What safety factor will be necessary to allow an extraction

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Reference no: EM13531079

A lead-zinc mine is to be developed by a room-and-pillar layout.  The mine is located at a depth of 500ft, the overlying rock has an average specific gravity of 2.56, and the pillar rock wast tested and found to have a uniaxial compressive strength of 15,000 psi.  What safety factor will be necessary to allow an extraction ratio of 75%?

Reference no: EM13531079

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