2009-12-23_HYDROLOGY - M2006003 - Laserfiche WebLink

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Mr. Andy Rodriguez, P.E. December 22, 2009 Page 2 Depletions Currently 0.56 acres of ground water surface is exposed in dewatering trenches at the Parker - Dersham Mine (WDID 0203026). Consumptive use from the operation of this site consists of 12.5 acre -feet of water lost in product (4% moisture of 425,000 tons of raw material), 1.67 acre -feet for on -site dust control and 1.66 acre -feet of evaporation from the 0.56 acres of exposed lake surface. The total consumption at this site from mining operations is 15.83 acre -feet. The depletions from the mining operation were lagged to the stream using the SDF method. The construction of the slurry wall at the Baseline Resource site affects the timing of the lagged impacts on the South Platte River. The applicant previously prepared a numeric model to account for this affect. According to the model, the SDF for the Batch Plant production well (concrete production and dust suppression) was estimated to be 176 days and the SDF for the evaporation loss and water lost in product was estimated to. be 205 days. Replacements The proposed source of replacement for this pit is nontributary ground water pumped from an existing Laramie -Fox Hills aquifer well and fully consumable effluent leased from the City of Aurora. The nontributary Laramie -Fox Hills aquifer water will be withdrawn by an existing well pursuant to permit no. 64750 -F. Additional information regarding the well is shown below: Well Field WDID None Well Field Name None Relevant Water Right Case Number None Well WDID 0210166 Well Name Hall Irwin LFH 64750 -F Relevant Well Permit 64750 -F Well Location NE' /4, NE % <, SE %, SEC 36, T1 N, R67W, 6TH PM A uifer - Laramie -Fox Hills Allowable AF Amount 43.5 AF Maximum Pumping Rate 100 gpm The well is currently permitted for industrial, commercial and augmentation use. The Applicant's accounting includes the 2% relinquishment requirement for the nontributary Laramie -Fox Hills water. In addition to replacing 10.86 acre -feet of depletions resulting from this mining operation at the Parker - Dersham Pit, 17.29 acre -feet will be pumped from the Laramie -Fox Hills well to replace depletions resulting from operations at the Baseline Resource site in accordance with the C.R.S. 37 -90- 137(11) SWSP approved for Hall- Irwin. Since the Laramie -Fox Hills water is being used as a replacement source for both plans, the applicant's accounting for each SWSP must specify the total amount of Laramie -Fox Hills water released and the amount associated with each SWSP.