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USGS COMMENT RESPOtJSES <br /> <br />This document will serve to answer questions posed by the USGS in <br />their correspondence of i•tarch 27, 1931, and will follow the format <br />used by the USGS. <br />1. In as far as possible main entries in the 4Jild Seam <br />and D Seam will be superimposed under the Poains in <br />the E Seam operation. As WSC is now a longwall mine <br />and the bulk of the coal which was mined fran the E <br />Seam was mined by room and pillar, using inefficient <br />mining methods, it is not possible to lay out a long- <br />wall mining plan in the D Seam and bJild Seam and super- <br />impose all of the Mains in the D Seam and l•lild Seam <br />under corresponding works in the E Seam. <br /> <br />• <br />Where it is not possible to superimpose the 14ains they <br />will cross barrier pillars or pillar remnants. !•1SC <br />will anticipate the difficulties posed by pillar <br />punching and will take extraordinary steps when such <br />excessive weight is noted or expected in the mine. <br />WSC presently utilizes supplemental roof support including <br />steel bars on wood legs, cribs, pumpable resin grout, resin <br />roof bolting and is investigating steel arch sets. IJSC <br />will balance competent mining techniques with proven roof <br />support techniques to advance these mains safely through <br />difficult conditions if it is economically feasible. If <br />IJSC finds the conditions too hazardous, or uneconomic, !JSC <br />will abandon such attempts. This will be accomplished <br />through consultation with representatives of the USGS. <br />..... ~,~ <br />