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U.S. Department of Energy
Office of Scientific and Technical Information

Roof rock structures and related roof support problems in the Pittsburgh coalbed of southwestern Pennsylvania

Technical Report ·
OSTI ID:7312739
The Bureau of Mines investigated severe coal mine roof support problems along a section of main entries in the Pittsburgh coalbed in southwestern Pennsylvania to identify the causative factors. The mine roof was examined in detail, and various sedimentary structures are described that contributed directly to irregular and unstable roofs. Small-scale paleochannels, scours, and related slickensides were identified as the leading cause of bad roofs, and isopach maps were prepared to illustrate a method whereby the presence of these structures could be inferred in advance of mining. Probably second in importance was the occurrence of relatively incompetent flaggy, poorly cemented sandstone, weakened by coal and micaceous laminae. No effect of in situ stresses on roof stability was detected.
Research Organization:
Bureau of Mines, Pittsburgh, PA (USA). Pittsburgh Mining and Safety Research Center
OSTI ID:
7312739
Report Number(s):
BM-RI-8230
Country of Publication:
United States
Language:
English