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Keywords: entry 32Close
Publisher: American Rock Mechanics Association
Paper presented at the The 18th U.S. Symposium on Rock Mechanics (USRMS), June 22–24, 1977
Paper Number: ARMA-77-0334
... ABSTRACT : Even though pillars were 88 feet square and only 8 feet high, with entries 32 feet wide to give an extraction ratio of only 46%, the standard room-and-pillar layout at depths in excess of 2,500 feet resulted in undesirable roof conditions. A plan was conceived for using small...
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