2012-02-16_REVISION - M2002020 (9)

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It should be noted that the mining and reclamation plan includes backfilling remnant mining pits that currently exist as groundwater ponds (NE Pond and SE Pond). The combined water surface area of these two ponds is approximately 43 acres. As seen in the attached letter (November 1, 2001, Office of the State Engineer to Hart Environmental), a pre -1981 exposed groundwater credit of 45.5 acres is associated with the Greeley West Pit original permit boundary. Therefore, final reclamation of the amendment area does not require backfilling of the existing NE Pond and SE Pond. Diversions and Impoundments Roads to the east, west, and south of the mining area will effectively minimize stormwater surface run -on to the mining site, so run -on diversion structures are not anticipated. The existing grade of the proposed amendment area generally drains to the existing on -site ponds. Therefore, diversions for stormwater that falls directly on the affected area will be contained in the ponds or active mining cell. The ponds will effectively contain stormwater flows and prevent surface runoff from the site. Stormwater entering the active mining cell will be controlled in the groundwater dewatering trenches and, if necessary, circulated through a settling basin prior to being discharged to the adjacent 35 Avenue drainage ditch. Material Processing and Associated Facilities A portable processing facility, potentially consisting of crushing, screening, and washing will be located on the east side of the proposed amendment area. Pit run material will be hauled or conveyed to the processing plant where raw material and product stockpiles will be located. If necessary, a mine office /scale house trailer, fueling /lubricating station, generators, and outdoor storage may also be located near the east side of the amendment area. Alternatively, a portable processing plant may be set up in the bottom of the pit to size and screen material prior to it being hauled off -site. Or, the material may be hauled off -site as pit run for direct use or processing elsewhere. Commodities to be Mined and Intended Use Sand and gravel for use as construction materials will be the primary products produced from the amended 25 Avenue Site. Although the existing 25 Avenue Site and Greeley West Pit have been previously mined, borehole drilling and testing has verified that the proposed amendment area still contains a significant commercial deposit of sand and gravel. In addition to the commercial sand and gravel materials, clay, silt, and other non - marketable materials will be used on -site to backfill previously excavated pits. Use of Explosives Since the material is unconsolidated alluvium, no explosives or blasting is required. Greeley 25 Avenue Site DRMS 112 Permit Amendment Application Page 9