Information Circular1950 - Mines and mineral resources |
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Page
... prevented continuation of Lining by shrinkage stoping because of weakened walls . Cut and fill stopes were begun on the lower levels . EXPLORATION The The rate of mining is paralleled by exploration . Underground , the walls of ...
... prevented continuation of Lining by shrinkage stoping because of weakened walls . Cut and fill stopes were begun on the lower levels . EXPLORATION The The rate of mining is paralleled by exploration . Underground , the walls of ...
Page 2
... prevent the wearer from inhaling harmful quantities of dust by removing dust from the air he inhales . A dust respirator is not to be used as a permanent substitute for dust- control measures . It is to be used as a temporary substitute ...
... prevent the wearer from inhaling harmful quantities of dust by removing dust from the air he inhales . A dust respirator is not to be used as a permanent substitute for dust- control measures . It is to be used as a temporary substitute ...
Page 3
... prevent exhaled air from passing outward through the filters . The filters are made of paper or felt . Paper filters and some felt filters are discarded after use , but most of the felt filters may be used repeatedly after having been ...
... prevent exhaled air from passing outward through the filters . The filters are made of paper or felt . Paper filters and some felt filters are discarded after use , but most of the felt filters may be used repeatedly after having been ...
Page 5
... prevent the exhaled air from passing through the filters . To keep dis comfort to a minimum , headbands should be adjusted no tighter than is necessary to obtain a dust - tight fit and yet keep the facepiece from becoming dislodged ...
... prevent the exhaled air from passing through the filters . To keep dis comfort to a minimum , headbands should be adjusted no tighter than is necessary to obtain a dust - tight fit and yet keep the facepiece from becoming dislodged ...
Page 9
... prevent accidents from explosions and carbon monoxide poisoning from using compressed air . Performance Characteristics of Electric Methane Indicators Performance tests were made of a commercial electric - methane indicator . The ...
... prevent accidents from explosions and carbon monoxide poisoning from using compressed air . Performance Characteristics of Electric Methane Indicators Performance tests were made of a commercial electric - methane indicator . The ...
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13 north 37 south anthracite anthracite mines bituminous coal bituminous-coal and lignite blasting blends Bureau of Mines carbon dioxide carbon monoxide cars catalyst cent mines cent circuit coal bed Coal Mine Inspection coal mines coal-mine inspectors coke concentrate conditions and practices cost County cut and fill D.C. Approval drilling dust allaying electric engineers equipment explosions feet Figure fill stoping fire area fiscal year 1949 fuel gas mask gasification Gunnison County haulage high-volatile Highland Surprise holes hydrogen inches installed investigation Joy Manufacturing June 30 lignite lignite mines loading machine main east entry mechanical method mill mineral mines cent mines Mines Information Circular motor operations oxygen Per-No percent Pine Creek Pittsburgh plant Pocahontas portal properties reports respirators rock dust roof support samples seals shaft SHOSHONE COUNTY shrinkage stoping steel surface surface magazine switch synthesis gas tests timber tons Total tunnel Type underground ventilation volts zinc