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Results 91 - 100 of 111
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...
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...
This 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...
Geological 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.
Coal 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...
This 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.
Coal 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...
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...
Degasification of the Mary Lee Coalbed Near Oak Grove, Jefferson County, Alabama, by Vertical Borehole in Advance of Mining1/1/1974 - Reports of InvestigationsA 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Alabama, to degasify the gassy Mary Lee coalbed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fu...
1/1/1973 - Reports of InvestigationsAs one of its projects for degasification of major panels of coal prior to mining within them, the Bureau of Mines conducted methane emission studies during development of a set of three headings 1,800 feet in a major coal panel (2,700 by 3,500 feet) wh...