2010-11-12_PERMIT FILE - C1981010A (8)

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3.5.4 Regrading Boxcut Spoils Boxcut spoils are produced when beginning a new pit or lengthening an existing pit. One dragline boxcut will be opened in K -ridge area during the permit term.. Topsoil removal in this area (Map M10 series) will be sufficient to allow the boxcut spoils to be regraded without contamination of adjacent soils. The boxcut spoils are part of the Horse Gulch Fill.. Map M12 shows the approximate postmining contours for this area. Regrading will begin as soon as practical (Section 3.5.2). Additionally, boxcut spoils may be produced as a result of lengthening the existing pits. This could occur in all pits at the Trapper Mine during the proposed permit period. When a pit is lengthened, care will be taken to regrade the spoils to insure that the final grades blend into the natural topography of the sur- rounding areas (refer to the Postmining Topography Map, Map M12, and Section 3.5.3). Alterations to the regrading program will be made to insure that the regraded area resembles the undisturbed topography of the surrounding areas. At the end of each pit, additional topsoil is salvaged to provide an ample buffer zone. This is required to prevent any contamination of soil materials. In areas where boxcut spoils will occur at the end of the pits, the spoils will be recontoured to provide a smooth transition from the regraded areas to the undisturbed areas. Boxcuts are required occasionally in the ends of the pits to lengthen the pits and will result in more coal being recovered. The north ends of the pits are where the depth of the coal and the amount of spoil material is the greatest. The postmining topography map, Map M12, illustrates the final grading of boxcut spoils created by extending the pits. The slopes of the regraded areas will be similar to the slopes encountered on the pre -mined land and are also approximated on Map M12, Postmining Topography. 3-44 'Mt d6 5 12 ��o