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Murari P. Shrestha, P.E. <br />August 25, 2010 <br />Page 2 <br />future potable water use at the New Horizon North and the Cyprus Block properties will <br />be similar to the existing uses at the New Horizon Mine. <br />Average potable water use and consumptive use is summarized in Table 1. Annual water <br />use has averaged 0.61 acre -feet per year (af /yr). As expected, there is greater demand in <br />the summer months as a result of the irrigation water use. <br />In order to estimate indoor and outdoor consumptive use, we assumed that there was zero <br />irrigation water use in the months of December through February, and used the average <br />of those months to estimate the non - irrigation water use throughout the year. We <br />understand that the future New Horizon North and Cyprus Block mines will operate with <br />septic water disposal systems, and as a result, we applied a consumptive use factor of <br />15% for the indoor water use portion of the potable water requirement, including vehicle <br />washing. Washing of vehicles occurs year round, and a portion of that water returns to <br />the stream system, but consumption is projected to be greater than indoor uses. Therefore, <br />we estimate that the 15% consumptive use is appropriate for the non - irrigation <br />consumptive use, and accounts for the increased consumption resulting from vehicle <br />washing. Outdoor water use was estimated based on the difference between total water <br />requirements and indoor water use. We assumed that the irrigation water will be applied <br />by a sprinkler system, and therefore, we used an irrigation efficiency of 80% to estimate <br />the consumptive use of the irrigation water. <br />Based on this approach, indoor water requirements are estimated to be 0.40 af/yr, and <br />indoor consumptive use is estimated to be 0.06 af/yr. Irrigation water requirements are <br />estimated to be 0.21 af/yr and irrigation consumptive use is estimated to be 0.17 af/yr. <br />Total potable water requirements are estimated to be 0.61 af/yr and total potable <br />consumptive use is estimated to be 0.23 af/yr. <br />Potential Impacts to Wells Resulting From Well and Dewatering Pumping <br />Analysis of Water Level Change in Neighboring Wells Resulting from Potable Well <br />Operation <br />The water supply wells at New Horizon North and the Cyprus Block mine areas will only <br />be used for potable purposes and will not be used for the dewatering of the mine. The <br />potable wells will be completed in the Brushy Basin Formation, which is the same <br />geologic unit in which most neighboring water supply wells are constructed. The Brushy <br />Basin is stratigraphically located below the coal zone to be mined by Western Fuels. <br />Because Western Fuels' new wells and neighboring wells will be constructed in the same <br />aquifer, the potential exists that water level drawdowns can propagate through the Brushy <br />Basin Formation, resulting in well -to -well interference. This analysis quantifies the <br />potential water level change resulting from the operation of Western Fuels' potable water <br />supply wells. To complete this analysis, we determined appropriate aquifer characteristics <br />for the Brushy Basin Formation, determined average demand rates, determined a centroid <br />location at each mine property, determined distances from the centroid location to <br />neighboring wells and calculated projected water level drawdowns resulting from the <br />operation of wells at the New Horizon North and Cyprus Block mine properties. <br />www.hbawater.com <br />