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down to the depth of quality aggregate material. Backfilling and/or grading of side slopes may follow behind the <br /> mining activities before mining in the cell is complete. <br /> As mining progresses,topsoil,overburden, and non-marketable materials will be removed and stockpiled for use in <br /> reclamation activities. In the South cell,topsoil and overburden will first be stockpiled along the west and north sides <br /> of the area, used for screening during the South cell mining activities. Once mining in the South cell is complete, <br /> overburden from the West cell may be transported across Highway 7 to backfill the South cell. During mining in the <br /> West and East cells,topsoil will be segregated and stockpiled in the locations shown on Exhibit C Mining Maps. As <br /> mining progresses,overburden will be taken directly to mined out slopes for use in reclamation. Topsoil and <br /> overburden stockpiles will be configured to have side-slopes no steeper than 3H:1 V. If the stockpiles are inactive for <br /> more than one growing season, such as the stockpiles used for screening, they will be seeded with the fast-growing <br /> grass seed mixture below. <br /> Stockpile Grass Seed Mixture <br /> Grass Species Rate <br /> (#PLS/acre) <br /> Intermediate Wheatgrass 6.0 <br /> Blue Grama 1.5 <br /> White Sweetclover 1.5 <br /> Rates are for broadcast seeding. <br /> Other than those used for screening, long-term stockpiles are not anticipated. Temporary stockpile materials will <br /> continually be used for reclamation and the stockpiles will likely be disturbed on a frequent basis and seeding the <br /> stockpiles may not be practical during the operation. If stockpile seeding is not used,surface roughening will be <br /> maintained to limit wind and water erosion, <br /> Most of the proposed Tucson South Resource Permit Boundary Area is within the regulatory floodplain of South <br /> Platte River. Because of floodplain regulatory restrictions,stockpiling will occur within a mining cell whenever <br /> possible with the top of stockpile elevation lower than the pre-project grade. Stockpiles within the modeled floodplain <br /> above the existing ground surface, such as those used for screening,will be created parallel to potential South Platte <br /> River flood flows. The stockpiles will be no longer than 300 feet, with minimum spacing of 100 feet between <br /> stockpiles for flood flows to pass(see Exhibit C, Mining Maps). Stockpiles outside of the modeled floodplain are not <br /> proposed to have any restriction on length or orientation. <br /> Additional mining and reclamation procedures will be used within the regulatory floodplain to minimize damage from <br /> potential flood flows. Flood season is considered to be April 1 through September 30. The slopes will either be <br /> maintained during mining or established with reclamation backfill. If flood waters reach the mining cells prior to <br /> complete reclamation,the 3H:1 V slopes will allow controlled flow into the cells while reducing the potential for head <br /> cutting and damage to the creek channel. <br /> A Floodplain Use Application will be submitted to Adams County for this project. Adams County is the regulating <br /> authority on the flood permit; however,Adams County may request review and comment from Urban Drainage and <br /> Flood Control District(UD&FCD). <br /> Aggregate Industries Tucson South Resource <br /> Permit#M-2004-044112 Permit Amendment <br /> Page D-5 <br />