new concrete to set. This might happen with small, poorly balanced skips, but in a period of 4 years at one of the largest mines of the district, where a hoisting speed of 4000 ft. per minute is usual, I do not recall a single derailment. The accompanying sketches, Figs. 51 and 52, show the usual designs em- ployed. In preparing for the collars the shaft is carried down to firm bedrock, the size of the outside dimensions of the concrete, the temporary lining making the outside form for the concrete. When sufficiently firm ground is reached, the size of the shaft is contracted to its regular dimensions, forming a ledge upon which the concrete is started. The inside form need only be built high enough to give the concrete at the bottom a good set when the lower frames may SHAFT WORK 91 be moved above. The collar can be built to any height required by dump facilities and tracks. The walls are proportioned according to the depth of the shaft, the concrete mixture and whether or not reinforcing is to be used. When well reinforced on the hanging walls with old rails, rope and the usual collection of old iron found around a mine, 12 in. is probably the minimum thickness. To make the cribbing water-tight, care must be taken that the ledge is clean, the concrete well tamped, and when left over night should be left rough and well wet the following morning. For this purpose a fire hose attached to the column-pipe will be found convenient. In filling in the concrete a chute is all that is necessary Longitudinal Section of Shaft. Ifl - _ a Cross Section of Shaft. FIG. 51. SECTIONS OF INCLINED SHAFT. for shallow work, but if the fall is too great the sand and rock tend to separate and the concrete should be lowered into place. When first finished the ground water appears to seep through and below the cribbing, but this stops in time, due probably to clogging of the pores of the cement. If considerable water is running when the cribbing is installed it may be necessary to drain in some special way and stop the holes later with plugs. In the cribbing the dividers and runners are built at the same time as the walls. The dividers between the compartments are concrete posts normal to the dip about 1X2 ft. in section and spaced at 6 ft. centers. The dimensions of the runners vary with the type of skip and may be square or battered; 12X12 in. is a good section. One mine has runners 14 in. high with a i4-in. face and 16 in. wide at the base. The first rails are anchored by straps to the runners of the rockhouse and are held in place on the concrete at intervals of 3 ft. by a pair of cast-steel clips, cast to fit the flange of the rail. 9 2 HANDBOOK OF MINING DETAILS Through the clips 3/4-in. bolts, heads up, pass through 3/4-in. galvanized pipes set in the concrete, terminating in No. 20 galvanized-iron boxes, 3X4X 12 in., which are laid transversely in the runner. The box permits the insertion of a washer-plate and nuts. Some companies use bolts with threads at both ends, but this makes tightening difficult, especially if one nut goes on hard and the other easily, and the threads are apt to wear on the upper end with any motion of the rail. Square heads and nuts are preferable as offering greatest purchase for a wrench and least wear. For tight places bolts are made with Plan of Shaft Collar ^ ^ _Un. Ledge for Doors ^ m % m Bevel to end 11 'of ruuuers x n iM 'Hy\ f^tcx FIG. 52. DETAILS OF CONNECTION OF CONCRETE SHAFT RUNNERS WITH WOODEN RUNNERS OF ROCK HOUSE. hexagonal heads as they can be manipulated more readily. Old galvanized- iron pipes cut to proper lengths for the bolts were found to be cheaper than having special tubes rolled and made a part of the box. A piece of old 3-in. pipe laid outside the runner permits the bell rope to be extended into the shaft house, and a piece of old hoisting rope forms a good core for supporting the runners. In finishing the top of the collar, provision must be made for attaching the runners of the permanent rock house. In the case illustrated in Fig. 51, the rock house was to have a channel section to which wooden runners would be bolted. Long 2-in. bolts were to be placed at the proper distance at the side of each runner; these would lie between angles riveted back to back on the back of the channel and the bolts would tighten down on a washer-plate at the upper SHAFT WORK 93 end. If doors are to be hung over the shaft a i-in. length should be made all around each compartment by thinning the walls by that amount, and the neces- sary holes for bolts and lock provided. An opening is left at the side of the ladderway to admit the air and water pipes from conduits or ditches. The hanging wall of these mines needs little or no support, and the runners for the rails are built directly on the foot wall of the shaft, saving room that has hitherto been given to cross ties. They are similar to the runners in the collar, but usually a little higher to allow for the irregular foot wall. The adhesion to the foot wall is usually neglected, and an anchorage made of drill steels set at intervals in the foot wall to carry the entire weight of the runners. In steeply inclined shafts the outer ends of the drill steels are supported by tie bolts from ring bolts set in the foot wall a few feet above. Tie bolts set at intervals in the concrete outside the rails support the rails by a long hanging bolt bent at the lower end and passing through the web. The guide sheaves for the ropes are supported on structural- steel cross pieces from runner to runner laid in the concrete. Pulleys for the bell rope are screwed into wedge-shaped rocks set at convenient intervals in the side of the runner. FIG. 53. SHAFT TUBBING ARRANGED FOR INJECTION OF GROUTING. Injection of Grouting Behind Shaft Tubbing. An original method was employed at the Hildesia shaft at Diekholzen, Germany, for insuring a perfectly water-tight joint between the upper ring of a set of tubbing and the bearing ring above it. As the tubbing is erected from below, resting on a similar bearing ring at a lower point in the shaft, a small space, of variable size, always remains around the top of the uppermost ring, and this has to be carefully closed, gen- erally with pine or poplar wedging. In the case under discussion, illustrated in Fig. 53, after the upper ring had been put in position, the space between it and the rock wall was filled with 94 HANDBOOK OF MINING DETAILS cement grouting to the level dd f , and the wooden wedging e was inserted in the usual manner. At four equidistant points around the shaft, lo-mm. holes /were bored through the wood. At four other equidistant points, 45-mm. holes g were bored through the web of the cast-iron lining, close under the upper flange; these holes were fitted with pipes and couplings. By means of hose, one of the latter holes was connected to a pipe from a high-pressure pump, and cement grouting was forced into the space i. The three other holes of this set were closed as soon as cement began to come through them, with the escaping air. More cement was injected, until it began to escape through the holes in the wedging, and these were then tightly closed. Further additions of grouting, under a pressure of 80 to 90 atmospheres, were then applied, for the purpose of forcing the cement into every crevice of the rock wall, and also into the grain of the wedging. By exercising this unusual precaution, the chance of leakage, especially during the winter when the tubbing contracts, was entirely overcome. Grouting in Quicksand. A new method of grouting in quicksand is given in Engineering News. A pipe large enough to serve as a cement-injection tube is fitted at its lower end with an auger point and a helical-screw blade; just above this blade several holes are drilled in the wall of the pipe and fitted for discharging grout outward over the upper surface of the blade. This boring apparatus is twisted down, if necessary with the help of jetting, by water pumped through the pipe. When it reaches the desired depth, grout is pumped into the pipe, and at the same time the drill is turned backward so as to with- draw it. The grout flows out along the face of the blade, and becomes mingled with the layer of sand above by the rotation; the resulting mixture is passed by the turning of the screw blade to the space below, where it builds up in a cylindrical body corresponding to the volume swept through by the blade. When the drill is wholly withdrawn, it may be sunk again alongside the first location, and thus a large mass of contiguous, coherent cylinders of consolidated sand can be formed. The process is patented in Germany. SHAFT STATIONS AND SKIP POCKETS Shaft Station in Inclined Foot Wall Shaft (By Claude T. Rice). At the mines with a flat-dipping vein, in the Michigan copper district, the skips are almost universally loaded by dumping the cars directly into them. Turn- tables are used for switching the cars, which are made to hold approximately 2 1/2 tons. Generally the shafts are sunk in the vein, and the spur tracks come up to the sides of the shaft; the main track continues through to the other side of the plat, along the hanging wall, and the turntables are placed in front of the shaft on the main track as shown in the small drawing in Fig. 54. The skips generally hold 7 tons, so that it takes three cars to make a load. Two cars stand ready to be dumped, while a third car is on the main track. SHAFT WORK 95 The arrangement of the station at the 3ist level of Wolverine No. 4 shaft which is sunk in the foot wall about 25 ft. from the vein is shown in Fig. 54. On the south side of the shaft a recess is cut so that two of the cars can be dumped on the side, the third car being dumped from behind; on the north side only one car is dumped from the side turntable and the other two are dumped from behind, the empty car being switched over to the side-dump track to get it out of the way. On the south side, in the back part of the station, it will be noticed that a square corner is cut. This was for the small hoist used in sinking the shaft FIG. 2 FIG. 54. SHAFT STATIONS IN INCLINED SHAFTS. deeper from that level. When the station is cut in this way a brow of ground is left under the crosscut; to support this a reinforced concrete pillar is put in at the Mohawk mine before the brow has begun to give any trouble, and the floor of the station is laid with reinforced concrete, 6 in. thick, designed to stand a load of 400 Ib. per square foot. Large Underground Station in a Coeur d'Alene Mine. One of the largest and most complete underground timber, boiler and hoist stations in the United States is newly completed at the Morning mine of the Federal Mining & Smelting Co., Mullan, Ida. Its construction involved several inter- esting problems. The station is situated at a point nearly 2 miles from 9 6 HANDBOOK OF MINING DETAILS the entry of the No. 6 tunnel, now the main haulage way of the Morning mine. In this tunnel electric haulage is used, ore being handled in trips of fifteen 5-ton cars. About 1000 tons of ore are produced each day, and practically the entire output must pass through this station. Ample space for the handling of the ore and timber trains was therefore a prime requisite in the laying out of the station. The station proper is 100 ft. long, 36 ft. wide, and is 24 ft. high in the clear at the shaft, dropping to a height of n ft. at a point 200 ft. distant. There is a wide double-track approach. A boiler room, about 28 X 19 ft. in size, opens off from the farther end of the station. Adjoining the boiler room is the hoisting-engine room, 30X47 ft. in size. .Hoisting FIG. 55. GENERAL PLAN OF TIMBER, BOILER AND HOIST STATIONS, MORNING MINE, MULLAN, IDA. An interesting problem arose in connection with the placing of the engine. A shaft with compartments 4 ft. 8 in. X 5 ft. 2 in. in the clear had been decided upon, and this would throw the sheave wheels 5 ft. 6 in. apart. It was, however, deemed wise to use an engine similar to that in use at the Mace mines in order to facilitate repairs, etc. The reels on this engine are spaced 4 ft. 8 in. apart. For a while this promised to make trouble, until the expedient SHAFT WORK 97 of setting the engine off at an inclination to the axis of the shaft was hit upon. The crankshaft of the engine is in 1/2 ft. from the center of the shaft and inclined from its long axis at an angle of 31 57'. This throws the sheaves at the proper distance apart. The cableway from the engine to the sheaves is an inclined raise through solid rock so that no headframe structure is required. From the collar of the shaft to the center of the sheaves is 100 ft. An old hoist set in line with the long axis of the shaft will handle timber. (The sheave for this is only 45 ft. above the collar of the shaft.) The general layout of the station is shown in Fig- 55- Five feet from the wall plate of the shaft is an ore bin 26 ft. long (parallel to the long axis of the shaft); it is 25 ft. wide and 52 ft. from toe to top, the bottom having a 45 slope. This bin was excavated out of solid rock and is armored on the front inside face with 6o-lb. rails. Skips automatically dump ore into the bins from which it is drawn directly into the 5-ton cars of the electric trains. In cutting out the station some interesting rock excavation was done. The face was advanced carrying its full height and width. To do this four lo-ft. bars set end to end and blocked tight with 3-in. planking were used across the face. The line of bars was arched slightly toward the face, from which it was braced with the wedge timber. This formed a "compression" truss and although many miners object to running two machines on a bar, on the score that the bar will not hold tight, three or four machines were continually operated on this series of bars, and no special trouble was experienced from fitchered holes. For this work 3 5/8-in. piston drills were used, and as many as 190 eleven-foot holes put into a round. The cuts and lifters were fired first, then the other holes. Electric battery firers were used in all cases. One round of holes usually broke enough rock to fill 400 of the 35-cu. ft. capacity cars. Only two settings of the bars were necessary for drilling the entire face: The first was on the muck pile and the second lower down after the face had been mucked clean. Concrete Floors for Shaft Stations. At the Mohawk and Wolverine mines, Michigan, the stations at the inclined shafts have reinforced-concrete floors which are absolutely fireproof and can be put in almost as cheaply as timber floors, taking into consideration the sets that would have to be used to carry such a floor. These concrete floors are made 6 in. thick and are designed to carry a load of 400 Ib. per square foot. The reinforcement used by W. F. Hartman, the engineer who designed the floors, consists of a double layer of 4-in. triangular mesh reinforcement, threaded with 3/8-in. strands of old hoisting cable, running crossways to the strands of the triangular mesh, and at 6-in. centers. In order to protect the reinforcement from fire and corrosion it is placed about i in. from the bottom of the concrete. Skip Pockets. At the Bunker Hill mine, near Amador City, Calif., skip 7 9 8 HANDBOOK OF MINING DETAILS pockets are arranged to facilitate the handling of ore and waste. The usual custom is to have pockets beside each other, each discharging into a different shaft compartment. The objection to this is that it permits the handling of only one class of rock in each compartment from any level. It also means that trammers must switch their cars to the proper track when dumping at the skip pockets. The shaft at the Bunker Hill is inclined, having two hoisting com- partments. To overcome the objections mentioned above, a waste and an ore FIG. 56. ARRANGEMENT OF SKIP POCKETS AT BUNKER HILL MINE. pocket are arranged, one over the other, each pocket discharging into both shaft compartments. Below levels the shaft is widened out to three times its regular height and is carried so for nine sets. The compartment above the shaft is partitioned off as a waste pocket and the one above that as an ore pocket. The timbers between compartments are heavily lagged and lined with strips of iron off the guides in the shaft. By this arrangement each of the tracks at the station serves both pockets and no needless switching of cars is necessary. The accompanying drawing, Fig. 56, illustrates the idea of the skip pockets. Either ore or waste may be drawn at any level whenever desired. With such an arrange- ment only a single track is required at stations. Skip Pocket and Station at Leonard Mine, Butte. In Fig. 57 is shown the general idea of the arrangement and timbering of the skip pocket and station, on the i8oo-ft. level, in the No. 2 shaft of the Leonard mine at Butte, Mont. The .excavation for the skip pocket is started at a point five timber SHAFT WORK 99 sets (25 ft.) from the shaft. It is carried straight down for two sets and then benched in three 5-ft. steps, the bottom being two sets wide. From the bottom of the pocket the excavation is carried down the width of the shaft for three sets. A sheet-steel gate operated by a compressed-air cylinder controls the dis- charge of ore from the pocket into an apron, also of sheet steel. The lip of this apron, when lowered, extends over the edge of the skip so that the ore is run directly into the latter. The lip of the apron is raised and lowered by com- pressed air. To operate the gate and apron, a man stands on a platform on the second set of the compartment beside the shaft. V V /I Lagging Packed with Waste Plat Open X, -AirOpera'l jgj-Apron/ rn/ 'ted Chute Gate I/ / FIG. 57. SKIP POCKET AT l8oO-FT. LEVEL OF LEONARD MINE, BUTTE, MONT. The level station is first timbered with square sets, as shown by the dotted lines in the sketch. Two 8Xio-in. stringers are then run out under the top caps for three sets, one end of each stringer being blocked up from the shaft- wall plate, the other from a cap of the third set from the shaft. Support is thus given to the roof of the station, while the first two sets of square-set timber are removed and replaced by the permanent station sets. Stringers are then blocked up in a similar manner, to span the next two sets, timbers removed and replaced, etc. The posts of the station sets are 13 ft. long, made of i4Xi4-in. timber, 12 X i4-in. material being used for the caps. The space, usually a couple of feet high, above the station timbering, is filled in with waste; 3-in. lagging is used over the top and sides of the station sets. 100 HANDBOOK OF MINING DETAILS A i-in. space is left between pieces of lagging to allow a free circulation of air and thus check rotting of the timbers. A station may be carried back as far as is necessary to provide ample room for handling cars. Beginning with the fourth set from the shaft, the bottom of the station should be raised 1/4 in. per set to give the necessary grade to the approach. The station at the Leonard mine is 21 1/2 ft. wide and provided with a double-track approach. DRIVING ADITS AND DRIFTS Practical Considerations and Methods Timbering Special Types for Heavy Ground. PRACTICAL CONSIDERATIONS AND METHODS Fast Drifting. Speeds as high as 60 ft. per week are obtained in cross- cutting the slate formation in the Kennedy mine at Jackson, Calif. Three shifts are worked and two machines run on one bar. As soon as a round is fired, the bar is rigged horizontally across the face. Then, working on the muck, the two drillers put in the back, breast and cut holes. By the time these are in, the shovelers have cleaned up the muck pile enough to allow a lower setting of the bar from which the lifters are drilled. In this manner no time is lost by the machine men in waiting for the muckers to clear away the rock from the face, and each man can put in his full shift at the work to which he is assigned. Such small refinements of methods should be carefully observed in the operation of a large mine and may represent the difference between a profitable or losing operation.' Maintaining Grade in Driving. In driving and tunnel work the miners unconsciously tend to increase the grade toward the face at a steeper angle than is desirable for drainage or for favoring the tramming of loaded cars. Too much grade is disadvantageous because the grade favoring loads is so great that the cars tend to run faster than considerations of safety should permit; greater effort is required to move empty cars up the grade; natural ventilation is interfered with, the results being especially noticeable at the face ; and, in some cases, the unnecessary loss of ore in the backs above the drift may be undesirable. The grade of drifts in some of the older mines of Corn- wall is as great as 5%, often 7%. At the present time a drift is rarely driven at a greater grade than i%, which is twice the grade recommended by some authorities. To avoid driving at too great a grade, a template should be provided which the miners can use as often as they desire and without losing much time. Such a template may be made by cutting a board of con- venient width and thickness so that it is exactly 100 in. long. The edges should be planed true and parallel. A line is then drawn from the upper corner of one end to a point i in. below the upper corner of the opposite end and the board sawed along this line. The board is then turned over, and a level- tube let into the edge, which is so adjusted that the bubble will be in the center of the tube when the edge of the board is in a horizontal plane. In use, the 101 102 HANDBOOK OF MINING DETAILS is 'laid Augle Iron' _/o~| ^L_ & -For Lever _T~ -For Lever 2'//x l" For Lever/ c Plate Augle Irons -For Lever FIG. 93. CHUTE GATE AT MAMMOTH COPPER MINE. type of iron gate for an ore chute is in use on the large ore passes from the stopes where top-slice caving is being done. A large amount of ore must be handled quickly through these chutes, so that it requires a strong gate with a positive action. The details of the gate are shown in Fig. 93. The particular feature of the Mammoth chute gate is that it is closed by raising a door through the stream 149 HANDBOOK OF MINING DETAILS of ore passing from the chute instead of by lowering one, as in the ordinary types. Where ore is running rapidly through a chute, it is quite difficult to lower a gate into this quickly, whereas lifting the gate through the stream of ore presents no difficulty. The frame of the chute gate is made of two angle irons, bent as shown, between which the gate of 3/8-in. steel slides. One angle iron is cut away on the lower part of the frame. A bar of 2 i / 2 X i-in. iron is bolted to the lower side of the gate and slides through a guide at the lower part of the frame. The gate is operated by a lever connected to this bar and pivoted on the frame. Sheets of 3/8-in. steel cut as shown in the drawing, are riveted to the frame and form an extension of the sides of the chute and a projecting lip. The entire gates are riveted together and set up before being taken into the mine, so that they are ready to be set in place in the ore chutes. The all-steel construction of this chute gate renders it substantial, but at the same time rather expensive, so that its use is only warranted where large quantities of ore are handled. Gate for Lump Ore Bin (By Guy C. Stoltz). A gate commonly used on lump-ore bins at the iron mines, Mineville, N. Y., is shown in Fig. 94. The _ \VPInte: Section FIG. 94. AIR-HOIST GATE FOR COARSE 3 Plank, supported by G"X 8"Sticks Side Elevation One Column removed. ORE. gate is made of 2 i/2-in. plank, with an outside steel plate, 1/4 in. thick, 4 1/2 ft. square, and an inside plate of same area and i / 2 in. thick. Three axles, 21/2 in. square, turned to 2 1/4 in. diameter at the ends to receive rollers of 4 in. diameter and 2 in. face, are bolted between the plates. The 2 i/2-in. plank acts as a cushion, also gives weight and stiffness to the gate. The rollers run in the guides formed by riveting 4X4-in. angles to the two i2-in. I-beam columns. HEADFRAMES, CHUTES, POCKETS, ETC. 151 On the bottom of the gate a heavy 3-in. angle iron is riveted to the plates to protect them from wear. The addition of two rollers to each side working at right angles to main rollers would improve the gate by lessening the friction due topside motion, for then any binding of the gate would be met by roll faces. The gate is fitted to a timber headframe by having, say, ioX lo-in. posts take the FIG. 95. FINGER CHUTE FOR FILLING WHEELBARROWS. place of I-beams and 4X4-in. hardwood strips bolted to posts to act as guides. This latter type is generally used at the underground storage pockets where it is essential to have a positive working gate which will close the instant the skip has been filled. S. L. LeFevre, assistant general manager for Witherbee, Sher- man & Co., designed the gate. 152 HANDBOOK OF MINING DETAILS A Finger Chute (By A. Livingstone Oke). An adaptation of the well-known finger chute employed by me, while manager of a mine in Chihuahua, Mexico, is shown in Fig. 95. The ore coming into the breaker floor from an aerial tramway was being dumped direct on a grizzly, the fines going into the battery bin and the oversize accumulating on the floor above, whence it was shoveled into wheelbarrows and taken to the breaker. To avoid the shoveling, the finger chute was put in and two out of three peons were displaced. The fingers receive hard usage and should be built strongly. Their weight keeps the ore back, as, from the position of the fulcrum, they may be considered to have their center of gravity just where it is most effective, i.e., in front of the sliding ore. They are easily controlled and saved all the hard work of shoveling. Other types of chute were tried, but failed to be of service. Steel Arc Chute Gate. A strong and durable arc chute gate of simple pattern is used on the flat-raise ore pocket in the Pittsburg- Silver Peak mine, FIG. 96. STEEL ARC CHUTE GATE AT PITTSBURG-SILVER PEAK MINE. near Blair, Esmeralda county, Nev. The entire output of the mine, about 500 tons per day, is handled through these chutes; hence gates sufficiently strong to withstand the wear, and with a positive action, must be used. The type shown in Fig. 96 has given satisfaction. The frame of the gate is made of two pieces of 3/4X3-111. iron bent on an arc with a radius of 22 1/2 in. and turned back at either end, and bolted with i-in. bolts, to the hub of the gate. These pieces of 3/4-in. iron are spaced i in. from the edge of the gate and fastened to the 3/8-in. sheet steel that forms the arc of the gate, with four 3/4-01. rivets. By using single pieces of heavy iron to fasten the arc to the hub and extending entirely across either end of the gate segment added stiffness is obtained. The hubs are 3 in. thick, 6 in. wide, 10 3/4 in. long and bored for a 2 3/i6-in. axle. One of the chief advantages of this type of gate is in the few parts required for its construc- tion, and hence the simplicity of setting it up. There are only five pieces to the gate and for putting them together, four bolts and eight rivets are required. HEADFRAMES, CHUTES, POCKETS, ETC. 153 The components of the gate are a piece of 3/8-in. sheet steel, 34X 26 1/4 in., U form the arc segment of the gate, two 3/4X3-^. iron bars, 33 1/4 in. long, for the frames or spokes, two cast-iron hubs of the pattern shown in the drawing, eight 3/4-in. rivets, and four i-in. bolts. Cananea Arc Type Gate. The arc-type gate shown in Figs. 97 and 98 is used in the ore-bin chutes at the mines at Cananea, Mexico. It may also be FIG. 97. ELEVATION OF CANANEA BINS. modified for use in underground chutes. The novel feature of the gate is the axle which is made of round iron bent as shown in the lower part of Fig. 98. The center of the rod, of which the axle is made, is flattened and bolted to the sheet forming the door. The position of the gate in the ore bin is shown in Fig. 97, in which illustration is also shown the manner of building the steel chute, below the gate, so that there is a hinged lower portion which is counter- '54 HANDBOOK OF MINING DETAILS balanced by a weight permitting the swinging of that portion of the chute up and out of the way of passing trains. The details of the steel chute are shown in the upper part of Fig. 98. A runway is built in front of the bins to give easy access to the handles operating the gates and so that the operator can take a posi- tion above the top of the car he is loading End. Front. FIG. 08. DETAILS OF METAL PART OF ARC-TYPE GATE FOR CHUTES. SKIP LOADERS Skip Loader at the Original Consolidated. At the Original Consolidated mine, Butte, Mont., a novel skip-loading arrangement is being used in place of the ordinary ore pocket discharging directly into the shaft. The ground at this mine is rather heavy and it was not thought advisable to take away support from the shaft by cutting out the ground for skip-pockets. By using small apron chutes mounted on wheels, the skips were formerly loaded directly from cars. This method is, however, slow and requires too much labor shifting and dump- ing the cars, etc. To avoid this, the arrangement shown in Fig. 99 was devised and has already been installed on several levels of the mine. Above the ordinary station, 10 ft. high in the clear, an additional space, 61/2 ft. clear above the station proper, is cut and timbered with I2X i2-in. material. The top of the station timbers forms a platform upon which a man can stand while operat- ing the air gates on the chute. At the third station set from the shaft a two- compartment raise, inclined toward the station at 80 from the horizontal, is put up to the level above. This chute is carried 4 ft. 10 in. square overall and is timbered with loX lo-in. material framed in y-ft. sets, with dividers of 5X10 HEADFRAMES, CHUTES, POCKETS, ETC. 155 FIG. 99. SKIP LOADING ARRANGEMENT FOR ORIGINAL CONSOLIDATED MINING CO., BUTTE, MONT. 156 HANDBOOK OF MINING DETAILS material midway of each set. The chute compartments are lined with 5X10 material on the bottom, and 3X10 on the top and sides. The inclined raise terminates at its lower end in the hopper-bottom pocket A. The chutes are provided with steel gates, operated by compressed-air cylinders B. The dis- Measure Holding One Skip of Ore FIG. IOO. SKIP-LOADING ARRANGEMENT AT SCRANTON MINE, HIBBING, MINN. charge is into a long sheet-steel, swinging spout C, the lip D of which, when turned down projects into the shaft far enough to deliver rock into the skip. The steel apron-chute is pivoted at its top end, so that the lower or discharge end may be swung to either shaft compartment. This chute is supported by a chain E, that is fastened to the pulley F. This pulley runs on a short track, thus HEADFRAMES, CHUTES, POCKETS, ETC. 157 enabling the spout to be easily swung. The lip of the spout is connected by a line, passing over two blocks, to the counterbalance G. This weight serves to keep the lip raised, so that the spout will swing clear of the shaft timbers. The counterbalance is lifted and the lip let down when a skip is to be loaded, the spout being swung out of the way when not in use. When loading a skip, one man climbs up to the platform and operates the air gate on the raise (or pocket), while another swings the spout, lowers the lip and calls out when the skip is filled. By having the loading arrangement at a station instead of below in the shaft, time and labor are saved. The inclination of the raise carries it to the level above at a point far enough away from the shaft, so that the nuisance of having cars block the station is done away with. Having the approach to the shaft clear is an important advantage of this skip loader. Ore Pocket FIG. 101. GATE FOR SKIP-LOADING CHUTE, GRANBY CONSOLIDATED MINES. Measuring Pocket for Skips. A skip pocket designed by C. F. Jackson for the Scranton mine at Hibbing, Minn., is shown in Fig. 100. The principal feature that commends this pocket is the fact that it opens in such a way that the shaft is clear at all times. A number of similar pockets are in use, but they open into the shaft and are more or less dangerous. In addition this pocket provides a safe place for the operator. He is on the platform above the pocket. 158 HANDBOOK OF MINING DETAILS One man can both draw the ore from the chute and fill the skip from this pocket which holds just one skip load, 91 cu. ft. The pocket is opened by means of a rope and pulley. As the rope is moved it turns the lower pulley off center and i Loading --12 Skip % Rivets f'T FIG. 102. THE WHITFORD MILLS SKIP-LOADING DEVICE. the weight of the ore opens the pocket. The chain prevents the wheels from turning too far past the center. Skip Loading Chute. Details of an ore chute for loading skips used at the HEADFRAMES, CHUTES, POCKETS, ETC. 159 mines of the Granby Consolidated company, Phoenix, B. C., are shown in Fig. 1 01. It is an improved form of finger chute, combining fingers with a sheet-iron gate for holding the fines. In the operation the sheet-iron gate is raised first by the air lift, then, as the arm is raised still higher by the piston of the air cylinder, the fingers are raised and the coarse ore allowed to escape. When the air is released the fingers fall first, catching the coarse rock, and there is a sufficient interval of time for the chute to clear itself before the sheet-iron gate is closed. The operation is rapid and the skips are filled nearly as fast as the skip tender can operate the valves. Whitford-Mills Skip Loading Device (By E. M. Weston). An appara- tus for loading hoisting skips devised by Messrs. Whitford and Mills, respec- tively general manager and engineer of the City Deep, Ltd., Johannesburg, S. A., is shown in Fig. 102. It is designed to load 5-ton skips faster than could be done by means of Kimberley chutes. The idea consists essentially of a second skip in each compartment in front of the main doors of the bin at the bottom of the shaft. These skips hold five tons, as do the skips in the shaft, and are to be filled from the bin while the hoisting skips are running in the shafts. They are hung at A and balanced so that their movement while tipping is controlled by guides B, in such a manner that the hoisting skips on their descent tips them automatic- ally by engaging the hooks C on either side. The loading skips themselves never project into the shaft even while tipping. In this manner hoisting could be carried on without any pause except for reversing the engines, say 15 seconds. One possible drawback to the use of the device might be the possibility of damage to the apparatus by a skip reaching the loading station with too much velocity; but as electric winding is rapidly being adopted, this system can easily be adjusted for automatic action, and steam winding engines could also be provided with one of the well-known types of automatic reversing and breaking devices. Red Jacket Ore Pockets. The Red Jacket shaft of Calumet & Hecla is the one shaft in the United States equipped with a Whiting hoist. This is used in raising the ore, while an ordinary drum hoist is used for raising men. Skips holding 71/2 tons are used and the shaft is arranged so that the pockets for the different skips are on alternate levels. These skip pockets are large enough to hold 9 tons, but only three cars, a skip load, are dumped in at a time. The pocket is lined with steel, on top of which, both on the sides and bottom, wear- ing plates are bolted. The steel bottom plate rests on a cast-iron bottom plate 4 in. thick which in turn rests on a bottom of 12 X i2-in. timbers, as trouble was experienced with the steel bottom plate when it rested directly on the timber bottom on account of the size of the boulders some weighing a ton and a half that are dumped from the cars into the skip pocket. This skip pocket has a hand-operated swinging door as shown in Fig. 103. The door piece A is hinged at the top, the strain on the hinge seats being carried back to rock wall of the pocket pit by means of two bolts equipped with turn- i6o HANDBOOK OF MINING DETAILS buckles. A lever, B, leads back from this door to the main locking lever, C, to which it is connected by a pin joint. The door as it swings back after it is released by easing on the band brake (with which the shaft of the locking lever is equipped so as to prevent the return of the door before the pocket has emptied itself, as might be the case if there was much fine ore in the pocket) forces this locking lever past dead center so that the weight of the ore pressing against the door holds the lever against the inside stop that limits its downward motion. The outward swing of the door is limited by the locking lever coming in contact with a similar stop at the other end of its range of travel. In case that this lock- Elevation Looking West FIG. 103. DETAILS OF A STEEL ORE POCKET IN RED JACKET SHAFT. ing lever sticks so that a man cannot conveniently start it by a moderate lift on its outer end, the skip tender resorts to the use of a wooden auxiliary lever that is fastened to the back post of the pocket so as to aid in starting the locking lever; but this is not usually necessary. To bridge the gap between the skip and the mouth of the pocket, an apron E, is provided, which is thrown in by means of either of two levers D, shown in the drawing. This apron also is equipped with a wearing plate. Measuring Pocket for an Inclined Shaft. The North Kearsarge shaft No. 4 is sunk in the foot wall of the lode, and the ore is trammed to loading bins at the shaft that serve two levels. These bins are covered with a grating of crossed rails so that boulders must be broken to 18 in. to go into the bins. On the skip chutes proper a counterbalanced arc gate that closes from below through a system of togglelevers is used, as shown in Fig. 104. On the measur- HEADFRAMES, CHUTES, POCKETS, ETC. 161 ing pocket, doors of unique design are used. The lower one opens and closes the upper gate so they might be described as being of the clam-shell type. Owing to the shape of the levers by which the two gates are suspended the bottom gate moves up less rapidly than the top gate and therefore always closes after and over the other. This is illustrated in Fig. 104 which shows the gates open in full lines and closed in dotted lines. On each side on the lower gate is a semicircular arm in the top of which is a notch. Two hooks, connected by a bar and seated on the posts that brace the bottom of the measuring pocket, Concrete Pier Concrete Stringer FIG. 104. SKIP-LOADING DEVICE AT OSCEOLA MINE. drop into these notches and latch the gates in position when they are closed. By means of a lever these hooks are raised, then the weight of the ore forces the back door backward and the front door forward, giving the ore a free passage down to the skip. Extending from the front gate are the arms carrying the counterweights, one on each side. These are adjusted so that a slight lift is necessary on the lever arm of the gates to close them, but the adjustment is so close that the jar of the skip gate as the skip leaves the bin will close the doors. An Underground Ore Pocket. At the iron-ore mines of the Tennessee 162 HANDBOOK OF MINING DETAILS Coal, Iron & R. R. Co., on Red Mountain, Ala., hoisting is done in skips of lo-ton capacity. In sinking slopes .without an ore pocket, the skip is lowered until it rests against a pentice of rock, and there receives ore noisted, by an auxiliary engine from the face of the slope, in 2-ton end-discharge cars .dumped by an ordinary curved-rail tipple. These 2 -ton cars run over the rock pentice and, when no pocket is used, dump directly into the skip. This necessitates the use of an auxiliary steel car which can be attached to the rear of the skip and pulled out with it, or else the holding of the skip at this point until it can be filled from the small cars. To eliminate this waste of time, an underground pocket is used in the slopes of the Tennessee company, on the Ishkooda and Section of Hopper Am \ / Top of Rail "lope Track ^ ounterweight. Box loaded with Rock. Top of Rail Slope Track Bars FIG. 105. UNDERGROUND ORE POCKET Fossil divisions. The design and method of setting up this pocket are shown in Fig. 105. It is of zo-ton capacity, and is set so that the skip can be run under the pocket and filled directly without any loss of time. The pocket is hopper shaped, and made of i/4-in. plate; it is fitted with hinged bottoms opening out- ward, as shown. These bottom doors are braced with 4o-lb. rails at the ends, abutting at the center line of the bottom of the pocket. To the ends of these rails are fastened ropes which pass up and over two 2o-in. sheave wheels and down on one side of the pocket framing where they are connected to a yo-lb. HEADFRAMES, CHUTES, POCKETS, ETC. 163 rail. A latch operated by a lever, details of which are shown, holds this rail, and consequently the gates in a closed position. By releasing the latch, the weight of the ore is allowed to open the pocket bottom, but sufficient counter- balance is attached to the yo-lb. rail to swing the gates closed after the pocket has discharged. The pocket is supported from two lateral 12X12 timbers which are carried on 12X12 cross-timbers hitched into the walls of the slope. HEADFRAMES, TIPPLES AND DERRICKS How to Erect Three-leg Shears (By A. Livingstone Oke). The correct way to erect three-leg shears, using a tackle and rope from a hand or power Foot Hitch Method of Erecting Three-Leg Shears Plank for foot to slide on Alternative Method, Applicable with Light Shears Crorspiece ^ v Lashed to the two Legs FIG. I06. PLAN AND ELEVATION OF THREE-LEG SHEAVES. winch, is shown in Fig. 106. The three legs are laid out first on the ground, as shown in the plan, two of them being placed with the butt ends at the distance A which is to be the spread of the shears when erected. On these two legs a cross piece is secured, either by lashing or by pegging down, as shown in Fig. i. One end of the tackle is attached to the cross piece and the other end to the single leg. It is necessary to lift the center off the ground 2 or 3 ft., before 164 HANDBOOK OF MINING DETAILS applying the power. The hauling line from the tackle should come from the single leg as this is the one that slides. Boring the holes for passing the pin should be done by laying out the three legs, as shown in the plan, with the spread A equal to the proposed base when erected. In this way there is no risk of the pin being bent, as the angle between these two legs remains constant and cannot be altered without bending the pin. The height of the shears may be altered by moving the middle leg nearer or further from the other two. Headframe for a Prospect Shaft. The sinking of a prospect shaft is often done under unnecessarily dangerous conditions. It is taken for granted that such work must be hazardous because, until ore has been found, the safety of the miners is not regarded as warranting extra expense. For this resaon much prospecting work is done with meager equipment and poorly constructed head gear. Until a depth of 40 or 50 ft. is reached a windlass may be used, but for 4 x 24-in. -Bolts 12-in. \8* 10 T ! 10-in.^ 1 1-in. Tie BodB 1 8x 10- H-in. Drift Pins 1 7-ft~3--i.il* 18-in. long a Drift Pins 10 /$?v"- i-ln. Tie Bodi Sill Plan. 10-in. Vertical Member. Back Brace. Side Elevation. FIG 107. PROSPECT HEADFRAME AT SAND GRASS SHAFT. deeper work, to a limit of 200 ft., a horse whim will be needed, which requires nothing more than a tripod to support a sheave about 1 5 ft. above the collar of the shaft. When, however, the shaft is to be sunk to greater depth than 200 ft. it will be found more economical to use some form of power hoist; generally a geared hoist is used. A power hoist will require a substantial headframe. That the headframe need not be inordinately expensive is demonstrated by the cost of the structure shown in Fig. 107. This headframe is well suited to the purposes of an important prospecting shaft; it was designed by ]. M. Fox, assistant super- intendent for the Tonopah Mining Co., and was built at the Sand Grass shaft. It is a substantial structure, and insofar as the headframe has to do with the safety of shaft sinking, provides abundant security. With such headframes it HEADFRAMES, CHUTES, POCKETS, ETC. 165 has been possible to raise 100 tons of ore per day through a one-compartment shaft from a depth of 300 ft. without crowding. The headframe is quite strong enough for prospecting work and is designed for use with a cage in counterbalance when mining of ore is started. In case more room is desired about the collar of the shaft, the lower diagonal brace can be made vertical. In the construction of this headframe, 3200 board feet of 8Xio-in. timber were required. All daps were cut i in. deep and painted with creosote to protect them from decay. The headframe after it was erected was painted in order to preserve it from the weather. The wages of carpenters at Tonopah vary between $5 and $5.50 per 8-hour shift, yet the cost of this headframe complete and in place was but $330. The most important items were 3200 board feet of lumber at $37.50 per thousand; framing timbers and erecting labor, $120; iron work, $65. A 3/4-in. hoisting rope is used and until actual mining begins, or while the shaft is being sunk, a bucket of about 18 cu. ft. or a little over i ton capacity is used for raising rock. Headframe for a Winze Hoist. In mining operations it is frequently the case that a shoot of ore has been followed down in some part of the mine remote 6'x S'x s Tapped 1 8^ Loading Bin 6 x s'lnslde Measurement Framework 6"x C'Timbei Bottom S'x ItfVlank Sides tsjrClMh FIG. IO8. ORE BIN AND HEADFRAME FOR A WINZE HOIST. from or not connected with the main hoisting shaft. The desire to develop rapidly the shoot and other reasons may make it necessary to raise more rock or ore through a winze than can be handled by the usual hand-operated windlass and bucket, and it becomes necessary to equip the winze with a power hoist and headframe to carry the sheave. The accompanying illustration, Fig. 108, i66 HANDBOOK OF MINING^DETAILS furnished by Percy E. B arbour, is of a headframe for a winze such as was de- signed for use in the Copper Mountain mine in Nevada. The design follows closely the usual two-post surface headframe, but is not so high nor is it built of as heavy timber as is usually deemed necessary for a surface structure. The details are fully shown in the illustration. The station is cut out as closely as possible to just admit of the erection of the headframe and is, .of course, prefer- ably situated where the walls are strong enough to require minimum timbering. While no guides are shown in the illustration, if it is desirable to use them while sinking with a bucket, they may be supported in the same manner as if the head- frame were at the surface. To receive the ore and rock raised and facilitate the loading of cars, a small box-like ore bin is built in front of the frame. An Underground Hoist. The accompanying illustration, Fig. 109, shows the method of arranging the hoisting equipment for a large winze that was sunk Front Elevation and Section of Head-gear FIG. lOQ. ARRANGEMENT OF AN UNDERGROUND HOIST. by N. T. Tregear for the Black Mountain Mining Co., operating a copper mine near Magdalena, Sonora. The winze was sunk to a depth of 400 ft. from the No. 8 tunnel at a distance of 1200 ft. from the portal. Below the collar there are HEADFRAMES, CHUTES, POCKETS, ETC. 167 two compartments, each 4 1/2X5 ft. in the clear, while above the collar there are two compartments, each 4 1/2X5 ft-, that were carried up to support the sheaves and to obtain head room above the tunnel for an automatic dumping skip and two ore pockets. The sheave- wheel bearers are dressed timber 111/2 X 15 in. and 26 ft. long; the bearing posts are 12X12 in. section, as are also the supporting bearers and dividers. The housing is made of 8X8-in. timber; the shaft sets are 8X8-in., and the auxiliary dumping set is of 7 1/2X11 i/2-in. timber; two of the collar bearers are 12 X i2-in., and two 8X8 in., and the guides are 5 1/2X5 i/2-in. section. The shaft sets are spaced 5-ft. centers, the station sets 1 5 ft. and the dumping set 20 ft. The winze is lagged with 2 -in. lumber. Details of a Wooden Headframe. In Fig. no the details of the head- frame of the Clermont shaft at Goldfield, Nev., are shown. This is an excellent example of the simple A-frame type of head gear. The total quantity of timber used in the construction of the headframe was 23,000 board feet. There were also used 3300 Ib. of bolts and rods, and 500 Ib. of cast-iron washers. Overwinding Allowance in Head Gears. In cases of overwinding, acci- dents frequently happen from a blow by the liberated end of the rope, and the rope itself may also be damaged. To prevent this, a drag rope forms a useful auxiliary. This may be of light wire rope carried on a small light drum placed near the detaching gear, the free end of the rope to be formed into a loop of such size as to allow the hoisting rope to run through freely, yet too small to admit the rope capping; this loop to be lightly fixed just over the detaching ring. When an overwind takes place, the freed end of the hoisting rope is. at once held in check by the drag rope. The drag-rope drum might be provided with a brake or a coil spring inside, so as to prevent the rope running out too freely. The headgear should be of sufficient height to allow for a fair overwind in addi- tion to the working height. As a general rule, it is suggested that the distance in feet from the underside of the sheave to the pin which connects the rope to the skip or cage standing at the point in which the journey is properly completed should not be less than the average hoisting speed in feet per minute divided by 200. For example, if the average hoisting speed be 3000 ft. per minute, the overwinding allowance would be 15 ft. Tipple Construction in the Birmingham District. The tipples used by the Tennessee Coal, Iron & R. R. Co. and the Republic Iron Co. at the slopes of their iron-ore mines on Red Mountain, Alabama, are different from those seen at any other slopes in the Birmingham district. These companies hoist in 10- ton skips, whereas most of the other companies use trains of five 2 -ton cars. The constructional details of the tipples at a slope on the Muscoda division of the Tennessee company's ore mines are indicated in Fig. in. The slope entry is not perpendicular to the main railroad loading-track below the tipple, this accounting for the angle at which the Nos. i and 2 bents are placed. The tipple carries two sets of tracks one above the other. The upper one, set at 6-ft. gage, engages the rear wheels of the skip, thus elevating it into the position i68 HANDBOOK OF MINING DETAILS HEADFRAMES, CHUTES, POCKETS, ETC. 169 - Q-. 170 HANDBOOK OF MINING DETAILS of dump shown by dotted line. The front wheels follow the lower tracks which are set at the regular 5-ft. spacing. The door of the skip is hinged at the top and held tightly closed during hoisting, by the bale of the skip. When the rear of the skip is raised the bale swings up and allows the door to open and the load to discharge. The ore is dumped into a bin holding about 150 tons and made long enough at the top so that the skip will not have to be dumped within close confines in order to discharge entirely within the bin. The ore bin is built with double planking on bottom and sides and is 9 ft. wide, about 26 ft. deep at No. 3 bent and has slopes to the bottom of 40 and 38, as shown in drawing. This insures that the ore will feed freely to the gyratory crusher, which is set on a concrete base, between No. 2 and 3 bents. The crusher, a No. 8 Austin, delivers its product directly into railroad cars which are let down the track by gravity. Details of the framing of the bents, five of which are used in this par- ticular tipple, are shown fully in the drawing. They are framed from 12X12 timbers battered 3 in. to i ft. and cross braced with 3X10 plank. The bents are set on concrete bases. The details of the corbels of the No. 2 bent are also given in the cut. This construction gives a strong and satisfactory tipple at a not too excessive first cost. The Tennessee company uses these wooden tipples at all of its ore mines on Red Mountain, but the Republic company has substi- tuted steel construction for the wooden type. The general form of tipple, how- ever, is retained. ORE BINS Cananea Ore Bins (By Claude T. Rice). The drawings given in Fig. 112 show the standard bin construction that has been adopted at the mines at Cananea, Mexico. The bin has a bottom sloping at 45, and the inside is lined with sheet iron 3/16 in. thick, in which the holes for the nails are countersunk. This slope at the bottom has been found sufficient for the Cananea ores, but it is well when building bins with a sloping bottom to bear in mind that heavy sulphide ores of copper when coming damp from the mines are apt to pack in a bin having a bottom slope of 45. Such was the experience at the new ore bins built at the Highland Boy mine at Bingham for the use of consolidated tramways, and I understand that such also was the experience with some of the heaviest ores at the Cerro de Pasco mines in Peru. In a bin with a sloping bottom the weight is practically all thrown on the front posts, so at Cananea it is the prac- tice to use double front posts. When a bin is designed it is the custom at Cananea to lay out the plan of the sheet-iron lining, so that when the construc- tion is ordered the plans can be taken to the machine shop, and the lining be prepared and marked, ready for putting in place in the bin. By planning the details in advance and having all parts ready, costly delays in the erection of the bins are avoided. Tonopah Orehouses. In the orehouses at Tonopah special provision is HEADFRAMES, CHUTES, POCKETS, ETC. 171 1 / / " 5 ' / g = I x 01 L 172 HANDBOOK OF MINING DETAILS > o * - -H u ni-n x r.I in CQ / n 5-9 x 9 -ni-r,I x si -d ._, HEADFRAMES, CHUTES, POCKETS, ETC. 173 made for sorting the ore. The drawings shown in Fig. 113 give the details of construction of the new bins at the Red Plume and the Silver Top shafts, which were designed by J. M. Fox, while assistant superintendent for the Tonopah Mining Co. The older bin of the Mizpah orehouse was built with a sloping bottom, but that form is not so cheap in the first cost, and also requires great expenditure to keep it in repair. The Silver Top and the Red Plume orehouses required from 43,000 to 45,000 board feet in their construction, and as they had flat bottoms, the only protection required was a small amount of sheet iron around the mouths of the gates. The capacity of each bin is about 450 tons. The cost was between $5000 and $6000 each completed, with Oregon spruce at $37.50 per thousand, and erection done by contract in a camp where carpenters earn from $5 to $5.50 per 8-hour shift. The upkeep for the last two years has been practically nothing. The Mizpah orehouse has a bottom sloping at 40, so that it has to be protected with a sheet-iron covering. It took 110,000 board feet to build that orehouse and the capacity is between 400 and 450 tons. As ihe orehouse was erected early in the life of the camp when the cost of materials was excessive, it would not be fair to use the actual cost in a comparison. However, it costs two and one-half times as much to build a sloping-bottom bin as one with a flat bottom. One of the commendable features of the Tonopah orehouses is that the grizzlies are placed so that the ore is dumped against instead of with the slope. This insures a better screening action on the grizzlies. In order to sample the fines from the grizzlies a 3-in. channel iron is carried underneath clear across the grizzlies and at right angles to the bars, but at an angle of between 30 and 35 from the horizontal, so that the fines, which are caught in the channel sampler after falling through the grizzly openings, i 1/2 in. wide, slide down into a sample box on the floor of the orehouse. Besides the economy with which the timber has been used in the erection of the bin, a leading feature of the construction is the commodious arrangement of the upper part so as to facilitate the sorting of the ore. The oversize from the grizzlies runs into a small upper ore-pocket, having feed holes at the bottom which permit the ore to run out by gravity upon the sorting tables as sorting progresses. Consequently, the ore with only a little scraping is in a thin layer in front of the ore sorters so that they can quickly throw the pieces of waste into a mine car on a track nearby, while the ore can be easily scraped into holes in the floor that lead to the ore bin proper. These openings are so placed that a man cannot easily walk into them. The Tonopah-Belmont orehouse is noteworthy for the novelty, at least in metal mining, of the manner of constructing the ore bins, which is quite similar to some of the bins that have been built at eastern cement works. The floor of the bin is carried on a series of separate inner posts, while the outside posts, against which the bottom beams abut, extend to the top of the bin and serve as binding posts, as it were, to give stability. The accompanying elevations and 174 HANDBOOK OF MINING DETAILS sections (Figs. 114 and 115) show the details of this type of construction. The sorting shed construction is quite similar to the arrangement in the orehouses of the Tonopah Mining Co., except that instead of the ordinary bar construction of the grizzlies, they are made of cast-steel plates i in. thick with bored holes 2 in. in diameter at the top and 2 in. at the bottom face, arranged in staggered holes and with plates set at an angle of 40, at which they clear themselves well. The ore hoppers above the sorting tables are lined with steel. In the construction of the orehouse 73,000 board feet of lumber was used. The bin has a capacity of about 750 tons, being divided into three compartments, Detail Sections Cop Joint Through C-C Through A-A Through B-B Left Chute, Bin and Upper Floors, through C-C Center Chute, through A-A Section through E-E Right Chute, through B-B FIG. 114. SECTIONS OF TONOPAH-BELMONT OREHOUSE. two of 10,000, and the other of about 5000 cu. ft. capacity. The structure is 51 ft. long by 28 ft. wide by 64 ft. high to the top of the ridge pole. The main sill timbers are bolted to massive concrete mud-sills, while the bin is supported on seven bents of four posts 1 2 X 1 2 in. each. The outer posts reach from sill to top of bin, while the inner line of posts support the longitudinal caps on which the bin floor rests. This floor is made of 3 X 8-in. planks placed on edge, and is continuous across the whole width, with the outer ends resting on girts that are framed into the outer post. To increase the stability of the bin the girts and long posts are heavily reinforced by 8X i2-in. cleats and sway braces. HEADFRAMES, CHUTES, POCKETS, ETC. 175 The sides of the bin are made of a double lining of 2X i2-in. planks, with joints broken, while the partitions also are made of 2-in. planks. There are six steel-lined loading chutes, three on each side of the track. These are fitted with No. 3 Bolthoff lever gates, with movable steel spouts. A clearance space of 1 8 ft. is provided above the rails, so that a locomotive can go under the bin. Above the bin the orehouse part is covered with galvanized, corrugated iron. Concrete Storage Bin (By Fremont N. Turgeon). A reinforced-concrete storage bin, interesting for its size, ease of construction and cheapness, is at one end of Witherbee, Sherman & Co.'s new magnetic-concentrating mill, at Mine- ville, N. Y. It is circular in section, 25 ft. in outside diameter, and 45 ft. high. End Elevation Side Elexation FIG. 115. ELEVATIONS OF TONOPAH-BELMONT OREHOUSE. It has a capacity of 1500 tons of crude ore, of which about 1000 tons will run out without handling. The foundation is of rough uncrushed mine stone bonded together with a lean mixture of tailings and cement in the ratio of 10 : i. The walls are 18 in. thick at the bottom, and decrease 2 in. in thickness every 9 in. up to the top, which is 10 in. in thickness. The mixture of the walls is 4:1, tailings and cement. The reinforcing is wornout steel hoisting cable, i 1/8 in. in diameter, spaced as shown in Fig. 116. The ends of each hoop of cable are fastened together with old cable grips. Vertical cables are i 7 6 HANDBOOK OF MINING DETAILS placed every 4 ft. about the circumference and anchored in the foundation, and the hoop cables are fastened to each vertical cable with ties of old bell wire, and are placed 4 in. from the outside circumference. The forms were i-in. matched boards nailed to circular forms cut from 2-in. plank, spaced every 4 ft. vertically, and supported by short studs from the set below. The entire outside form was made first, then the reinforcing put in and fastened and supported on the outside form, the work being done from a staging inside the bin ; then the first 9 ft. of inside form was put in and tied to the outside form with i/2-in. tie rods, and the walls cast. On top of this the next 9 ft. of - 12" -o 14" 16'" 1 I VW/y////tyy/;///////r7/>///>//////;;;////////////77^ FIG. Il6. CONCRETE STORAGE BIN, MINERVILLE, N. Y. form was erected and the walls cast, and so on to the top. The concrete was raised by an elevator to the level of the top of the form being cast, and carried to the form by wheelbarrows through a small door in the outside form which was subsequently closed. The walls of the bin are thicker than necessary, to allow for the wear of the ore sliding down, as the bin is emptied daily. As may be seen, all ore does not run out naturally. To overcome this, before being used the bin was filled with crushed barren material until it ran out of the door, and ore was put in on top of this. VIII HOISTING AND TRANSPORTATION Theoretical Considerations Notes on Practice Hoists Miscellaneous Devices Aerial Tramways. THEORETICAL CONSIDERATIONS Graphic Solution of Skip Loads (By F. W. Collins). The pull on the bail of a skip used in an incline shaft and the load on the wheels can be determined graphically by the method illustrated in Fig. 117. In the sketch 6 is the angle FIG. 117. GRAPHIC DETERMINATION OF PULL ON A SKIP BAIL. of inclination of the shaft; AH, a vertical line drawn through the center of gravity of the skip; AG is the center line of the front wheel drawn normal to the rail; EF, the center line of the rear wheel drawn normal to the rail; E is the point of intersection of EF with the center line of the bail; A is the point of intersection of AH with AG, the center line of the front wheel. After completing this con- struction lay off on AH the distance AD, the weight of the skip and load, to any convenient scale, and draw BD, parallel to AG, and BC, parallel to the center line of the bail; then BD will be the load on the front wheels, BC the pull on the bail, and AC the load on the back wheels. The bail need not be parallel to the rails and may be hinged at any point. Vertical Unbalanced Loads Lifted by First Motion Hoists. The ac- companying charts were prepared by L. F. Mitten of the Vulcan Iron Works, 12 177 HANDBOOK OF MINING DETAILS i 7 8 Wilkesbarre, Penn. The first, reproduced in Fig. 118, is plotted from the following formula: Load= 3.1416!) P= Initial pressure at the throttle. A Area of cylinder. L= Stroke in feet. D= Diameter of winding drum in feet. Diameter Drum in Feet. Vertical Unbalanced Loads Lifted by First Motion Engines at Various Steam Pressures with Drums from 4' to 12'Diameter. Based on Initial Pressure at the Throttle, and One Cylinder only being Operative. Diameter Cylinder Steam Pressure. Diameter Drum in feet. FIG. Il8. CHART FOR FINDING THE PROPER-SIZED ENGINE WHEN THE UNBALANCED LOAD AND THE STEAM PRESSURE ARE KNOWN. Either cylinder of the pair of engines is capable of starting the unbalanced load given, inasmuch as one cylinder may be on a dead center and would there- fore be inoperative. The steam pressure is taken at the full initial pressure at throttle. An efficiency of 85 % has been taken, this having been found after various tests to be a fair average. HOISTING AND TRANSPORTATION 179 Knowing the unbalanced load and the steam pressure at the throttle, the proper-sized engine for the work may be found without any figuring whatever. It will also be readily seen that, having the size of the engine cylinders, the -7 /- / 3500 S2500 eet BOO S +///// ti ii > Rev 1! utions per Minute, ) 2(0 250 90 100 200 300 400 m m 70 800 900 1000 UOO 1200 ^ \ i ^. V M \N \DZSK x^. \ t> FIG. IIQ. CHART FOR DETERMINING THE ROPE SPEED IN HOISTING. vertical load that can be lifted by them may also be found for any steam pressure and various diameters of drum. As an example, find the size of engine capable of handling a vertical unbal- i8o HANDBOOK OF MINING DETAILS anced load of 12,000 Ib. with loo-lb. steam pressure at the throttle. The rope manufacturers give the working load for i-in. rope as 6.8 tons. However, in actual practice, for this load a i i/4-in. rope would probably be used and wound Rope Speed in Feet per Minute. 1 1 1 s s i rit 1 1 1 fi i 1 1 i Allowance for Changing Cars or Dumping same = 15 Seconds. FIG. 120. CHART TO DETERMINE NUMBER OF CARS HOISTED PER HOUR. Capacity in Feet per Foot of Face. Straight Face Grooved Drums. 100 WO 120 130 140 150 160 170 180 100 200 210 220 230 240 250 260 270 230 200 300 310 320 330 340 350 360 370 13' FIG. 121. CHART FOR DETERMINING THE FACE OF A GROOVED DRUM. on, say, an 8-ft. diameter drum. Follow the horizontal line marked 12,000 until it is intersected by the diagonal line at or about the vertical line rep- resenting an 8-ft. diameter drum; then follow the diagonal line down to left side HOISTING AND TRANSPORTATION 181 of chart; follow horizontal line across until it is intersected by diagonal line at or about the line representing loo-lb. steam pressure; follow this diagonal line as previously described to left side of chart; follow horizontal line until proper Capacity in Feet per Foot of Face. Drum not Grooved. 100 110 120 130 HO 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 13'0 12'0' n'c" 3*0" FIG. 122. CHART TO DETERMINE THE FACE, WHEN THE DRUM IS NOT GROOVED. Capacity in Feet per Foot of Face. Conical Grooved Drums. 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 13*0" 12'6" 12' 0" n'e" 11' 0" io'e" lO'O" 1 9'0" Q 8*6" 8'0" I 7 '"" C'6" e'o" sV 5'0" 4'6" 4'0" S'e" 3'0" FIG. : ^ ^ ^ ? / x x x x x .. x / , / ^ f / x x x ^ x X X / ^ / / x X x x x x X ^ ~t / / > s X x x X ^ x x ^ x s / / .x ? x x X x X ^ | B / x / ? y ? .X ^ x x x x^ X / ^/ X X 1 x x x x X X X 1 ^^ X / / J vX ' X X x ^ X x - x "" / V / x x;v ^,0^ X x x X xx ^ x ^ // > / / x x 3 ^> ^ x ?r X ^ x^ x/ / / x / X ' x x fer s X x x^^ x // X x x / x / x pg.^5j^ ^x- *J / */\/ X x x x x x x] x ^ 1 ^ X // XX x x X x ' X , x x ' / x x, x x x X ^ X x^ X' ^ ' / x. x x, x x x x^ /> x, x . x x x x^ x X- ''x x ^ x 1 ^ ^^ X X ^^ x x x x^ x ' [23. CHART TO DETERMINE THE FACE OF A CONICAL DRUM; THE DIAMETER SHOULD BE THE MEAN DIAMETER. combination of stroke and diameter are found. For the work in hand the following engines would be satisfactory: 24X48 in. or 28X36 in.; the 24X48-in. size would probably be selected. 182 HANDBOOK OF MINING DETAILS Determining the Rope Speed in Hoisting. In determining the rope speed in a hoisting operation when the average piston speed, the length of stroke and diameter of drum are known, the second chart (Fig. 119) provides a handy method of calculation. As an example, let us assume an average piston speed of 600 ft. per minute, and a 48-in. stroke; then, following the horizontal line on the chart at 600 until it is intersected by the diagonal line representing a 48-in. stroke, follow this line to the upper section until it is intersected by the diagonal line representing an 8-ft. drum; by following the horizontal line to the side of the chart the rope speed is found to be 1890 ft. per minute. Diagram showing Amount- of Rope Wound on Drums of various Diameters and Faces. FIG. 124. Determining the Number of Cars Hoisted per Hour. The third chart of the series enables the quick calculation of "cars per hour," when depth of shaft and certain other factors are known. As an example, assume the shaft is 475 ft. deep, and a rope speed of 1900 ft. By referring to Fig. 120, it will be readily seen that from a shaft 475 ft. deep we can get out two cars per minute, or 120 cars per hour. This chart is based on an allowance of one quarter of a minute for changing cars and a double-compartment shaft. HOISTING AND TRANSPORTATION 183 Determining the Face of Winding Drums. In determining the face of winding drums when the diameter of the drum and the rope diameter are known, the charts reproduced in Figs. 121, 122, and 123 will be found useful. Assume that the drum has a diameter of 8 ft., and that the rope diameter is i 1/4 in.; also that the shaft is 475 ft. deep; then referring to Fig. 121 it is found that an 8-ft. diameter drum will wind 227 ft. per foot of face. The drum required would therefore have to be, say, 2 ft. 6 in. face, which would allow a sufficient number of grooves at one end of drum for fastening the rope. The other charts shown in Figs. 122 and 123 would, of course, be used in Diagram showing Power Required to Haul Cars on Various Pitches. Note:- Shaded Portions on Pitch Diagonals show Amouut to be Added for Rolling Friction, varying from 50 Lbs. per Ton on the Level to 5 Lbs. on Vertical Lift, lower for Rope is Worked separately and Added to Power for Cars. Equivalent Pull on Rope doe to Load on the Plane. Pitch of Plane in Per cent, or Rise in Feet per 100 Ft. Horizontal. FIG. 125. the same manner as illustrated above. The diameter used for conical drums, however, should be the mean diameter. Determining the Amount of Rope Wound on a Drum. In determining the amount of rope wound on drums of various diameters and faces, the chart given in Fig. 124 provides a quick method of calculation. It is, of course, essential that the circumference and diameter of the drum are known. The 184 HANDBOOK OF MINING DETAILS chart also assumes that the face of the drum is a known quantity. With these factors at hand, the method of calculation is self-evident. Power Required to Haul Cars on Various Pitches. The sixth chart, reproduced in Fig. 125, is intended to simplify the calculations for determining the power required to haul loads on planes of various pitches. For example, it is desired to haul two loaded cars, each weighing 6000 lb., up a plane 1000 ft. long, having a pitch of 40 from the horizontal, at a maximum rope speed of 500 ft. per minute. What is the equivalent rope pull ? What is the brake horse- power required to handle the load? Two loaded cars weighing 6000 lb. each equals a load of 12,000 lb. exclusive of winding rope. Referring to the diagram, follow the horizontal line representing 12,000 on the chart until it is intersected by the diagonal line representing 40. Directly above this point of intersection will be found the rope pull, which in this case is 7900 lb. It is also found that a 3/4-in. rope will be satisfactory and. that this size rope weighs 0.88 lb. per foot. Following down this imaginary line representing 7900 lb. until it is intersected by the diagonal line representing 500 ft. per minute rope speed, one finds 120 h.p. applied to the load, or the brake horsepower required. The horsepower to be delivered by this hoist motor would be 141 ; this is based on an efficiency of 85 % for the entire equipment. It has been found that a 3/4-in. rope would be re- quired and also that this size rope weighed 0.88 lb. per foot; 1000 ft. of rope at 0.88 lb. equals 880 lb. By working this out as was done for the loaded cars, it is equivalent to 9 h.p., which should be added to the 141 h.p., making a total of 150 h.p. Rope Capacity of Drums. The rule used by the A. Leschen & Sons Rope Co. for computing the rope capacity of any size of drum, is as follows: Add the depth of flange in inches to the diameter of the drum, and multiply this result by the out to out width of the drum. This product is then multiplied by the figure below corresponding to the size of the rope used: i in 4.16 if in o. 138 f in i . 86 i in o . 1 16 fs in 1.37 T| in 0.099 \ in i .05 if in 0.085 i 9 g in 0.828 if in 0.074 fin 0.672 2 in o. 066 f in 0.465 z\ in 0.058 in 0.342 ai in 0.052 i in o . 262 2f in o . 046 1 1 in o. 207 2^ in 0.042 \\ in o. 167 This rule applies, of course, to a drum on which the rope is to be wound in successive layers up to the full height of the flange. NOTES ON PRACTICE Flat Rope vs. Round Rope. A correspondent asks about the comparative results in practice of flat and round wire ropes. He says that he has had the best results from the flat rope, and considers it the safer because of being open to HOISTING AND TRANSPORTATION 185 closer inspection. His superintendent contends, however, that round cable is the better, and cites Lake Superior and South African practice. Our corre- spondent asks, What are the manufacturers' claims? With respect to this matter a leading manufacturer of wire rope informs us that flat rope is now used only in exceptional cases, there being but little demand for it, owing to its greater cost. The effect of wear in round wire rope shows first in the outer layers, and any- thing radically wrong can therefore be readily detected. Round wire rope ex- poses less surface to atmospheric oxidation than flat rope, and the core wires, which are saturated with grease, are less likely to suffer from oxidation or cor- rosion from the action of water, and especially water containing acid, so that as far as safety is concerned round rope is considered to be superior to flat rope. The superiority of round rope in point of safety is generally recognized by engineers. This explains why round rope is so generally used at Lake Superior and in South Africa. Some engineers go so far as to say that the use of flat rope ought to be forbidden. A round rope may have a good many broken wires and still be safe, owing to the tight binding of this kind of construction ; whereas in flat ropes the binding is much looser and broken wires quickly become a serious danger. Remarks on Hoisting Ropes. The latest Prussian statistics on shaft hoisting ropes were exhaustively and critically discussed by Professor Herbst, of Aix-la-Chapelle, in a series of articles in Gluckauf. His general conclusions are as follows: The protective effect of lubrication ha- not been plainly proved in dry shafts. This observation suggests that the present lubrication processes for wet ropes leave room for improvement, although it is certain that all now-known lubricative agents rapidly disintegrate m shafts where the water is salty or sour. Future experiments in this direction may provide a remedy. Galvanizing or coating with zinc does not appear to have a really protective effect in wet shafts, the reason probably being that zinc coating has but little power of resistance to salt water. It is also suggested that the wires have suffered in the galvanizing process, for, although it has been proved by Winter and others that the process, when properly and carefully executed, does not unfavorably affect the ropes, it is also well known that it often reduces the tensile strength of the rope by 50% or more. The hauling efficiency of ropes in dry shafts stands in the proportion of 100 to 60 or 70 to that in wet shafts, a fact which, in view of the high price of ropes, means a substantial economic advantage for dry shafts. Tensile strength between 160 and 1 80 kg. per square millimeter does not unfavorably affect the flexibility or hauling strength of the ropes, while ropes of more than 180 kg. per square millimeter have given substantially lower efficiency figures. The greater or less strain, as expressed by a higher or lower safety factor, put upon ropes has had no influence upon their consistency. It may, therefore, be assumed that the advantages of a higher factor of safety are neutralized by its disadvantages l86 HANDBOOK OF MINING DETAILS that is, greater rope thickness combined with reduced flexibility and greater dead weight. Uses for Old Hoisting Cable. As old hoisting cable has had most of the stretch taken out of it, it makes good reinforcement for concrete work. At the Red Jacket shaft of the Calumet & Hecla company old hoisting cable is un- stranded and the strands are also used on the underground-haulage systems for the wearing ropes. In removing the grease from the cable, burning was tried, but it took the temper out of the wires and the strands would untwist, so now only a part of the grease is taken off the cables before they are unstranded. The unstranding is done in lengths of 600 ft. A block and tackle is fastened to each end of the cable and it is stretched so that it will be clear of the ground. In attaching the blocks to the cable a clamp is used consisting of a bar with a hinged top piece which is tightened on the rope by a bolt at the other end. The block and tackle at each end is fastened to a swivel so that the cable can twist in either direction as it is being unstranded. Two strands are unstranded at a time and each of these strands is fastened to a block so that they can be kept tight as they are being unstranded. These blocks are fastened at some distance from each other as well as from the main cable, so that neither one of them will inter- fere with either the other or the main rope while it is being unstranded. About 2000 ft. of cable can be unstranded in a day, and about 12,000 ft. of single-strand rope obtained. Both i-in. and y/8-in. hoisting rope has been unstranded for the haulage systems. This old rope has been found to work quite satisfactorily for the hauling rope, but good rope must be used for the tail rope if a return rope from the same engine that does the hauling is used, as the unstranded rope will not readily pass through the pulleys. Strands of i 3/8- in. rope have also been tried, but they were found to be too stiff. In case a rope brea.ks or a broken wire begins to ball up on the rope, the individual wire or the ends of the broken rope are heated so as to take out the temper, and then the ends are tied together and hauling is continued until the rope can be spliced properly. Gravity Planes at Cheever Mine (By Guy C. Stoltz). The Cheever Iron Ore Co., operating at Port Henry, N. Y., trams the concentrates, resulting from magnetic separation, by gravity planes to the loading chutes of the Delaware & Hudson switch on the shore of Lake Champlain. Topography favored the instal- (ation of two planes, the first plane being 700 ft. long with a drop of 55 ft., and the second about 2000 ft. long and a drop of 193 ft. The grade is not at all regular. The tracks conform, wherever possible, to the surface of the ground. Three 3o-lb. rails are laid at 3-ft. gage on each plane and four rails with the spread for turnouts are laid at the half-way points. Side-dump steel cars of 4 i /2-ton capacity are used. A trip of two loaded cars is released on the slight down grade at the storage bin and on their downward journey to the first turn- table they pull the two empty cars, attached to the other end of the cable, to the loading bin. At the turntable the loaded cars are deflected about 60 and HOISTING AND TRANSPORTATION 187 attached to the free end of the cable for the second plane and on their downward course pull up two more empties. Sheaves with brakes are installed at the top of each plane. At the terminal of the second plane the cars are delivered to a turntable and trammed by hand to the several loading chutes. It is intended to replace the first turntable by a steeply banked curve, which will increase the capacity of the system and lower the surface-tramming cost by almost one-half. Car Stopping Devices on Gravity Inclines. It is of great importance to have, at the upper end of every gravity plane, a device to regulate the admission of cars, one at a time, to the plane, and at the same time protect the men working at the bottom. Fig. 126 illustrates three different types of appliances used in Germany to accomplish this. The device shown in Fig. i consists of a pair of stops, one at the extreme top and the other a distance of 2 m. down the incline; both are raised into effective position by cams keyed to axles which lie underneath and across the track. The movement of the axles is controlled by levers connected in such a way that a single motion of the hand lever will raise one stop into position and simultaneously drop the other out of position. The first motion of the hand lever drops the upper stop, permitting the car to start down the incline. The car is blocked by the second stop, until a motion in the opposite direction lowers this stop, allowing the car to pass down the incline, and raises the upper stop into position to retain the next following car. The apparatus shown in Fig. 2 consists of an axle about i m. long, lying below and parallel to the rails, and supported in this position by two journal boxes. To each end of the axle is fastened an arm, at 90 to one another, of such length that the extreme end of each arm will reach out and rest upon the top of the adjacent rail, thus forming an obstruction to the wheels of the cars. When one rail is blocked, the other is free, so that to permit the cars to pass one at a time it is only necessary to rotate the axle through a few degrees alternately to one side and the other. The top tender does this with his foot. The type of which two views are shown in Figs. 3 and 4 consists of a heavy, square beam pivoted at its ends and extending across the top of the incline at a sufficient height to permit the loaded cars to pass beneath it. At one end of the beam is a single-notched ratchet engaging a pawl, which prevents the former from rotating beyond a certain point. Two strong arms are fastened to the square beam in such a way as to block the passing of a car on either track so long as the pawl holds. The latter can be released by pulling the handle on the end of the cord, which is within reach of the top tender, allowing the car to pass. As soon as it has gone far enough, the arms fall back into their first position, and their impetus carries the notch in the ratchet to within reach of the pawl, when the device is ready for the next car. It is apparent that the appa- ratus interposes no obstruction to the passing of a car coming up hill. The danger to be apprehended in the device last described is that, if two i88 HANDBOOK OF MINING DETAILS HOISTING AND TRANSPORTATION 189 cars should follow one another closely, in passing over the knuckle, by the time the first car had gone far enough to release the restraining arm, the second car would be so far advanced as to prevent the ratchet from establishing connection with the pawl, and the second car would race the first one down the hill. Tail Rope Haulage Operated by Skips. At the Republic mine, Michigan, where an unbalanced ore skip is used, the descending skip furnishes power for hauling empty ore cars. The tram has a length of 900 ft., and has a sufficient down grade for the loaded cars to run out by gravity. The car is of the double- truck type, side dump, weighs 6500 Ib. and carries 31/2 tons of ore. A tail rope is attached to the car and is connected with a winding drum on the axle of the sheave. This drum is 8 ft. in diameter, the same as the sheave. A friction clutch is used to operate the drum. There is also a brake on the drum to control the speed of the outgoing cars. Both brake and friction clutch are operated by a wire rope from the station level. An indicator is also used to show the exact position of the car on the track. The car dumps automatically. Of course in this particular case the skip remains at the surface until the car has reached the bin and is ready for its return trip. As the skip descends, the friction clutch is thrown in, and the empty car is drawn back to the shaft ready to receive the ore when it comes up. This scheme works excellently with a shaft that is not working at its full capacity or where the stopping of the skip for a few moments does not interfere with the output. A second drum is now being installed at the same mine. This one will only be 4 ft. in diameter, as the distance for tramming the ore is less. In a system of counterbalanced skip a similar scheme is used, except that the ascending skip also brings in the empty cars. In this case the loaded car goes out as the skip descends and then returns as the skip comes up. The drum is at the station level and is operated by a rope drive from the sheave. The drum, as before, is provided with friction clutch and brake. This adds a little extra strain on the hoisting cable, but not enough to seriously affect its working. An Underground Haulage System (By Albert H. Fay). The problem of handling a large tonnage of ore underground is usually a serious one, especially in the matter of cost. The system that is now being installed between the 700 and 800 levels by Witherbee, Sherman & Co., promises to be one of great impor- tance in handling the magnetite ore in their mines at Mineville, N. Y. The installation is expensive and could be used only by mines handling a large tonnage for a number of years. Up to the present the mining has been carried on by working on large faces of ore 50 to 75 ft. high and several hundred feet wide. The ore was shot down to the foot of this face and then shoveled by hand into the mine cars which were pushed to the shaft by hand. The ore is heavy and in most cases it requires at least three to five men to handle a single car. The scheme now under way consists of a haulage way installed 60 ft. below the present working level. This underground passage is in the form of an I 9 o HANDBOOK OF MINING DETAILS ellipse, with a circumference of about 1000 ft., and opens an orebody 500 ft. wide, 60 ft. deep, with an indefinite length. At least 1,000,000 tons of ore are now blocked out to be handled by this installation. Along this drift are at least a half-dozen raises, inclined at about 45, which will be used as mill holes. The mining will be carried on by stoping down, setting the machine drills near the raises and shooting the ore down to the loading platforms. The large number of raises will give ample space for a number of machines and as the work progresses it will give still more room. As the ore passes down through a raise, it falls upon a loading platform built of concrete. This platform is 4 1/2 ft. high, 10 or 12 ft. long, 8 or 10 ft. wide according to the condition of the ground, with a loading chute 3 ft. above the top of rail. It is built with a slope from the back to the front as well as a slope from each end to the center. The chute will be covered with sheet iron. At the shaft an 8oo-ton storage bin has been built, the bottom of which is 46.5 ft. below the top of the car tracks. The tipple is 26 ft. long and will dump three cars at once. It is operated by an electric motor and revolves upon trunnions. The bin gate and the loading chute are operated by air hoists. An auxiliary tipple at the left will dump only one car at a time and is to be used only when tramming by hand in case the electric motor haulage system is out of commission. This is also to be used as a waste pocket when it is necessary to dispose of waste from the same loading station. Between the shaft and the bin is a rock pentice which serves as a support for the auxiliary tipple and at the same time forms the front wall of the ore pocket. The cars are of three tons' capacity and will be handled in trains of nine cars each. The motor truck has two 25-h.p. motors operated on 2 20- volt direct current. The haulage track is 45-lb. rails. While lighter rails could be used, practice has demonstrated that the heavy rails are better as they are not easily broken by heavy pieces of ore falling upon them. They are also more solid, require less ties and give a better track. The motor in passing around the track gathers up the loaded cars and pushes them in front. When the tipple is reached, three cars are dumped. These are then pushed through the tipple and three more dumped until all are empty. The motor then goes around the tipple on a side track and couples the nine empty cars on behind. When the first loading station is reached, the loaded cars are picked up, and one, two or three empty cars left in their place as may be desired. In this way the motor will be in operation all the time and with an 8oo-ton storage bin it will be possible to keep the hoist working up to its full capacity without the loss of time which was usual when the cars were operated by hand power. When this equipment is completed, it is expected to be able to handle 1000 tons per lo-hour shift. The ore is hoisted in self-dumping skips. I am indebted to S. LeFevre, chief engineer, Witherbee, Sherman & Co., for the above information. An Underground Hoisting Station (By S. A. Worcester). Fig. 127 shows the layout of a winze hoisting station in a mine in southwestern Colorado. HOISTING AND TRANSPORTATION 191 The winze is nearly square in section and is divided into three compartments. The largest compartment is rectangular in section and is used for hoisting ore in cars of 22oo-lb. capacity, two cars being placed tandem on the single deck of the cage. The i5o-h.p. electric, two-reel cage hoist occupies a large room excavated in hard rock at the west side of the station; it is not shown in the illustration. The flat rope from one of the reels runs over the large upper sheave at the left, thence down to the cage. The flat rope on the other reel runs over the lower sheave supported on an A-frame thence down the shaft to an overbalance weight. This weight is made of several sections and is similar to the ordinary elevator weight. It is so weighted that the work of the motor when raising the weight is the same as when raising the cage with its maximum load. FIG. 127. WINZE HOIST STATION IN A COLORADO MINE. The two other compartments are nearly square in section. One is used as a pipe and ladder compartment, the other is lined with planks throughout and is used only as a bucket hoistway for sinking operations. This bucket is raised by the 75-h.p. electric motor shown in the upper room on the right- hand side of the illustration. When the bucket has been raised above the level of the floor of this room the counterbalanced door is lowered and the dumping rope shown at the left of the bottom of the bucket is hooked into the ring at the bottom of the bucket. Upon lowering, the bucket turns over and dumps its load into the bin below from which the ore or rock is drawn into cars and hauled 2400 ft. along the vein then 2200 ft. through an adit to daylight; thence 192 HANDBOOK OF MINING DETAILS it is conveyed 11,500 ft. by a Blei chert tramway to the mill. The operating levers of the hoist are placed near the winze so that the hoist engineer can attend to the dumping. At the left of the illustration a third room is shown, excavated in rock, in which is shown a 5o-h.p. two-drum hoist. Above this room the position of an inclined raise is shown. The hoist rope passes up the raise for 500 ft., over a sheave, thence down to the cage. The y/8-in. rope on the drum passes over a sheave at the collar of the winze, thence down the cage compartment to an overbalance weight that runs by the side of and is similar to the weight used on the cage hoist. The raise hoist is used for raising men, timbers and supplies to the upper levels. Direct current for all these hoists, for other hoists in the mine and for the mine locomotives is supplied from a storage- battery plant at the surface. The battery is charged by rotary converters and a booster, the current being generated at a hydro-electric power plant several miles from the mine. Catenary Hoisting Cable. There is an unusual installation of a hoisting cable at the Republic mine, Republic, Mich. In order to utilize a central power plant, it became necessary to have a cable operate across a small lake a distance of 1800 ft. before the headframe of the shaft could be reached. The shaft is about 800 ft. deep and is inclined at an angle of 70. In constructing the cable across the lake, the towers for supporting the cable would be very high if an attempt had been made to keep the cable in a straight line from the drum to the shaft. A catenary curve between the two places was figured out on the basis of the breaking load of the cable. Towers were erected at intervals of 100 ft. entirely across the lake, the one near the center being only 10 or 12 ft. above the level of the lake. The catenary is so flat that the cable has no tend- ency to lift off the pulleys and at the same time the friction on the pulleys is less than it would be if the cable were worked in a straight line. A large saving also resulted from the construction of smaller towers. Double Hoisting Cables. At the Beust shaft of the Deutschland mine at Hasslinghausen, Germany, the slipping of the cable is prevented by using a double rope running on double-grooved sheaves. Thus the bearing area on the packing in the sheaves is increased. The cables are attached to the cage by a drawbar to which the cables are fastened by turnbuckles. These turn- buckles permit the strain on the cables to be equalized. Bolts prevent the moving of the turnbuckles by the twisting of the ropes. Hoisting Cable Run through a Drill Hole. A 6-in. drill hole from the surface penetrated a body of ore which later was stoped out. Upon sinking the drill hole ore was struck at a lower level and a winze sunk with the drill hole as a center. In order to work the winze to any depth it would have been neces- sary to install a hoist underground, which was not practical. A hoist was there- fore erected at the surface and the cable operated through the drill hole. Ore was hoisted to the main working level and then trammed to the hoisting shaft. HOISTING AND TRANSPORTATION 193 Rapid Hoisting with Wire Guide (By Hugh C. Watson). A remarkable feat of hoisting is the one now in operation at La Ojuela mine in the State of Durango, Mexico. By means of wire guides and an unbalanced, first- motion hoist, a bucket holding about 1800 Ib. of ore is filled, hoisted, dumped and returned to the bottom of a lyoo-ft. shaft in 2 minutes 10 seconds. This is not record time, but ordinary hoisting speed. It has been done in 2 minutes flat. Wire-rope guides are not the best that can be used, but they have certain advantages, especially when working a mine on a prospecting basis, where first cost is one of the essential features. The principal advantages are small cost, ease and speed with which they can be installed and shifted, that they will work in any sort of a vertical shaft, and, considering the speed attained at Ojuela, they do not seriously limit the capacity of the haulage system. Six men are employed in connection with the hoisting plant: One is the hoist man, two are topmen and three are fillers. The topmen do nothing but close the doors, dump the bucket and open the doors for the down trip. Of the three men at the bottom of the shaft, one sits above the ore-bin door with a bar to see that the door does not get stopped up. One stands directly in the shaft to hook and unhook the buckets as they are pushed to him by the third man. The empty bucket is caught on a low truck set to receive it between the guides. The man in the shaft unhooks it from the crosshead, the third man gives his full bucket a push that shoves the empty bucket and its truck to the far side of the shaft, the shaft man then hooks the full bucket to the crosshead and gives the signal to hoist. The bucket now at the bottom is filled while the other bucket is being hoisted and dumped. The bucket itself is of the ordinary type attached to the bail slightly below center, and kept upright by means of a link and ear. The doors on the shaft are of the type known locally as "doghouse." They are simply two doors which, when closed, form a gable over the mouth of the shaft on which the ore slides into a bin on either side. The guides are 5/8-in. four-strand, galvanized- steel, wire rope. They are attached at the bottom to a cable that is stretched across the shaft below the track level. This cross cable is anchored on each side of the shaft to a i i/2X i8-in. eye-bolt, which has a split point and wedge to keep it fixed solidly. On top, these guides pass over two small sheaves and down to a drum that serves to hold an excess of rope and is also fitted with a counterweight, a crank handle and dog, so that the guides can be easily and rapidly tightened. This is only one of the many ways that these guides can be fastened; in fact, on this same mine there are at the present time seven shafts that have wire guides, and each one has its own system, each taking advantage of some peculiar condition existing in that shaft. The crosshead is made in the shape of a triangle, of 6X6-in. pine, and at the lower side two lead guide blocks are used of such a form as to be easily 13 J 94 HANDBOOK OF MINING DETAILS changed and solidly attached to the triangle. The guides last indefinitely, but the guide blocks have to be constantly replaced. On shaft No. 4, which hoists about 200 tons daily, the guide blocks last four days. When lowering men, four accommodate themselves on the triangle, four stand on the edge of the bucket and two, sometimes three, climb into the bucket. The principal disad- vantage of this method of hoisting is that it offers absolutely no way of attaching safety devices, and that it takes a larger shaft for the same size of bucket. The principal advantages, other than those already mentioned, are that no timber is required in the shaft, the system can be used either with the balanced or un- balanced method of hoisting, and that by this method a bucket can be passed through a cave or a big stope, where it would be costly to put timbers. This last is the principal reason for its adoption at Ojuela. Concrete Chute Bridging a Level. Concentrating hoisting at a few levels is a practice that is growing in favor at many large mines. At the Osceola, No. 13 shaft of the Calumet & Hecla company, the ore from five levels, each 100 ft. apart, is delivered at the level through a chute in the shaft pillar. This chute is inclined at an angle of 40 from the horizontal. The ore is drawn from it into a car of 7 1/2 tons capacity, the flow of ore being controlled by a chute gate of the hinged type. As this chute was cut after the levels were driven, it was necessary to continue it from the opening in the roof of the drift diagonally across to the similar opening in the floor, near the opposite wall. This was done by bridging the gap with a long, reinforced-concrete box without ends. The bottom of the box was made 24 in. thick, and was reinforced with old 30- and 4o-lb. rails. Large blocks of rock from the vein walls, some of which were 1 6 to 1 8 in. diameter, were imbedded in the concrete in making the bottom, as it was believed that this material would withstand abrasion by the ore better than concrete alone; a 1:2:5 concrete mixture was used. The sides of the box were made 12 in. thick at the floor and tapered to a thickness of 6 in. at the roof. The cover or top of the box was made of concrete 12 in. thick, and it, as well as the sides, was reinforced with old rails. An opening in one side of the box at the floor on each level afforded means of dumping ore into the chute. A grizzly was placed over the opening, and was held in place by a 12 X i2-in. timber, to which the grizzly bars were screwed. A Cheap Mine Road (By S. H. Brockunier). Recently I had occasion to build 2600 ft. of a side-hill road to the Erie mine, Gaston, Calif. I had only a week to complete the road and the problem was further complicated by fallen trees 3 or 4 ft. in diameter, and several hundred feet of swampy ground, so I decided to place main reliance on dynamite. The first day only two pairs of men were put to work, one pair at each end of the road, in order to see how much they would accomplish and how many men would be needed. In this way I estimated that eight men would complete the road in seven days; as a matter of fact the ditching of the swamp detained them a day longer and eight days were actually consumed in the construction. The men were given HOISTING AND TRANSPORTATION I9S 40% dynamite, fuse, caps, augers, and bars. They were told to put 5-ft. vertical holes along the upper side of the proposed road and loosen the earth with dynamite, regulating their charges so as to move the earth as much as possible toward the downhill or lower side. In this way not a pick was used on the entire road and shoveling was reduced to a minimum. When a fallen tree was encountered it was bored for a charge of dynamite, blasted in two, and pushed out of the way. The swamp was corduroyed with 8-ft. slabs blasted from fallen trees. These slabs or poles should have been 12 ft. long, because if shorter they rock too much in soft mud. Cutting and splitting trees with dynamite is an easy method when compared with axe, saw, hammer and wedges and the necessary men to handle such tools. The total cost of this road was, seven boxes of dynamite, $49 ; fuse and caps, $13 ; labor, $202 ; total, $264. This is at the rate of 10 cents per lineal foot for an 8-ft. road. The day the road was completed a 6ooo-lb. load was drawn over it with ease and it has been teamed over steadily ever since. HOISTS Snatch Blocks Applied to Hoisting (By Stephen L. Goodale). At the Bristol mines, at Pioche, Lincoln county, Nev., a large amount of rich ore was FIG. 128. SNATCH BLOCK APPLIED TO MINE HOISTING. taken out from an oreshoot or chimney close to the Gipsy shaft, and as the work got away from the shaft a small electric hoist was installed. This was found to be an expensive arrangement, especially as the electric drill, on account of which the dynamo was primarily installed, proved unsatisfactory, and the dynamo had to be driven for this hoist alone. This meant an extra man at $4 per day to drive the dynamo, also the hoisting engineer below and the hoisting engineer at the top of the Gypsy shaft, each of whom got $4 per day. 196 HANDBOOK OF MINING DETAILS To replace this, two i2-in. snatch blocks were placed at the 45o-ft. station one in the floor of station at A, as shown in Fig. 128, close to the shaft, and one at B hung from a well braced stull in line with the winze. The bucket was hoisted from the winze and lowered to a truck on the station level. The hoist rope was run out to get slack and taken off the snatch blocks; the slack was again taken up and the truck run to the shaft. The snatch blocks were placed, as shown in the diagram, to allow the main hoisting rope being carried around the snatch blocks and down the winze. This arrangement could be worked rapidly and lessened the number of men, cutting out the high-priced engineer at the May Day shaft and replacing the $4 man at the 450 level with a $3 man, whose duty it was to manage the hoisting from the winze and the placing of the hoisting rope around the snatch blocks. Frequently also during a shift this man was able to get out several hundred pounds of high-grade ore near the shaft. It might seem that there would be danger of overwinding and pulling out a snatch block, considering that the bucket had to be stopped within 8 in. of a given point on the 450 level, and that the hoisting engineer had to rely largely on a bell signal. Again, it was difficult to maintain a mark on the rope for the engineer's guidance. However, no trouble was experienced. While this cannot be considered an ideal arrangement for mining a large deposit, still it worked satisfactorily for prospecting more than 100 ft. below the level of the snatch-block station. A Simple Form of Lift. A coal lift used at some of the steam plants on the Mesabi range is shown in Fig. 129. The coal is dumped on the ground outside .Pulley 2 Groove Pulley 3 Groove Pulley FIG. 129. SKETCH SHOWING PISTON ARRANGEMENT FOR COAL LIFT. the boiler house. It is then loaded by hand into i-ton cars and trammed to this lift and elevated to the bunkers. In most of the newer plants, where it is possible, the coal is discharged directly from the railroad cars to the bunkers, thus saving the extra handling with the lift. The device is operated by a steam cylinder about 10 ft. long by 12 or 14 in. in diameter. At the end of the piston rod is a double-grooved sheave over which two 3/4-in. cables operate. One end of these cables is fastened at A , so that in this way when the piston moves 10 ft. it will lift the car 20 ft. The car platform works between guides and is balanced by a counter-weight B. Steam is turned on at C, the exhaust D being HOISTING AND TRANSPORTATION 197 open, forcing the piston along and lifting the car of coal. To lower the car, shut off the steam and open the exhaust valve E and the weight of the car will operate the device by gravity. The area of the piston must be such that the product of the area, steam pressure and distance shall be in excess of the load, multiplied by its distance. If these are equal it gives a balanced system and no movement takes place. The amount of steam consumed is small, simply enough to fill the cylinder. The steam and exhaust valves may be at any convenient place, not necessarily as shown in the diagram. Cable Drum for Lowering Timber. One of the best cable drums for letting mine timber and lagging down a shaft is shown in Fig. 130. This I Shaft FIG. 130. DEVICE FOR LOWERING TIMBERS IN IRON MINES. form is in use by most of the underground mines of northern Minnesota. The timber or lagging is loaded on a small car and pushed to the edge of the shaft. A double slip noose is placed around the timber and the rear end of the car raised up so the load drops into the shaft. It is allowed to drop slowly down the shaft by the friction band E, controlled by the lever L. As the rope A is unwinding, the rope B is being wound up and is kept to the side of the shaft by a guide on the collar of the shaft. The end of rope B reaches the collar as the load strikes bottom; and another load is then attached to rope B, which again pulls up the unloaded rope with chain. The drum is of sufficient length to allow for any reasonable length of rope. The larger the load handled more turns of rope are necessary to hold it. A 3/8-in. wire rope is used in most cases and will wear for years. The friction band E is made of strap iron 4 in. wide and 1/4 in. thick. The shafts are lined with plank placed 198 HANDBOOK OF MINING DETAILS vertically, so that the bundle of moving timbers does not catch in the shaft timbering. A Portable Winch. A portable winch is an extremely useful piece of machinery at any mining operation. At the Republic mine, Republic, Mich., an ordinary hand winch is mounted upon a heavy frame which in turn is mounted upon trucks for a standard-gage track. A 7 i/2-h.p. electric motor is also mounted on the same frame and connected by belt to the pinion shaft which operates the drum. A friction clutch is used to throw the drum in gear. This winch can be moved to any point where there is a car track and is easily anchored by fastening to the rails, or by means of chains to stakes in the ground. Where electric power is available, this arrangement is quite satisfactory, as power can be obtained from any point along the line. The entire apparatus is not so heavy but that it can be moved over smooth ground without the aid of rails. This one is used where a temporary hoist is required, and also in the erection of trestles for car tracks on stock piles. Combination Timber Hoist and Winch. The design of a combination drum for lowering mine timbers and a winch for hoisting is shown in Fig. Coimterweight- FIG. 131. TIMBER HOIST AT HEMATITE MINE, ISHPEMING, MICH. 131. The apparatus here described is used at the Hematite mine, Ishpeming, Mich. The drum is 18 in. in diameter, 3 ft. long and is mounted upon a heavy frame of 8X 8-in. timbers as shown. On one end of the drum is a brake wheel and band, also a cog wheel into which a small pinion meshes. This pinion may be thrown out by means of a lever A , and the timbers lowered by the use of the band brake only. The drum is divided into two sections, upon HOISTING AND TRANSPORTATION 199 which are placed two cables. As one cable is run out with the lowering of the timber, the other cable is being wound up ready to receive a second load of timbers. In the event any of the timbers are too heavy for the brake to control their descent, the pinion may be thrown in and the crank employed. The winch may be used in hoisting pieces of machinery. Interchangeable Arrangement for Steam and Electric Hoist. At the Gold Cliff mine of the Utica company at Angels Camp, Calif., the hoisting engine is simply arranged for the use of either electric or steam power. The hoist was originally built for steam power, but it is more economical now to use electricity as a motive power, so it has been rigged for direct connection FIG. 132. INTERCHANGEABLE ARRANGEMENT FOR STEAM OR ELECTRIC HOIST. to a motor. When electric power is to be used for driving the engine, the connecting rods to the steam cylinders are taken off and a specially constructed rim with ratchet gearing fastened to the crank, the rim engaging the pinioned drive pulley on the motor. The crank on the engine is a solid wheel. A wheel of larger diameter, the size desired to secure the proper hoisting speed, is turned down so as to fit flush against and partially over the crank, the projecting edge forming a rim or tire about the latter. Both the crank and the auxiliary wheel are drilled for tapered bolts by which they are fastened securely to each other. Fig. 132 illustrates the details of construction. The rim can be slipped over the crank and bolted to it in a few minutes; then, by disengaging the connecting rods on the engine, the hoist is ready for electric driving. A rawhide pinion is used to reduce noise and friction. This arrangement permits a satisfactory interchangeable driving of the hoist without making any serious alteration of the plant. A Cone Friction for Mine Hoists. Friction hoists are used at mines because they are usually the simplest and cheapest hoists that can be built. When two drums are mounted on one shaft for hoisting in balance, it is often desirable to work one drum while the other is at rest and one of the methods of transmitting motion from the engine to these drums is by means of a friction 200 HANDBOOK OF MINING DETAILS gear. The friction hoist finds its widest application in mining where heavy loads are raised while the engine is using steam and light loads are lowered at a speed controlled solely by the brake and friction gear, no steam being used in the engine. Most friction hoists are not built with reversing engines unless occasional heavy loads are to be lowered. Hoisting through winzes where rapid return of the empty bucket is a requirement is a typical use of the friction hoist. There are two types of friction gear more widely used than others for driving hoisting engines, the band and cone frictions. The band friction consists of two semi-circular bands of wrought iron that carry wooden shoes and which can be tightened to grasp the drum in a manner exactly similar to the operation of a band brake. The cone friction consists of a ring, in snape like the frustrum of a hollow cone, which is bolted to the part of the hoist actuated by the engine through gears. This cone engages a similar larger cone bolted to the drum. Where one such ring is used on the drum the gear is termed single cone friction; if there are two rings, one of which engages the outside and one the inside of the engine cone, the gear is called a double cone friction. The engine cone is therefore male and the drum cone female. Contact is made and broken by shifting the drum laterally upon its shaft. Such lateral movement of the drum varies from 1/32 to 1/8 in. and is effected through a hand lever operating shifting devices that vary in construction in hoists of different manufacture. In the earlier forms of friction gear two metal surfaces were employed but when any slip occurred the amount of heat developed was excessive. This form was succeeded by that in which one member was made of wood and the other of iron or steel. In the double cone hoists the male cone is made of wood and the female cones of iron as it is easier to replace the male cone when worn out; the wooden cone of course wears more rapidly than the metal. Some manufacturers make the wooden cones so that the friction surface is against the grain of the wood as such a surface wears longer; the surface parallel to the grain gives a better hold and as replacement of the cone is easy some manufacturers prefer to use this surface and change cones more frequently. Single cones can be adjusted as they wear but this is compensated in part by the greater amount of wear they are subjected to over double cones. The object of making the gears in the form of a truncated hollow cone is to get sufficient surface of contact and reduce the amount of end thrust. The best angle, for the face of these cones, as determined by experiments, is 30; that angle is best for quick release and brings the least pressure against the mechanism for shifting the drum on its shaft. An improvement in wooden cones is shown in Fig. 133. The two surfaces of the wooden male cone that engage the iron surfaces of the female cones are bored, staggered as shown. Into the holes cork cylinders, a little larger in diameter than the holes, are forced under pressure so that they bulge above the level of the wooden surface. The convex surfaces of the cork insets are HOISTING AND TRANSPORTATION 20 1 then planed flat but allowed to project about 1/32 in. above the wooden surface of the cone. A peculiar fact noted in the use of these insets is that while both wood and cork surfaces eventually wear the corks always protrude about the same amount until the cone is worn out due, no doubt, to the squeeze to which the cork is subjected by being forced under pressure into a comparatively small hole. In the cone with cork insets, the holding power on the drum is increased about 100%. This means that the hoisting engineer has only to exert about one-half the pressure on the lever to hoist the load. The cone withstands the effects of heat better than the plain wooden cone, in fact the cork will not burn so readily as the wood and as the drum does not slip as much as with wood, the cone is more durable. Oil and water do not cause slipping to anything like the extent that they do with a plain wooden surface. The cone also takes hold and lets go more quickly. FIG. 133. A HOIST FRICTION WITH CORK INSETS. The efficiency of a friction cone has nothing to do with the elasticity of the materials, but with the character of the surfaces in contact. The good results obtained by the use of cork insets seem to indicate that a yielding surface is an advantage, but in the light of more recently developed friction devices this is not proven to be the case in all instances. Deep Sinking with Gasoline Hoists. At the Boston & Ely property at Kimberley, Nev., prospecting has been done by sinking shafts far beyond what is generally thought to be the range of gasoline hoists. Of course/ it probably would have been more economical to use larger hoists driven by electricity, but the work shows what can be accomplished with gasoline engines by those who understand them. By means of a i5-h.p. Fairbanks- Morse gasoline hoist having a rope speed of 200 ft. per minute, the shaft, which was timbered with 4X4-in. sets, was sunk to a depth of 840 ft., using a bucket and crosshead that gave, with the weight of the rope, a dead load of one ton. This 840 ft. was the limit of the rope and so, when a new rope was ordered, a 40- 202 HANDBOOK OF MINING DETAILS h.p. gasoline hoist of the same make was installed, but with the old hoist a speed of 50 ft. per month was attained in sinking. With the 4o-h.p. hoist the shaft was sunk to a depth of 1126 ft., it having been enlarged from one and a half to two compartments below the noo-ft. level. In sinking to that depth a bucket and crosshead were used, but cleaning out broken rock became too slow; it took 41/2 minutes to hoist and return a bucket when the shaft was that deep. A cage and car were therefore substituted, and an air-driven hoist installed on the noo-ft. level. Then by means of a bucket, which dumped into a bin on that level, the shaft was sunk below that point without trouble, as sinking could go on independently of the surface hoist, at least up to the capacity of the bin. From the bin the rock was loaded into a car and hoisted to surface on the cage. This made a gross load of 3500 Ib. on the hoisting rope, which was a 5/8-in. Hercules steel rope, weighing 62 1/2 Ib. per foot. Steam Hoists for Shallow Mines (By Sven T. Nelson). Several years ago, in the iron-ore fields of northern Minnesota, a large number of mining companies were hoisting from comparatively shallow depths with primitive slide-valve engines of the poorest fuel economy. By shallow mines are meant those from 200 to 1200 ft. deep. The average load handled, exclusive of the rope and skips, is 5 tons, and ordinary service requires a speed of 700 to 1000 ft per minute. Some 30 years ago corliss engines or engines with an automatic cut-off were just being introduced for hoisting purposes. These new plants were chiefly in the Lake Superior copper district. They consisted largely of regular mill engines, purchased from the corliss engine builders; some were furnished with gear and pinions and some were not. The drums were built up of wood at the mine. With these exceptions, the hoists then in use were equipped with slide-valve engines of the commonest type. Crude as were the first corliss hoists, and numerous as were the objections and jibes cast at them on account of their "trappy" and "complicated" mechanism, the reduction in fuel consumption which they secured by means of the automatic cut-off was so great, that the slide-valve engine was soon crowded from the field. The iron companies of the northern Michigan field were also impressed with the fact that corliss hoists did their work on from one-third to half the fuel required for the slide-valve pattern. The first engines installed at any of the iron mines with a detachable valve gear for automatically closing the steam valves were not of the corliss type, but of the same type as an engine that is still built at Fitchburg, Mass., by the Brown Engine Co. A modified type of the Brown engine was adopted by one of the hoisting-engine manufacturers of that time, and several of them installed. These engines were found to be satis- factory and were economical on low steam pressures. However, they did not lend themselves so successfully as the corliss type to the constant increase in steam pressure, which took place with improvements in boiler manufacture. From this time the corliss engine became the standard for deep hoisting HOISTING AND TRANSPORTATION 203 practice throughout the Lake Superior region and the western mining fields as well. By deep mines are meant those ranging from 1000 to 5000 ft. in depth. With the knowledge and experience gained in designing hoists for deep mines at their command, the engineers attacked the problem of securing hoisting economy for shafts of more moderate depths. It is out of the question to use first-motion corliss hoists for this work, on account of the limitations in speed of corliss valve gear requiring engines unduly large for the service required. In shafts only a few hundred feet in depth after the load is accelerated, but a few revolutions of the engine will be made with the automatic cut-off in action, so that a direct-acting corliss hoist would be not only needlessly high in first cost, but more extravagant in fuel than a slide-valve engine of the simplest type. Corliss-geared hoists were tried for some of these shallow mines, but as in the case of first-motion plants, engines disproportionately large had to be furnished, to keep the number of revolutions as low as possible. Difficulty was also incurred in certain fields, in securing engineers who would and could take proper care of a corliss engine; so that mine managers continued to use the old- fashioned, plain slide-valve hoists, with their excessive cost for fuel. After much study, the type of hoist known as the automatic slide-valve hoist was worked out, and has now been in satisfactory use for several years. 32 Revolutions omitted, all practically the same. Start Bottom FIG. 134. CONTINUOUS DIAGRAM FROM AN AUTOMATIC CUTOFF HOISTING ENGINE. That this design fulfils the conditions will be seen readily from a study of the continuous indicator diagram, shown in Fig. 134, taken from the hoist of this pattern at the Webb mine of the Shenango Furnace Co., at Hibbing, Minn. The hoist consists of two slide-valve engines each 16X18 in. geared to a single drum 6 ft. in diameter by 6 ft. long. It takes steam at 145 Ib. boiler pressure and runs at 140 r.p.m., hoisting a load of 5 tons of ore in addition to the weight of the rope. Two skips are used in balance, so that their weight is offset. The diagram represents the entire trip from the start at the bottom to the dump. Each diagram indicates one revolution of the engine. The gear and pinion ratio is four to one, so that the engines make four revolutions to one of the drum. As there are 57 diagrams the depth of the shaft is 269 ft. and the load is hoisted in 14 revolutions of the drum. In starting from the bottom, it should be noticed that the first diagram takes 204 HANDBOOK OF MINING DETAILS steam three-fourths of the stroke, the second about five-eighths of the stroke, and the third about one-third of the stroke; at this point the acceleration is completed. From there on, up to the point referred to as "collar of the shaft," the engine is cutting off at about one-fifth. At this point there is a drop in pressure, as indicated by the diagram, and the length of admission of steam to the cylinder. When this point is reached, the engineer closes the throttle partially to slow up for the dump ; this puts the automatic cut-off out of action, in precisely the same manner as the dashpots cease to drop when a corliss engine is being retarded. From the point called " collar of the shaft" to the point referred to as the "dump and finish" the regular slide-valve action is secured, just as would be the case for the entire distance from top to bottom were it not for the automatic cut-off. The three individual diagrams, below the continuous diagrams, were set aside from the continuous diagram so that users of engines not familiar with continuous diagrams can tell from these the action of the valve gear and the steam distribution. The slightly jagged appearance of the lines is due to the high speed at which the engine was running and a small amount of water in the indicator pipes, which caused the indicator pencil to chatter. It should be noted that in hoisting engines, hand adjustment of the point of cut-off is out of the question. It would require an engineer's constant attention to give his engine steam for the entire stroke when starting the load, to set the valves at the proper point of cut-off when the load is under full motion, and to lengthen the cut-off again, at the end of the trip. This is obviously impossible, nor would it be possible for the engineer to set the cut-off at its most economical point each time, owing to variations in steam pressure and load. The engines of the Webb mine hoist and of others of this type, are of the plain, double, slide-valve pattern, and the valve gear places no limit on the speed at which they can be run. The mechanism controlling the automatic cut-off is so arranged that no extra thought or action is required of the engineer. When the throttle lever is pulled, the first 2 or 3 in. of its movement opens the main throttles, admitting steam during the entire stroke to start the load from the bottom, as shown by the first cards. As the lever is pulled back, it admits steam to an auxiliary valve mechanism and cylinder. The piston of this cylinder actuates a crank and shaft which in turn moves a vertical rack at the rear end of each cylinder. These racks engage pinions, one at the outer end of each cut-off valve stem. The admission of steam to the auxiliary cylinder therefore automatically places the main valves in the position of shortest cut-off, and this action is shown in the cards as above described. At the end of the trip, the reversal of the lever, to close the main throttles, admits steam to the opposite side of the piston in the auxiliary cylinder, and the cut-off is restored to its first position. The hoists are built with drums ranging from 6 to 8 ft. in diameter, and with engines from 14 X 14 in. to 16X24 in., adapted for steam at i5olb. pressure. HOISTING AND TRANSPORTATION 205 The hoisting speeds range from 700 to 1000 ft. per minute and the loads from '5 to 7 tons. MISCELLANEOUS DEVICES Sheave Supports for Underground Hoists. At the Red Jacket shaft, it is necessary to work the lower part of the Calumet & Hecla company's ground by means of a blind shaft or winze that starts from the 57oo-ft. level of the Calumet No. 2 shaft. There an electric hoist is installed which is controlled Concrete FIG. 135. SHEAVE SUPPORT IN SHIFTING GROUND. by the Ward Leonard system of wiring. The ground around the station has a tendency to move and so it is necessary to mount the sheaves so that the settling of the ground will not cause trouble. This is done as shown in Fig. 135. Two I-beams are put together as posts and anchored in hitches so that they will stand the strain coming upon them. To these posts are bolted maple blocks, long enough to extend beyond the steel posts and take the side thrust of the sheave. The sheave shaft with the sheave wheel loosely mounted on it is then bolted tightly in its seat in the maple blocks; maple blocks are also used as cap pieces. In this way of supporting a sheave there is only one babbitted bearing to maintain, while the main feature is that, in case either post should move relatively to the other, the wooden blocks will adjust themselves to the change and any serious trouble be promptly remedied. In case the movement is 2O6 HANDBOOK OF MINING DETAILS great, new blocks can be put in cheaply and the shaft lined up again. If two babbitted bearings are used in this ground that has a tendency to settle and move, endless trouble arises. Arrangement of Sheaves at the Tobin Mine. In Fig. 136 is shown the arrangement of sheave wheels that had to be adopted at the Tobin mine, Crystal Falls, Mich., in order to use the hoisting engine without turning it around. The old shaft was in ground that will eventually be mined and the new shaft was sunk 1000 ft. deep in the foot wall and back of the engine room. The drums are 8 ft. in diameter, 8 ft. long and operated by a Nordberg engine. B Old Shaft New Shaft' FIG. 136. ARRANGEMENT OF HOISTING PLANT AT THE TOBIN MINE. The sheave wheels which are anchored in front of the engine room are 8 ft. in diameter and held in place by i2-in. framed timbers weighted down with rock. While these additional wheels add to the friction losses, no trouble has been experienced with this plan. Three-ton skips are hoisted from the bottom of the shaft in 30 sec. The wheels at A are incline.d, to conform with the slope of the rope to the top of the shaft house. Rope Guard for Idler. Trouble is often experienced in keeping hoisting ropes on their idler wheels, especially where the angle to the sheave wheel is very great. This can be overcome by means of the simple device shown in Fig. 137 which is in use in many mining districts. The wheel B slides hori- zontally on its shaft to allow for the wind on the hoisting drum. Unless there is ample pressure exerted on the idler wheel by the hoisting rope, it will jump off; and especially is this so when there is any slack in the rope. Ropes are supposed to keep in place by the weight of the rope on the wheel, the idler wheels being placed in a straight line with the sheave wheel and the drum or, if anything, slightly above that line. In using this device it should be placed in a straight line with the drum and the sheave wheel. The slotted wheels, C and D, are held in place by two straps of iron, one placed on each side of the idler wheel B, as in sketch. The bearing edge of the upper wheels should be about 3/8 in. above the hoisting rope. Rope Idlers for Inclined Shafts. In the conglomerate shafts of the Calumet & Hecla company where, owing to the necessity of not cutting into HOISTING AND TRANSPORTATION 207 the foot nor the hanging wall, , the shaft must follow the lode in all its changes of dip, the rope idlers or rollers are subjected to severe wear, and some of them have to be replaced once per shift, while the average life of an idler in the whole shaft is not over a week. It is important, therefore, to make the idlers in a cheap and simple way. They are maple logs turned down to a diameter of 1 6 in. and a face of 24 in., in which three grooves are turned along which the cable may run as the idler is shifted in the shaft. Through the center FIG. 137. IDLER WHEELS FOR HOISTING ROPES. of the idler a i i/2-in. hole is bored for the axle. Formerly an iron pipe was inserted in the idlers for a thimble and the idler revolved on a fixed axle. This arrangement is the cheaper and is good enough for shallow shafts where the hoisting speed is not great, but there is too much friction to use such idlers with high rope-speeds as it is impossible to grease them properly. The idlers now generally used have a fixed axle that rests in two bearings on the idler frame which is wedged in place in the shaft between the cedar ties of the I gide Elevation Section FIG. 138. IDLER FOR SKIP ROPE IN SHAFTS. skip tracks. These frames are set in the shaft so that the rope passes through the right-hand groove of one idler, the center groove of the next and the left- hand groove of the next. By changing the idlers from one frame to another they may be completely worn out. This type of idler is used in the amygdaloid mines of the district, except at the shafts of the Osceola Consolidated, where a built-up idler is used. This idler, as the amygdaloid shafts are sunk at a regular dip, does not have to be 208 HANDBOOK OF MINING DETAILS made so wide to insure the rope staying on the idler, while as the wear is not so great as in the conglomerate shafts, the idler part is built up of segments so that the wear will come end-on instead of sidewise with the fiber of the wood. These built-up idlers are 18 in. diameter and 10 in. wide. There are three layers of octant segments held together by flanges and bolts through the apex of each, as shown in Fig. 138. The outer segments are sawed from 4 X6-in. maple or beech planks, being cut so that the grain runs approximately length- 6- 5 /8-in. Bolts Pipe Tap FIG. 139. IDLER FOR HOISTING ROPES USED AT CHAMPION MINE. wise, while the inside segment, the one that takes the wear, is sawed from a 2X6-in. plank of the same material. It is, therefore, possible to replace the segments without throwing away the whole idler when only a few of the seg- ments in a layer are worn. The outer segments are made with a shoulder 1/2 in. deep turned in them to receive the flanges so that the bolts that run HOISTING AND TRANSPORTATION 209 through the idler will not extend beyond the sides to wear and cut the rope in case it should slip off the idler. These idlers have been in use several years. They last much longer than do the other types, and as they are lighter, they get up to speed when the rope comes on them quicker than do the others. In the conglomerate mines they cannot be used, because the wear is so great that it does not pay to try to increase the life of the idlers by complicating the design. Idler for Hoisting Rope in Inclines. In the shafts of the Copper Range company in Michigan which have a dip of about 70, the hoisting ropes are carried on wood-lined idler sheaves at intervals of about 33 ft. The idler, as shown in Fig. 139, is made of two malleable-iron castings bolted together to grip the wood lining pieces in the jaws of the wheel. On the jaws are cast two beadings for cutting into the wood and holding it tightly. The wood FIG. 140. DEVICE TO PREVENT OVERWINDING. filling pieces, which are sawed so that they take the wear on the ends of the fibers on the wood, are in two pieces arranged so as to stagger the joints between the segments of each half of the lining. These segments are cut so as to have a 'chord of about 6 in. across their outer face. The wood pieces should be sufficiently thick so that when the nuts are brought tightly home on the bolts the two pieces of the frame will not quite touch. Then the bolts can be tight- ened so that the pieces of wood will be held securely even if they shrink. Owing to the fact that the hoisting cable does not have much side play in these shafts, a face of 4 1/2 in. on the idlers is sufficiently wide. The rim of the casting is 14 2io HANDBOOK OF MINING DETAILS much wider than the spokes so the bolts that hold the frame pieces together are well within the protection of the rim and, in case the rope should slip off the idler, it would not come in contact with the nuts on the clamping bolts. The bearings for the idlers rest on I-beams carried on concrete pedestals from the bottom of the shaft, and the whole frame is in turn protected from injury by the skip by means of wooden buffer pieces running along over the main I-beams and in turn carried on I-beam crosspieces. Device for Prevention of Overwinding. The device shown in Fig. 140 is installed at a German shaft to prevent overwinding. At a point about 30 cm. above the highest normal position of the cage is pivoted an axle, carrying at its center a lever A, which projects out into both hoisting compartments, and at its end the pulley B, to which a length of chain is attached at two points, as shown. The middle point of this chain is connected to a wire rope which, after passing over the pulley D, hangs down a suitable distance and is kept taut by the weight E. A short piece of rope F connects the first rope with an end of the latch G, which engages the top of the lever H. The rope / attached to H, leads to the throttle valve of the engine, and also to the valve of a steam- actuated brake. A slight upward pressure against either end of the lever A thus lifts the latch G, allowing the weight J to act through the rope 7 on the engine. The same effect could be produced electrically, though possibly not with equal certainty, by establishing contact through the guide shoes of the cage, and providing a magnetic release for the latch G. Device for Cleaning Flat Wire Cables (By M. J. McGill). An arrange- ment that I have used successfully for cleaning hardened grease, dirt and rust from flat wire cables is illustrated in Fig. 141. The contrivance consists of a box made in four parts to be hooked and stapled together, in which is fastened a U-shaped steam fitting through which the cable is passed. The bottom of the box is first placed on a platform above the collar of the shaft, the cage or skip being lowered just far enough so as to clear all the cable fastenings. A fitting B, made as shown in the drawing, with two i-in. pipe legs with i/i6-in. slots and capped ends, is placed with one leg on each side of the cable, the slots being turned a trifle downward. The top parts of the box are then placed and hooked to the bottom parts. An opening just large enough to admit the fitting, so as to make it as near grease tight as possible, is made -in the side of the box. A steam line is coupled to the fitting B, and the steam turned on, while the cage is slowly dropped. As the cage drops, the cable passes through the steam fitting, and being subjected to the scrubbing action of live steam is readily cleaned. The time required to clean thoroughly depends on the condition of the cable. A few minutes after applying the steam, grease and dirt will begin rolling over the blocks C C, which are placed across the inside of the box to strengthen it and to divert grease toward the nipples at the end of the box, from which it falls into buckets placed to receive it. In three hours' time I have thoroughly cleaned 1500 ft. of the worst-looking HOISTING AND TRANSPORTATION 211 cable that one can imagine. Some cables of equal length that were not in such bad condition only required 1/2 hour. This apparatus has proved superior to any I have seen or read of for thoroughly cleaning flat wire cables. I always lubricate the cable immediately after cleaning. Mine Signal Switch. A mine signal switch designed by A. H. MacGregor, Palatka, Mich., is shown in Fig. 142. The principal feature in this switch is that it is strong and not likely to get out of order as does a more delicate one under the rough usage of the miner. The parts are mounted upon a hardwood board, 1X8X16 in., and inclosed within a box as shown by the dotted line. The switch lever is of 3/16X1 i/4-in. steel upon which a copper contact is .soldered. The lever is pivoted at B and is held in position by a bar A , which prevents any side movement. The copper bar C is in contact with the lever at i'w.i. Pipe 2 W.I. Pipe FIG. 141. CLEANING DEVICE FOR FLAT- WIRE CABLES. all times. The circuit is completed with the contact C '. A No. 10 tension spring breaks the circuit as soon as the operator releases the handle D. The switch is placed about elbow high so that it requires some effort to operate it. In this way the contacts are positive and distinct, and there is no fluttering as is the case when a switch is in such a position that it can be operated rapidly. The board and handle D are covered with an insulating paint. The device has been in use over a year and is now installed at several of the Pickands-Mather mines. Another type of spring switch used in connection with an electric signal system is shown in Fig. 143. It is built in a metal box 6X ioX 5 in. deep with a hinged door on one side. When giving signals the operator catches hold of the 212 HANDBOOK OF MINING DETAILS wooden handle that hangs below the box, pulls down, and the spring in the box breaks the circuit as soon as the operator releases his hold. Th? signal system, which is used in connection with this switch, flashes a light in addition to ringing the gong. Electric Signals for Underground Tramways (By W. S. Grether). Fluorspar associated with galena occurs in a vein near Rosiclare, on the Ohio PIG. 142. SIGNAL SWITCH AT BALTIC MINE, MICH. .Ineulatlod. 6 in. ard Rubber Mnsulation Wood Handle FIG. 143. SPRING SWITCH FOR ELECTRIC MINE SIGNAL. River, in southern Illinois. The vein has been prospected for a length of 2 or 3 miles and to a depth of 500 ft. ; it is from 3 to 20 ft. wide. In mining the ore is cleanly broken from the foot and hanging walls and not more than 10% of the ground broken is waste. The drifts are tortuous and not of uniform width which makes electric haulage impracticable on the 235-ft. or main working level. The ore is mined by overhand stoping and the i-ton tram cars are loaded HOISTING AND TRANSPORTATION 213 from wooden bins situated 20 ft. apart along the single track in the drift. The cars are moved by men to the three-compartment shaft sunk midway between the ends of the vein; mules are used to pull the empties, 10 cars per trip, back to the loading bins The excessive grade of the drift, i 1/2%, prohibits hauling the loaded cars with mules. Ore is trammed from either end of the mine, one end being called the south, the other the north workings. The caging at the shaft is often delayed on account of wrecks, lowering timbers, etc. The trammers in the ends of the workings perhaps 2000 ft. away are not aware of these conditions and formerly continued to bring cars to the shaft, making matters worse on account of the limited switching facilities near the old station. To overcome this difficulty a simple electric signal system was installed. . Where magnified -* /^\ (0,\^ under strong Light. v~7-^^ Green Light BELL SIGNALS Flash . , ~^- ~ _T_ 1 _~ ~_ _^=S5>. .Electric Bell actuated ~ by Fulling a Handle in Mine. i FIG. 144. A GERMAN SIGNALING DEVICE. A switch and two no-volt, i6-c.p. lamps, one green and one white, are placed on the south side of the shaft, and similar equipment is installed in the south workings near the loading bins. Similarly, switches and red and white lights are placed on the north side of the shaft and in the north workings. All switches are left open except when signals are being sent. When the eager wants cars at the shaft he closes the switch three times. The trammer, when ready to move cars to the shaft, answers with three signals. Likewise when the trammer wishes to push cars to shaft, he signals three flashes to the eager; if the eager is ready he flashes three in return. In this way blockades at the shaft are avoided and the trammer may utilize his time while waiting for signals in oiling cars or cleaning the track. An Electric Signal Device (By P. B. McDonald). Two German signal devices for hoisting, the general scheme of operation of which is shown in Fig. 144, have been installed in the Negaunee mine hoist house. When a man in 214 HANDBOOK OF MINING DETAILS the mine pulls the signal handle, two things happen in the engine room. The electric bell rings and a strip of paper resembling a stock exchange ticker tape is punched with a hole. By means of a strong magnifying device and mirrors, a magnified reflection of the small hole punched in the strip of paper appears in a horizontal aperture. Thus if the hoist engineer is not sure of the number of bells which were rung, a glance at the black circles tells him, also the strip of paper serves as a permanent record in case a dispute arises as to the signals that were given. In addition to these electric signal devices the old style mechanical bell will probably be ins-tailed, for use when the electrical apparatus is out of order. The green light flashes only when the paper strip of the punch- mark mechanism is exhausted. Hand Bell Signal Wiring (By Guy C. Stoltz). The disadvantages of hand signaling are: The difficulties presented in counterbalancing the long line 6x6 Purlin ,"x2Vi' Spring Steel Arrangement at Hoist House Guide for Skip Wire down - Shaft Guides for Bell Wire through Shaft Arrangement at Shaft House FIG. 145. ARRANGEMENT OF SIGNAL-BELL WIRING AT PORT HENRY, N. Y. of bell wire necessary to reach the lowest levels in the shaft; in guiding the wire through the shaft over the several angles to the stations and to the hoist house with the least friction; and in keeping the system taut to eliminate all possible lost motion. The system installed must be positive and hand ringing should accompany every electric bell or light- signaling installation. In Fig. 145 a HOISTING AND TRANSPORTATION 215 satisfactory method of rigging is shown. The strap of spring steel introduced before the gong does away with any lost motion to the gong and keeps the wire taut to the counterbalanced triangle at the headframe. Here the wire is kept on a winch and the necessary length is guided over a small pulley to prevent kinks, and down the shaft by cranking the winch. A grip is clamped to the wire after the required length has been unreeled, and this, bearing against the triangle, makes the wire fast. In this way the wire is kept one length with no splicing and as longer wire is required on sinking, the winch has a supply. Hand-holds for signaling are clamped to the wire at each station. The wire is guided through the shaft by passing between sets of 2 i/2-in. pulleys placed in an iron frame. This frame is secured to the shaft timbers. The counter- weight is attached to the triangle in the headframe and is varied in amount as required. AERIAL TRAMWAYS The Solution of a Cableway Hoist Problem. At Mine 21, Mineville, N. Y., the greater part of the ore in the open pit was hoisted and carried to the gondola cars on the surface by means of a Lidgerwood traveling suspension cableway. The towers on opposite sides of the pit were 400 ft. apart, the greatest hoisting depth 300 ft. vertically, and the carriage was usually carried out about 200 ft. where the bucket was dumped by hand. Some time after installation and as hoisting depth increased the scoop on being raised began to rotate in mid air, twisting the fall block cables and throwing out most of the ore. The problem as to how to guide the scoop in its upward journey required some little attention. Many schemes were suggested and many were tried. A leading rope manufacturer recommended trying his non-twist rope. This was given a trial but did not help matters in the least. The master mechanic finally devised the following scheme. An i8-in. arm was attached to the fall block frame and from this a 5/i6-in. wire rope was run over two i2-in. sheaves (spaced 10 ft. apart center to center and hung by a frame to the traveling cable) and then to an overhanging light counterweight. The rope and counterweight proved to be a satisfactory guide. In fact the rope alone was sufficient to steady the scoop during the ascent, the only part played by the counterweight being to keep the small rope taut so it would travel well over the auxiliary sheaves. Besides preventing the twisting of the block this arrange- ment also serves, to some extent, to prevent the load from swinging. Turning Device for Tramway Track Cables. The companies that erect tramways instruct that the track cable be frequently turned so as to equalize the wear, but this has proved to be a direction easier to give than execute. For instance, at the United States tramway at Bingham, the tramway men tried, without success, for over a year to turn the cable. The directions usually given by manufacturers are for twisting the cable by means of stilson wrenches. Sections of the cable can easily be turned, but 216 HANDBOOK OF MINING DETAILS the difficulty is to make the cable stay in the new position, for if not held it gradually works back to the old position. To obviate this difficulty, Joseph Ruttle, foreman of the Highland Boy tramway, Bingham, Utah, has devised a method of turning and holding the cable that is certain in its operation. The device for accomplishing this, known as the Ruttle turning strap, has been in use some time, and it is probably as much due to its use as to any other one cause that the old Highland Boy tramway was noted for the long life of its track cables. The turning strap consists of an iron strap 2 1/2 in. wide, made of No. 12 band steel that is clamped to the track cable by means of two T-head bolts, which have their flat heads turned toward the passing buckets. This band steel is continued to form an arm 12 in. long, and then a 3/4-in. round rod is bolted to the end of this arm between two nuts working on a right- and left- handed threads. In order to prevent the outer bolt from working off and allowing the arm of the clamping strap to swing around and catch on the bucket, a cotter pin is inserted in a hole drilled through the end of the rod. This rod is made long enough to pass through a detaining brace, or loop, which is made by bending double a 3/4-in. round rod. The iron loop is just wide enough for the arm of the turning clamp to move freely back and forth, with the stretch of the cable, and is made 3 ft. long, so as to provide for that much stretch. The detaining brace, or loop, is fastened by means of two 3/8X4-in. lag screws to the timbers of the tower, the rod being flattened to 3/8 in. where it comes in contact with the tower timbers. The turning straps are put on the track cable at each tower. Whenever it is observed that the track cable is wearing, or about once in two weeks, the cable is turned one-eighth way around by means of stilson wrenches, the clamping bolts on the turning clamps having been previously loosened. Then the clamps are again tightened on the cable. Needless to say, the twisting must be done in the direction of the twist of the cable, or else the strands will be unlaid. Cable Clamp for Tramway (By Claude T. Rice). Tramway cables have to be frequently stretched, especially in the early period of the operation of a tramway. This is a troublesome task, owing to the design of the cable clamps in common use. The clamp furnished by the tramway companies is made of two iron plates, with a shallow central groove to increase the contact and consequently the friction of a cable when the clamp is tightened. At the end, the two plates are given an outward bend, so as to keep apart the ropes that are fastened to the plates of the clamp. Two different strands of the block and tackle system are attached to the twisted lengths in the ends of the two clamping plates. Thus there is little if any clamping effect obtained from the pull of the ropes, the entire pressure of the cable being obtained from the tightening of the six bolts that hold the plates together. On the traction cable this design of clamp holds fairly well, but with the HOISTING AND TRANSPORTATION 217 r^f *i rr^'T Wi 2i8 HANDBOOK OF MINING DETAILS heavier track cables it does not give satisfaction. Joseph Ruttle, foreman of the Highland Boy tramway at Bingham, Utah, has devised the clamp that is now in general use at Bingham. This clamp is simple in design, effective in its operation, easy to put on the cable, even by one man, and can be cheaply made in any machine shop. This clamp is caused to grip by the pull of the tightening tackles and so is correct in principle. The tramway man has only to give the grip pieces a slight blow to cause an initial grip on the cable. In case the clamp should be put on at a point where the cable is larger than elsewhere, and there should be any slipping, the clamp adapts itself to the diminishing diameter of the cable and grasps the cable more securely than ever. This device is unpatented and has been in use on the Bingham tramway for at least a year. The Ruttle clamp consists of a base plate A, referring to Fig. 146, with raised sides, to which are bolted two cover plates B that partly cover the top of the base plate. The sides of the base plate taper toward the rear end, so, as the clamping pieces C move along the channels formed by the base plates, they are forced nearer together and grip the cable more securely. The base plate has a curved neck, to which the blocks are attached by a ring. The clamping pieces have the face toward the cable turned to the diameter of the cable on which the clamp is to be used, but by having other sets of grips the clamp can be quickly changed so as to be used on larger or smaller cables. The faces of the grips are segments of a cylinder, so they adapt themselves to the cable when it is considerably worn. In order to hold the grip pieces in the channels in which they travel, a hemispherical pocket is bored in the grip piece to receive a 3/8-in. steel ball, while in the base plate a cylindrical groove is cut under each cover plate, in which the steel ball may travel. This groove is made long so the grip pieces may spread far enough apart at the head end to facilitate placing the clamp on the cable. When the grip piece is in its farthest position at the other end of the groove, its two faces are considerably nearer together than the diameter of the rope. The angle given to the back raised edge of the base plate deter- mines the length of the groove, while the angle of the back edge and length of the base plate itself are determined by the length of gripping surface that is necessary to give a secure hold on the cable. Oiling Tramway Track Cables. The machine used to oil the track cables on the Balaklala aerial tramway, at Coram, Calif., consists of a carrier frame arranged to carry an oil tank having a capacity of 10 gallons. This carrier frame is fastened to a set of trolley wheels turned upside down, so as to secure a space between the wheels for the oil jet directly over the track cable. There are two gear wheels, one of which is mounted on the extended axle of one of the trolley wheels and the other secured to the trolley frame and carrying a wheel for the belt running the rotary oil pump which is mounted on the tank. By these gear wheels the speed of the oil pump is regulated. HOISTING AND TRANSPORTATION 219 By means of a cock in the pipe leading to the oiler the supply of oil to the cable is controlled. After a rain the supply is so regulated that enough oil is fed to run down and cover all the cable, while at other times the supply is only enough to cover the upper side. When the valve has been properly regulated to give the right amount of oil, the carrier is gripped to the traction rope and the automatic oiler is sent out over the line. This oiler works satisfactorily at the Balaklala mine where it was designed. Oiler for Tramway Buckets. It is necessary to oil the wheels on the carriers on tramways, especially new ones, frequently. Moreover, the amount of oiling necessary seems to bear some relation to the roughness of the topog- raphy of the country across which the tramway is built. In the early stages of the life of a tramway two miles long, it is necessary to oil the buckets every trip, and later at least twice a day, while with tramways four miles long the bucket carriers have to be oiled at least every other trip. This oiling can be done at either end of the tramway, but generally it is far more convenient to do the oiling at the loading station, while the bucket is being loaded. The usual arrangement is to have a tank of oil placed at some convenient point above the loading-track station so that enough fall is given to the oil to insure a quick feeding of it to the carrier wheels. The oil is led through a small rubber tube to the metallic tip used for insertion into the oil holes on Top End E B A - V v1Te f FIG. 147. NONLEAKING OILER FOR TRAMWAY BUCKETS. the wheels of the carrier carriage. To shut off the feed of oil, a spring clamp or pinch cock is generally used on the feed tube. Besides being inconvenient this is wasteful, for most of the oil in the tube below the point of clamping drops out while the tip is being transferred from one oil hole to another. This waste of oil is not only a source of needless expense, but it increases the danger from fire, and in time makes the loading station a greasy, sloppy, disagreeable place. To obviate these objections, W. H. Cole, master mechanic at the Highland Boy mine, Bingham, Utah, devised the oiler shown in Fig. 147. The Cole oiler is attached to a feeding hose just as the tip is in the crude device commonly used. But in this oiler the oil cannot be turned on until the oiler has been inserted to the bottom of the oiling hole, and the feed is shut off the instant that the pressure is taken off the oiler. As a result there is no wasting of oil and the accompanying disagreeable features are eliminated. In addition, the oiling can be done quickly and easily. The oiler is turned out of two pieces of brass A and A', to form the shell, 22O HANDBOOK OF MINING DETAILS while the interior mechanism consists of a spring valve B, working upon a valve seat C. Leak about the valve is prevented by three oil rings D, in which no packing is used, as whatever oil may ooze down the valve rod forms its own natural packing at these grooves. The barrel is i in. in diameter, 4 in. long and the surface is milled to render it easy to grip. The surface of the piece A' that fits into the rubber hose is corrugated to aid in attaching the oiler securely to the feed hose. The valve has a play of 3/8 in., and the stem is fluted, the upper end of the stem being sharpened so as to assist the feed of the oil into the oil chamber E, when the valve is opened. The discharge hole in the valve tip F is bored to 5/32 in., connection with the oil chamber being through the hole G, bored at right angles to the discharge hole. When the tip of the oiler is pressed against any resisting surface, as the bottom of the oil hole on the carrier wheels, the valve is forced back against FIG. 148. WIRE-ROPE ANCHORAGE. the shoulder, and oil flows from the oil chamber in the oiler through the tip. When the pressure is removed, the spring forces the valve back on its seat and the transverse openings in the body of the valve are closed. This oiler can easily be made at a machine shop at small expense. It has been in use at the High- land Boy mine since the starting of the tramway which conveys the ore to the Tooele smeltery of the International company, and has been found to work admirably. Anchoring Wire Ropes (By A. Livingstone Oke). The diagrams shown in Fig. 148 may be found useful to illustrate the methods that may be adopted for anchoring wire ropes. In Fig. i is shown in section and plan how to secure the end of the rope in soft soil, such as a gravel bank. A trench is dug in the form of a T, its size depending on the load to be put on the rope. With HOISTING AND TRANSPORTATION 221 this arrangement, which is one of the more generally employed methods, the angle of lead of the rope must not exceed that shown by the dotted line at A. If a steeper lead becomes necessary the modification shown in Fig. 2 may be used, in which case the trench is undercut as shown, and the planks inserted normally to line of lead. In Fig. 3 is shown a method of anchorage to a post and is to be recommended where some means of tightening the rope has to be allowed for. Fig. 4 shows a method which admits any desired angle of lead to the rope; it consists of a pit with its lower sides undercut to admit inserting the cross timber. Fig. 5 is an adaptation of the method shown in Fig. 3, where the lead is horizontal. Fig. 6 shows a method particularly adapted for more permanent work in mines. Fig. 7 is the better method, the end of the bar being split for a wedge and the whole calked with lead; for vertical upward pull cement may be used. IX SKIPS, CAGES, CARS AND BUCKETS Mine Buckets Ore Cars and Skips Mine Cages Special Carriers Unloaders. MINE BUCKETS Drill-steel Bucket. A bucket for handling drill steel in stopes can be easily and cheaply made as follows: The essential parts, as shown in Fig. FIG. 149. BUCKET FOR DRILL STEEL. 149, are the bucket, handle and a ring d. The bucket is made of 3/i6-in. sheet steel, 30 in. deep and 10 or 12 in. in diameter. The bottom is made of heavier steel, and reinforced by straps a riveted over the bottom plate. The ring d is of the same diameter as the bucket and is made of i/2X2-in. 222 SKIPS, CAGES, CARS AND BUCKETS 223 iron or steel. It is fastened by two rivets on each side to pieces c, 4 in. long, 1/2X2 in., which form one link in the handle and hold the ring in a horizontal position. The straps b are also 1/2X2 in., and are 20 in. long. This, how- ever, should be regulated by the length of steel to be hoisted. The ring is fastened to the long straps by a link, and three or four links above the ring will be sufficient to fasten to the hoisting rope. The bucket may be made light or heavy, according to the work to be done. A bucket of this description is being used by the Vermont Copper Company. Tram Car for the Prospector (By Guy C. Stoltz). In the Gowganda district, Ont., where a real tram car is a luxury to the prospector, he has fBail FIG. 150. BUCKET AND TRAM PLATFORM. evolved the substitute shown in Fig. 150. The half barrel, strengthened by iron strips, is fitted with bails and used as a bucket. It is hoisted by windlass from the prospect shaft, and at the surface is swung out on a movable platform and detached from the winding rope. The platform, 3 ft. square, is made of 2-in. plank, fitted with notched runners, and rests on the inverted V guide rails, which are spiked to a floor, covering the trestle bents. The windlass men draw the bucket of waste rock to the dump at the end of the trestle by a rope attached to the ring shown on the platform. In summer axle grease and in a freezing temperature water is applied to the runners and guide rails. 224 HANDBOOK OF MINING DETAILS The Mineville Ore Bucket. Buckets used in Mineville, N. Y., for hoisting from an open pit or a large winze present certain advantages over the usual cylindrical type in the manner of loading and dumping. They are of the stone-boat type. The bucket can be drawn to the foot of the stope of ore, where the low sides and large rilling area facilitate the loading by hand shovels. Preparatory to hoisting, the chain which is attached by U-bolt A (Fig. 151) to the bail is made fast to the lip of the bucket by passing the hook on the free end of the chain through a 3-in. ring B welded in the eye of a strap of flat iron which is riveted to the bottom of the bucket. The hook is bent at such an angle that after passing through the eye it can be forced back FIG. 151. IRON-ORE BUCKET USED BY PORT HENRY IRON ORE CO. against the chain and locked in this position by a slip-ring C. The bucket after being locked is hoisted vertically to the top of the pit and then carried out horizontally on the traveling cable to the loading tracks, or in the case of a winze near the top of the headframe the bail is hooked by an auxiliary rope and as the bucket is lowered it is carried out to the dumping chute. By knocking the slip-ring with a shovel, the hook is released and the bucket dis- charges its contents. The bucket is 24 in. deep, 4 ft. 6 1/2 in. long and weighs noo Ib. The body is made of i/2-in. steel plate, with the corners reinforced by 3X3Xi/2-in. angle iron. SKIPS, CAGES, CARS AND BUCKETS 225 Joplin Bucket Cars. With a few exceptions, the hoisting in the lead and zinc mines of southwestern Missouri is done in buckets "cans" and "tubs," as they are called in the district. This permits the use of narrow-gage track, so that sharp curves can be laid around the pillars and through the " drifts," as the openings between the pillars are called. Because, as a rule, the tubs hold only about 800 lb., 1250 Ib. being the maximum capacity, a light track can be used that is cheap to install and quickly and readily changed. In fact, in many of the mines the track, made of 8-lb. rails, is lifted up bodily, ties and all; the ties are usually 2-in. planks. This system is flexible, and admirably adapted to the conditions prevailing in the district. The hoisting system is excellent, and because of the simplicity of the hooking and tramming routine that has been evolved, these tubs can be hoisted at an average rate of one in 35 seconds without great exertion on the part of the men. Indeed, more than 1000 tubs have been hoisted in one shift of 7 1/2 hours by a single engine, and with the hoistman Side View of Tub Truck Bottom View of Tub Truck FIG. 152. BUCKET CARS USED IN THE JOPLIN DISTRICT. dumping the tubs himself. At some of the mines, cars have been used under- ground, but it is questionable whether they are more economical. The only advantage of the car over the tub is that it is more difficult for the shovelers to build "windies" in them. In the vernacular of the district, tubs loaded with boulders in such a way as to leave the maximum free space between them, are called "windies." Many excellent features are embodied in the construction of the tub cars. For instance, the wheels are mounted loosely upon the axles, and the axles are loosely attached to the truck by sleeve bearings, so as to admit of lateral as well as up and down movement of the wheels in respect to the truck. This is an important feature, because of the lightness and temporary nature of much of 15 226 HANDBOOK OF MINING DETAILS the track that is used in these mines. By the use of the sleeve attachment, the four wheels of the car stay on the rails, no matter how rough the track is. It is impossible for the truck to run on three wheels at rough places in the track which, with trucks of the ordinary type of axle, is a common cause of derail- ment. The looseness of the attachment and the open bearing make the use of oil impossible, so cocoa butter is used to lubricate the axle and the sleeve bearings. There are two types of bearings used on these tub cars, and likewise there are two types of axles. Some of the cheaper trucks are equipped with round axles and sleeves of the first type shown in Fig. 152, but the round axles, which are from i 1/4 to i 1/2 in. in diameter, turned down slightly at the ends, frequently break just at the points where the holes are drilled to receive the pins that limit the side motion of the axle in the sleeves. At one mine, instead of using two pins, a piece of old pipe is put over the round axle to form the shoulders that limit the side play, and this pipe is fastened to the axle by a rivet through the axle halfway between the sleeves where the bending strain is least. But probably 90% of the axles in the district are of square section, turned down for 3 in. at each end to receive the wheels. These axles seldom break. The truck proper consists of two 2X6-in. pieces of oak fastened together by two crossed iron straps on the under side at the bearings, while the deck of the truck consists of two 2-in. planks, 10 to 12 in. wide, nailed to the two 2X6-in. pieces. The gage ranges from 14 to 16 in., but the latter is coming to be regarded as the standard. ORE CARS AND SKIPS Wooden Ore Car. A simple type of ore car used by the Sulphur Mining & R. R. Co. at its mine near Mineral, Va., is illustrated in Fig. 153. The FIG. 153. SULPHUR, MINING AND RAILROAD CO.'S ORE CAR. side, end and bottom boards of the cars are of i i/2-in. white oak, braced with 3/4X3-in. wrought-iron bars. The cars are designed for a capacity of 41 cu. ft. SKIPS, CAGES, CARS AND BUCKETS 227 As the cars are dumped by a revolving tipple no arrangement is provided for unloading. The car is strong, easily constructed and is to be commended for use at the mine where lumber and labor 'are cheap. The wheel base is 24 in., length of car, inside, 60 in. and outside dimension 64 1/2 in. The i/4-in. plates are on timbers that extend 4 in. beyond the end of the car and serve as a bumper. A Joplin Car for Boulders (By Claude T. Rice). In the mines of the zinc and lead district of southwestern Missouri the ore is hoisted in buckets, then dumped on grizzlies spaced 4 1/2 to 6 in. apart, and the barren portion of the oversize is sorted out and taken to the dump. The headframes are of the derrick type in which the hoist is placed at a height of 50 ft. or more from the ground. Therefore, it is'not desirable to use a large car for tramming boulders as it would require a heavy trestle from the derrick to the boulder pile. More- Detail of Straps H Detail of Latch E FIG. 154. CAR FOR TRAMMING BOULDERS, AS MADE AT JOPLIN. over, because the life of most of the mines is short, a cheap construction is desirable. As will be seen in Fig. 154, the car is an end dump one having a turntable deck carried on a wooden truck. The wooden box of the car, which is open at the front end, is hinged to the turntable. The edges of the side boards are bound with strap iron and are reinforced by the bands H, passing under the body of the car and up the sides. The box is prevented from dumping by a simple hook on one side of the box. The loaded car holds about 1000 Ib. of boulders. Tram Car for Stope Filling. The accompanying drawing, Fig. 155, shows the details of construction of cars used in the stopes at the Copper Range mines at Painesdale, Mich., where a waste-filling system of mining is used. These cars hold a ton of waste and have the long, low bodies charac- teristic of copper-country mine cars. The long body is of advantage in 228 HANDBOOK OF MINING DETAILS spreading the filling, as it allows the filling to be dumped somewhat farther to one side than could be done with a car with a short body. The height that the shoveler has to lift the ore is also reduced. The body of the car is fastened to the truck by a hinge carried on a turntable on the truck frame. The wooden truck is now being made of fir. Some of these cars are equipped with Peleter bearings as are cars on the main levels, while others have ordinary bearings. The bolt passing through the hinge can be taken out easily when the car is to be raised into or lowered out of the stope, and the body dismounted for handling it through the chutes. Tram Car with Automatic Door. A tram car with an automatically opening and closing door has been constructed under the direction of A. J. x %-in. Angle Strap . /Strap . /. . pS^ . - - - - - - pSb - - - - - - - p Strap % x 2-in. Strar between Cross-bars of Upper Ring and 3; Top of Maple Truck O FIG. 155. TRIMOUNTAIN CAR FOR STOPE FILLING. Cummings, superintendent of the Cheever Iron Ore Co., operating near Mine- ville, N. Y. Previous to the use of a car rigged with a door in this manner, a door was used which required the tram man to open it before entering the tipple. If the door would not open, as was often the case, the loaded car had such momentum that it would enter the tipple and turn to the dumping angle, thus making it difficult to open the door. Trips were attached to the tipple to open the door, but nothing could be rigged conveniently to close the doors mechanically. Open-end cars, designed by Koppel, were used, but these required extra care in loading large lumps of ore at the open end to prevent the fine ore from rolling out on the tram tracks. It was necessary to have the car SKIPS, CAGES, CARS AND BUCKETS 229 fitted with a door in order to load to full capacity. The Koppel cars were then rigged with the automatically operated doors and these have been entirely satisfactory. Iron plates are tapped and riveted near the top and center of the sides of the car and to these lugs are screwed. Two arms of flat iron are attached to the lugs and extend out to the front end where they are split and riveted to the door. On the horizontal center line of the door a strip of flat iron is riveted and the ends are swedged to i-in. diameter to receive rollers which extend beyond the body of the car. The door is kept in position by resting on two supports formed by splitting the flange of the channels at the end of the car and bending them to the proper angle. As the car enters the tipple and dumps, the rollers carrying the door are guided in a horizontal course by riding on 4X5~in. maple pieces bolted to each side of the tipple frame. Side Dump Mine Car (By Claude T. Rice) . Where ore is hauled in trains, the cars must be of the side-dump type to be economical. Side-dump cars are also better adapted to dumping into raises at the side of the tracks, or into the skip pockets in a shaft station or into the bins at the surface. The lifting Trunnion -EH ncuRm j 4"I-beam \~- Cast Steel Truck - := \Q) FIG. 156. - SIDE-DUMP CAR USED AT NORTH STAR MINE, GRASS VALLEY, CALIF. of the car and its load a sufficient height to raise it out of the "keeps" and the swinging of the whole load around so as to dump the car over the side is wasted energy. Side-dump cars have been in use at the North Star mines at Grass Valley, Calif., for several years, the first having been designed by Gerald Sherman, who also introduced them at the Copper Queen mines at Bisbee, Ariz. Fig. 156 illustrates the details in the construction of the cars in use underground at the North Star mines. Roller bearings are used on the latest cars and the wheel base is only 16 in., on account of the sharp turns in the drifts. The car has a capacity of 20 cu. ft. and holds, as loaded at the North Star mine, about 1800 Ib. The cars weigh 750 lb., are easily made and cost $40 each. The 230 HANDBOOK OF MINING DETAILS frame of the car consists of two cast-steel end supports riveted to two 4-in. I-beams by two rows of rivets on each side. The trunnion is also made of cast steel and is riveted to each end of the car body. The car is reinforced by three i-in. angle irons on each side. No catch is necessary to prevent the car from upsetting while being hauled by a mule or pushed by a man, but were these cars to be made up into trains to be hauled by electric motors, a catch would have to be put on them to keep the car from turning over because of the greater speed at which curves are taken. Cradle for Dumping Mine Cars. At the Copper Range mines in Michigan the bodies of the mine cars are fastened tightly to the trucks so that cradles FIG. 157. MINE-CAR DUMPING CRADLE. must be used to dump them at the shaft. In dumping on a level, as when filling a stope, the rails at the edge of the raise coming up from the stope below are bent down and then turned up into a hook to catch the wheels. In this way the body is allowed to drop enough so that the rock will slide out of the car. The details of the cradles which are made to template are shown in Fig. 157. SKIPS, CAGES, CARS AND BUCKETS 231 Two strap-irons protect the front of the cradle timbers where they hit the floor of th'e station when the cars are being dumped. The axle on which the cradle turns is provided with collars to limit the side play of the cradle, while the axle is carried in strap bearings on two 6X6-in. timbers that extend back under the ties of the track so that they are securely anchored in place, and through them the cradle itself. Thimbles protect the cradle timbers from wear by the axle, and the rails on the cradle are turned up at the end so that the car cannot be pushed off into the shaft. In dumping, the front of the car either strikes the station floor or else the top of the skip if that happens to be raised a little too high, so that owing to its long body, the car cannot go over far enough to overbalance itself. Such would not be the case if the car had a short body like most mine cars used in the West. In order to prevent accidents from men stepping on the cradles, the cradles, when installed, are always tested, even though made alike and according to template, and a cradle must be able to hold the weight of a man standing on the far edge without dumping. Otherwise a cradle might sometime throw a man into the shaft when he happened to step on it. The car rests on the cradle in such a way that a little lift is necessary to dump it. Calumet & Hecla Ore Cars. The Calumet & Hecla is one of the few companies in the Lake Superior copper district, that uses ore cars having doors. At the other mines the cars are open at the front end and closed at the back. The men pile boulders at the front to hold in the finer dirt and this is a waste of time. All the Lake Superior cars are built with the body resting directly on the axles so as to allow them to be made with the sides as near the ground as possible. The usual capacity is 2 1/2 tons, hence the cars are made with long bodies, especially where the tracks have the usual 3-ft. 4-in. gage; a 4-ft. gage is used at the Calumet & Hecla mines. Owing to the wide gage the cars have to have a short wheel-base compared to their length so as to allow them to make the turns without cramping. The front axle is bolted directly to the body of the car while the rear axle is attached to the forward axle by two distance straps that slip loosely over the axles. The front hole in the strap is made circular to allow the axle to turn in it when the body of the car is being raised to dump, while the back hole is made square to go over the square part of the back axle. In the center of the back axle there is a lug that fits into a hole in the bottom of the body so as to prevent side swing while the car is being pushed along the track. The front door of the car is made to swing up and is carried from a cross rod in the ends of two horns that extend above the car so as to afford plenty of space for rolling in boulders. The door at the other end of the car is made to drop down so as to allow perfect freedom in handling the boulders. This door only comes two-thirds the way to the top. As the rear door is sometimes 232 HANDBOOK OF MINING DETAILS used as an apron to aid in loading boulders, it is secured to the car by four straps instead of three, as in the case of the front door. These doors are locked by a rather ingenious device. To the doors are fastened two bolts with nuts on them, a link intervening so as to give flexibility, as shown in Fig. 158. By means of the nut, which is a tight fit on the locking rods, the length of the locking pin is adjusted so as to give the proper tension when the bolt is down in the keeps. The keeps into which the locking bolts drop are made of cast iron and are bolted to the sides of the car. The back Front Door itching Bolt > Keep 51 Keep ^Wheel Guards^ &3i <^^> <^^ * <^ Front Axle Attached Side Elevation of Car Body. Fits on Square Section of Axle f Latchln g Bolt and Kee *> .Edge of Carbody j Distance Strap Square Section Loose Fit on Round Section of Axle Rear Axle Front Axle not attached attached to to Body Body Axle Turned Round to here _Gag.e 3-ft.4-in. or 4-ft. Edge of Carbody Side Elevation of Distance Strap. Plan of Truck. FIG. 158. TWO-DOOR CAR FOR TRAMMING BOULDERS. end of these keeps is slightly rounded so that the bolt is tightened as it is shoved down in them, while the bottom part is straight and designed to be perpen- dicular to the locking bolt when it is down in the keeps. A slight knock on the end of the locking bolt loosens it so as to open the gate, but the bind against the keep is sufficient so that no jar can loosen the door while the car is being trammed. The accompanying sketch shows the keep in detail. To prevent SKIPS, CAGES, CARS AND BUCKETS 233 234 HANDBOOK OF MINING DETAILS fine rock from dropping upon the axles, wheel guards made of 2-in. angle iron are bolted to the side of the cars. The wheels are loose on the axles being held on by keys. Coeur d'Alene Mine Car. In Fig. 159 is shown a type of mine car used in the Cceur d'Alene district of Idaho. This particular car is used at the |<- ~~6ac{e4 L l" -->( FIG. 1 60. MAN CAR FOR AN INCLINED SHAFT. Morning mine, of the Federal Mining & Smelting Co., at Mullan, and is similar to the Bunker Hill & Sullivan cars. The capacity of the car is 68.3 cu. ft., and it is used in the long adit tunnels in which ore from the mine is conveyed to the mill or shipping point. The advantages of this type of car are in its strength and durability, with which is combined simple structural SKIPS, CAGES, CARS AND BUCKETS 235 details and rapidity of operation. The body of the car is made of i/4-in. steel plate, reinforced with angle iron. The patterns of the plates forming the body of the car are shown in the drawing. This body, with sloping bottoms, as shown, rests in a cradle made of 4X 8-in. wooden beams set on end, and sup- ported from the axles. The car axles are heavy, being 3 1/2 in. in diameter, turned to 2 3/4 in. at the bearings. The wheels are 20 in. in diameter, running on a 24-in. track. The overall dimensions of the car are: Width, 51 1/4 in.; height, 55 5/16 in.; length, 90 1/2 in. The bottom of the body of the car consists of two sections of steel plate hinged along the sides of the sloping bottom of the body. Each flap is weighted along its center with i6-lb. rails and supported by chains from a winding shaft across the body of the car. The car is dumped by simply loosening the ratchet gear controlling this winding shaft. The weight of the ore and the rails on the bottom doors serve to swing them open. A few turns of the winding shaft suffices to close the car again. The handle used for this purpose is kept at the point at which the cars are to be dumped. One man dumps all the cars of a train. The winding axle terminates at one end in a ratchet wheel. A dog engages this ratchet and the dog is locked in place by a keeper. The dog and keeper are each pivoted to the body of the car. To dump the car, the keeper is knocked up so as to disengage the dog from the ratchet wheel. The details of this dump mechanism are shown in the drawing. One man is able to dump 15 cars in about 3 minutes. Copper Range Man Car. The car used for lowering and raising men at the mines of the Copper Range company, in the Michigan copper district, is shown in Fig. 160. It is designed for use in a shaft sunk at an inclination of 70 from the horizontal and is a two-deck car, there being room for 13 men on each deck. The sides of the car are covered with i/2-in. mesh wire cloth, and the front is closed by gates, one for each deck, that slide in channel guides, a set of which is provided for each gate at the front of the car. The gates may be locked in position above the men's heads, or waist high by throwing the lever which pushes two rods out through holes in the channels provided for the purpose. The flooring of the upper deck is held in place by two pairs of channels, between which it slides, so that it may be removed when timbeis are to be lowered. The lower parts of the gate guides are also cut away, so that the gates can readily be removed when the car is to be used for this purpose, and a bolt that hooks into eyes on each side of the car just below the upper deck, and which prevents spreading or bulging at the sides, can likewise be removed to make room for the timbers. The hood at the top of the car is hinged so it may be laid back when 3o-ft. rails are to be lowered. In order to prevent accidents that might occur if one of the wheels should break while the skip is in motion, two pairs of skids are attached to the under part of the body, which, in the case of such breakage, would support the car upon the rail. Copper Range Ore Skip. The 6-ton skips used in the Copper Range mines in the Lake Superior copper country, present several novel details of 236 HANDBOOK OF MINING DETAILS construction, especially in the manner of attaching the draft lugs to the body of the skip, the system of oiling the wheels, and attaching the collars to the different lugs, bails and wheels. All hubs on which collars are used, are drilled for a split pin which holds the collars in place. The hubs are also cut with slots at 45 that receive the rivet pins of the collar. In the drawings of the Champion skip given in Fig. 161 the details of the draft lug and the collar used with it are shown. Projecting from the inside *\ II Detail 'of Bridle J - -J ~ ' ' lq P o o b 'o , "1 ,V> Ij3j 9 "p;v*f a Detail of Draff Luq g Pm Hole and Collar y Side Elevation Elevation of Bottom FIG. l6l. DETAILS OF THE SKIP USED AT THE CHAMPION MINE. surface of the collar and at 90 from the hole drilled to receive the split pin, are two pins riveted into holes in the collar. In assembling the collar on the lug, the pins are slid into the notches to the bottom and then the collar is turned through an arc of 45. This causes the pins to enter the grooves and when they are against the ends of the two grooves, the holes for the split pins in the -collar are in line with the holes in the axle and the split pins may be forced through. In this way the collar is held at four points instead of at two, and thus held securely. All of the other collars are attached in a similar way. The body of the skip is reinforced at the lugs by an extra plate. The bridle strap is bent so as to clear the front wheel. In order to keep the skip SKIPS, CAGES, CARS AND BUCKETS 237 as low on the rails as possible, the wheels are mounted on hubs riveted to the sides instead of on axles. At the bottom there are two reinforcing straps, while on the under side and at the front end there are two straps that take the wear that comes on the skip's bottom when going over the roller of the dumps. By attaching the draft pins by lugs riveted to the body or the inside of the skip, the lugs are fastened much more securely than if riveted to the outside, as is the usual way. The method of oiling the wheels is shown in the drawing of the axle. The ends are hollow and three holes in the walls let the grease out to the wheels. The wheels are made with a receptacle in them that also becomes filled with grease and acts as a reservoir, there being four holes drilled through the brass bushing to connect with the reservoir. These grease cavities are closed by a screw plug that cannot be taken out without removing the collar from the axle. The grease is shot into the wheels by a plunger gun that screws into the axle. Formerly when the wheels of the skip were filled with oil and the oiling of the axles was done by oil feeding down on them from these reservoirs, the wheels had to be filled four times per day, while the grease well has to be filled only once in 48 hours. The rope is attached around a thimble. This thimble is now made solid instead of having its sides cut away and only reinforcing ribs going across, as they were formerly made; that construction proved to be too weak. The manner of attaching the lugs and collars, as well as the methods of oiling with- out the necessity of taking off the collars, was devised by W. J. Richards, the master mechanic of the Copper Range Consolidated Co. The Franklin lo-ton Skip. There is but one hoisting compartment in the No. i amygdaloid shaft of the Franklin mine near Houghton, Mich., so in order to raise the desired tonnage, a skip of 223 cu. ft. or 10 1/2 tons' capacity is required. This skip is by far the largest in the Lake Superior copper country. The front wheels of the skip, as shown in Fig. 162 are carried by bracket axles which are bolted to the body of the skip, the clearance between the inside face of a wheel and the body being about i in. A reinforcing plate through which these bracket-axle bolts pass stiffens the body of the skip at that point. The body is also reinforced at the draft lugs. Because of the small clearance of the front wheels it is necessary to bend the bridle strap so that it will clear the wheels. At that part of the bottom of the skip on which the ore from the loading pocket falls when the skip is being filled a wooden lining is used which extends a little below the reinforcing plate for the bracket axles. The rest of the bottom is reinforced by steel channels, every other one of which is inverted; all are riveted together as shown in the section A-A in the illustration. The skip is equipped with skids that will take the weight in case a wheel breaks, and also with guide shoes that run over a concrete stringer in the shaft and which will guide the skip in the event of its jumping from the rails. The rear axle is pivoted and is carried in sleeves which allow a play 2 3 8 HANDBOOK OF MINING DETAILS of i 1/2 in. The front and back wheels are alike and are made of manganese steel, while the increase in the tread necessary on the rear wheels for dumping the skip is obtained by a separate hub that is carried outside the main wheels and on the same axle. This hub is a cheap steel casting as it does not have to take much wear. At the rear are lugs for attaching below the skip a truck for lowering timbers. The skip weighs about 61/2 tons. The skip track is 5-ft. gage and is made of 8o-lb. rails carried on concrete stringers of the Mohawk type. I i 1 1 .a 1 i'i C b 1 .S Top %-in. Plate S J 1 '"* l! ! -* 1 I 1 i'i" 1 5 s 5 i Vi-in. L 6 i G x }-in. L -11- ft. 6-in. iJi ?L_* -In. Plank Filler 15-ft. yA-irr. 5-ft. -A $ fil 1-in.BarFni! 'V'' _iP E /Lining and Bolts 12 x 1,^-in. Plate Section A-A FIG. 162. THE 10-TON SKIP FOR THE FRANKLIN MINE. Skip and Dump Plate for Vertical Shaft (By Lee L. Wilcox). A modi- fication of the De Beer's type of skip for a vertical shaft, which is an improvement over the old type, is shown in Fig. 163. The top of the old type of De Beer's skip was square and trouble was experienced from ore falling back into the shaft. This not only gave the shaft an untidy appear- ance, but in a few instances the men working near the shaft were seriously injured by falling pieces of ore. Attempts were made to improve the skip; in one instance a lip was riveted to the bottom plate; in another a filling piece was attached to the dump plate, thus throwing the lip up farther from the SKIPS, CAGES, CARS AND BUCKETS 2 39 edge of the shaft. These changes proved to be only partially successful in stopping the ore from falling back down the shaft, but they introduced other faults which were nearly as bad. The lip would spread the discharge of ore so that it would lie on the dump angles, causing the skip to stick as it descended ; and the filling piece decreased the inclination of the skip when dumped so that it did not clear itself readily. When the new Pettit headframe was built it was decided to make some changes in the design of the skip. It was made longer in proportion to the base than is customary; the dimensions being, base 3X4 ft. and length 6 ft. on one side and 5 ft. on the other. The base dimensions are unusual, because of local conditions. Under ordinary conditions it would have been made nearly ~ Amide -I A 'Coffer 0|0 FIG. 163. SKIP AND DUMP PLATE USED IN A MINNESOTA IRON MINE. square. The additional length, however, throws the lip considerably farther away from the shaft and all the ore is discharged well back from the edge of the shaft. By incorporating the extended lip in the body of the skip itself, as shown in the illustration, the trouble caused by the ore gathering on the dump plates was entirely overcome. The new skip was satisfactory from the start. A few changes were made in the dump plates which are worthy of mention. The dump angles were shod with a 3/8-in. strap; as this strap is worn it can readily be replaced without removing the dump angle itself, thus making the repairs much easier and simpler. The plate was reinforced behind the dump roller by a channel. This prevented the bending of the plate at this point which on the larger skips is troublesome. 240 HANDBOOK OF MINING DETAILS Automatic Skip for Inclined Shafts. In Fig. 164 are shown the details of a 48-011. ft., open-top skip used by the Salt Lake Copper Co. at its mine at Tecoma, Nev., in a shaft inclined at a low angle from the horizontal. The design presents several novel features, such as a curved bottom at the front for directing the ore when the skip is in discharging position and attachment of the bail at the lower end or back of the body of the skip. l'V 1(; Turu ^ ^^ 6 , v . . _.,_ ^ Beariug Ck- ^x ;< 32 Gage- Side Elevation Rear Elevation FIG. 164. A SKIP FOR FLAT-DIPPING SHAFT. Dumping Skip for Winze (By K. Baumgarten). The automatic-dumping skip shown in Fig. 165 was installed by the Black Mountain Mining Co. in the vertical winze in the Cerro Prieto mine, 40 miles southeast of Magdalena, Sonora, Mex. The skip was designed for the purposes of sinking. The total length of the shoes was 20 ft., which admitted of lowering the bucket 16 ft. below the guides. The hoisting compartments were 4 ft. 6 in. by 5 ft. in the clear; the guides were 5 i/2-in. surfaced Oregon pine. A i-ton skip was small for the size of compartment, which was larger than usual ; the problem was to arrange a bucket of convenient height for shoveling and at the same time to provide sufficient height, such that when the bucket was turning over in the dumping guides, it would not begin to empty its load until the lip was clear of the edge of the winze. The capacity of the bucket was 23.5 cu. ft. or about i.i tons. The shipping weight was 1732 Ib. After arrival at the mine, the springs SKIPS, CAGES, CARS AND BUCKETS 241 were added, the "fingers" taken off and increased to 12 in. length, and a false bottom of 2 -in. plank put in, thus increasing the weight by about 60 Ib. a total of about 1800 Ib. The hoisting equipment was a 5o-h.p. three-phase induction motor, 2 20 volts, geared to a drum carrying about 500 ft. of 3/4-in. wire rope. The load designed for this set was 3 500 Ib. but the hoist was operated to a depth of 400 ft. under a load of about 4000 Ib., or, roughly, 15% overload, exclusive of rope weight. The cost of the skip was $195, to which may be added $18 for freight and $3 for duty, a total of $216 at the mine. No originality is claimed for the design, except that the wearing plates within the .Bucket, Side nd End Plates I . ~ l' Front Elevation. Section FIG. 165. AUTOMATIC DUMPING SKIP FOR WINZE. shoes are omitted, and to which may be attributed the smooth running, as there are no projections between the shoes and the guides. In six months' operation no repairs were necessary. The dumping guides were made at the mine, but proved to cost only slightly less than the skip. It would have been cheaper to have had them made at an outside machine shop, where the equip- ment for such work was at hand. 16 242 HANDBOOK OF MINING DETAILS A Timber Skip. At the South Eureka mine, near Sutter creek, Calif., a special skip is used for lowering timbers. The shaft is inclined at angles varying up to about 70. The timber skip is hung below the rock skip from a ring on the bottom of the latter. It is made from an old skip by taking out the top plate and using an extra long bail, hung from the axles of the front wheels. By having the top of the skip open, timbers can be taken out by simply swinging them down, thus obviating the necessity of raising and lowering the skip for jacking. The extra length of bail enables long timbers to be handled. Counterbalance for Skips. The counterweight used at one of the iron mines of the Cleveland- Cliffs Co., at Ishpeming, Mich., consists simply of one 8-ft. section of i4-in. cast-iron pipe with flanges, mounted in a frame made of plate and angle iron. The two side pieces are i/2X 16 in.X 10 ft., the upper and lower ends being fastened together with iXio-in. plates. The runners are made of 3X 4-in. angle iron spaced 9 in. apart. These run on 8-in. wooden guides in the shaft. The runners are also lined with i/4-in. plates both on the angle iron and on the i/i6-in. side plate. This lining is easily removed in case of excessive wear and repairs can be easily made. A wooden block is placed in the bottom to act as a cushion and also add to the strength. The cast-iron itf'u- Bolt Hinge\^A-3"x3" " ^A- 3 Dia. FIG. l66. IMPROVED SKIP AT ADAMS IRON MINE. pipe being hollow gives ample room to add any amount of scrap iron in order to give it the desired weight. Another type of counterbalance used by the same company consists of a piece of solid steel shafting about 10 in. in diameter which runs inside of a i2-in. pipe. The pipe thus takes place of a guide. Other counterbalances used at various mines consist of a steel frame work in which large pieces of cast iron are mounted and may be removed or added to, as desired, in the same manner as on elevators in buildings. Skip Improvements. The new skips that are being made for the Adams mine, near Virginia, Minn., are equipped with 3 /4-in. compression springs SKIPS, CAGES, CARS AND BUCKETS 243 beneath the crosshead to lessen the shock on the cable when starting to lift the skip full of ore. The use of springs on skips is not common although they have been used on cages. In the old skips two 3X3-in. iron bars were used under the skip to support the load. The skip is hinged to o'ne of these bars for dumping purposes, and when vertical simply rests on the second one. These two bars are about 18 in. apart. Dirt will accumulate on the top of A, Fig. 166, if square, and prevent the skip from occupying its true position; hence the use of round bars. The skip being 5 ft. high, 1/2 in. of dirt or ice will throw the top of the skip i 2/3 in. out of plumb. MINE CAGES A Three-deck Man-cage. The hoisting of men consumes a large amount of time and hence reduces the amount of ore that may be hoisted daily. Wither- bee, Sherman & Co. recently constructed a three-deck cage for hoisting men from the mine. The capacity is 30 men per trip. The framework consists of channel and angle iron, while the sides are inclosed with 3/8-in. wire screen, 2 -in. mesh. The front of the cage is inclosed by means of sliding screen doors. The cage is to be operated in an inclined shaft and for this reason is mounted upon wheels. It is built so that the floor of the cage is horizontal, while the sides conform to the slope of the shaft. When the cage is not in use it will be removed from the shaft by means of a block and pulley which operates on an I-beam track. The cage will thus be carried to one side of the shaft house and entirely out of the way. The time required for making the change from the ore skip to the man skip is small. The present skip will hoist only 10 men so that with this new cage the men will be hoisted in one-third of the usual time. Hiawatha Mine Cage (By H. L. Botsford). In Figs. 167 and 168 are shown a type of cage and safety catch much used in the Lake Superior iron districts. The drawbar A is free to slide through the crosshead or supporting frame, until the cage is carried by the plate and jamb nuts B. Chain connec- tions between the drawbar and the cam shafts cause the latter to rotate when the drawbar is raised. The springs E are of the helical type and are placed con- centrically around the cam shafts, one to each shaft. The springs are fastened to the side of the cage and to collars F keyed to the shafts. Any rotation of the shafts produces a torsional stress in the springs. Should the hoisting rope break, the cam shafts are turned into such a position that the cams are brought into contact with the guides and cut into them sufficiently to stop any downward motion. This cage is also provided with two bolster springs G and H, one within the other and both concentric around the drawbar. Their purpose is to lessen the strains in the hoisting cable due to a too sudden starting or stopping of the cage, and also to draw down the drawbar in case of the failure of the hoist- ing rope, thus permitting the full force of the cam-shaft springs E to be expended in forcing the cams into contact with the guides. There are several holes in the 244 HANDBOOK OF MINING DETAILS chain pulleys /, and the spring collars F for the fastening of the chains K and the springs E. This permits of careful adjustment to secure the proper tension in the springs E. The cage is substantially a type made by the Lake Shore Splice 1 FIG. 167. HIAWATHA CAGE WITH SKIP ATTACHED. Engine Works of Marquette, Mich., and is shown with a Kimberley skip at- tached below it, for hoisting ore. A Light Mine Cage (By H. L. Botsford). A type of cage used in the West is shown in Fig. 169. This cage is of light construction, and is used for hoisting SKIPS, CAGES, CARS AND BUCKETS 245 246 HANDBOOK OF MINING DETAILS S-""* SKIPS, CAGES, CARS AND BUCKETS 247 small loads. The springs are of the spiral type, two in number. The inner ends of the spirals are fastened to collars keyed to the cam shafts, and the outer ends are bolted together. Unlike the cage described in the preceding article, the springs are not attached to the frame of the cage. The cams are circular in outline, with grooved surfaces. They are mounted eccentrically on the cam shafts, which gives them their gripping effect upon the guides. The bonnets of these cages are usually attached by hinges so that they may conveniently be swung up out of the way when long timbers are being lowered. It will be noted that the guide shoes are short, whereas in the other cage the guide shoes were nearly as long as the cage. For a cage of this type which is intended especially for raising small loads it is not necessary that the guide shoes be long. The two sets of light short shoes should be set as far apart vertically as can be conveniently done as the greater the distance between them, the more will they tend to steady the cage during hoisting. SPECIAL CARRIERS Harness for Lowering Mule Down a Shaft (By W. F. Boericke). Where there is no incline by which mules may be taken underground, the animals must be lowered either in a specially constructed mule cage, or swung down by means of a harness similar to the one here described and illustrated in Fig. 170. Wherever conditions are right, the preference should be given to the harness. The mule cage is heavy, cumbersome, difficult to get the mules into, and its use means a loss of time in getting the cage in and out of the shaft. To swing a mule with a harness is by no means as formidable a job as it appears at first. The harness itself is a simple affair, and can be made at the mine, out of pieces of old canvas or rubber belting, securely riveted together. The dimensions given in the sketch are adapted for a poo-lb. mule. The harness, when fitted on the mule, should be fairly snug, but the straps should not be buckled too tightly. If the mule is accustomed to harness, he will allow it to be put on without trouble. The parts lettered T T should come a trifle below his sides. The part S should be low enough to insure that the mule will be seated firmly when he is swung into the shaft. The head and neck, of course, come through the space A. When all is ready, the mule is led to the collar of the shaft, and a heavy chain attached to the hook, and made fast to the center of the cage. Planks should be laid across the shaft, so that as the mule is raised, his feet will not catch in the timbers. The signal is given to hoist slowly, and the astonished animal is swung out over the shaft, bearing a marked similarity to a dog begging. The planking is then removed, and the cage slowly lowered. If there are bad places in the shaft, it may be well to tie the feet together, but this makes a delay at the bottom, and is usually unnecessary. When the mule is near the bottom, a rope is tied to the back of the harness, and the animal drawn to one side, so that he lands on four feet. In an actual case, from the time the mule was swung 248 HANDBOOK OF MINING DETAILS into the shaft, until he was led to the stables at the bottom, was 6 minutes, the shaft being 150 ft. deep. Automatically Discharging Bailers (By W. H. Storms). Many mine managers prefer bailing to pumping water from mines, and undoubtedly there are conditions where bailing is less expensive than pumping. Fig. 171 shows two types of self-dumping bailers; one a cylindrical valve bucket, the other a skip fitted with a hinged valve which opens to admit the water when the skip FIG. 170. HARNESS FOR LOWERING MULES. sinks in the sump. Both are arranged to operate in inclined shafts. The automatic-discharge features will be appreciated by those who have had no experience with bailers of this kind. The right-hand illustration shows the steel barrel on the skids S and also its position, by means of dotted lines, when discharging. This is accomplished by cutting out a section A of the skids upon which the bucket slides. This section is supported on a pivot B. A counterweight W holds the section in place when the bucket is below, or even when resting upon it when empty, but when it is drawn up out of the shaft filled with water the excess of weight of the bucket and the SKIPS, CAGES, CARS AND BUCKETS 249 water below the pivot, as compared with that above it, causes the loose section of the skids to swing backward into the vertical position indicated by the dotted lines. The engineer then lowers the bucket without leaving his station at the engine, until the valve spindle V rests upon the floor, which forces the valve up- ward, thus allowing the water to escape and flow away. The engineer then raises the bucket slowly and the counterweight W pulls the skids, with the empty bucket upon them, back into position and the bucket is lowered again into the shaft. 7 // FIG. 171. AUTOMATIC DISCHARGING BAILERS. The illustration to the left shows an ordinary water-skip with a hinged valve in the bottom. The track, generally of T-rail, T 1 , is spiked to stringers 5 in the headframe, and dumps provided for both ore and water by cutting out sections of the stringers and track and making gates G G as shown. The gates swing on the hinges H H, that for the water-dump being about 3 ft. above the collar of the shaft. When a skip is to be dumped the proper gate is opened and upon the arrival of the skip at this point the forward wheels follow the curved rails and run out upon the horizontal track, as shown in the sketch. The engineer con- tinuing to hoist slowly, the lower end of the skip is lifted from the main rails and its contents dumped. There is one thing to be carefully avoided in operating this device. When the skip is approaching the dumping place the hoisting speed must be slackened to a moderate rate or the forward wheels are liable to collide with the upward extension of the track at A , thus doing serious damage to the headframe, or parting the cable. The bumper keeps the wheels from 2 50 HANDBOOK OF MINING DETAILS running so far forward that the skip will not automatically descend the shaft again when empty. By having a movable bumper, however, the water-skip can be run in on that dump and secured there by dropping a piece of light timber between the rear wheels and the skids. The cable can then be detached and made fast to the ore skip. In this way either ore or water may be hoisted in the same shaft compartment, by using two suitable skips. A Two-ton Water Car (By Guy C. Stoltz). The type of water car used at Mineville, N. Y., to un water Mine 21 is shown in Fig. 172. Two cars of 528 gallons' capacity were hoisted in balance an average distance of 450 ft. on a 60 FIG. 172. WATER SKIP USED AT MINEVILLE, N. Y. double-track incline. They were automatically filled in the mine and automatic- ally discharged at the surface into a series of wooden troughs. The greatest number of cars hoisted during a lo-hour shift was 812, while 600 was the average rate per shift. The hoisting capacity at maximum speed was equal to a pump fitted with a lo-in. discharge delivering 715 gallons per minute. The average quantity hoisted was 528 gallons per minute. The water tank was made from a lo-ft. length of 3-ft. stack, the lower end headed with 2-in. pine and held in place by a 2 X 2-in. hardwood ring which was bolted to the circumference of the stack at the bottom. The top was not headed. The bottom timber head was reinforced at its center by a truss of 3/4-in. iron bearing on a 4X4Xi2-in. SKIPS, CAGES, CARS AND BUCKETS 251 wooden strut. The tank, which was attached to a set of wooden stringers by flat iron hangers, was mounted on the ordinary skip axles. The lower lo-in. segment of the tank door was hinged and upon lowering the car into the water the pressure would automatically open the segment and allow the water to enter. As the car was hoisted above the level of the water the door would close due to the hydraulic pressure of the contents. The door was automatically opened at the dumping point on the surface by the operation of a system of lever arms. These were attached to the door and so pivoted that a plank guide A would inter- cept the trolley arm B and lower it to such a position that a lateral movement of 8 in. toward the top of the car would be delivered to the gate. Upon lowering the car the gate, which was heavier than the reciprocating system of levers, would close. Back rails should be provided to prevent the car from leaving its track as it enters the water. Scraper for Cleaning Slopes. The stopes of the Calumet & Hecla mine dip at about 38. The empty stopes are not filled and after the stoping is finished, FIG. 173. A LAKE SUPERIOR STOPE-FLOOR SCRAPER. a considerable quantity of ore is left on the floor, especially if the floor is rough. This ore, when there is not much to be handled, is worked down to the level by hand. When much ore has accumulated on the floor, it pays to use the scraper, the construction of which is shown in Fig. 173. A sprag is set in the top of the stope, and a small air hoist is installed at the bottom. The rope that goes from the hoist to the rear end of the scraper passes through a pulley carried by the sprag, while another rope from the hoist goes directly to the front ring of the scraper, so that the air hoist, besides pulling the scraper with its load of ore in front of it to the bottom of the stope, also pulls it back again. The scraper works well when the foot wall is not too rough and practically no hand shoveling of the ore is necessary, but if the ore lies in pot holes in the foot wall, it must be shoveled out to a smoother part of the foot wall, where the scraper can get at it. 252 HANDBOOK OF MINING DETAILS This scraper was designed by Capt. Samuel Richards, of the Calumet & Hecla company, and has now been in use for several years, both in the amygdaloid and in the conglomerate stopes. The main plate of the scraper is 5/16 in. thick, and is strengthened by means of three 3X3/4-in. iron straps that come together near the front, so as to distribute the load to the haulage strap. A ring is provided for fastening the rope from the hoist to the front end, while at the rear is a chain that is fastened to two eyebolts that go through the two outside straps. To this the return rope is fastened. There are also riveted to the rear of the scraper two plates carrying two handles. By means of these handles the men are able to steer the scraper, and by pulling up or shoving down on them regulate the quantity of ore that the scraper takes on its trip down the stope. In case the scraper has a tendency to ride over the ore, owing to the compact way in which it lies on the foot, car wheels can be hung on these handles, and the scraper made heavy enough to dig into the pile of ore. A Scheme for Transporting Lumber (By W. F. Du Bois). A contrivance that was very useful to me in transporting lumber is illustrated in Fig. 1 74. The FIG. 174. A LUMBER LIZARD. wagon road ended 3/4 of a mile from the mine where I wished to put up an office and mine buildings. The slope from the end of the road to the mine was between 30 and 40, so that it was impossible to go down with a wagon. The " lizard" used is 2 1/2 ft. wide, 2 ft. long and made of 2-in. plank. On the top is a piece of pine 3X5 in., beveled so that it is 3 in. thick on the back and i 1/2 in. in front and spiked to the 2-in. plank with 2od. nails. The first planks or boards to be hauled are spiked on top of the 3X 5-in. piece with 2od. nails and the successive layers of boards nailed to each lower layer. After 1 8 or 20 boards, SKIPS, CAGES, CARS AND BUCKETS 253 1 8 ft. long, are securely spiked, an ordinary i2-ft. log chain is put around the boards, back of the 3 X 5-in. plank. The end of the chain is fastened to a single- tree by a grabhook. One horse could easily pull the load down the back of the ridge to the mine. On arriving at the mine the chain was thrown off and each board pried loose. The chain and singletree were hung on the harness and a boy carried the lizard as he rode the horse to the lumber pile after another load. The lizard lasted 1 2 loads. Four trips a day were made. A Wagon Oil Tank (Chester Steinem). In view of the increasing use of crude oil as a fuel and for combustion in oil engines, a description of a tank 2-in. R. Provide with Sliding Gate for Manway Section A-B Two % -in. Steel Plates Kiveted in eacb Tank, to act as .baffles. J-in, Flange, 2-ln. Nipple, 2-in. Gate Valve, 2-U- Plug with Chain. 6-in. 2-f-W- } \Sp\ke S\ L y :x ^ pik H Plan. A Engineering g Mining Journal FIG. 215. METHOD OF FASTENING A GUARD RAIL. of Sydney, N. S. W., has been tested by W. H. Warren, professor of engineering at Sydney University and proved to have 1.29 times the holding power of a black- iron spike of square section and 1.30 times that of one of circular section. The spike is made by twisting a bar of square, hexagonal or octagonal cross-section, so as to form a helix of large pitch, and a square head is forged at the top. The SAFETY APPLIANCES 299 original bar can be of fluted or plain section. The spike is driven into a hole bored to a depth of 4 in. in a railway sleeper; the spike revolves as it is driven into the hole. Short Guard Rail and Fastening (By G. M. Shoemaker). A satisfactory guard rail and method of fastening is shown in Fig. 215. A shorter piece of rail may be used in making it than with the older method. The purpose of a guard rail is to guide the flange of the wheel away from the point of frog and 6 in. of rail should be sufficient to do this, 3 in. on either side of the point of frog. With the old method it is necessary to use a much longer piece to get sufficient spiking surface to make the rail fast. In the old method, unless notches are cut in the bases, it is necessary to drive the spikes between the outer rail and the guard to prevent the base of each from meeting. By this method the ball of each rail is brought closer together thereby making the liability of derailment less, especially so in the case of a bent axle or a wheel which has become wobbly from wear on bore or axle. Mining Track Frog. The cheap, simple but effective device shown in Fig. 216 is used in some of the Utah mines for guiding the wheels of mine cars to the rails when passing from a smooth floor or from a turntable. It is com- posed of a piece of 2-in. plank, 15 in. wide (if used with i8-in. track) FIG. 2 1 6. TRACK AND FROG. and 2 1/2 ft. long. One end is cut into a rojmding point and the edge of the plank is protected by a piece of strap iron, 2 in. wide, nailed on. The device is then spiked down between the ends of the rails, with the point toward the turning place, leaving enough space between the edges and the inner sides of the rails for the flanges of the wheels to pass. Unlike most other devices for this purpose, this contrivance does not get battered out of shape, does not require a blacksmith to make it, and never fails in its duty. Mine Track Switches. At many mines it is the practice to order standard switches direct from supply companies, while at others the switches are made at the mine, usually by the blacksmith, who makes them according to his own ideas, guided by the data supplied by the foreman of the track-laying crew. Standard switches are expensive when bought from supply houses. Made-at-the- 3oo HANDBOOK OF MINING DETAILS mine switches are comparatively cheap, but unless well made they cause much trouble from cars being derailed. At the mines of the Tonopah Mining Co., the engineering corps designed the switches illustrated in Fig. 217. These are made at the company's shops according to standard specifications and are suit- able for tracks where the tramming is done by hand. The car is made to take the turn by shifting the rear end in the opposite direction. The switches are so placed that only the empty cars need be so shifted; the loaded cars, run- ning in the opposite direction, take the straight-away track. FIG. 217. ONE- AND TWO-WAY MINE SWITCHES. Calculating a Crossover Switch. The following formulas for calculating the lengths and distances required to lay a crossover switch between two parallel tracks in a mine were published in Coal Age. The data usually given are: The frog number, ; the gage of the track, g\ and d, the track centers. The data required are found by the following formulas: The chord of lead rail, c= 2 ng; the radius of lead rail, R=nc; the frog angle, sin. 1/20= ; the length of lead rail, L=~ R-, the length of the follower, /= ^ L; the length of straight I oOTT \. track, r ; the lead of switch, x=R sin. a-, the frog distance apart, sin. a y=r cos. a g sin. a', and the distance between switches, D= 2X+ y. The letters in the formula refer to the dimensions specified in Fig. 218. SAFETY APPLIANCES 301 Gravity Tram Switch (By B. A. Statz). While operating a small milling plant near Kelly, N. M., I had trouble with a surf-ace tram connecting the mine and mill and having a total length of 2300 ft. The tram line was single track, with a 30-in. gage, having a switch or turnout in the center; the brake was of a drum type, so arranged that each car had to pass, coming and going, on the same side of the switch. The grade of the tram line ranged from 15 to 40. The * s $ .Point r*- . ~- k *-/ U-. / ^J. x H ^J"S ./ *L* 1 FIG. 2l8. CALCULATING A CROSSOVER SWITCH. cars used held two tons of material and had straight bodies. When the cars were running at fairly good speed the front wheels of the cars would be i in. above track when on the steepest grade, hence when the cars came to the lesser grade the front wheels nearly always missed the track, causing delay. To overcome this I put in the switch, shown in Fig. 219; the switch was cast in a local foundry. This arrangement worked admirably in conjunction with cars designed so that the top line was level when the car was on the steepest grade. Bottom FIG. 219. SWITCH FOR GRAVITY TRAM. A switch such as is shown in the accompanying drawing was put in at both ends of the turnout. The tongues of these switches were made of wrought iron and coupled together. These slid over a cast-iron bed plate. The switches were set opposite from one another, of course, so that the car would pass on the switch. Consequently, the car coming up would throw over the tongues of the switch at the head of the turnout, while the car going down would throw over the tongues of the switch at the bottom end of the turnout. So, when the car at 302 HANDBOOK OF MINING DETAILS the top was loaded and the car at the bottom dumped, and they began their journeying again, the switches were set so that each car traveled along the same side of the turnout that it had taken before. A Double Gage Turnout. The turnout shown in Fig. 220 is used, states Frederick MacCoy (Eng. News, Jan. 25, 1912), wherever 36-in and 4 ft. 8^-in. tracks are employed together at the Esperanza mine in the El Oro district, Mexico. A motor car runs on the narrow-gage tracks, drawing either narrow- er standard-gage cars. One lever is used to operate both switches. Frogs A and B are standard while C is a crossing frog. An Automatic Switch. The accompanying illustration, Fig. 221, indicates the design of a switch operated by gravity instead of a spring. It can be FIG. 22O. DOUBLE-GAGE TURNOUT USED ON MINE TRACKS. easily used on trestles where there is space beneath the tracks. It consists simply of the ordinary two short rails fastened together as in the case of a spring switch. Beneath the connecting bar is a small lug which is engaged by an L- shaped lever. One arm of the lever is 2 ft. long, and the other i ft. At the angle point it is fastened to a post or beam. The short arm has a wide face which en- gages the lug on the bar above, and by means of a small weight on the end of the lever it throws the switch. It works satisfactorily, and has been in use by the Cleveland-Cliffs Iron Co. for a number of years. It is arranged so that it is opened by the loaded cars and then closes, thus throwing the empty cars on an- other track upon their return. SAFETY APPLIANCES 303 FIG. 221. GRAVITY SWITCH FOR ORE CARS. FIG. 222. THE PETERSEX SWITCH. HANDBOOK OF MINING DETAILS A Convenient Switch-throwing Device. The switch-throwing device shown in Fig. 222 is in use at the Homestake mine, and is made at Newport News, Va., by Peter H. Petersen, a former employee of the Homestake company. The function of the apparatus is to permit the switch being set in either position: When trailing a closed switch no adjustment is necessary, the action being auto- matic; and when facing it, the required adjustment can be made by the engineer from the train. The device consists of a triangular lever box composed of two plates spaced by roller-shaped fillers on the bolts, and pivoted at D. The switch rails are connected to this lever box through a bell crank and bar E, which is pivoted at the bolt M . The gravity lever B with weight P is pivoted be- tween the plates at D. When B is in the position shown, it rests on the bolt C and holds the switch points against the right-hand rail, thus keeping the left- hand track open. When B is thrown over center, it rests on the bolt A , raising E and holding the points in the opposite position. if* Track Track Track Track (10 diam. 1'wide) Axis FIG. 223. TURNTABLE USED IN HIGHLAND BOY MINE. When trailing a closed switch, no matter for which track it is closed, the switch points will open to let the cars pass through and adjust themselves again to their former position after the last car has passed over them. The engineer or motorman can throw the lever to set the switch for either track he desires while his locomotive is passing over the switch points. When facing a switch, should it be placed wrong, the engineer drives to the throw, adjusts it to suit, and then moves off the switch points, whereupon the weight sets the switch to SAFETY APPLIANCES 305 its new position. Or a rope may be attached to B, run through a pulley directly over the pivot D and extended to any point along the track, permitting the engi- neer to set his switch as he approaches it. Thus no switchman or extra trainman is necessary. Turntable for Mine Cars. A turntable of simple construction and requir- ing no bed other than an ordinary tie is shown in Fig. 223. In place of switches or iron plates such small turntables are used at tunnel crossings, in the Highland Boy mine of the Utah Consolidated, Bingham Canon. The turntables act quickly, are easy and cheap to build and keep in repair, and save space at the tunnel junctions. A piece of i/4-in. iron plate is riveted to two 3/4X i-in. iron Drilled d S 2 Rails of CQuntHuak 2 by iH-in. Steel FIG 224. TURNTABLE USED IN SOME MICHIGAN COPPER MINES. strips placed with the larger dimension vertical and spaced the same as the tracks, a continuation of which they form. A hole for a 3/4-in. spike is punched in the center of the i/4-in plate and on its under side about the center point a ring of i/4X i-in. iron 10 in. in diameter, is riveted. This completes the turn- table. A tie slightly over 10 in. wide is laid at the point about which the turn- table must pivot and to this it is spiked. The spike acts as the pivot and the ring on the underside of the i/4-in. plate serves as a bearing on the surface of the tie. A plentiful supply of grease is provided at this point to keep the table turning easily. There is practically no opportunity for dirt to get on this bearing sur- face, so little attention is required for the device. A Ball-bearing Turntable. Turntables are generally used at the shaft stations in the inclined shafts of the Lake Superior copper country, as the tram 20 306 HANDBOOK OF MINING DETAILS cars generally hold from i 3/4 to 2 1/2 tons. At the Tamarack, however, where the shafts are vertical and the cars hold 21/2 tons as loaded, turnplates are used. These are somewhat thicker and hence more rigid than turnsheets, the usual substitute for turntables in other districts. The turntables are not especially rapid in operation as, owing to the weight of the loads, speed is not so important as in Western mines where ton-cars are used. The turntables are put in the main tracks on the hanging- wall side of the shaft and are used so as to get the cars on the short tracks that lead right up to the edge of the plat. Some of these turntables are made with ball bearings, while others have two flat bearing rings. The turntables with the balls are stiff at first, but after the balls have worn smooth they are superior to those with bearing rings. If any- thing, the top part of the turntable could be cast a little heavier as occasionally an arm breaks. The gage shown is 3 ft. 4 in. which is the standard of many mines in the copper country. Fig. 224 shows the turntables used in the Wolver- ine and Mohawk mines; the Calumet & Hecla company uses a similar table on tracks of 4-ft gage. XI PUMPING AND DRAINING Operation of Pumps Air Lifts and Eductors Mine Drainage OPERATION OF PUMPS A Useful Pump Formula (By A. Livingstone Oke). Some years ago, while in charge of the work of unwatering a mine in Portugal, I noticed the following simple relation between the tons of water delivered per hour by the pump and the diameter in inches of the pump plunger, or piston: Tons per hour equal the plunger displacement in cubic feet per hour times the weight of a cubic foot of water divided by the number of pounds in a ton. r = FIG. 239. SAIL FOR SHAFT VENTILATING. the heavy gases remained at the bottom while the fresh air merely worked to the surface again. When sucking air out, the draft through the bag is strong enough to carry the heavy gases up without trouble. Ventilating Stopes in Bisbee (By F. W. Holler) .Ventilation in the Bisbee mines is natural as far as possible. Most of the shafts are connected on the different levels, and usually the levels are cool enough for comfort*and the air is VENTILATION AND COMPRESSED AIR 337 good. Levels are 100 ft. apart and are connected in many places by raises which are put up for prospecting purposes as well as to help the ventilation. Before doing extensive stoping, a raise is put through from one level to the next. Then stoping is started from this raise, keeping the latter in the corner of the stope which will vary in size from a square section four sets on a side to one seven sets on a side. In some cases the raise ventilates the stope naturally. In other cases the air in the raise may be good, but a set or two away it may be just the opposite. In this event special methods of ventilation are necessary, and several of these follow: The man way set of the raise is covered over with plank on the working floor of the stope, and the floor is removed in one of the sets in the far corner of the stope, thus forcing the air to travel across the working floor, down into the far corner and back to the raise on the floor below. In this way two floors of a stope can be ventilated if there is a current of air in the raise. When there is not a current of fresh, cool air in the raise, small centrifugal blowers run by electric motors are used to blow air from a main air passageway to the stope. Suction from Winze Open -+ .A B- Closed j Main Discharge - ? <"\ *4 Discharge to, *. Drift V cL Open wer Bli Suction Cloied by Wooden Door FIG. 240. PIPE ARRANGEMENT FOR FAN BLOWER USED ON COMSTOCK LODE. Six- or eight-inch galvanized pipe is used to conduct the air. Occasionally, compressed air is used in stopes where it is not deemed advisable to put in blowers. Results obtained are not good considering the power used and the quality of the air, but by using jets with the compressed air the results obtained are better; however, they do not compare with those obtained by using centrifu- gal blowers. Piping Arrangement for Fan Blower. In Fig. 240 is shown a simple pip- ing arrangement for reversing the air current from a fan blower. The scheme is 33 8 HANDBOOK OF MINING DETAILS employed on the 2ooo-ft. level of the Union mine, at Virginia City, Nev., where a Sturtevant, multivane blower is used to supply air to a winze from which levels are being opened. The main discharge of this blower is 20 in. in diameter and the fan is run at 1120 r.p.m., being belt connected to a 2o-h.p. motor. The power consumption is about 16 h.p. Ordinarily the fan is used merely to blow fresh air down the winze through the 20-in. main-discharge pipe. After blasting it is, however, necessary to draw the foul air and gas from the winze. The 2o-in. pipe then acts as a suction pipe, the air current being drawn (into the blower) through the parallel length of 1 5-in. pipe and discharged through the 2o-in. pipe and connecting i5-in. pipe. A wooden door or gate is used to close the suction end of the blower and the gates A , B and C in the pipes con- trol the air current. The sketch shows the blower drawing air from the winze and discharging it into the drift. After clearing out the winze the door is removed from the suction of the fan, valves A and C closed, B opened, and fresh air is blown into the winze. This is a much simpler arrangement than is usually seen and requires a minimum amount of pipe. The wooden gate to close the sue don end of the fan can be quickly constructed of a few nails and some plank. It is much quicker and more economical to draw out bad air than to force it out by blowing in fresh air. In the winze mentioned, no time has to be lost between shifts even though the temperature of the air would quickly rise to above 120 F. if artificial ventilation were not resorted to. By this arrangement it is possible to deliver the gases directly to an upcast air current instead of allowing them to mingle with the air currents about the winze station. Mine Ventilation through a Drill Hole. In underground operations it is necessary to have two openings in order to insure good ventilation. The second opening is generally made by sinking a new shaft. In the case cited here, the ore could be handled readily through one shaft, and .a churn drill hole was used for the second opening. The apparatus is a fan about 2 ft. in diameter with a horizontal bottom discharge 8 in. in diameter. To this nozzle is fastened a short piece of canvas air pipe slightly larger than the casing of the drill hole with which it connects. The fan is belt-driven by an 8-h.p. upright engine. The engine obtains its steam from the boiler at the shaft several hundred feet distant. The apparatus is in an open field in the southwest part of Joplin, with no protection from the weather. Ventilation by Drill Holes (By W. F. Boericke). In the shallow zinc mines of Wisconsin, drill holes, aside from their primary purpose of serving to prospect the ground, are of considerable use later in ventilating the under- ground workings. The holes are usually put down with churn drills and are seldom much over 125 ft. deep, with a diameter of 6 to 8 in. The drilling cost is usually about 60 to 80 cents per foot, depending upon the amount of drilling. Where the holes are at different elevations, a small current of air usually passes down one and up the other. This can be augmented by erecting a high standpipe above one, thus increasing the draft. If one of the holes is wet, as VENTILATION AND COMPRESSED AIR 339 frequently happens, the dripping water aids considerably in catching the air and carrying it down, on the familiar principle of hydraulic compression. Some- times a small fan and motor forces a strong current down, or a suction fan may be used. Occasionally a sail is rigged to deflect the wind down the hole. A more effective means than the last is employed at the Ross mine, Linden, Wis. The device is simple and inexpensive, and can be made by the mine blacksmith. It consists of several lengths of ordinary y-in. galvanized stove pipe joined together and projecting 6 ft. above the ground. The bottom piece is Iron Weight to Counterbalance Force ol Wind . __ -\ FIG. 241. STOVE-PIPE VENTILATOR FOR DRILL HOLES. sunk down the drill hole through the soil until it strikes rock. Guy wires hold it firmly in a vertical position. The top section consists of two pieces of pipe, one flared slightly so as to fit easily on the other. Strap iron, bent into angles, is riveted as shown in Fig. 241, and iron washers, with a bolt slipped through the strap irons, allows one to turn freely on the other. The top piece has an ordi- nary stove-pipe elbow securely fitted to it, which in turn is fastened to the funnel, a wide concave piece dimensioned as shown. The fan-shaped piece on the rear is, of course, to turn the device so as to face the wind at all times. A piece of bar iron is suspended from the front of the mouth of the pipe in such a way as to counterbalance the force of the wind when blowing against it. Self-acting Mine Doors. A device, used in a German mine, by which a 340 HANDBOOK OF MINING DETAILS door across an airway can be opened automatically by an approaching car or trip is illustrated in Fig. 242. The rail G is supported horizontally, at about 2 1/2 it. above the ground, by two stulls on one side of the track, in such a way that the end of the rail toward the approach of a car is closer to the track than the other end. A slotted shoe B slides on this rail. Fastened to it is one end of a rope which passes around suitable pulleys, the other end being fastened to the outer edge of the door. A counterweight g is also connected to the sliding shoe to assist its return movement, if the usual pressure is insufficient. A FIG 242. SELF-ACTING MINE DOORS FOR DOUBLE TRACK DRIFT OR TUNNEL. car coming in the direction of the arrows strikes the shoe B, and by pushing it ahead opens the door; by the time the door is open wide the shoe has traveled sideways far enough to allow the car body to pass it, but the door is prevented from closing by the springs s, which rub along the side of the car. When the car has passed, the natural weight of the door, which is purposely hung out of plumb, assisted by the wind pressure and the counterweight, causes it to close. A Mine Air -door (By P. L. Woodman). Details of a mine air-door and of an opening and closing device used in the motor-haulage drifts of the Copper Queen mine are shown in Fig. 243. The doors are opened and closed without stopping the train. When a train approaches, the motor or end car pushes the doors which are free to swing in either direction; upon opening, they are caught and held by the latches set in both walls and on each side of the door set. The releasing lever is operated by a cord a hundred feet or more in length con- veniently hung at the roof of the drift. The motorman simply pulls the cord in passing and the levers release the doors allowing them to swing shut. VENTILATION AND COMPRESSED AIR 341 Starting a Ventilating Fan Automatically (By S. A. Worcester) .The Conundrum gold mine at Cripple Creek, Colo., now being operated under a lease to me, is ventilated by a system of my invention, with a large fan operated by a i5-h.p., three-phase induction motor. The motor is started from i to 2 hours before the shift goes to work, so that no gas will remain in the mine at " tally." For the first 2 or 3 weeks this starting was done by a miner who went to the mine early for this purpose. Later I devised and put in use the arrange- ment shown in Fig. 244, which saves several dollars each month, besides being accurate and reliable. FIG. 243. DETAILS OF MINE AIR-DOOR AND CATCHES. The starting box A is the ordinary starting compensator used with induction motors, and has three "on" positions and the "off" position. The one-day weighted clock B is wound by pulling down the weight chain C, thus raising the weight D. The marks on the wall indicate the travel of the weight per hour and show how far the weight should be raised to start the fan within a given length of time. When the motor is stopped, the starting lever E is set as shown, in the "off" position, and is held in this position by the releasing lever F. The releasing lever has a bucket G suspended near its outer end and with its bottom a little below the surface of the water in the can H, which is an ordinary square 5-gal. oil can, with the top cut out. The bucket is made from a piece of 6-in. galvanized air pipe with a wooden plug for a bottom; a hole about 1/8 in. in diameter is bored through the bottom. The bail K of the bucket is hooked and hung on the trigger L. When the clock weight D descends and lowers the long arm of the trigger, the bucket is unhooked and drops, carrying down the releasing lever F far enough to allow the starting weight M, which is fast to the handle E and moves 342 HANDBOOK OF MINING DETAILS with it, to drop one notch, bringing the compensator to the first "on" position. The bucket now sinks slowly as the water enters through the small hole in its bottom, requiring 18 seconds to lower the releasing lever so as to pass the second step of the weight M, and 12 seconds more to release the third, or full- speed step, 30 seconds being required to bring the fan to full speed. The water has a little oil on its surface to prevent evaporation. The operation of this arrangement is independent of manual skill and care and assures an easy and reliable start, with no danger of throwing the belt of! or burning out fuses. The fan draws air from the surface through a long tunnel. It is situated in a short crosscut from the tunnel to the hoist shaft and about 150 ft. below the FIG. 244. AUTOMATIC STARTER FOR VENTILATING FAN. underground electric-hoist station. The air current is forced directly down the main hoisting shaft. The engineer visits the fan usually once each day, to see that the oil is feeding properly, and no further attention is required, except stopping and setting the starter for the proper time. Before this ventilation system was installed the mine, which has about 3 miles of workings, was often entirely filled with mine gas, from the seventh level to the adit-tunnel entrance, a vertical distance of about 800 ft. The seventh level was inaccessible in even the most favorable weather and the gas zone was more than 150 ft. deep in all ordinary weather. One or more men had been killed in this mine by the gas which contains, by government analysis, 10% of carbon dioxide. The mine had been practically aban- VENTILATION AND COMPRESSED AIR 343. doned for 5 years on account of the gas. The ventilation is now perfect in all parts of the mine, and completely independent of weather conditions. The fungus or mold which was at first found throughout the mine, has all dried up and disappeared, and the air is cool and pleasant; candles will burn in all parts of the workings. (By J. H. Dietz). A method similar to that described by Mr. Worcester was employed at the coal mine of the Laning-Harris Coal & Grain Co., at Wellington, Mo. The fan at this mine is of the propeller type, belt driven by a i5-h.p. direct-current motor, and is placed directly in the air course, 1500 ft. from the mouth of the slope. The motor is operated by a type 70 Cutler- Hammer self starter, which replaces the elaborate mechanism Mr. Worcester has attached to his ordinary starting compensator. The simple solenoid, drawing the starting switch slowly over the contacts as soon as the current is turned on, takes the place of the counter- weight/ oil can, 6-in. pipe and system of levers, described in the above article. The fan can then be stopped or started from the engine room simply by opening and closing the switch, which is equipped with a counter-weight for closing, operated by a string attached to the winding stem of an ordinary one-dollar alarm clock. This enables the fan to be started from the engine room at any predetermined time, and makes a simpler, cheaper, more convenient and reliable arrangement, with the advantage that it can be purchased properly made and ready to install. The fan was manufactured and the starting arrangement installed by the Eagle Foundry & Machine Co., of Fort Scott, Kan. In addition to the equip- ment described, the motor is supplied with a variable-speed controller, without release, so that the fan can be operated with a 50% variation in speed, depending on the weather conditions and the mine resistance. This fan requires no attention, except for oiling, and is equipped with special self-oiling boxes, so that one trip a week is sufficient attention for the entire equipment. When the fan was installed, there was a delay in shipment of the speed con- troller, and the fan was connected direct and run at the normal speed of the motor. The fan gave so much air that it became necessary to cover one-half of the discharge opening with a temporary wood brattice to enable the miners to hold a light anywhere in the workings. The fan is now running at minimum speed, with capacity for 50% increase, to take care of the future growth of the mine. THEORETICAL AND PRACTICAL CONSIDERATIONS IN THE USE OF COMPRESSED AIR Volumetric Efficiency of Air Compressors (By F. D. Holdsworth) . The term "piston displacement" or "displacement capacity," commonly used by air-compressor builders as a measure of capacity, expresses the quantity 344 HANDBOOK OF MINING DETAILS of air which would be delivered by a compressor in which there were no losses to prevent a discharge of a cylinderful of air at every stroke. Certain losses, however, are unavoidable. These include: The reduction of cylinder volume, due to the space occupied by the piston rod; clearance space at each end of the cylinder; leakage past the piston and the inlet and discharge valves; failure to completely fill the cylinder during the intake stroke, due to loss of pressure through inlet ports and passages; rarefaction of the in- coming air by absorption of heat from the air passages and piston. These losses materially reduce the quantity of air actually delivered; and the ratio between the actual delivery and the theoretical displacement, expressed in per cent., is termed " volumetric efficiency." This is sometimes measured from indicator cards by dividing the length of the atmospheric line included within the boundary lines of the card by the total length of the card. Results obtained by this method are misleading, as they invariably indicate that a com- pressor is being operated at greater efficiency than actually is the case. Com- pressors showing efficiencies, as calculated from indicator cards, as high as 95% have been found to have efficiencies of 85% or even less when the actual air delivered was carefully measured. For instance, a compressor, through faulty design of its inlet valves or having insufficient inlet- valve area, might have its cylinder filled with air at 2 Ib. below atmospheiic pressure, which would cause a serious drop in volumetric efficiency, yet with leaky discharge valves or with considerable absorption of heat through contact with heated surfaces, the pressure existing in the cylinder at the completion of the intake stroke might be almost or quite up to atmospheric pressure. An indicator card taken under such conditions would naturally lead to the con- clusion that the cylinder was practically full of air and that its volumetric efficiency was correspondingly high. In order to determine with accuracy the quantity of air actually compressed and delivered, the quantity of air entering or leaving the compressor must be measured. The measurement of the entering air by a gasmeter, for instance, is a troublesome matter, owing to the large volumes to be handled and to the fact that the pulsations of the compressor might affect its accuracy. The calibration of such large meters ; s likewise difficult. Measurement of the air after compression is, therefore, usually attempted. In small compressors the air is sometimes compressed into receivers of known capacity or is measured by allowing it to displace water in such receivers, the quantity of free air delivered being proportional to the amount of water dis- placed; but a much more convenient method and one which may be applied to compressors of large or small capacity, with equal accuracy and with inex- pensive apparatus and preparation for test, is by discharging the compressed air through orifices of known area and determining the quantity of equivalent free air by calculation. The apparatus for this method consists of a manifold, as large or larger VENTILATION AND COMPRESSED AIR 345 than the discharge pipe of the compressor, with numerous branches having orifices of different diameters attached and equipped with valves. One that I use has eight orifices, ranging from 3/32 to 5/8 in. in diameter. These orifices are carefully reamed holes in steel plates, which, for the larger sizes, are i / 2 in. thick, and for the smaller, 3/8 in. thick. The back or pressure side of the hole has its approach rounded to a radius 1/16 in. less than the thickness of the plate, leaving the remaining i/i6-in. length of the hole cylindrical. After the hole is thus finished, its actual diameter is carefully determined by micrometer and its area calculated. The rate of flow through this type of orifice is obtained by the use of Flieg- ner's formula, the accuracy of which I have verified by carefully conducted tests in forcing compressed air contained in receivers of known volume through these orifices by displacing it with water. It is better to use a number of small orifices, as the formula is known to give unreliable results on orifices much larger than 5/8 in. diameter. The manifold is tapped for a pressure gage and a thermometer well. An accurate pressure gage should be used, as it will be noted from the formula that the quantity of air discharged is directly proportional to the pressure and any inaccuracies in determination of pressure will materially affect the results. A reliable thermometer should be used and for a two-stage compressor should have a scale reading not less than 300 F. Pressure and temperature are the only quantities required to be observed for use in the formula. ' In preparing for a test, the main air line should be disconnected near the air receiver and the orifices attached at that point. All other outlets from the receiver or from the piping between the compressor and the receiver should be either blanked or protected by valves known to be tight, in order to insure that all the air furnished by the compressor will be discharged through the orifices. A thermometer should be placed in the path of the air entering the compressor as near the cylinder as possible. For determining the speed of the compressor, a revolution counter should be attached at some convenient point. In making a test, the proper combination of orifices required to maintain the desired pressure is determined by experiment, and it is usually found necessary to run the compressor for about 2 hours, discharging through these orifices, before the pressure and temperature reach a maximum and remain fairly constant. When this point is reached, an observer, on signal, records the counter reading and another observer begins taking readings, at i -minute intervals, of the pressure and temperature at the orifices. The observer at the counter should then record the temperature at the compressor intake. At the end of 10 or 15 minutes, sufficient pressure and temperature readings will be obtained and the observer at the counter will, on signal, again read the counter; the difference between the last and the first counter reading will give the total revolutions for the interval of the test. Knowing the dis- placement of the compressor per revolution, the total displacement for the 346 HANDBOOK OF MINING DETAILS test period will be the product of the total revolutions and the displacement per revolution. The quantity of air discharged through the orifices, deter- mined by the formula, using the observed data at the orifices, divided by the total displacement, will give the volumetric efficiency. If accurate results are desired, the barometer reading at the time of the test should be known, which may usually be obtained from the nearest Weather Bureau station. This, together with the temperature at the compressor intake, should be used in the formula given below for reducing the pounds of air per second obtained from Fliegner's formula to cubic feet of free air per minute. Fliegner's formula is: AP in which G=flow in pounds per second; A = area of orifice in square inches; P = absolute pressure of the air behind the orifice; T= absolute temperature (F.) of the air behind the orifice. The weight of a cubic foot of air is found by the formula: in which W= weight of i cu. ft. of air; B = barometer reading in inches of mer- cury; and T absolute temperature (F.) at the compressor intake. The following extract, from a test recently made in New York City on a two-stage, direct-connected, motor-driven compressor to determine its volu- metric efficiency, will serve to illustrate the use of the formula. The compressor had a low-pressure cylinder 26 in. diameter, a high-pressure cylinder 15 1/2 in. diameter, each with a stroke of 18 in. The piston rods in each cylinder were 2 1/2 in. diameter. The orifices used were as follows: 2 5/8, 2 1/2 and i 5/16 in. diameter, having a combined area of 1.083 m - The observed data were as follows: Revolutions per minute, 188; gage pressure at orifices, 97 lb.; barom- eter, 30.1 in., or 14.8 lb.; temperature (F.) at orifices, 251; temperature (F.) at compressor intake, 41. Then, per second. Then the weight of i cu. ft. of air at the intake temperature was = 460+41 whence 2 ' 4 ^X6o= 1814.4 cu. ft. 0.0796 of free air per minute delivered by the compressor. This quantity, divided by the actual displacement of the low-pressure pis- VENTILATION AND COMPRESSED AIR 347 ton, gave the volumetric efficiency in per cent. This displacement in this case at the observed speed, with allowance for the piston rod, was found to be 2070 cu. ft. per minute whence =0.8765, or the compressor actually dis- charged 87.65 % of its displacement capacity. Testing Air Consumption of Drills. The apparatus herein described has been satisfactorily used in testing the air consumed by rock drills. As shown in Fig. 245, a vertical air receiver is connected to the compressor line by a i -in. pipe, fitted with a globe valve, and a i-in. outlet pipe is led from the receiver to the drill. Water gages are placed one above the other through- out the entire height of the receiver, and a pressure gage is supplied. At the bottom of the receiver a 3-in. pipe with globe valve, furnishes water, and between the receivei and intake valve a tee connection is provided as a discharge. r Discharge Connection FIG. 245. AIR TANK AND CONNECTIONS. Before starting the test, water is allowed to flow into the receiver until it is just visible in the lower gage, and a chalk mark is made opposite this level. The receiver is then filled with air at the desired pressure, the air shut off and the test begun. As the drill takes air from the receiver, the operator maintains a constant pressure by regulating the water valve. Simultaneously with the stopping of the machine a chalk mark is made at the water level then shown by the gage and the water drained off in preparation for the next test. The distance between chalk marks, depth of hole drilled and time of drilling are noted. The cross-section of the tank being known, the distance between the chalk marks makes it possible to find the volume of air used, at the given pressure, and from these figures the amount of free air can be computed. 348 HANDBOOK OF MINING DETAILS It may happen, states Coal Age, that in spite of the control provided by the water supply, the air pressure will decrease during a test. In this event, the amount of free air used may be calculated as follows: Let P = Initial pressure, P! = Final pressure, B = Height above initial water level to top of receiver, A = Cross-sectional area of receiver in square feet, R = Rise of water in receiver, in feet, H = Atmospheric pressure. Then each foot rise of water in the tank, represents the consumption of A cubic feet of air and if the pressure had remained constant at P, the volume p_l_ TT of free air used would have been given by VRAX ^ However, the expansion of the air that remains in the receiver, from pres- sure P to P v represents the consumption of a volume of free air equal to /pi TT p I TT\ F x = A (B R) I ^ 1 and the total amount of free air used is then F+ V v It may prove to be simpler to let V represent the initial amount of free air in the tank at pressure P, and V l represent the final amount of free air at pressure P x . Then V=AB^- and VVi will give the amount of free air consumed during the test. Proportions of Air -mains and Branches. The accompanying table, showing the number of branch pipes of a given size that can efficiently be sup- plied with air from a main of given size, is taken from a bulletin issued by the Green Fuel Economizer Co. and is based upon the laws of the flow of air through pipes. The figures in the vertical columns to the left are the diameters of the mains; the numbers at the head of the vertical columns, the diameters of the branch pipes; the other numbers in the table show the number of pipes of the diameter designated at the top of the vertical column, equal to one pipe of diameter designated in the column to the extreme left on the same horizontal line. For example, it is desired to find the diameter of the main equivalent to thirty 8-in. pipes. Follow down the vertical column for 8-in. pipes until the nearest number to 30 is found, then follow out horizontally to the left-hand column. The number there found will be the diameter of the main required, in this example 31 in. Conversely, the number of pipes of a given section that a given main can supply, can be determined from the table. VENTILATION AND COMPRESSED AIR EQUALIZATION TABLE FOR PIPES 349 Diameter of mains Diameter of branches i 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 2 3 4 5 6 7 8 9 10 ii 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 5-7 16 32 56 88 129 1 80 244 3i7 402 5oi 613 737 876 1026 1197 I37S 1580 1775 1985 2250 2525 2800 3060 3425 3738 4100 4440 4898 5312 5631 6i54 6675 7075 7735 8265 8715 2-7 "5.7 9-7 16 23 32 42 56 7i 88 107 129 152 180 208 239 275 312 345 398 460 493 543 590 677 725 800 864 920 1070 1140 1208 1280 1355 1435 1625 2-3 3-6 5-7 8-3 12 16 20 26 32 39 47 56 65 76 88 IOO 114 130 145 160 1 80 202 219 243 265 289 315 344 374 401 433 470 497 537 575 1.8 2.8 4.1 1.6 2.3 i.S 7-6 9-9 12 16 19 23 27 32 37 43 49 56 61 7i 77 88 97 1 08 121 129 141 151 168 184 196 212 229 242 260 279 4-3 5-7 7-o 2.8 3-6 4-5 1-9 2-4 3-i i-3 1-7 2.2 1-3 1.7 i-3 ii 13 16 18 21 24 28 32 35 4i 47 So 55 62 68 74 79 88 96 103 109 119 127 138 146 157 1.2 9-9 ii 13 16 18 20 22 26 29 32 35 39 43 48 52 56 59 63 70 76 82 88 94 IOO 6-7 4.8 3-6 2.8 2.2 1.8 1.4 I .2 1.2 i-3 i.S i-7 10 12 14 15 18 20 22 4 27 29 32 35 38 40 42 45 Si 56 60 64 68 7-7 8.8 5-7 6.5 4-3 5-0 3-4 3-9 2.8 3-2 2.3 2.6 1-9 2 . 2 1.6 1.8 10 13 14 16 17 19 21 23 25 28 30 32 35 37 40 43 45 49 9-8 10 12 13 14 15 17 19 2O 22 23 25 27 30 32 33 37 7-8 8.9 10 ii 12 13 14 16 i? 18 19 21 23 25 26 29 2.4 2-9 3-1 7-6 8.0 5-7 6.4 4.6 5-2 3-8 4.2 3-2 3-5 9-6 10 ii 12 13 14 15 16 18 19 20 22 7-5 8.3 9- I 9-9 IO ii 12 13 14 16 16 18 6.1 6.8 7-5 8.0 8.9 9-3 IO II 12 13 13 14 5-i 5-7 6.2 6.7 7-4 8.0 8.5 9-1 10 ii ii 12 4-3 4.8 5-2 5-7 6.1 6-5 7-i 7-6 8.4 8.9 9-3 IO 3-6 4.1 4-4 4-7 5-i 5-7 6.0 6.4 7- i 7-6 7-9 8.6 Compressor Precooler. Compressor efficiency can be materially increased in warm weather by a simple and inexpensive precooler. It should be empha- sized in the beginning that water or moist air should have no chance to mix with the compressor suction. Fig. 246 shows how the cooling nest of tubes should be connected by a wood or light iron conduit to the suction valves of the compressor. The nest of pipes can be made up of odd sizes of iron, or even 350 HANDBOOK OF MINING DETAILS tin or galvanized-iron speaking tubes can be used. If water is worth saving it can be pumped back at slight expense, though the flow should be regulated to just the quantity required to keep the pipes wet. These should be wrapped with thin cloth and should be placed in the open, preferably where prevailing winds or drafts will cause a maximum evaporation. As an extreme example of the efficiency of this arrangement, the following may be stated: The difference between the temperatures of wet and dry thermometers at a large plant in California in summer has reached 40, the difference between no and 70. This difference in the temperature of com- pressor intake amounts to over 8%. The arrangement shown in the sketch precludes the saturation of the air with water, as recently complained of in South Africa, where precooling by spraying water directly into the intake was attempted. In fact, if the temperature of the water supply is below the Iron or Tin Pipes wrapped with Cloth FIG. 246. PRECOOLER FOR AIR COMPRESSORS. dew point, and an abundance is available, water will actually be condensed out of the air as drawn to the compressor and can be drawn off from the bottom of the cool-air conduit. Washing Air for Compressors. The site of the compressor plant of the Penn Iron Mining Co. is on a sandy bottom-land at the base of a hill that fur- nishes more or less sand during windy weather. As the result of these condi- tions sand would get into the compressors and cause trouble. A scheme for washing the air was resorted to which is shown in Fig. 247. A concrete box 5 1/2 ft. wide, 5 ft. high and 16 ft. long was constructed. In the bottom of the box three i2-in. cast-iron pipes were laid, extending the full length of the box. The pipe is supported by the end walls. The lower side of the pipe is perforated with the sufficient number of i/2-in. holes to allow the air to enter. Water is placed in the box so as to cover the perforations in the pipe i in. deep. This, however, is adjustable and can be arranged for any depth necessary. The box is covered with plank so that all the air must enter through the water-covered holes in the i2-in. pipe. The intake pipe from the com- pressor enters from the top of the box and does not extend to the water; there- VENTILATION AND COMPRESSED AIR 351 fore it does not take up much suspended water. However, the air does absorb a certain amount of moisture as it passes through the water. To reduce the amount of moisture in the air, the air is cooled as it passes from the first stage of the compressor to the second stage by passing through 150 ft. of water-cooled pipes. A small perforated water pipe is placed above the air pipe to furnish water for cooling the air. There is a trap between the two stages of compression to catch the condensed water. L. F. Armstrong, mechanical engineer for the company, designed this apparatus. FIG. 247. CONCRETE BOX FOR WASHING AIR. Air Compressor Lubrication. Explosions within the cylinders of an air compressor are usually caused by the ignition of inflammable gas, the presence of which is due to the use of too much lubricating oil of low flash point. The heat liberated from the air during compression may cause vaporization of the oil and the vapor mixing with the compressed air forms an explosive mixture that may be ignited at the temperature attained by the air in the cylinder. Excessive use of oil is open to the further objection that oil tends to cause sticking of the valves. Ordinarily, air cylinders and pneumatic tools require less oil than steam cylinders. A lubricant that is free from the above-mentioned objections to the use of oil is soapy water, with which a small quantity of flake graphite has been mixed. The flakes of graphite remain suspended in the water until admitted to the interior of the cylinder, where they exhibit a tendency to attach themselves to the metallic surfaces, imparting a superficial glaze that is smooth, acquires a high polish and prevents actual contact of metal with metal. A small quantity of the mixture provides a safe and sufficient lubricating layer. As the soapy water may cause rusting, it is advisable to introduce a little oil into the cylinder 352 HANDBOOK OF MINING DETAILS when shutting down the compressor. The graphite is not affected by any degree of heat attainable in a compressor cylinder; it will not be carbonized or baked into a hard or gummy mass to interfere with the action of the valves, and under no conditions can it be volatilized. Storing Compressed Air in a Natural Rock Receiver. At one of the mines in the Rossland district there are two electrically driven compressors with a combined capacity of 7500 cu. ft. of free air per minute. These machines were described by C. Sangster in Power, Dec., 1909. Air from the compressors is stored in a crosscut the capacity of which is not less than 22,000 cu. ft. In free air compressed to eight atmospheres, it will hold 176,000 cu. ft., or the entire output of the compressors for 23 minutes. Allowing that one-third of this air is available at a working pressure, as cited, ten drills could be operated for 50 or 60 minutes after the compressor was stopped. The advantage of such a large storage is noticeable in the engine room. It tends to balance the rapid fluctuations in the load, the compressor and rope drive run more steadily and the unloaders cut out less often. The motors are not subjected to the strains of the load being constantly thrown off and on. In the mine, a hoisting engine or a group of drills rnay be thrown on or off without seriously affecting the air pressure. In short, it stores and restores the air, piling up a reserve when a machine is stopped and giving it back when a sudden call is made. Using a Pump for Compressing Air. It is occasionally desirable to use a pump as an air compressor where only low pressures are required, when the "Compressed Air Outlet FIG. 248. PIPING FROM PUMP TO TANKS. work to be done is of only a temporary character and any makeshift will suffice. The scheme is shown in Fig. 248. The drain valve is closed. The pump is then slowly started and when primed the air valve on the suction line is opened just enough to prevent the pump from entirely "losing its water." By proper VENTILATION AND COMPRESSED AIR 353 regulation of this air valve the pump will take in a large volume of air with each stroke and just enough water to keep the plungers and valves fairly well sealed. When a pressure of 8 or 10 Ib. is reached the air valve on the suction line is closed, the pump takes water and the receiver is nearly filled. This forces the air out of the receiver and increases the pressure at the same time. Should more pressure be desired the air-outlet valve is closed and the re- ceiver is drained into the suction tank. The small valve shown on top of the receiver admits air when the receiver is being drained. The operation men- tioned is then repeated. Incidentally it is not the most economical way of compressing air. Reheating Compressed Air with Steam. The practice of reheating compressed air by mixing it with steam is employed generally in the Cceur d'Alene mines of the Federal Mining & Smelting Co. Results obtained at these mines seem to indicate that this is the most economical and efficient method of getting the full measure of energy from the air. At the Mace mines, air at QO-lb. pressure for drills, and steam for the hoist were formerly conducted the 3000 ft. through the entry tunnel in separate pipe lines. The air is now compressed to 100 Ib., mixed with superheated steam at the compressor house and piped into the mine in one line to supply both hoist and machine drills. The daily saving by this arrangement is figured at about $40, and bes'des an increase of 10 Ib. in pressure is gained for drills. The steam plant formerly required 14 tons of coal per day, while from six to eight tons is all that is burned now. The boiler at this plant is rated at 80 h.p. and the capacity of the com- pressor is 4000 cu. ft. of free air per minute. No trouble has been experienced from either freezing or condensation. Reheater for Air Hoist. The six levels below the Sweeney tunnel, in the Last Chance mine at Wardner, Ida., are reached by an inclined winze contain- ing two skipways and a manway. A compressed-air hoist operated in balance serves these lower levels with skips of 3o-cu. ft. capacity. Trouble was experi- enced from the hoisting engine freezing, so that reheating of the air had to be resorted to. Gasoline torches playing on a coil of air pipe were tried, but with poor success, until finally the scheme now used was hit upon. A 3-in. perfor- ated air line is run into the drum of a 4O-h.p. fire-tube boiler, the air passing up through the heated water and being piped to the hoist from the steam chamber. A check valve is used on the air line before it enters the boiler, so that as the reheated air is drawn to the hoisting engine, more air is admitted to the boiler, but, at the same time, water is prevented from backing into the air pipes. The air pipe in the boiler is closed at its end and drilled with i/4-in. holes, through which the air escapes. With the reheater, the air pressure is raised from 5 to 15 Ib., depending upon the rate of consumption, and no trouble is experienced from the hoist freezing. Only a small wood fire is kept under the boiler, not more than 3/4 cord of slab wood being burned per 24 hours. Electric Reheaters. At the Bully Hill copper mines in Shasta county, 23 354 HANDBOOK OF MINING DETAILS Calif., a novel type of reheater is used in connection with pumps operated by compressed air. The arrangement is an electrical resistance coil inclosed in a pipe through which the compressed air passes directly before being utilized. The arrangement was worked out by H. A. Sutliffe, electrician for the Bully Hill Copper Mining & Smelting Co., and has proved thoroughly satisfactory. The reheater consists of two principal parts, i.e., an outer jacket and an inner length of pipe upon which is wound the resistance wire. The air line is bushed to the pipe jacket and through this jacket are tapped, as shown in Fig. 249, two i/2-in. holes provided with insulated stuffing boxes through which the flexible lead wire is connected to the resistance coil. Asbestos Packing shing n 4 Pipe Flexible Feed Wire Galv. Iron Wire 8 turns per Mica Cloth / 0.01" thick' \ I! V ft V \ \\ \ \\\ N> v\ *\ V \ A Paper ft \\. \\ \\ \\ \\ \\ \v \\ n v T>- \\ w \\ \\ *--^" * lf *- JP y//////> k 26 long Detail of 2"Pipe FIG. 249. ELECTRIC .REHEATER USED AT BULLY HILL, CALIF. In the design shown the resistance coil is wound on a section of 2-in. pipe, 26 in. long, the jacket pipe being 4 in. in diameter. The central pipe is first wrapped with i/8-in. asbestos paper, and this in turn covered with mica cloth o.oi in. thick. Over this is wrapped a helix of No. 14 galvanized-iron, tele- phone wire pitched eight turns to the inch. At points i in. from either end, the central pipe is tapped for set screws, at four equally spaced points about its circumference. These set screws serve to keep the resistance coil from touch- ing the outer pipe jacket. The wire coil is so wound as to not touch the set screws. A reheater, as described, is designed for a no- volt 40-ampere current and will use approximately 6 h.p., yet at the Bully Hill mine a saving of at least VENTILATION AND COMPRESSED AIR 355 $6 per month has been effected, it is claimed, by each reheater installed. The reheaters are credited with raising the available air pressure 5 Ib. With the electric reheater it is well to have the valve controlling the air engine, pump, etc., for which the air is being heated, connected with a pilot light, so that when the engine is shut off, attention will be called to that fact at once and the reheater will be disconnected. If this is not done there will be danger of burning out the reheaters as they soon become hot enough to destroy themselves if allowed to run after the air is cut off. Placing Air Pipes in Shafts. Extensions of the compressed-air mains in the Champion shafts of the Copper Range Consolidated Co., in the Lake Superior copper country are made in 20o-ft. lifts. The work is commenced by placing a tee in the shaft opposite the station at the bottom of the lift ; then carrying up the piping for 200 ft. to connect with the air main already in posi- tion. The tee at the lower station is securely fastened by an iron yoke to a carrier timber. The pipes are then lowered and put together until the next level above the station is reached. There another tee is put in the line imme- diately above and below which yokes are used both to anchor the main and to prevent swinging at that point. When this tee has been put in place the other pipes are lowered and, by using a pipe of the necessary length, the top of the extension is brought to within 6 or 8 in. of the bottom of the main already in place. A flange is screwed tightly home on the upper end of the top pipe and yokes are attached to anchor the line in position. The connection with the part of the main already in place is made after i p.m. on Saturdays at which time no drills are running in the mine so that the air can be shut off without interfering with mining work. Jacks are placed under the lower end of the extension pipe and the yokes are loosened so that all the weight comes on the jacks. The blind flange on the lower end of the part of the shaft main already in place is removed. The flange on the upper end of the extension is turned in the direction of unscrewing so that the bolt holes in upper and lower flanges are in line. The little loosening usually necessary does not cause leakage. Then the 2oo-ft. length of pipe is raised by the jacks until the flanges come tight together. The flanges are then bolted together, usually with a gasket between to make a tight joint. The yokes, of which there are two for each ico-ft. length of pipe, are then tightened to hold the main in position. During the operation, large wrenches are used to prevent turning of the upper part of the line when the extension is being raised. Making the connection takes an hour; two men are needed at the jacks, four at the yokes and two, with the boss timberman at the point where the connection is made. A Method of Hanging Air Pipes (By Claude T. Rice). The Copper Range company intends to connect its different properties in Michigan so that in case a compressor breaks down at one mine air can be delivered to it from another. Already the Trimountain and the Baltic mines are connected in this manner. The air pipe is carried above ground so that any leaks can be read- 356 HANDBOOK OF MINING DETAILS ily detected. Supports of the type shown in Fig. 250 are used. Timber legs have been used, this having been found a good way to employ old pipe. Any old piece of 2-, 2 1/2- or 3-in. pipe or old boiler tube 8 ft. or more in length was used for the legs. This pipe was bent to a radius of 12 in. at the middle and the legs given a spread of i in. in 4 in. Each piece of pipe was flattened at the top and a i-in. hole punched through it to receive the 3/4-in. hanger bolt that holds the air pipe. These pipe supports are footed in concrete pedestals about 24 in. on an edge and buried in the ground. The under surface of the top of the pipe is set to grade so that a constant and standard length of hanger can be used in suspending the pipes from the supports. Support Support /Support Support ~ Dotted Lines /indicate Swing from Expansion. Supporter) FIG. 250. OLD-PIPE SUPPORTS FOR AIR MAINS. These supports are placed along the line at a maximum interval of 25 ft. No expansion joints are used in the entire line which is about 11/2 miles long. Instead the expansion that would occur in the line with a change in tempera- ture of 100 F. is figured for each straight stretch of pipe. This stretch of pipe is anchored at the middle, and the expansion is taken care of by the side swing of the pipes at the turns, or changes in direction. In case this is too much to be taken care of in that way with the ordinary course of the pipe a double-angle turn or reverse bend is put in long enough to allow the expansion VENTILATION AND COMPRESSED AIR 357 to be taken up by the swing of the pipe at this turn without danger of loosening the joints. Often this turn is anchored in the middle so as to take care of the expansion of two stretches of pipe, but generally each turn is made to serve only one. In case that the stretch of pipe that must take up the expansion is short, the pipes are occasionally put in hot so that the end pipe of the expansion leg is pulled in the beginning in the opposite direction to that in which most of the expansion will occur. Owing to the pipes being suspended in swings at the supports, little resistance is offered to the movement of the pipes, and the expansion can be taken care of easily in this manner. Stopping Leaks in Air Receivers. A convenient method of stopping leaks around a loose rivet in air receivers or steel water tanks, or even for emergency Interior of FIG. 251. TAPER BOLT FOR STOPPING LEAKS. repair work on boilers, and one which can be made entirely from the outside, is to use a taper bolt with copper sleeve, as illustrated in Fig. 251. The head of the faulty rivet is cut off, and the rivet knocked out of the hole or else the rivet may be drilled out. A taper bolt A, large enough to pass through the hole, and threaded up to i 1/2 in. of the large end, is inserted in the rivet hole and a piece of copper pipe B, of the same internal diameter as the diameter of the bolt, is lipped over the threaded portion of the taper bolt; it should project 1/4 to 3/8 in. on each side of the plates. A washer C and nut D are then put on and the nut screwed up with a long-handle wrench. The bolt can be used for withstanding pressures up to 200 Ib. per square inch with safety. The bolt may be used for repairing other small leaks such as may occur in pump columns by drilling out a hole at the point where the leakage occurs. A variety of uses for such a bolt will be suggested by the drawing. Pipe Lines as a Factor in Rescue Work. The introduction of com- pressed-air pipe lines into all the workings of a mine might be utilized to pro- vide fresh air and even food to men imprisoned after explosions or through 358 HANDBOOK OF MINING DETAILS falls. This does not involve much expense, as mines are usually equipped with compressed-air apparatus, and the piping leading into the mine is of such a nature as to withstand considerable damage from the exterior. Telephone wires inserted within the air pipe might also serve a useful purpose in saving life. Water in the Air Line. One of the difficulties attending the use of com- pressed air arises from an accumulation of water in the pipe line. From time to time devices have been suggested to draw this water, some homemade and others of the workshop variety, but perhaps one of the most simple and in- genious forms has recently been developed in England. It possesses numerous advantages, among which may be mentioned automatic action, small size and light weight, which facilitates installation. In Fig. 252 is shown the internal construction of this water ejector. It consists of a gun-metal cylinder with three apertures, two being threaded for pipe, the third being a small hole at the bottom, normally closed by a small FIG. 252. EJECTOR VALVE FOR AIR LINE. cone-shaped valve. This valve forms part of a gun-metal spindle carrying a copper float and provided with a plunger, upon the top of which pressure is exerted by the air in the pipe line. This is balanced by an upward pressure on the under surface of the plunger from the air from the water inlet. Under normal conditions, the pressures on the piston and float are balanced. If, however, water enters the chamber from the water inlet, the float is lifted, its length of travel being limited by a stop, and the water outlet is uncovered. The pipe-line pressure from the water inlet thereupon blows the water out of the chamber, the valve remaining open until ejection is complete. When air blows out of the water inlet, the greater pressure on the top surface of the piston forces the valve down into its seat, and the emission of air is stopped. It is, VENTILATION AND COMPRESSED AIR 359 therefore, impossible for air to escape after the accumulated water has been discharged. In Fig. 253 the method of connecting the valve to the pipe line is shown diagrammatically. Where grit or other foreign substances are likely to get into the pipe line a strainer valve X is inserted at each of the points indicated. Freezing of Compressed-air Pipe Lines (By Stacy H. Hill). In northern countries great inconvenience is caused by the freezing of com- pressed-air pipe lines. The difficulty has been eliminated to some extent at permanent, well-regulated properties by burying the pipe. Even in these in- stallations trouble is often experienced in the smaller lines to blacksmith shop or exploratory shafts, which may be at some distance. A method whereby this difficulty could be eliminated for all time would be acceptable and has been the cause of much study, as nothing disorganizes a force of men so much as the gradual or sudden loss of air supply. Ejecting Valve -Drain FIG. 253. PIPING FOR EJECTING VALVE. In the latitudes where weather from zero to 40 below is occasionally experi- enced, the pipes freeze from the circumference, gradually diminishing the pipe area until the passage is entirely stopped. As a preventive of this, the intro- duction of salt or sal-ammoniac has been found very effective up to the moment of entire blocking of the pipe. At a number of properties a barrel of salt is kept in the engine room and at regular periods, usually at the beginning and middle of each shift, several pounds are introduced into the pipe line just beyond the air receiver. The pressure is then increased by the air compressor and the salt blown through the pipe, flushing out the ice. The quantity of salt necessary is, of course, dependent upon the size of the plant. There is a record of one line transmitting approximately 1000 cu. ft. of free air per minute for 1700 ft., where 2 bbl. of salt were used in the course of the five winter months and completely did away with all freezing troubles. In pipe lines where sags exist, no trouble is encountered by freezing in the dips, as the salt collects as brine, preventing freezing. For quick relief from 3 6o HANDBOOK OF MINING DETAILS a partly frozen line, the pipe is sometimes used as a part of an electrical circuit temporarily until the pipe is warmed sufficiently to blow the ice out. Electric Heater for Air -line Drains (By G. C. Bateman). When the Cobalt power companies first started to supply compressed air on a large scale to the mines, trouble was experienced in the winter by the water from the air collecting in the low parts of the pipe lines and freezing. In the pipe lines of the British Canadian Power Co., this difficulty was overcome by the use of an electric heater, designed by James Ruddick, the general superintendent for that company. The device, as shown in Fig. 254, consists of a heater which is placed in a small box built over the drain cocks in the pipe line. These drain cocks are placed wherever there is a drop in the line, so that the water will drain both ways to the cocks. Heater with coils for 220 volt circuit FIG. 254. ELECTRIC HEATER USED ON COBALT AIR MAINS. The heater, which is placed underneath the drain cock, is so designed that it fits snugly into the box, and a pipe leads from the cock to the outside of the box. This pipe is cut off flush with the box so that there is no danger of freez- ing on the outside. The frame of the heater is made of iX i/4-in. iron, and on this frame insulation knobs i in. in diameter and i 1/2 In. long are mounted back to back, as shown in the accompanying illustration, one bolt being sufficient for the two. The coils are made by winding No. 14 galvanized-iron wire on a y/8-in. rod, each coil consisting of 100 turns. The heater takes 220 volts, each coil being equivalent to u volts and 20 amperes. The coils are arranged so that there is at least an inch of space between them. There is a double-pole switch with 3o-ampere fuses in each box and the wiring is mounted on cleats to prevent fire. Although the heater takes only 20 amperes the stronger fuses are used to take care of the current when starting, as the coils take more current when cold than when warm. The power required is 4 kw. for each heater. VENTILATION AND COMPRESSED AIR 361 The British Canadian Power Co. controls about 15 miles of pipe line be- tween 6 and 10 in. in diameter, and several miles of smaller sizes. There are about 25 heaters in use, and since their installation no trouble from freezing has been experienced. This device can be used advantageously wherever there is trouble from the freezing of surface lines, and as it is a simple device it can be built at the property. For pipes of smaller diameter than those mentioned, a heater of about half of the capacity of the one described can be used, in which case it would be necessary to have current at 1 10 volts, or less, and sufficient coils can be connected in series, to suit the voltage available. To increase or lower the voltage of the heater, it is only necessary to add or take out coils as the case may be. Should it be found that the heater does not warm up sufficiently, a coil or so can be cut out. INDEX Abandoned shafts and open cuts, 12 Acetylene lamps, 10 Adams mine, 242 Addy, G. E., 46 Adits and drifts, driving, 101 Aerial tramways, 215 Air blast, hydraulic, 335 -compressor lubrication, 351 compressors, volumetric, efficiency of, 343 escape on small pump columns, 316 exhaust, preventing freezing of, 59 for compressors, washing, 350 -hammer drilling in sticky ground, 46 drills, boring flat holes with, 60 hoist, reheater for, 353 lifts and eductors, 319 -mains and branches, proportions of, 348 pipes, hanging, 355 receivers, leaks in, 357 Allen, Robert, 50 Allouez mine, 12 Amalgamated Copper Co., 265 American Museum of Safety, 276 Anaconda gates, 295 Anchoring wire ropes, 220 Anderson, A. E., 24 Anderson, W. S., 319 Angels Quartz mines, 149 Arentz, S. S., 147 Argonaut mine, 123, 132, 285 Arizona-Parral Mining Co., 323 Armstrong, L. F., 146, 351 Automatically discharging bailers, 248 Automatic bucket dump, 257 -tripping device, 253 cut-off for electric pumps, 315 skip for inclined shafts, 240 switch, 302 trip for ore cars, 271 Automobile in mining, 9 Austin-Manhattan Consolidated Mining Co., "5 Aymard's dust collector, 65 B Back stoping, modified system of, 122 Baggaley, W. B., 259 Bailers, automatically discharging, 248 Balaklala aerial tramway, 218 Ball-bearing turntable, 305 Barbour, P. E., 132, 166, 313 Bateman, G. C., 360 Baltic mines, 355 Battery method of stull timbering, 134 Belen mine, 315 Benito Juarez Mines Co., 323 Birmingham district, tipple construction, 167 Bisbee mines, 336 Blackberry mine, Mo., 28 Blackburn, Ward, 46 Black Mountain Mining Co., 166, 240 Blasting and handling of explosives, 24 cap, 25 gelatin, 35 in stopes, method of, 125 in wet shafts, 29 placing holes for, 102 preparations for, 26 Boericke, W. F., 247, 289, 338 Bohn, J. V., 144 Bolts, securing loose rock by, 74 Bonanza Flat section, Utah, 112 mine, 263 Bonus system, 70 Boring flat holes with air-hammer drills, 69 Boston & Ely mines, 201 Boston & Montana Co., 317 Botsford, H. L., 81, 243, 244, 283 Boudoire, Louis, 320 Breast stoping, placing holes in, 125 Bristol mines, 195 British Canadian Power Co., 360-361 Brockunier, S. H., 194 Brown Engine Co., 202 Brown, H. Lawrence, 53 Brown, H. S., 126 Bryant safety crosshead, 280 Bryant, Thomas, 280 363 364 INDEX Bucket cars, Joplin, 225 drill-steel, 222 dump, automatic, 257 Mineville ore, 224 -tripping device, automatic, 253 trolley for shaft sinking, 72 Buckets for winze, self-dumping, 257 mine, 222 sinking, 259 tramway, 219 Bulkheaded ore chutes, 141 Bully Hill Copper Mining & Smelting Co., 354 Bully Hill copper mines, 353, 354 Bunker Hill & Sullivan, 234 mine, Calif., 97, no Bunks, improvements in, 13 Burke mines, 257 Burra Burra mine, 144, 267 Butte-Alex Scott Copper Co., 69 Butte Coalition Co., 317 rapid shaft sinking in, 69 Cable clamp for tramway, 216 drum for lowering timber, 194 old, uses for, 186 Cables, flat wire, device for cleaning, 210 Cableway hoist problem, solution of a, 215 Cage, Hiawatha mine, 243 landing chairs for, 289, et seq. light mine, 244 safety catch for, 283 three-deck man, 243 Cages, safety gates for, 293 testing safety devices, 287 Calumet & Hecla Co., 30, 137, 159, 186, 205, 206, 231, 306 mines, 55, 57, 82, 134, 135, 136, 194, 251, 286 ore cars, 231 Calumet system of lighting fuse, 30 Camp Bird mine, 74 Cananea arc type gate, 152 mines, 152 ore bins, 170 Candle tests, 30 Car, Copper Range man, 235 mine, side-dump, 229 turntable for, 305 stopping devices on gravity inclines, 187 water, 250 Car, wooden ore, 226 Carbon dioxide criterion for ventilation, 332 Carriers, special, 247 Cars, mine, cradle for dumping, 230 hoisted per hour, determining the num- ber of, 182 Cartridges for tamping, 32 Catenary hoisting cable, 192 Centennial-Eureka ore, pocket and gate, 140 Cerro de Pasco mines, 170 Cerro Prieto mine, 240 Chain ladders in waste chute, 130 Chairs, landing, 289 on headframe, 287 on the cage, 291 skip, at Argonaut mine, 285 Champion mine, 62 Chapin mine, 61, 293 Charts, labor and tonnage, as aids in reducing costs, 7 Checking men in and out of mines, i Cheever Iron Ore Co., 186, 228, 270 mine, 263 "Chinaman," modified, 146 Christensen, A. O., 106, 107, 325, 333, 335 Chuck bolts, shaping, 53 for piston drills, 52 Chute, bulkheaded, 141 device for clearing hung-up, 38 draining, 325 gate at Mammoth mine, Kennett, Calif., 149 steel arc, 152 skip loading, 158 City Deep, Ltd., 159 Cleaning drill holes, 58 flat wire cables, 210 Clermont mine, 121, 167 Cleveland-Cliffs Iron Co., 242, 302 Clunes mines, 138 Coal lift, simple form of, 196 Cceur d'Alene district, 234, 334, 353 mine car, 234 Cost sheets, standard, 3 Colby mine, 277 Cole, N.H., 219 Coleman, F. H., 316 Collins, F. W., 177 Columbus Consolidated mine, 313 Combination post and set timbering in shafts, 82 timber hoist and winch, 198 INDEX 365 Comparative strength of several styles of framed timber sets, no Compressed air. See also Air. pipe lines, freezing of, 359 storing in a natural rock receiver, 352 use of, 343 Compressor precooler, 349 Compressing air by water pump, 352 Comstock Lode, no, 114, 117 Concklin, B. M., 109, 127 Concrete chute bridging a level, 194 in inclined shafts, 90 floors for shaft stations, 97 powder house, 42 reinforced, in a tunnel, 112 storage bin, 175 uses of, 88 water column, 317 Cone friction for mine hoists, 199 Continental Zinc Co., 317 Conundrum mine, 341 Convenience and protection of employes and equipment, 10 Copper King mine, 146 Mountain mine, 166 Queen mines, 119, 229, 340 Range Consolidated Co., 41, 62, 209, 235, 237, 355 man car, 235 ore skip, 235 mine, 53 227 330 Corner framing of shaft timbers, 75 Cornwall mines, 101 Counterbalance for skips, 242 Cradle for dumping mine cars, 230 Crane for changing skips, 267 Crimping fuse caps, 26 Cripple Creek district, 105 Crosshead, Bryant safety, 280 Crossheads and safety catches, 277 Crossover switch, calculating, 300 Crushing ore underground, 144 Cummings, A. J., 228 Cutting fuse, 26 timber by small hammer drills, 59 Cyanide tailings for stope fillings, 127 Daly West mine, 121 Dam, strength of a, 23 Dangerous ground on the Mesabi Range, 127 Deep sinking with gasoline hoists, 201 De Lashmutt, I., 9 Del Mar, Algernon, 143 Detonating high explosives, 37 Detonators, necessity for strong, 37 Deutschland mine, 192 Diamond hitch, 17 Dietz, J. H., 343 Disposal of waste, 22 Dixie Queen mine, 9 Doe Run mines, 289 Donnelly, J., 121 Doors, mine, 339 Drainage, mine, 343 Draining an ore chute, 325 a shaft through a drill hole, 323 with well points, 324 Drifting with stope drills, 105 Drift timbering for heavy ground, 117 timbers, joint for, 119 Drill bits, design of, 46 mechanical sharpeners, 50 for soft ground, 46 holes, cleaning, 58 ejecting sludge from, 51 in opencut and tunnel work, 103 post collar, 53 with removable screw, 53 -steel bucket, 222 bundling of, 61 steel handling at Champion mine, 62 Drilling into misfired holes, 31 with double screw columns, 60 Drills in wide stopes, scaffolding for, 124 removing stuck, 56 testing air consumption of, 347 Driving adits and drifts, 101 inclined raises with stoping drills, 106 in loose ground, 114 vertical raises with stoping drills, 107 Drums, rope capacity of, 184 Du Bois, W. F., 252 Ducktown mines, 144 Dumping devices, 253 skip for winze, 240 Dunn mine, 86 Dust arresters, 64 prevention on the Rand, 64 water blast for allaying, 67 Dwyer dust arrester, 66 Dynamite, 25 thawing, 42 366 INDEX Eagle Foundry & Machine Co., 343 Economics of management, i of practice, 60 Edgerton mines, 138 Edholm, C. L., 317 Eductors, mine, 323 Electric heater for air-line drains, 360 pumps, automatic cut-off for, 315 reheaters, 353 turbine pumps, unwatering a mine with, 313 signal device, 213 signals for underground tramways, 212 Electricity, thawing dynamite by, 44 Emergency chairs on headframes, 287 Employes and equipment, convenience and protection of, 10 Englebach Machinery Co., 323 Enterprise mine, 325 Equalization table for pipes, 349 Erie mine, 194 Esperanza mine, 302 Expansion joint for pipe lines, 317 Explosives, "don'ts" in using, 24 handling of, 24 storage of, 40 False set for spiling ground, 115 Fast drifting, 101 Fay, A. H., 189 Federal Mining and Smelting Co., 95, 234 257, 258, 278, 353 Finger-pin timbering in swelling ground, 117 Finger chute, 152 Fisher, F. L., 295 Flat rope vs. round rope, 184 Fleming, W. L., 112 Floessell, W. H., 298 Forell, J. H., 58 Fort Wayne electric drill, 57 Foundation Co., 89 276 Fox, J. M., 164, 173 Framing for tunnel sets, no of round timbers, 132 Franklin mine, 237 lo-ton skip, 237 Freezing of air exhaust, preventing, 59 of compressed-air pipe nlies, 359 Fremont Consolidated mine, 87 Frog, mining track, 299 Fuller, J. T., 31, 34 Fuse, table for cutting, 28 Calumet system of lighting, 30 Fuses, 25, 26, 27 Gate for controlling mine water, 329 for lump-ore bin, 150 for ore-bin chutes, 143 for ore chute, 149 Gates for shafts, 294 Geronimo mine, 323 Gold Cliff mine, 199 Goldfield Consolidated fire equipment, 16 mines, 12, 14, 118, 121, 147 stoping at, 121 Goodale, S. L., 195 Gowganda district, 223 Grade in driving, maintaining, 101 Granby Consolidated Co., 159 Graphic solution of skip loads 177 Gravity planes at Cheever mine, 186 draining, 327 tram switch, 301 Great Fingall mine, 329 Green Fuel Economizer Co., 348 Grether, W. S., 212 Grizzlies, underground, 144 Grouting in Quicksand, 94 Guard rail and fastening, 299 Guards at shaft stations, 296 Guiding a drop shaft, 89 Guides in shafts, supporting, 86 Guy-rope tightener, 2 1 Gwin mine, 267 H Hammer drills, cutting timber by small, 59 Hancock, H. L., 137 mine, 54 Hand bell signal wiring, 214 Handling drill steel at Champion mine, 62 Hanging air pipes, 355 Harmony A mine, 263 B mine, 263 Harness for lowering mule down a shaft, 247 Harris, H. E., 60 Hartman, W. F., 97 INDEX 367 Haulage system, underground, 189 Headframe for a prospect shaft, 164 for a winze hoist, 165 Headframes, chutes, pockets, etc., 149 emergency chairs on, 287 tipples and derricks, 163 wooden, details of, 167 Head gears, overwinding, allowance in, 167 Heavy ground, drift timbering for, 117 method of mining in, 112 Hecla mine, 59, 334 Hematite mine, 198 Herbst, Professor, 185 Hiawatha mine cage, 243 High explosives, use of, 34 Highland Boy mine, 7, 170, 216, 218, 219, 220, 305 Hildesia shaft at Dickholzen, 93 Hill, S. H., 59, 359 Hitches, moil for cutting timber, 59 Hoisting and transportation, 177 Hoisting-bucket hooks, 273 Hoisting cable run through a drill hole, 192 cables, double, 192 determining the rope speed in, 182 drums, rope capacity of, 184 ropes, remarks on, 185 snatch blocks applied to, 195 station, underground, 190 thimble for, 276 uses for old, 186 with wire guides, 193 Hoisting cages, 5 Hoists, 195 cone friction for mine, 199 deep sinking with gallsone, 201 safety hook for, 274 sheave supports for, underground, 205 steam' and electric, interchangeable arra- rangement for, 199 steam, for shallow mines, 202 underground, 166 Holdsworth, F. D., 343 Holler, F. W., 336 Holley, C. E-, 277 Homestake company, 304 mine, 304 Hooks and thimbles, 273 hoisting-bucket, 273 safety crane, 274 Hoster, M. T., 26, 310 Houses, portable, 14 Humes, James, 115 Hung-up chute, device for clearing a, 38 Hydraulic air blast, 335 lack of oxygen in, 332 Idler for ho sting rope in inclines, 209 rope guard for, 206 Inclined shafts, concrete in, 90 Injection of grouting behind shaft tubbing, 93 Inspection department of the Goldfield Con- solidated, 1 6 Institution of Mining and Metallurgy, 3 Interchangeable arrangement for steam and electric hoist, 199 International Smelting & Refining Co., 220 Iron Blossom mine, 86 Ives, L. E., 72 J Jack for machine drill columns, 55 Jackson, C. F., 157 James water blast, 67 Johnson, F. L., 19 Joint for drift timbers, 119 Joker m'.ne, 263 Joplin bucket cars, 225 cars for boulders, 227 district, 124 scraper and loading stick, 35 Kennedy, F. A., 88 Kennedy mine, 101, 117, 254, 263 Kenner, A. R., 297 Keystone mine, shaft timbering at the, 79 Klug, G. C., 329 Knots and ties, 17 Labor and tonnage charts as aids in reducing costs, 7 wasting and labor saving, 4 Lake Shore Engine Works, 244 Lament, D., 307 Lamps, acetylene, 10 Landing chairs, 285 chair for cages, 289, el seq. for skips in inclines, 286 Laning-Harris Coal & Grain Co., 343 La Noria mine, 333 3 68 INDEX La Ojuela mine, 193 Last Chance mine, 353 Latrine, sanitary underground, 14 Lay, Douglas, 43 Le Fevre, S. L., 151, 190 Leonard mine, 42, 266 shaft No. i, 317 Leschen & Sons Rope Co., 143, 184 Leyner drill, 64 Lift, simple form of, 196 Lighting fuse, Calumet system of, 30 Lining for ore chutes, 142 Loading holes, 27 Loose ground, driving in, 114 Lumber, scheme for transporting, 252 Lump ore bin, gate for, 150 Lunt, Horace, 105 M Machine drill columns, jack for, 55 MacCoy, F., 302 MacGregor, A. H., 211 Mace mines, 334, 353 Magazines, powder, 40 May, Lawrence, 257 McDonald, P. B., 60, 102, 213 McFarlane, G. C. 85 McGill, M. J., 210 McMillen, D. A., 78 Mammoth Copper Mining Co., 149 Management, economics of, i Measuring pocket for an inclined shaft, 160 for skips, 157 Mendelsohn, Albert, 53 Mesabi district, 22, 37 mining dangerous ground, 127 steel shaft sets, 88 Miami Copper Co., 265 Mine air-door, 340 buckets, 222 cages, 243 drainage, 323 dust prevention on the Rand, 64 eductors, 323 road, cheap, 194 signal-switch, 211 track, 297 Mineville ore bucket, 24 Mining records, i Regulations Commission, 331, 332 track frog, 299 Misfired holes, drilling into, 31 Missouri zinc district, 21 Mitten, L. F., 177 Modified " Chinaman," 146 system of back stoping, 122 Mohawk mine, 58, 97, 306 Moil for cutting timber hitches, 59 Montana mines, 28 Morin safety crosshead, 277 Morning mine, 95, 234, 258 Morse, A. J. & Son, 16 Mother Lode, 117, 138, 141, 267 Mount Morgan mine, 39 Munro Iron Mining Co., 81 N Nagel, Oskar, 323 National Tube Co., 274 Negaunee mine, 213 Nelson, S. T., 202 Nevada-Douglas Copper Co., 147 Newberry, A. W., 315 Newport mine, i Nipissing mine, 277 Norden, F. F., 276 North Kearsarge shaft, 160 North Star mines, 52, 229 O Oiler for tramway buckets, 219 Oiling tramway track cables, 218 Oke, A. L., 152, 163, 220, 307 Oliver Iron Mining Co., 44, 109, 287 Ore bins, 170 gate for, 150 -bin chutes, gate for, 143 car, wooden, 226 cars and skips, 226 automatic trip for, 271 chute construction, 147 draining an, 325 gate for, 149 chutes, 140 bulkheaded, 141 lining for, 142 safeguarding, 142 crushing plant underground, 144 houses and bins, 6 pocket, underground, 161 pockets, Red Jacket, 159 skip, Copper Range, 235 INDEX 369 Original Consolidated mine, 154, 265, 280 self -dumping skip, 265 Osceola Consolidated, 207 mine, 55 Overwinding allowance in head gears, 167 device for prevention of, 210 Oxygen, lack of, in hydraulic air, 332 Parrish, K. C., no Partitions in shaft, necessity for, 75 Pa^coe, R. H., 257 Patton, W. H., 79 Penn Iron Mining Co., 10, 350 Petersen, P. H., 304 Pickands-Mather mines, 212 Picking floor, movable, 146 Pillars, recovering ore from, 124 Pipe lines as a factor in rescue work, 357 expansion joint for, 317 Piping arrangement for fan blower, 337 Piston drill, 58 drills, chuck for, 52 Pittsburgh mine, 335 Pittsburg-Silver Peak mine, 152 Poderosa mine, 291 Pohle air lift, notes on, 319 Portable houses, 14 winch, 198 Port Henry Iron Ore Co., 263 Powder house, concrete, 42 with concrete roof, 41 magazines, 40 storage underground, 42 Power required to haul cars on various fitches, 184 Practice, economics of. 60 Primer, 26 Priming with electric fuse, 38 Prospect shaft, headframe for a, 164 Pump cylinder, repairing, 316 formula, 307 station at Leonard mine, Butte, 317 Pumping and draining, 307 Pumps, electric, 314 for fire protection, 315 sinking, 310 Pursers' dust arrester, 64 Quicksand, grouting in, 94 Quincy mine, 54 Ragged Chutes mines, 332 Rainsford, R. S., 124, 285 Rand drill steel and bits, 50 Ray Consolidated mine, 143 Recovering ore from pillars, 124 Red Jacket ore pockets, 159 shaft, 186, 205 workings, 136 Reh eater for air hoist, 353 Reheating compressed air with steam, 353 Reinforced concrete in a tunnel, 112 Repair shops, underground, 12 Republic Iron & Steel Co., 10, 12, 167, 170 mine, 189, 192, 198 Rescue work, 13, 357 Rice, C. T., 7, 10, 16, 41, 56, 82, 94, 134, 170, 216, 227, 229, 355 Richards, S., 286 Richards, W. J., 237 Rigging ladders to reach stope backs, 128 Road, mine, 194 Robinson Deep mine, 50, 127 Rock drills, 46; see also Drills Rogers shaft at Iron River, Mich., 81 Rope capacity of drums, 184 guard for idler, 206 idlers for inclined shafts, 206 speed in hoisting, determining the, 182 wire splicing, 19 wound on a drum, determining the amount of, 183 Ross mine, 339 Round timbers, framing of, 132 Rubidge, F. T., i Ruddick, James, 360 Ruttle, Joseph, 216, 218 Safeguarding ore chutes, 142 Safety appliances, 12, 273 catch for cage, 283 crane hooks, 274 crossheads for hoisting buckets, 277 device for cages at the Chapin mine, 293 dump for sinking bucket, 254 gate for cages, 293 hook for hoists, 274 37 INDEX Salt Lake Copper Co., 240 "Sand filling" stopes in the Transvaal, 126 Sand Grass shaft, 164 Sangster, C., 352 Sanitary underground latrine, 14 Santa Gertrudis Co., 323 Sargeson crosshead, 277 Scaffolding for drills in wide stopes, 124 Scheer, Charles, 14 Scranton mine, 157 Scraper for cleaning stopes, 251 Semple, C. C., 60 Self-acting mine doors, 339 tipple, 268 Self- dumping bucket for winze, 257 Severy, C. L., 291 Shaft gates, 294 sinking at Stella mine, New York, 71 at the Pioneer mine, 68 Butte-Alex Scott Copper Co., 69 station in inclined foot wall shaft, 94 stations and skip pockets, 94 concrete floors for, 97 timbering at the Keystone mine, 79 timbers, corner framing of, 75 extending, 78 holding with wire cables, 87 placing, 86 two-way, 73 work, 68 Shafts, inclined, rope idlers for, 206 placing air pipes in, 355 strong partitions in, 75 use of steel and concrete in, 88 Shallow mines, steam hoists for, 202 Shaping chuck bolts, 53 Shears, three-leg, 163 Sheave supports for underground hoists, 205 Sheaves, arrangement of, at the Tobin mine, 206 Shelton, Thomas, 323 Shenango Furnace Co., 88, 203 Sherman, Gerald, 229 Shoemaker, G. M., 299 Shops, underground repair, 12 Short, J. M., 323 Shoveling in square-set stopes, eliminating, 123 Side-dump mine car, 229 Signal device, electric, 213 switch, Baltic mine, 211 wiring, hand bell, 214 Signals for underground tramway, 212 Sinking buckets, method of handling, 259 pump and its troubles, 310 Skip and dump plate for vertical shaft, 238 chairs at Argonaut mine, 285 changing device at Leonard No. 2 shaft, 266 dumps in New York iron mines, 261 Franklin zo-ton, 237 improvements, 242 loader at the Original Consolidated, 154 loaders, 154 loading chute, 158 Original Consolidated self-dumping, 265 pocket and station at Leonard mine, Butte, 98 pockets, 97 and shaft stations, 94 timber, 242 Skips, cages, cars and buckets, 222 crane for changing, 267 measuring pocket for, 157 Slicing system, stoping with the, 121 Smillie, Sheldon, 90 Smith mine, Mineville, N. Y., 263 Snake Creek tunnel, 112 Snatch blocks applied to hoisting, 195 Soft ground, drill for, 46 South Eureka mine, 141, 242 Speaking tubes in mines, 12 Spike, new track, 298 Spiling ground, false set for, 115 Splicing wire rope, 19 Splitting and spitting the fuse, 27 Square-set stopes. eliminating shoveling in, 123 Staging, staple for temporary, 109 for high set-ups in stopes, 129 Standard cost sheets, 3 ore chute, 147 Staple for temporary staging, 109 State, B. A., 301 Steam hoists. See Hoists. shovels, breaking ground for, 37 Steel and concrete, uses of, 88 ore chute for use in high-grade stopes, 140 in shafts, uses of, 88 shaft sets on the Mesabi Range, 88 Steinem, Chester, 253 Stella mine, shaft sinking at, 71 Sticky ground, air-hammer drilling in, 46 INDEX 371 St. Lawrence Pyrites Co., 71 St. Louis & San Francisco R. R. Co., 22 Stobel, E. G., 313 Stoltz, G. C., 150, 186, 214, 223, 250, 261, 270 Stone, C. J., 69 Stope backs, rigging ladders to reach, 128 filling, cheap, 126 cyanide tailings for, 127 tram car for, 227 sets, leaning, 132 Stopes, high-grade, steel ore chute for, 140 scraper for cleaning, 251 staging for high set-ups in, 129 timbering wide, 137 Sloping, 121 at Gbldfield Consolidated, 121 drills, driving inclined raises with, 106 vertical raises with, 107 with the slicing system, 121 Stopping flow of water from a drill hole, 329 leaks in air receivers, 357 Storage bin, concrete, 175 of explosives, 40 Storms, W. H., 17, 75, 79, 248 Stuck drills, removing, 56 wrench for removing, 56 Stulls, placing and cutting, 130 Stull timbering, battery method of, 134 Sulphur Mining & R. R. Co., 226, 268 Sunnyside mine, 14 Sutliffe, H. A., 354 Swelling ground, finger-pin timbering in, 117 timbering, 85 Switch, automatic, 302 calculating a crossover, 300 double-gage turnout, 302 gravity tram, 301 Switch-throwing device, 304 Tailings for filling, 22, 127 Tail-rope haulage operated by skips, 189 Tamarack mine, 137, 306 Tamping, 27 cartridges for, 32 Tank, wagon oil, 253 Tennessee Coal, Iron& R. R. Co., 162, 167, 170, 268, 276 Copper Co., 35, 128, 144, 267 Testing safety devices on mine cages, 287 Tests, candle, 10 Thawing dynamite, 42 by electricity, 44 Thimble for hoisting cable, 276 Three-deck man cage, 243 Three-leg shears, how to erect, 163 Tilden, R. E., 42 Timber, cable drum for lowering, 197 sets, framed, comparative strength of , 1 10 Timbering, 75, no, 130, 134 drift, for heavy ground, 117 in shafts, combination post and set, 82 Keystone shaft, 79 placing sills beneath square sets already in place, 138 swelling ground, 85 wide stopes, 137 Timbers, drift, 119 extending shaft, 78 placing shaft, 86 round, framing of, 132 skip, 242 Tipple construction in the Birmingham District, 167 revolving, 270 self-acting, 268 tram car, 270 Tobin mine, 86, 206 Tonopah Belmont Orehouse, 173 Tonopah Mining Co., 12, 164, 173, 174, 300 ore-houses, 170 Tooele smeltery, 220 Track and switches, 297, 299 spike, 298 Traders' mine, 44 Tram car for stope filling, 227 for the prospector, 223 with automatic door, 228 tipple, 270 Tramway buckets, oiler for, 219 cable clamp for, 216 mine, 126 Tramways, aerial, 215 underground, electric signals for, 212 Transportation and hoisting, 177 Transporting lumber, scheme for, 252 Transvaal Mines Dept., 127 mines, 40, 125 Mining Regulations Commission, 127 Tregear, N. T., 166 Trimountain mines, 355 Tunnel sets, framing for, no Turgeon, F. M., 175 372 INDEX Turnout, double gage, 302 Turntable for mine cars, 305 U Underground haulage system, 189 hoist, 1 66 hoiscing station, 170 ore pocket, 161 powder storage, 42 repair shops, 12 station in a Cceur d'Alene mine, 95 Union mine, Virginia City, Nev., 338 United States mine, 121 tramway, 215 Unloaders and dumping devices, 253 Unwatering a mine with electric turbine pumps, 313 flooded mines, 307 shaft by compressed air, 320 Utah Consolidated Co., 305 Utica company, 199 mine, 130, 149 V Van Roi mine, 43 Ventilating fan, starting automatically, 341 mine workings, 333 stopes in Bisbee, 336 the working face, 335 with compressed air, 334 Ventilation and compressed air, 331 approved practice in, 331 by drill holes, 338 by suction, 333 carbon dioxide criterion for, 332 devices for improving, 333 of Transvaal mines, 331 Vermont Copper Co., 44, 223 Vertical unbalanced loads lifted by first motion hoists, 177 Volumetric efficiency of air compressors, 343 Vulcan Iron Works, 177 W Waldman mine, 277 Wallace, R. B., 293 Wallaroo & Moonta Mining and Smelting Co., 137 mines, 138 Ward-Leonard system of wiring, 205 Warren, W. H., 298 Waste chute, chain ladders in, 130 disposal of, 22 Water blast for allaying dust, 67 car, two-ton, 250 in mines, utilizing, 317 in the air line, 358 Watson, H. C., 193 Webb mine, 203 Wet ground, blasting in, 29 Wet shafts, blasting in, 29 Western Australian Royal Commission, 127 Weston, E. M., 29, 50, 51, 57, 64, 159 W. F. 2 shaft, 89 Whitford-Mills skip loading device, 159 Wilcox, L. L., 12, 238 Wilson, J. B., 38 Wilson, J. E., 122 Winding drums, determining the face of, 183 Wing sail for ventilating shafts, 335 Winze, dumping skip for, 240 hoist, headframe for a, 165 self-dumping bucket for, 257 Wire cables, holding shaft timbers with, 87 guides, rapid hoisting with, 193 ropes, anchoring, 220 splicing, 19 Witherbee, Sherman & Co., 142, 146 151, 175, 189, 190, 243, 263, 270, 315 Wittich, L. L., 22, 323 Wolverine mine, 97, 306 No. 4 shaft, 95 Woodman, P. L., 340 Worcester, S. A., 4, 190, 341 Wrench for removing stuck drills, ^6 Wagon oil tank, 253 Young, G. J., 114 RETURN CIRCULATION DEPARTMENT TO -^ 1 98 Main Stacks LOAN PERIOD 1 HOME USE 2 3 4 5 6 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS. Renewls and Recharges may be made 4 days prior to the due date. Books may be Renewed by calling 642-3405. DUE AS STAMPED BELOW MAV FORM NO. DD6 UNIVERSITY OF CALIFORNIA, BERKELEY BERKELEY CA 94720-6000 C. BERKELEY LIBRARIES C 2 T 7 b b E ? 1 M127C TN/4S" THE UNIVERSITY OF CALIFORNIA LIBRARY