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Cleat in bituminous coalbeds.

Authors
McCulloch-CM; Deul-M; Jeran-PW
Source
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 7910, 1974 Jan; :1-25
NIOSHTIC No.
10000624
Abstract
The natural vertical fracture system in bituminous coalbeds is called cleat. Cleat orientation commonly controls the direction of mining with major development paralleling the face cleat. Previous researchers have categorized the origin of cleat as endogenetic, relating the origin of cleat to compaction and coalification, and exogenetic, relating the origin of cleat to tectonic forces. In the coalbeds studied for this report it was found that tectonic forces were the controlling factor of cleat formation. Face cleats were formed as extension fractures during structural deformation, and butt cleats, as release fractures during erosion and uplift. The face cleat of the Pittsburgh coalbed rotates from n 80 deg w in northwestern West Virginia to n 57 deg w in southwestern Pennsylvania; the face cleat maintains a perpendicular orientation to the shifting axial trend of local structures. Cleat orientation in other bituminous coalbeds in Virginia, Utah, Oklahoma, and central Pennsylvania showed a similar relationship to local structure. Directional permeability of coal is directly related to cleat. Holes drilled perpendicular to the face cleat yield from 2.5 to 10 times the amount of gas released as compared with holes drilled perpendicular to the butt cleat.
Keywords
Mine-gases; Mining-industry; Methanes; Methane-drainage; Methane-control; Explosive-gases; Explosive-atmospheres; Underground-mining; Coal-mining; Control-technology; Engineering-controls
Publication Date
19740101
Document Type
IH; Report of Investigations
Fiscal Year
1974
NTIS Accession No.
PB-233420
NTIS Price
A03
Identifying No.
RI-7910
NIOSH Division
PRC
Source Name
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 7910
State
OK; PA; UT; VA; WV
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