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The Effects of Multiple Seam Mining on Longwall Operations.
Paper in Proceedings of the 2nd Annual Longwall USA Conference Coal Min PP 135-146 :135-146
The U.S. Bureau of Mines, in an effort to improve resource conservation, mine planning, and development, is investigating multiple-seam interactions associated with longwall mining. At a mine located in Dickenson County, Virginia, longwall gate entry and panel stability have been influenced by previous mining in coalbeds both above and below. The study mine operates in the lower banner coalbed. Directly superjacent, approximately 115 ft. The upper banner coalbed has been partially worked using the room-and-pillar mining method. Directly subjacent, approximately 730 ft, the tiller coalbed has also been worked using partial room-and-pillar retreat mining. The study mine has experienced problems during the development of the gate entries in areas of overmining and undermining. It is anticipated that the stress fields associated with the adjacent mining may further affect gate entry stability and face advancement during the extraction of the longwall panel. To assess the effects of overmining and undermining on production and ground stability, the Bureau of Mines gathered various geotechnical information at this mine site. Gate entry pillars were monitored to study their loading behavior as the longwall approached and passed potential problem areas. Ground conditions were observed as the longwall face advanced in order to evaluate the impact of overmining and undermining on production. The studies showed that overmining and undermining caused no excessive loading to gate road pillars, as measured pressure increases ranged from 100 to 400 psi, less than predicted values. P
Paper in Proceedings of the 2nd Annual Longwall USA Conference. Coal Min., PP. 135-146
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division