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• Plans for sampling overburden and topsoil to identify potentially deleterious materials have been <br />developed and are outlined in Section 2.05.4(2)(d) Topsoil (Redistribution). As previously <br />mentioned, investigations have determined that no acid or toxic materials will be replaced in the <br />upper four feet of the regraded spoil (Section 2.04.6, Geology Description). Surface runoff from <br />reclaimed areas wilt not come into contact with materials that would contribute to elevated levels <br />of acid or toxic constituents in the runoff. <br />Topsoil handling procedures (Section 2.05.4(2)(d), Topsoil (Redistribution) and revegetation <br />methods (Section 2.05.4(2)(e), Revegetation) have been developed to prevent erosion and . <br />minimize the additional contribution of sedimentto runoff. Plans presented in bath sections include <br />the establishment of topsoil piles, temporary seeding of topsoil piles, disking, mulching, deep <br />ripping and prompt reseeding of reclaimed areas. <br />The Surface Water Control Plans developed for New Horizon 2 mining area include temporary <br />diversions designed according to accepted engineering design criteria. They will be built to <br />minimize erosion and prevent additional contributions of sediment by limiting flow velocities and <br />tractive forces that cause excessive erosion. All temporary diversions will be removed and <br />reclaimed after mining has been completed. Culverts presented in the Surface Water Control <br />• Plans for both mining areas have been designed to feature adequate freeboard and ouffall <br />protection (riprap) to minimize erosion. <br />Surface Water Quantity. The sediment pond, diversions and culverts have been planned and <br />located to control all drainage into, through and out of New Horizon 2 mining area, and to insure <br />that changes in surface water quantity are minimized. <br />Postmining topographies are planned to approximate the original premining contours (see Section <br />2.05.4(2)(c), Backfilling and Grading). Replaced topsoil material will exhibit infiltration rates similar <br />to premining soils. Reclamation techniques used in the topsoiled areas (disking, ripping, mulching, <br />etc.), in combination with reestablished watershed topographies will minimize excessive rates and <br />volumes of runoff. <br />Stream Buffer Zones. A section on stream buffer zones in the New Horizon 2 mining area can <br />be found in Section 2.05.6(3), Protection of the Hydrologic Balance. A drainage ditch (diversion) <br />which routes runoff from disturbed areas to Pond 007 was constructed immediately outside the <br />stream buffer zone along Calamity Draw. Excess excavation material was spread on the ground <br />surface within the stream buffer zone. The operations plan for this ditch construction calls for no <br />disturbance to the main channel of Calamity Draw, no excavation within the 100 foot buffer zone <br />• and a resultant ditch that can convey the runoff from a 10-year, 24-hour storm. Any impacts to the <br />(Revised Jury 2006) 2.05.6(3)(b)(v)-5 <br />