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Results 51 - 60 of 68
1/1/1977 - Reports of InvestigationsThe Beckley Mine is one of five new mines in a heretofore unmined portion of the Beckley coalbed. The remoteness of these new mines from prior mining and their greater overburden preclude applying methane emission experience obtained in the old mines. F...
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.
The 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...
Methane Gas Content of the Mary Lee Group of Coalbeds, Jefferson, Tuscaloosa, and Walker Counties, Ala.It 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 ...
Examination 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...
Methane 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...
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...