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Upon completion of the site preparation or grading of a particular area, all disturbed areas which were <br />not paved, graveled, in rock or otherwise covered were mulched and seeded according to the <br />appropriate reclamation standards as detailed in the Reclamation Plan of this application. Since most of <br />the cuts in the "D" Portal Area, and the East Portal Area, and the major cuts for road construction were in <br />rock and have steep slopes, it was not feasible to place topsoil on these areas. Therefore, topsoil was <br />only used for permanent reclamation work. <br />Rills or gullies that form in cut or fill slopes will be stabilized, regraded, topsoiled and revegetated as <br />required by 30 CFR part 187.106. <br />The site grading for the "D" Portal Area was as indicated on Maps 24, 25, 26, 27 and 33, for the East <br />Portal Area on Map 89, for the water storage tank area on Map 52, and for the alluvial well area on Map <br />90. Several alternative layouts and grading schemes were considered for the "D" Portal Area. The one <br />selected, burying the Scullion Gulch stream channel in a large diameter pipe, resulted in the smallest <br />grading quantities, the smallest terrain disturbance, and the largest usable facilities area versus <br />disturbed area. The selected scheme also eliminated an open channel through the plant site area and <br />allowed a smaller number of sediment ponds. The Scullion Gulch Stream Diversion is shown on Maps <br />29, 30, 31 and 32. <br />The East Portal pad was constructed without disturbing the existing stream channel since the pad <br />• embankment slopes adjacent to the stream channel were constructed at 1.5h:1v. During the <br />geotechnical investigation for this area or during construction, had it been determined that a 1.5h:1v <br />slope would not be stable, a bin type retaining wall would have been installed to ensure the stability of <br />the pad embankment. <br />IV.J Sedimentation And Drainage Control <br />Sedimentation and drainage control systems utilized in the "D" Portal Area are shown on Maps 24, 25, <br />26, 27 and 34, in the Railroad Loading Area are shown on Map 103, in the Refuse Disposal Area are <br />shown on Maps 77, 77a, 78, 79 and 80, along the Conveyor and Slot Storage area on Maps 106-113, at <br />the Railroad Loop on Map 103A, and in the East Portal Area are shown on Map 89. These measures <br />were in addition to the use of mining and reclamation procedures intended to protect the quality and <br />quantity of the existing surface and groundwater. Emergency spillways on all ponds have been <br />designed to safely pass the peak flow from a 25-year, 24-hour storm event. Illustration 35 gives <br />calculations for the emergency spillway for the sediment pond inside the railroad loop. In this case, a <br />36" CMP was selected as the emergency spillway since it can safely pass a 100-year, 24-hour storm <br />event. Illustration 40 shows that the spillway design for Ponds RR-1 and RR-2 can pass 14.39 cfs when <br />only 11.5 cfs is the maximum flow of runoff. Illustration 39 shows that the ponds at the slot storage area <br />(SS-1 and SS-2) have double the capacity of a 10-year, 24-hour storm event. Since a 10-year, 24-hour <br />. Mine Permit Renewal #3 (Rev. 11/99) IV-36 <br />