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A Study of Roof Falls in Underground Mines on the Pocahontas No. 3 Seam, Southern West Virginia and Southwestern Virginia.
Ferm-JC; Melton-RA; Cummins-GD; Et Al
NTIS: PB/80-158983 :92 pages
The investigation consisted of three phases. The first was selecting for detailed study five mines that represented the range of roof conditions, mining practices, and geologic phenomena. The second consisted of detailed mapping in a "good" and a "bad" top area in each of the mines and resulted in a qualitative assessment of the geologic factors contributing to roof falls. In the third phase, five mines were selected in which most nongeologic factors believed to contribute to roof falls were relatively constant but displayed a wide variety of assessments from Phase II. The primary result of this investigation is that slickensides arising from different geologic causes are the major geologic features leading to roof falls. These slickensides are found in ancient slump deposits, fire clays and sandy fire clays, and channel contacts. The best top material is a sequence that consists of shale grading upward to sandy shale and sandstone within 30 feet of the top of the coal.
CP; Final Contract Report;
NTIS Accession No.
SC; VA; WV;
University of South Carolina