2024-05-21_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. A dragline/truck and excavator boxcut was opened in N Strike Pit during the 2017-2022 permit term. Topsoil removal in this area (Map M10 series) was sufficient to allow some of the dragline boxcut spoils to be regraded without contamination of adjacent soils. The truck and excavator boxcut material has been placed to the west and slightly above the pit where the material will reside until the final cut in the pit is complete and the material can be hauled back into the east end of the pit for final reclamation. Map M12 shows the approximate postmining contours for this area. Regrading will begin as soon as practical (Section 3.5.2). Some spoil material from this pit will be hauled to the A Pit ash dump area for final reclamation cover above regraded ash spoils. Approximately 500,000 bcy’s of material may be hauled to this area to provide for coverage of coal ash prior to final reclamation. A truck and excavator boxcut was opened in I Middle Pit during the 2017-2022 permit term. Topsoil removal in this area (Map M10 series) was sufficient to allow the creation of a temporary spoil pile between I and J East Pits where the material will reside until the final cut in these pits is complete and the material can be hauled back into the final J east pit for final reclamation. 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 an existing pit. 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 surrounding 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 topsoil. 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