Bulletin, Utgave 277U.S. Government Printing Office, 1928 |
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Side
... necessary fuel at a minimum cost in life and limb . The bureau plans to revise the handbook from time to time as developments in the industry , and further study and research , seem to warrant . SCOTT TURNER , Director . CONTENTS Page ...
... necessary fuel at a minimum cost in life and limb . The bureau plans to revise the handbook from time to time as developments in the industry , and further study and research , seem to warrant . SCOTT TURNER , Director . CONTENTS Page ...
Side
... necessary fuel at a minimum cost in life and limb . The bureau plans to revise the handbook from time to time as developments in the industry , and further study and research , seem to warrant . SCOTT TURNER , Director . CONTENTS ...
... necessary fuel at a minimum cost in life and limb . The bureau plans to revise the handbook from time to time as developments in the industry , and further study and research , seem to warrant . SCOTT TURNER , Director . CONTENTS ...
Side 11
... necessary that the time when definite artificial coursing of the air through a coal mine to dilute and carry away inflammable or noxious gases was unknown is forgotten . Systematic ventilation of metal mines is recent ; inflammable ...
... necessary that the time when definite artificial coursing of the air through a coal mine to dilute and carry away inflammable or noxious gases was unknown is forgotten . Systematic ventilation of metal mines is recent ; inflammable ...
Side 15
... necessary to sample and analyze the mixture of gases to deter- mine the proportions exactly . As coal mines became deeper and increasing amounts of methane were encountered , stronger ventilating currents were necessary . Then it was ...
... necessary to sample and analyze the mixture of gases to deter- mine the proportions exactly . As coal mines became deeper and increasing amounts of methane were encountered , stronger ventilating currents were necessary . Then it was ...
Side 25
... necessary to resort to the fractional dis- tillation method that depends upon the difference in the boiling points of various liquefied gases . The procedure is to liquefy the mixture by a surrounding bath of liquid air to the ...
... necessary to resort to the fractional dis- tillation method that depends upon the difference in the boiling points of various liquefied gases . The procedure is to liquefy the mixture by a surrounding bath of liquid air to the ...
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Vanlige uttrykk og setninger
afterdamp air current airways amount anthracite approved bituminous coal bituminous coal dust black damp blasting brattice breathing apparatus Bureau of Mines carbon dioxide carbon monoxide cars caused circuits coal beds coal dust coal mines coal-dust explosions coal-mine combustible conductors crosscuts danger Davy lamp detector determined detonator doors engineer entries explosion disasters explosions of gas face falls of roof feet fire bosses fire damp flame safety lamps foremen fractional distillation gases gassy mines haemoglobin haulage hazards hoisting hole ignite gas ignition of gas inches incombustible inflammable gas injuries installed intake air killed less longwall lower methane method miners mixture motor nitrogen nongassy open lights operators oxygen breathing apparatus passageway percentage permissible explosives pillars places portable propagation regulations rescue return air rock rooms samples sealed shaft shot firing shot-firing slope split stoppings storage-battery surface switches Tech tests timber tion trip trolley locomotives trolley wire underground ventilating current
Populære avsnitt
Side 39 - Therefore, it is not. possible to lay down a hard and fast rule that will apply to all the different conditions and characters of coal dusts found in the mines of the United States.
Side 53 - That detonators — preferably electric detonators — are used of not less efficiency than those prescribed, namely, those consisting by weight of 90 parts of mercury fulminate and 10 parts of potassium chlorate (or their equivalents).
Side 43 - ... per cent for each 1 per cent of gas. Where rock dust barriers are installed, the amount of dust used shall be at least 100 pounds per square foot of average cross section of entry, at the barrier zone. 7. Sampling Dust: After a mine, or any part of a mine has been...
Side 43 - A written record shall be entered in a book kept for that purpose in the mine office, showing the location at which samples have been taken, and the results of the analyses.
Side 53 - ... 3. That the explosive, if frozen, shall be thoroughly thawed in a safe and suitable manner before use.
Side 23 - ... the 4,000-foot section or area, a pillar shall be left of sufficient width to permit the driving of the two additional passageways. Separated pairs of parallel entries entering such area, properly maintained, will fulfill the foregoing requirements; and if coal on leased land is to be mined from a mine already existing either on public domain or on private land and in the opinion of the district mining supervisor the ventilation passageways and escapeways are adequate, said requirements may be...
Side 42 - It shall not contain more than 5 per cent of combustible matter, nor more than 25 per cent of quartz or free silica particles, nor absorb moisture from the air to such an extent as to cake and destroy its effectiveness as a dry dust. It may be made from limestone, dolomite, gypsum, anhydrite, shale, talc, adobe, or other inert material which meets the foregoing specifications.
Side 42 - ... working place in the section of the mine which it has been ventilating since leaving the intake to the point of union with the main return. "Exposed electric circuits" means any conductor or conductors of the electric circuit in the mine, other than trailing cables of permissible machines. which by virtue of their location are liable to be damaged by falls of roof, wrecks, etc., which may cause sparks or arcs in the mine atmosphere. An "isolated panel...
Side 22 - In every mine the lessee shall provide an escapeway or second means of egress to the surface, which, if a drift, slope, or tunnel exit, shall be separated at the surface from the first exit by not less than 50 feet of rock or coal in place; if either is a shaft or both are shafts, the exits shall be not less than 200 feet apart.
Side 22 - ... in proper condition for use. If such adjoining mine shall be abandoned at any time, or shall cease to operate indefinitely, the lessee hereunder shall be solely responsible for the cost and expense of maintaining such outlet, and in the event such outlet shall be abandoned or permitted to become unsafe for use, the number of men employed on any one shift shall be reduced below ten until such time as a second exit or escapeway shall be provided.