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15 BACK ILLING AND GRADING <br />3.5.1 Methods and Eauioment <br />Backfilling of the mined-out pits is accomplished primarily with the draglines as progressive cut by cut <br />mining takes place. Overburden and interburden material from the cut being excavated is used to backfill <br />the previous adjacent cut. A variety of dragline stripping techniques are used to strip overburden and <br />interburden. Backfilling is accomplished by casting waste material into the previously stripped cut Ash <br />from the power plant may also be used as backfill material (refer to Section 4.3.4). <br />Occasionally, dozers, scrapers, backhoes, front end loaders and trucks may be used in addition to the <br />dIragline for backfilling. However, in such instances, the amount of backfilling would be minor in respect to <br />what is accomplished by the draglines. Backfilling by dozers shall be done by pushing adjacent material <br />into the mined out pit If scrapers or trucks are used, they will either haul material directly into the pit, <br />place material in approved permanent fills or place the material adjacent to the piL In the latter case, the <br />material may then be pushed into the pit with a dozer or similar equipment <br />I <br />After the pit has been backfilled and the overburden stripping operation has progressed several cuts, <br />regrading operations begin. Regrading operations shape the backfilled areas to approximately the <br />configuration shown on the Postmining Topography Map, Map M12. Backfilling and grading operations <br />?mmence as soon as feasibly possible following coal extraction. The approximate areas to be backfilled <br />and graded each year are shown on Map M10A, Mining and Regrade. <br />Recontouring begins with "rough" grading. Dozers, graders or similar equipment are commonly used, but <br />occasionaly, the dragline is also used. Dragline grading work occurs either when the dragline is devoted <br />to specialty backfilling and grading or in conjunction with pit stripping operations. <br />,b(404 !, 3-37 <br />PR(f <br />9/21)07