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_.r~~ However, in some instances where suitable quality coal is near the surface, the <br />overburden may be removed with a cgnbination of dozers and scrapers. The over- <br />burden would then be hauled to a stockpile oc placed on mined-out areas fur even- <br />tual regrading and re COpsoiling. <br />The principle mining method used at Trapper is dip-line mining, i.e „ mining in <br />strips parallel to the down hill dip of the coal seams, Each pit is adjacent and <br />pat allel to the previous one. Pit widths vary according to the specific site. <br />Typically, each cut is initiated near the coal outcrop and worked down the hill <br />until the dipping coal becomes Coo deep to recover economically. pn occasion, <br />the cut may be worked up the hill. When more than one seam is recovered, the <br />parting is removed in one of several methods. Thin partings up [o ten feet thick <br />are removed with a dozer, backhoe or similar equipment, Thicker parCin~s are <br />removed with a dtagline, Parting may be stripped up-dip or down-dip depending on <br />the particular situation. SCrike-line mining may be performed instead of the <br />present dip-line mining method if geologic conditions allow. <br />The top of the uncovered coal is cleaned with equipment such as a front-end <br />loader, motor grader, or rubber tired dozer. The coal is then either ripped with <br />a dozer or drilled with a twig-masted coal drill and then blasted, Hole spacings <br />vary depending un coal thickness, <br />The holes are loaded with AN-PO or other blasting agents and stemmed with drill <br />cuttings, The blast circuit is then completed and the blast is initiated (refer <br />to Section 3.4). <br />Large 6ackhues or front end loaders are used to load the coal into haul trucks. <br />The coal haulers Cransport the coal from the pit to the power plant's grizzly or <br />a coal stockpile. The coal haulers exit the pit via an inclined ramp and enter <br />unto the haul road system ChaC connects each pit Co [he power plant's grizzly and <br />the coal stockpiles. At a later date, a conveyor system may replace part of this <br />truck haul. <br /> <br />3-14 <br />REVISED FEB 13 ~87 <br />