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Results 231 - 240 of 270
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1/1/1976 - Reports of InvestigationsA geologic study of the Mary Lee Group of coalbeds in the Black Warrior Coal Basin was undertaken to examine coal stratigraphy and determine regional trends and extent of the coalbeds.
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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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11/1/1975 - Reports of InvestigationsData are presented on the individual and combined effects of Bureau of Mines modifications on standard pneumatic rock drills in reducing noise.
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1/1/1975 - Reports of InvestigationsTo reduce the weight and bulk of equipment that mining personnel must carry underground, the Bureau of Mines and the Mining Enforcement and Safety Administration (MESA) investigated accurate and convenient gas samplers for use by mine inspectors in samp...
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1/1/1975 - Reports of InvestigationsThe methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to ...
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1/1/1975 - Reports of InvestigationsThis report describes a multipurpose borehole used for both degasification and the production of commercial-quality gas. The multipurpose borehole was drilled into a barrier pillar, and seven horizontal degasification holes and one pressure point hole w...
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1/1/1975 - Reports of InvestigationsGeological surveys were completed in six coal mines to study the overall geology of the coalbed, and to use the resulting data to evaluate the influence of the geological characteristics of the coalbed on safe and efficient coal extraction.
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1/1/1975 - Reports of InvestigationsAs part of the Bureau of Mines methane control program, the Pittsburgh coalbed was studied in Washington and Greene Counties, Pennsylvania, and in Marion and Monongalia Counties, West Virginia, where this coalbed is now being mined at its greatest depth.
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1/1/1975 - Reports of InvestigationsCoal is a soft and brittle material. Drilling rates in the Pittsburgh coalbed using a drag bit exceed 3 ft/min at 2,500-pound thrust. However, maintaining the bit on a horizontal trajectory or parallel to bedding planes to attain lengths of 1,000 feet i...
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1/1/1975 - Reports of InvestigationsThis report reviews experimental evidence indicating a relative permeability effect that causes the flow of methane to increase with time when a coalbed is degassed by boreholes.
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Content source: National Institute for Occupational Safety and Health, Mining Program