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- Mining types and methods:
- Longwall mining
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Results 91 - 99 of 99
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1/1/1992 - Reports of InvestigationsThis U.S. Bureau of Mines report summarizes a study of large-scale strata response to longwall mining at a western U.S. coal mine. This study utilized surface and subsurface measurements, geologic mapping, in situ stress measurements, and pressure cell...
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8/1/1990 - Conference papersThis paper describes research designed to quantify the behavior of a particular size abutment pillar prone to burst or bump (local terminology). This research has attempted to construct the stress and convergence profiles of the pillar.
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1/1/1986 - Reports of InvestigationsThe Bureau of Mines conducted studies to compare the effectiveness of the cross-measure borehole system with that of surface gob holes on two successively mined retreating longwalls in the Lower Kittanning coalbed. Only the cross-measure system was in o...
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1/1/1985 - Reports of InvestigationsThe cross-measure borehole technique is an effective method of controlling methane liberated by fracturing the roof strata in longwall gobs where overburden is less than 750 ft (229 m). About 71 pct of the methane produced by longwall mining in the Lowe...
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1/1/1983 - Reports of InvestigationsIn Europe, water infusion is used widely to reduce generation of respirable dust during mining. Its use in the United States is limited to a few plow operations in the Pocahontas No. 3 Coalbed. This Bureau of Mines report describes the technology for in...
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1/1/1982 - Reports of InvestigationsThe Bureau of Mines is developing underground gob gas drainage as an alternate means of methane control for U.S. longwalls. Holes are drilled into the roof over the panel and on retreating longwalls, towards the working face from a location inby the fac...
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1/1/1976 - Reports of InvestigationsMethane emission from two surface gob-degasification boreholes was measured by the Bureau of Mines. The investigation took place during mining of a 3,200-foot longwall panel in the Lower Kittanning coalbed in central Pennsylvania. The first hole was 500...
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1/1/1972 - Reports of InvestigationsThe use of a partially slotted 6.5-Inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 Coalbed was investigated. The value of gas removed by such a pipe under free-flow condition...
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1/1/1971 - Reports of InvestigationsThe purpose of this study was to determine the characteristics of methane emissions during coal extraction by a longwall mining system. The study was conducted over 22 consecutive shifts. The average methane emission rate from the Lower Kittanning coalb...
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Content source: National Institute for Occupational Safety and Health, Mining Program