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Cleat in bituminous coalbeds

Public Domain
File Language:
English


Details

  • Personal Author:
  • Corporate Authors:
    United States. Bureau of Mines
  • Description:
    "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." - NIOSHTIC-2

    NIOSHTIC no. 10000624

  • Subjects:
  • Series:
    Mining Publications
  • Subseries:
    Report of Investigations
  • Document Type:
    Text
  • Genre:
    Report
  • CIO:
    National Institute for Occupational Safety and Health (NIOSH)
  • Topic:
    Workplace Safety & Health
  • Location:
    North America
  • Pages in Document:
    25 numbered pages
  • NIOSHTIC Number:
    nn:10000624
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:93677e75581e4c5516126541740a2b8e43fabae0edbb129092b9309464b23f528a066dbe9bc1fde21b682540a1ae3f146f55d08d1e69ecac74338d11a088b53e
  • Download URL:
  • File Type:
    Filetype[PDF - 1.01 MB ]
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