Results 131 - 137 of 137

• Geology of the Lower Kittanning Coalbed and Related Mining and Methane Emission Problems in Cambria County, Pa.
  1/1/1979 - Reports of Investigations
  The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata.
• Methods of Determining the Orientations of Bedrock Fracture Systems in Southwestern Pennsylvania and Northern West Virginia
  1/1/1977 - Reports of Investigations
  This Bureau of Mines report describes photo-lineaments obtained from stereoscopic examination of vertical aerial photographs and by the ronchi grating study of aerial photoindex sheets. The photo- lineaments are compared with the trends of oriented frac...
• Use of Surface Joint and Photolinear Data for Predicting Subsurface Coal Cleat Orientation
  1/1/1976 - Reports of Investigations
  Coalbeds exhibit a directional permeability, with the maximum permeability oriented parallel to the face cleat. Thus, the most efficient pattern of vertical degasification holes for a coalbed is dependent upon cleat orientation. Analysis of surface joi...
• Determining Cleat Orientation of Deeper Coalbeds From Overlying Coals
  1/1/1976 - Reports of Investigations
  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...
• Selected Geologic Factors Affecting Mining of the Pittsburgh Coalbed
  1/1/1975 - Reports of Investigations
  As part of the Bureau of Mines methane control program, the Pittsburgh coalbed was studied in Washington and Greene Counties, Pennsylvania, and in Marion and Monongalia Counties, West Virginia, where this coalbed is now being mined at its greatest depth.
• Cleat in Bituminous Coalbeds
  1/1/1974 - Reports of Investigations
  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 endo...
• Geologic Factors Causing Roof Instability and Methane Emission Problems: The Lower Kittanning Coalbed, Cambria County, Pa
  1/1/1973 - Reports of Investigations
  A geologic study of Mines 32 and 33 in Cambria County, Pennsylvania, was conducted as part of a methane control research program.