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_.. <br />~ However, in some instances where suitable quality coal is near the surface, the <br />~ overburden may be <br />burden would then removed with a <br />be hauled to a combination of dozers <br />stockpile or placed on and scrapers. The over- <br />mined-out areas fur even- <br /> tual regrading and re topsoiling. <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 />parallel [o 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 too deep to recover economically. On 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 to ten feet thick <br />are removed with a dozer, backhoe or similar equipment. Thicker partings are <br />removed with a drag line, Parting may be stripped up-dip or down-dip depending on <br />the particular situation. Strike-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 twin-masted coal drill and Chen blasted, Hole spacings <br />vary depending un coal thickness, <br />The holes are loaded with AN-FO 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 ur front end loaders are used to load the coal into haul trucks. <br />The coal haulers transport 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 />onto the haul toad system that connects each pit to [he power plant's grizzly and <br />the coal stockpiles. AL a later date, a conveyor system may replace part of this <br />truck haul. <br /> <br />3-14 <br />REVISED FEB 13 '87 <br />