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May 29 Room and Pillar Mining Highwall Miner coal operations still not federally regulated by OSMRE Duration 7 48 rhmooney3 15 857 viewsThe paper points out that bord and pillar mining isthe most important method of coal underground coal mines and advocates that pillar design procedur

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Retreat mining is often the final stage of room and pillar 25 of American coal mining deaths caused by failures of The most common mining system is room and pillar In this system a series of parallel drifts are driven with connections made between these drifts at regular

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