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n <br />LJ <br />• <br />I~ <br />ofthe regraded spoil (Section 2.04.6, Geology Description). Surface runoff from reclaimed areas will <br />not come into contact with materials that would contribute to elevated levels of acid or toxic <br />constituents in the runoff. <br />Topsoil handling procedures (Section 2.05.4(2)(d), Topsoil (Redistribution) and revegetation methods <br />(Section 2.05.4(2)(e), Revegetation) have been developed to prevent erosion and minimize the <br />additional contribution of sediment to runoff. Plans presented in both sections include the <br />establishment oftopsoil piles, temporaryseeding oftopsoil piles, disking, mulching, deep ripping and <br />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. Theywill be built to minimize <br />erosion and prevent additional contributions ofsediment by limiting flowvelocities and tractiveforces <br />that cause excessive erosion. All temporary diversions v~ill be removed and reclaimed after mining <br />has been completed. Culverts presented in the Surface Water Control Plans for both mining areas <br />have been designed tofeature adequatefreeboard and outfall protection (riprap) to minimize erosion. <br />Surface WaterQuanliiy. The sediment pond, diversions and culverts have been planned and located <br />to control all drainage into, through and out of New Horizon 2 mining area, and to insure that <br />changes in surface water quantity are minimized. <br />Postmining topographies are planned to approximate the original premising contours (see Section <br />2.05.4(2)(c), Backfilling and Grading). Replaced topsoil material v~ill exhibit infiltration rates similar <br />to premising 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 be <br />found in Section 2.05.6(3), Protection of the Hydrologic Balance. A drainage ditch (diversion) which <br />routes runoff from disturbed areas to Pond 007 is planned to be constructed immediately outside <br />the stream buffer zone along Calamity Draw. Excess exgvation material will need to be spread on <br />the ground surface within the stream buffer zone. The operations plan for this ditch construction <br />calls for no disturbance to the main channel of Calamity Draw, no excavation within the 100 foot <br />(REVISED 329-96) 2.05.6(3)(b)(v) - 3 <br />