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Kattenburg Pit SWSP <br /> September 26, 2024 <br /> Page 3 of 11 <br /> Depletions <br /> The projected depletions for the period of this SWSP consist of net evaporation from <br /> exposed groundwater surface area, washing of mined product and dust suppression. No <br /> dewatering of groundwater is anticipated at the site. The anticipated net depletions for this <br /> plan are 3.94 acre-feet per year. <br /> Evaporation <br /> Evaporative loss will occur from exposed groundwater at the Kattenburg Pit. The exposed <br /> groundwater area at the site is expected to be no more than 0.1 acre during the requested <br /> approval period. Gross annual evaporation in the area is approximately 35 inches according <br /> to NOAA Technical Report NWS 33. After accounting for a historical consumptive use credit <br /> (calculated as 70% of gross monthly precipitation) that is allowed pursuant to C.R.S. 537-80- <br /> 120(5) and 537-92-305(12)(a), and after accounting for periods when the exposed <br /> groundwater is expected to be iced over, the net annual evaporation is estimated to be <br /> 25.24 inches. This results in a net evaporative loss of approximately 0.21 acre-feet per year. <br /> Water Lost from Mined Product <br /> United anticipates mining up to 150,000 tons of product during the requested plan period. <br /> During this SWSP period material will be mined above the groundwater table, and washed. <br /> Groundwater lost with mined product will be 2% moisture content by weight. The total <br /> water retained in the mined product is estimated to be 2.21 acre-feet per year during this <br /> SWSP period. Should product be mined below the groundwater table, the amount of <br /> groundwater lost with mined product will be 4% moisture content by weight. The Applicant <br /> must separately track the amount of material mined above the groundwater table versus the <br /> amount of material mined below the groundwater table. <br /> Dust Suppression <br /> United anticipates withdrawing 1.52 acre-feet per year for dust control use on the mining <br />