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Effects of abandoned multiple seam workings on a longwall in Virginia.
Chekan-GJ; Matetic-RJ; Dwyer-DL
MISSING 1989; :1-15
In order to reduce waste and improve resource conservation, mine planning, and development, the U.S. Bureau of Mines is investigating multiple seam interactions associated with longwall mining. Longwall gate entry and panel stability have been influenced by previous mining in coalbeds above and below a mine in Virginia that operates in the lower banner coalbed. Directly superjacent, approximately 115 ft, the upper banner coalbed has been partially worked by room-and-pillar mining. Directly subjacent, approximately 730 ft, the tiller coalbed has been worked by partial room-and- pillar retreat mining. The study mine has experienced problems during development of gate entries in areas of overmining and undermining. It is anticipated that stress fields associated with adjacent mining may further affect gate entry stability and face advancement during the exraction of the longwall panel. To assess overmining and undermining effects on ground stability, the Bureau gathered geotechnical information at the site. Headgate entries and pillars were instrumented and monitored to study loading behavior as the longwall face approached and passed potential problem areas. Measurements indicate that although increases in average pillar pressure were greater than predicted values, previous mining in adjacent coalbeds had little effect on headgate stability.
Mining; Longwall mining; Coal seams; Waste abatement; Room and pillar mining; Retreat mining; Coal mines; Environmental stress; Ground stability; Geotechnical engineering
IH; Report of Investigations
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division