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2.2-3 <br />• 2.2.3 Coal Processing and Work Area <br />Initial site construction was limited to the excavation of a small <br />bench, 2.1 acres, necessary to support the exploration operation. <br />This bench as shown in Figure 2.2-4 will be expanded to provide the <br />space necessary for operations associated with mine development. <br />The existing slope on the south will be cut back into the hillside <br />to provide additions: area. Material removed from this hillside <br />will be deposited in the valley to the northeast. Figure 2.2-14 <br />shows the configuration of the final bench and Figure 2.2-13 shows <br />the indicated sections. All available topsoil will be removed and <br />stockpiled prior to any other construction on the cut or fill areas. <br />This topsoil stockpile is shown in Figure 2.2-1. <br />As material is removed from the hillside, it will be placed in the <br />valley in hori2ontal lifts and compacted to insure stability. <br />Compaction will be done with the machinery used in construction of <br />the permanent diversion channel to the northeast which is designed <br />to pass the runoff from undisturbed areas around the mine bench. <br />This channel, which is designed to pass the runoff from a 100 year <br />24 hour event, will be constructed between the fill and the existing <br />ground as shown in Figure 2.2-14. Figures 2.3-2, 2.3-3, and 2.3-13 <br />provide the indicated sections and data used in design. <br />Cut slopes in the existing ground on the northeast side of the <br />diversion will be constructed at 1V:1H. The slope of the fill <br />• material on the south side of the diversion will be 1V:2H. Erosion <br />control will be provided by lining the channel with rock and <br />revegetating the slopes. <br />Final grade of the cut slope on the hillside to the south will be <br />1V:1.5H. As soon as practical after construction, this area will be <br />revegetated to minimize erosion. The outslope of the bench to the <br />northeast will be constructed at a slope of 1V:2H and will also be <br />revegetated. <br />Runoff from the undisturbed area to the south will flow in the <br />natural drainage to the west of the mine bench. From here, it will <br />be carried in the ditch on the south side of the haul road to the <br />first 18" culvert which will pass the flow beneath the roads to the <br />receiving channel. <br />Surface flow over the area disturbed by the mine bench will be <br />intercepted by collector ditches along the perimeter of the bench, <br />see Figure 2.3-1. These ditches will carry the flow to a culvert <br />inlet on the north corner of the bench. The culvert will divert <br />runoff down the slope and discharge into the sediment pond. These <br />ditches and ponds are designed to handle the flow from a 10 year 24 <br />hour precipitation event. The size and design of the ditches and <br />sedimentation ponds are described in detail in Section 2.3.4. <br />Runoff from the outslope of the bench will be directed into the <br />sediment pond. <br /> <br />~~ -~ 3 <br /> <br />