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Subsidence Resulting from Multiple-seam Longwall Mining in the Western United States--a Characterization Study.
MISSING :20 pages
This report details the investigation of multiple-seam longwall subsidence conducted by the U.S. Bureau of Mines from 1978 to 1989. A field investigation monitored ground surface movements over four upper seam longwall panels and six lower seam panels. The characteristics of the subsidence occurring as a result of mining these panels are examined; in particular, the angle of draw, subsidence development, total magnitude and areal extent, and critical width are evaluated and discussed. Comparisons are also made between the characteristics of multiple-seam longwall subsidence and single-seam longwall subsidence that occurred at the same site.
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