1988-04-11_PERMIT FILE - C1981008A (17)

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Plans for sampling overburden and topsoil to identify potentially deleterious materials have been developed and are outlined in Tab 21 (Minesoil Reconstruction). As previously mentioned, investigations have determined that no acid or toxic materials will be replaced in the upper four feet of the regraded spoil (Tab 6, Geology). Surface runoff from reclaimed areas will not come into contact with materials that would contribute to elevated levels of acid or toxic constituents in the runoff. -Topsoil handling procedures (Tab 21, Minesoil Reconstruction) and revegetation methods (Tab 22, Revegetation Plan) have been developed to prevent erosion and minimize the additional contribution of sediment to runoff. Plans presented in both Tabs include the establishment of topsoil piles, temporary seeding of topsoil piles, disking, mulching, deep ripping and prompt reseeding of reclaimed areas. The Surface Water Control Plans developed for both the Nucla Mine and Nucla East mining areas (see Exhibits 13-4 and 13-5, Tab 13, Facilities) include five temporary diversions designed according to accepted engineering design criteria. They will be built to minimize erosion and prevent additional contributions of sediment by limiting flow velocities and tractive forces that cause excessive erosion. All temporary diversions will be removed and reclaimed after mining has been completed. Culverts presented in the Surface Water Control Plans for both mining areas have been designed to feature adequate freeboard and outfall protection (riprap) to minimize erosion. Surface Water Quantity. Sediment ponds, diversions and culverts have been planned and located to control all drainage into, through and out of both the Nucla Mine and Nucla East mining areas, and to insure that changes in surface water quantity are minimized (see Exhibits 13-4 and 13-5, Tab 13, Facilities). Postmining topographies are planned to approximate the original premining contours (see Tab 20, Backfilling and Grading). Replaced topsoil material will exhibit infiltration rates similar to premining soils. Reclamation techniques used in the topsoiled areas (disking, ripping, mulching, etc.), in combination with reestablished watershed topographies will minimize excessive rates and volumes of runoff. Stream Buffer Zones. A section on stream buffer zones in the Nucla East mining area has been included in the Nucla Permit Revision Application and can be found in Tab 16, Protection of the Hydrologic Balance. A drainage ditch (diversion) which routes runoff from disturbed areas to Pond 007 is planned to be constructed immediately outside the 18-3 Revised 04/11/88