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Results 51 - 60 of 67
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1/1/1977 - Reports of InvestigationsThe Bureau of Mines evaluated the hydraulic stimulation of a gob degasification borehole to determine if this procedure would aid in degasifying a longwall panel.
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1/1/1976 - Reports of InvestigationsThe Bureau of Mines conducted research to determine the effectiveness of long holes drilled in solid virgin coal in degasifying an area of the Pittsburgh coalbed showing that horizontal holes drilled into a virgin coalbed from the bottom of any shaft wi...
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1/1/1976 - Reports of InvestigationsIt is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee Group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Alabama. It is calculated that approximately 90 pct of the methane is at ...
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1/1/1976 - Reports of InvestigationsExamination of several coalbeds in Walker County, Alabama, Cambria, Greene, and Fayette Counties, Pennsylvania, and Caleigh and Wyoming Counties, West Virginia, indicates that cleat orientations are similar throughout a vertical sequence of strata. Stud...
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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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1/1/1975 - 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 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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1/1/1975 - Reports of InvestigationsCoal degasification boreholes drilled from the surface have been successfully hydraulically stimulated to increase the flow of gas from the coal. This Bureau of Mines report describes the hydraulic stimulation procedure for a coalbed, the equipment requ...
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1/1/1974 - Reports of InvestigationsThe periphery of longwall panels in the Pocahontas No. 3 Coalbed is characterized by a zone of reduced permeability that inhibits the natural drainage of methane. However, natural drainage holes drilled during development have been found to reduce the g...
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Content source: National Institute for Occupational Safety and Health, Mining Program