2009-08-28_PERMIT FILE - M2009035 (3)

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1 12 APPLICATION PAGE 9 OF 35 is 33 Road Ditch located west of the project site. Settlement ponds will be approximately 1 acre in size with 3:1 side slopes. The location of the ponds will change as mining progresses to ensure the placement is at the low point of the respective pit. The outlet pipes will be 12-inch reinforced concrete pipe. The outlet invert will be placed at the top of water elevation within the 33 Road Drain to mitigate erosion. (5) During mining a minimum of 1-foot of sand and gravel material must remain over the Mancos Shale layer. Should ground water conditions in the area permit the contract may alternatively wet mine the 2-feet above the Mancos Shale layer. Wet mining will leave at least 1-foot of water at the bottom of the excavated area as the deposits of sand and gravel are removed. Either practice must be followed to protect the Mancos Shale from becoming oxidized. At no point in time should the Mancos Shale layer be exposed to ambient air conditions. (6) Once the area has been mined for the sand and gravel, overburden material removed in front of the active sand and gravel high wall area (and imported inert fill material) will be placed. The backfilling operations will lag behind the active sand and gravel high wall area. The backfill will be placed such that adequate compaction of the fill material can take place. The may be accomplished by backfilling the area in lifts, or by placing the fill on a gradual slope such that equipment have safe access to place and compact the fill material. Backfill materials will not be placed underwater. • (7) Site reclamation in accordance with the reclamation plan section. The northern settlement pond will be demolished prior to mining operations commencing in the southern mining area. (b) Earthmoving Initial earthmoving on the project site will be performed to ensure all drainage will be contained within the project site. Mining excavation will create two ponds. The ponds will be formed upon removal of sand and gravel below the ground water elevation. When ground water is encountered, the water must be pumped so that the sand and gravel material can be removed and the area can be reclaimed. The pumped ground water will be conveyed via surface drainage swales toward settlement ponds located at the southwest corner of each of the respective mining areas. The settlement ponds will be approximately one acre in size, with 3H: 1 V side slopes. The overburden removed from the pond area will be stockpiled around the pond perimeter. Earthmoving for the sand and gravel mining operations will consist of stripping and storing topsoil, excavating the overburden soils, mining the sand and gravel, backfilling the excavated areas using overburden soil and imported site materials, and replacing the topsoil. The typical sequence of operations is discussed in part (a) above. C