Guarding trolley and bare powerlines__ Comparison of underground and surface electrical hazards_ Safety standards for installing and using electrical equipment_ 1. Frequency trend of injuries from electricity at underground metal and nonmetallic mines, 1932-54_. 4 2. Frequency trend of injuries from electricity at opencut and nonmetallic mines, 1932–54__ 3. Guarded trolley wire at car-dumping station_ 4. Power cables installed in a metal-mine drift. 11 5. Electrical installation at a shaft station__ 6. Method of ground-fault protection on Y-connected, grounded, neutral power system___ 6133 9 19 5 Page 50 50 51 55 55 55 55 55 55 55 56 56 56 56 56 59 64 64 69 76 76 83 84 88 89 89 91 94 94 94 95 95 96 96 97 99 100 100 100 101 101 101 102 102 102 102 103 103 104 Fig. 7. Method of ground-fault protection with derived neutral on ungrounded delta power system___ 8. Method of ground-fault protection for low-voltage auxiliary equip ment on ungrounded delta power system__ 9. Control cubicles and transformer at a metal mine. Page 11. Modern enclosed-type switch panel at surface mill 12. Safe-type switching equipment and transformer_. 13. Transformer and fan installation at a metal mine. 14. Some types of trolley-guard hangers_ 15. Well-installed bus and feeder switches_ 16. Surface transformers enclosed and grounded. 17. Underground d. c. substation at a metal mine. 18. Mobile-type rectifier station at a metal mine 20. General view of opencut copper mine in Nevada. 19. Lamphouse with electric cap lamps and charging equipment_ 21. Frequency trend of injuries from machinery at underground metal and nonmetallic mines, 1932-54_. 22. Frequency trend of injuries from machinery at opencut metal and nonmetallic mines, 1932–54_ 23. Extended oil connections on underground crusher 24. Foot control on lathe. 25. Guarded drive on Airodyne fan in underground iron mine. 26. Enclosed gears on mine hoist_ _ 27. Guarded machinery in mine shop. 28. Guarded machines in carpenter shop 29. Guards on air hammer in mine shop. 30. Guarded and enclosed machinery in conveyor installation 31. Coal pulverizing and drying equipment. 32. Stench-alarm injector on compressed-air line... 33. Carbon monoxide recorder connected to compressed-airline in compressor room 34. Drifters operated from jumbo at iron mine_ 35. Air-leg drifter at phosphate mine___ 36. Column-arm drifter using coupled steel at copper mine.. 37. Wagon drills-toe- and knee-hole drilling-at underground quarry 38. Diamond core drill, air-driven, equipped with rod puller 39. Wagon and jackhammer drills operated from central portable compressor 40. Pneumatic-hammer drill, asbestos mine in Quebec---. 42. Churn-type blasthole drills. 43. Two-drill unit with dust collector_ 41. Drilling overburden with rotary drill at Utah copper mine_. 44. Scraper hoist with guards and rope guides.. 45. Scraper operating in soft iron ore - 46. Small pneumatic loading machine at New Mexico copper mine 47. Loading gypsum with diesel-powered shovel. 48. Electric shovel loading limestone in Illinois_ 49. Loading lead-zinc ore into shuttle car.. 50. Electric shovel, 64-yard dipper, loading ore into 25-ton truck 51. Insulated tongs used to handle 2,300-volt trailing cable.......... 52. Details of cable tongs__ 53. Extension ladder and guarded entrance platform on shovel housing-54. Anvil spark arrester.. 55. Cable cutter.. 56. Storage of tools underground_ 57. Frequency trend of injuries from falls of persons at underground metal and nonmetallic mines, 1932–54. 58. Frequency trend of injuries from falls of persons at opencut metal and nonmetallic mines, 1932-54_. 59. Guarded ladderway. 60. Safety gate in manway. 61. Ladder and timber boat at raise collar. 62. Iron ladder and portable staging for repair work in raise_ 63. Shaft enclosure at underground station 64. Grizzly for raise in scraper drift 65. Railed stairs and walkways for servicing mine pump- 1. Injuries from electricity at metal and nonmetallic mines, by mineral 2. Injuries from electricity at underground metal and nonmetallic mines, ELECTRICAL AND MECHANICAL HAZARDS AND FALLS OF PERSONS AT METAL AND NONMETALLIC MINES1 Metal- and Nonmetallic-Mine Accident-Prevention Course-Section 6 Revised by Lawrence H. Harrison2 and Frank E. Cash 3 PURPOSE AND SCOPE The first metal-mine accident-prevention course was prepared and published 1942-45 as a series of seven miners' circulars (Nos. 51-57). The course has been broadened, revised, and brought up to date and is being published as a similar series of seven miners' circulars on accident prevention at metal and nonmetallic mines. These circulars are: 1. Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents. 2. Falls of Rock or Ore (Miners' Circular 52), discussing the selection of mining methods to minimize the hazard of falling and sliding ground, the use of various types of support, and the protection of employees from falls of ground. 3. Hoisting and Haulage (Miners' Circular 53), presenting the hazards of hoisting and haulage in metal and nonmetallic mines and means of prevention. 4. Explosives (Miners' Circular 54), giving information on accidents and injuries due to storing, handling, and using explosives in metal and nonmetallic mines and precautions by which they can be prevented. 5. Fires, Gases, and Ventilation (Miners' Circular 55), explaining the causes of fires in metal and nonmetallic mines and the measures used to prevent, control, and extinguish them; describes gases found in mines and methods of detection and personal protection; and discusses necessity for the standards of proper ventilation. 6. Electrical and Mechanical Hazards (Miners' Circular 56), covering accidents and injuries from electricity and machinery and their prevention. Injuries from falls of persons are also discussed in this section. 7. Health and Miscellaneous Hazards (Miners' Circular 57), including data on dust hazards, means of protection and sampling devices, protective clothing and equipment, illumination, supervision, discipline, and safety training for employees in metal and nonmetallic mines. 1 Work on manuscript completed March 1955. 2 Mining electrical engineer, Bureau of Mines, Birmingham, Ala. 3 Formerly mining engineer, Bureau of Mines, Washington, D. C. |