Laserfiche WebLink
4 <br /> t i <br /> (3) The Operator/Applicant shall provide an estimate of the project water requirements including flow rates and <br /> annual volumes for the development,mining and reclamation phases of the project. <br /> Water use at the site is governed by the current well permit(Permit No.81342-F)and the associated Substitute <br /> Water Supply Plan(SWSP)for the site. Water use will be at its highest during the mining phase of the project. <br /> Mining at the site will intercept groundwater tributary to the South Platte River. Consumptive uses of groundwater at <br /> the site include evaporation from groundwater exposed to the atmosphere,water retained in material hauled off sites, <br /> and water used for dust control. <br /> Evaporative losses at the site are attributable to groundwater exposed in the dewatering trenches in the West and <br /> East cells(Phases 2 and 3),groundwater exposed in the settling pond,and groundwater exposed as a result of wet <br /> mining in the South cell(Phase 1). The dewatering trenches will be constructed following completion of the slurry <br /> walls surrounding the West and East cells. The maximum exposed surface area during the life of the mine is equal <br /> to the combined total mined area of the South Cell (Phase 1),the dewatering trench surrounding the West cell <br /> (Phase 2), and the settling pond associated with the West cell. The maximum exposed surface area during the life of <br /> the mine is estimated at 18.5 acres. Additional exposed groundwater from the old Tucson Pit(DRMS Permit No. M- <br /> 1991-140)has been incorporated into the permit boundary of the Tucson South Pit. Therefore,the maximum <br /> exposed groundwater allowed pursuant to the approved well permit is 25 acres. <br /> Evaporative losses were calculated as the difference between gross evaporation and effective precipitation. The <br /> NOAA Technical Report NWS 33, Evaporation Atlas for the Contiguous 48 United States(U.S. Department of <br /> Commerce)was used to determine gross evaporation;the average annual gross evaporation for this site was <br /> determined to be 43 inches. Precipitation was obtained from the Colorado Climate Center for the Brighton weather <br /> station. The gross annual precipitation for this site was determined to be 14.55 inches. Effective precipitation was <br /> calculated as 70 percent of gross precipitation;thus,the average annual effective precipitation was determined to be <br /> 10.19 inches. The maximum total annual evaporative consumptive use at the site is estimated at 68.25 acre-feet. <br /> The maximum annual production at the site is estimated at 1.25 million tons. The anticipated maximum volume of <br /> water lost in the material hauled off-site is 60 acre-feet per year. Maximum dust control requirements at the site are <br /> estimated at 5.0 acre-feet per year. The mine will be at the highest production during the months of May through <br /> August,and in combination with the weather,this period will require the greatest amount of dust control: The mine <br /> will be in production year-round and therefore dust control may be required during all months. The maximum annual <br /> operational water consumptive use due to the mining operation is estimated at 65 acre-feet per year. <br /> The maximum annual consumptive use from mining at the site authorized by the well permit is 133.25 acre-feet per <br /> year as shown in the following table. <br /> Evaporation 68.25 acre-feet <br /> Moisture Retained in Product 60.00 acre-feet <br /> Dust Control 5.00 acre-feet <br /> Total 133.25 acre-feet <br /> It is not anticipated that additional water will be required for reclamation of the site. Once reclamation is completed <br /> the City of Aurora will use decreed water rights to fill the ponds. <br /> (4) The Operator/Applicant shall indicate the projected amount from each of the sources of water to supply the <br /> project water requirements for the mining operation and reclamation. <br /> Aggregate Industries(Al)currently maintains a substitute water supply plan approved through the Office of the State <br /> Engineer for its mining operations along the South Platte River and its tributaries. Until the liners surrounding the <br /> Aggregate Industries Tucson South Resource <br /> Permit#M-2004-044112 Permit Amendment <br /> Page G-2 <br />