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<br />As the mining operation proceeds, 3.66 acre-ft of water per acre of exposed gravel pit <br />surface shall be consumptively lost as a result of post 1981 ground water exposure and <br />evaporation. Once the gravel pits reach their total eventual size of 100 acres, the associated loss <br />shall be 366 acre-ft per year. <br />During the mining operation, groundwater from the pit shall be required to wash the <br />gravel. Washing requirements for diversion are estimated at 1.2 acre-ft/yr per acre-ft of mined <br />material. The majority of this water is non-consumptive and shall return to the gravel pit once <br />used. It is estimated that water consumption resulting from water removal with the mined <br />product and washing shall be 4% of the product mined by weight. Soil tests have been performed <br />on the gravel material and have quantified the specific weight of the mined product as 2000 tons <br />per acre-ft. Since the specific weight of water is 62.4 Ibs per cubic foot, the consumptive use on a <br />volume basis of water associated with the mined material is 0.059 acre-ft/yr of water per acre-ft of <br />_ mined material or 2.94 x 10-5 acre-ft/yr of water per ton of mined material. <br />It is estimated that 50,000 to 100,000 tons ofg~avel material will be mined eacrti year.-k is- <br />estimated that each of the four cells will be mined for 6 to 15 years. The rate of extraction is-- ~ - <br />uncertain as it depends entirely on market demand. Gravel from each pit is expected to be mined <br />20 feet deep. The total eventual gravel extraction from the mine shall be 2,000 acre-ft or <br />4,000,000 tons which corresponds to a total consumptive use associated with the mined product <br />over the life of the mine of 118 acre-ft of water. <br />6 <br />