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Table 4.8 -1 Water Depletion Calculation <br />Revised (January 2013 PR -7) Estimate of Annual Use and Evaporative <br />Loss of Surface Waters Discharged From Trapper Mine <br />Evaporative Depletion From Impoundments <br />o Assume annual evaporative loss is 24 inches. <br />0 41 existing sediment ponds average 0.66 acres <br />surface area at high water mark = 41 " 0.66 ac' 2' <br />o Coyote Dam @ high water mark = 1" 12.00 ac' 2' <br />o Future life -of -mine sediment ponds = ((4 " .68) + 40) ac' 2' <br />o Existing stock ponds (66) Q average 0.13 ac = 66 " 0.13 ac " 2' <br />o Future life -of -mine stock ponds (41) = 41 " 0.13 ac " 2' <br />Depletion Due to Road Watering <br />0 Average annual quantity used for road watering. <br />Augmentation Due to Deep Wells/Pit Pumpage <br />• Assume 10% of pit water originates from surface runoff. <br />• Average annual Trapper well dewatering. <br />• Average annual Trapper pit dewatering = 32.17 " 0.9 <br />Total Adjusted Depletion Due to Mining - 2012 Estimate (PR -07): <br />Total Adjusted Depletion Due to Mining -1995 Estimate (TR -67): <br />0.66 (35 ponds + MF #3 + #1 +EMF #1 +EF #1 +WH +D #1 +HGEXu41 <br />54 12 ac -ft <br />24 00 ac -fl <br />6.24 ac -ft <br />17 16 ac -ft <br />10.66 ac-ft <br />Total = 112.18 ac -ft <br />Total = 115.25 ac -ft <br />Total Estimated Depletion = 112.18 ac-ft <br />115.25 ac -ft <br />227.43 ac -ft <br />4-172a <br />34.62 ac -ft <br />32.71 ac -ft <br />Total Augmentation = 67.33 ac-ft <br />227.43 ac -ft <br />-67.33 ac -ft <br />160.10 ac -ft <br />130.39 ac -ft <br />