Information Circular1950 - Mines and mineral resources |
From inside the book
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... placed above the drift sets . The pony sets are the same width as the drift sets , having 6 - foot posts instead of 8 - foot , as in the drift ; all posts , caps , and sills are 12- by 12 - inch timbers . Doubled 3 - inch lagging is ...
... placed above the drift sets . The pony sets are the same width as the drift sets , having 6 - foot posts instead of 8 - foot , as in the drift ; all posts , caps , and sills are 12- by 12 - inch timbers . Doubled 3 - inch lagging is ...
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... placed at the mile of the block in the lower level to serve es en ore 22ss . Croping is started and slopes upward at a low angle from the carni ore cite raise to the ends of the panel . A slusher is mounted ** the or Fass , and a cycle ...
... placed at the mile of the block in the lower level to serve es en ore 22ss . Croping is started and slopes upward at a low angle from the carni ore cite raise to the ends of the panel . A slusher is mounted ** the or Fass , and a cycle ...
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... placed at the midle of the block in the Lover level to serve es en ore 2288. Croping is started and slopes upward at a low angle from the coral ore cate raise to the ends of the rebel . A slusher is mounted ** the ore Fass , and a cycle ...
... placed at the midle of the block in the Lover level to serve es en ore 2288. Croping is started and slopes upward at a low angle from the coral ore cate raise to the ends of the rebel . A slusher is mounted ** the ore Fass , and a cycle ...
Page 8
... placed at the middle of the block in the lower level to serve as an ore pass . Stoping is started and slopes upward at a low angle from the central ore chute raise to the ends of the panel . A slusher is mounted at the ore pass , and a ...
... placed at the middle of the block in the lower level to serve as an ore pass . Stoping is started and slopes upward at a low angle from the central ore chute raise to the ends of the panel . A slusher is mounted at the ore pass , and a ...
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... placed at the middle of the block in the lower level to serve as an ore pass . Stoping is started and slopes upward at a low angle from the central ore chute raise to the ends of the panel . A slusher is mounted at the ore pass , and a ...
... placed at the middle of the block in the lower level to serve as an ore pass . Stoping is started and slopes upward at a low angle from the central ore chute raise to the ends of the panel . A slusher is mounted at the ore pass , and a ...
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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