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Currently, a Bucyrus-Erie 1300W dragline and a Marion 800 dragline are used for <br />overburden removal over the lower coal seams; a third dragline, aBucyrus-Erie 800 W, is <br />sometimes used to supplement the capacity of the BE 1300W or Marion 8050 machines in <br />the multi-seam scenario, and by itself in single seam operations. <br />The generalized multi-seam dragline sequence at the Colowyo operation is as follows: <br />The Bucyrus-Erie 1300W and Marion 800 draglines begin the sequence <br />removing the overburden over the "B", "C", and "D" seams in a single <br />sidecast mode, spoiling the overburden into the previously mined-out pit. The <br />"E" and "F" overburden is removed from the spoil side of the pit. The spoil <br />from the benching operation will be placed to allow the draglines sufficient <br />room and adequate reach to remove overburden while operating on the spoil <br />side. The draglines construct temporary ramps in order to walk to the spoil <br />side. <br />The "B" overburden is first drilled and blasted, removed by the draglines, "B" <br />coal is removed behind the advance of the draglines, then the drilling is <br />initiated on the overburden of the "C" seam. This sequence is typical through <br />the "F" seam. <br />Upon complete removal of the overburden over the "F" seam, the draglines <br />walk around the end of the pit to the nest cut to begin removal of the <br />• overburden over "B" coal seam. <br />• <br />2.05-7 Revision Date: 8/29/97 <br />Revision No.: TR-42 <br />