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Multislice mining for thick western coal seams.

Authors
Hackett-TD; Boreck-DL; Clarke-DR
Source
MISSING 1990; :1-27
Link
NIOSHTIC No.
10008434
Abstract
Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western U.S. thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine, where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600- to 800-ft) panels also provide increased coal recovery.
Keywords
Mining-industry
Publication Date
19900101
Document Type
IH; Information Circular
Fiscal Year
1990
NTIS Accession No.
NTIS Price
Identifying No.
IC 9239
NIOSH Division
DRC
Source Name
MISSING
State
CO
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