Ground control ramifications and economic impact of retreat mining on room and pillar coal mines
As the coal reserves at shallow depths become exhausted companies have to develop deeper deposits and increase percentage extraction to maintain production levels. Total extraction for room and pillar mines can only be achieved by pillar extraction. The unsupported roof increases during pillar extra...
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Virginia Polytechnic Institute and State University
2014
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| Online Access: | http://hdl.handle.net/10919/49815 |