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• 3.5 BACKFILLING AND GRADING 3.5.1 Methods and Equipment Backfilling of the mined-out pfls is accomplished primarily wRh the dreglines as progressive cut by cut mining takes place. Overburden and imerburden material from the cut being excavated is used to backftll the previous adjacent cut. A variety of dragline stripping techniques are used to strip overburden and interburden. Backfilling is accomplished by casting waste material into the previously stripped cut. Ash from the power plant may also be used as backfill material (refer to Sedian 4.3.4). Occasionaly, dozers, scrapers, backhoes, front end loaders and trucks may be used in addition to the dregline for badfilling. However, in such instances, the amount of Backfilling would be minor in rasped to what is accomplished by the draglines. Backfilling by dozers shall be done by pushing adjacent mater- ial into the mined out pil. If scrapers or trucks are used, they will either haul material directly into the pft or place the material adjacent to the pit. In the latter case, the material may then be pushed into the pit with a dozer or similar equipment. After the pit has been backfilled and the overburden stripping operation has progressed several cuts, regrading operations begin. Regrading operetons shape the backfilled areas to approximatey the • configuration shown on the Postmining Topography Map, Map M12. Backfilling and grading operations commence as soon as feasibly possible following coal extredion. The approximate areas to be backfilled and graded each year are shown on Map M10A, Mining and Regrede. Recontouring begins with "rough" grading. Dozers, graders or similar equipment are commony used, but occasionaly, the dregline is also used. Dregline grading work occurs either when the dregline is devoted to spedaRy Backfilling and grading or in conjunction with pit stripping operations. P2-~-I 3.37 1998 MAY T ~