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Sievers Pit SWSP Page 2 of 7 <br />August 7, 2013 <br />requires that you provide information to DRMS to demonstrate you can replace long term <br />injurious stream depletions that result from mining related exposure of ground water. <br />In accordance with approach no. 1, you have indicated that a bond has been <br />obtained for $295,172 through the DRMS to assure that depletions from groundwater <br />evaporation do not occur in the unforeseen event, or events that would lead to the <br />abandonment of the gravel pit. In addition, the Sievers Pit will be backfilled and reclaimed <br />as irrigated land once mining is complete, thus eliminating any long -term injurious stream <br />depletions related to exposure of groundwater. <br />Depletions <br />The anticipated consumptive use at the Sievers Pit mining operation is 51.12 acre -feet with <br />48.10 acre -feet depleting the stream during the SWSP period. The Sievers Pit is decreed for 2.6 <br />acre -feet for sand screen operation, 9.5 acre -feet for dust control of roads and crusher, 3.6 acre - <br />feet for concrete production, 5.1 acre -feet for asphalt production, and 0.2 acre -feet for domestic <br />use, and 5.1 acre -feet of pond evaporation. However, the uses covered by the decree in case no. <br />83CW65 during the SWSP approval period include only the 9.5 acre -feet for dust control of roads <br />and crusher and the 5.1 acre -feet for asphalt production, as shown on the attached Table 2. <br />This SWSP anticipates that a total of 6.0 acres of water surface will be exposed at the site <br />in the dewatering trench and ponds. During the SWSP period, the total evaporation loss from the <br />6.0 acres of exposed groundwater is estimated to be 15.5 acre -feet. Groundwater will also be <br />consumed during the process of mining aggregate. Previously the aggregate production at Sievers <br />Pit occurred above ground water table, therefore, the decree in case no. 83CW65 did not account <br />for the amount of water lost with the mined product since there was no ground water diversion. For <br />the purpose of this SWSP, Lafarge anticipates mining below the ground water table a maximum of <br />400,000 tons of aggregate per year resulting in a water use of 5.9 acre -feet, assuming 2 percent <br />water weight due to the dewatered state of the mine. Maximum dust control is anticipated to be <br />15.0 acre -feet, which is a 5.5 acre -feet increase from the decree. Therefore depletions that will be <br />covered by the SWSP will be evaporation from the exposed ground water in the dewatering <br />trenches and ponds, the water lost with the mined product and the increased amount of water used <br />for dust control. The other uses will remain within the limits as described in the decree in case no. <br />83CW65. <br />The Applicant proposes to divert surface water from Crystal River and deliver it to the pit via <br />the Kaiser - Sievers Ditch for temporary storage into a one acre storage pond before the water is <br />used in an aggregate wash plant at the site. The one acre storage pond does not expose <br />groundwater. A lateral on the Kaiser - Sievers Ditch which runs along the eastern boundary of the pit <br />will be used to deliver the water. The Applicant anticipates that approximately 9 acre -feet will be <br />required to initially fill the one -acre pond. The initial fill will be conducted during a free river period <br />when un- appropriated water exists in the Crystal River. Once the one -acre pond has been initially <br />filled, additional water will be delivered as needed to replace water consumed during the washing <br />process or evaporated from the pond. The total gross evaporation loss from the one -acre storage <br />