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Just south of Munger Canyon, Stove Canyon and Buniger Canyon are sub-basins within <br />the Big Salt Wash drainage system. Munger Canyon and the unnamed tributary are both <br />sub-basins of the East Salt Creek drainage. Development of mine workings during the <br />initial term will extend under portions of all of the above-mentioned drainage basins. <br />The central facilities area permit revision increased the permitted azea by 273.3 acres. <br />This area will be located along East Salt Creek beginning at the mouth of Munger <br />Canyon and extending southwazd approximately 1.5 miles to the proposed coal <br />processing waste disposal azea. <br />Prior to submittal of the central facilities area permit revision request in 1985, the planned <br />surface disturbance related to the mine consisted of the Munger Canyon Mine haul road <br />encompassing a 35-acre area extending from the mouth of Munger Canyon up to the <br />portal bench. Construction of the central facilities area, coal processing waste disposal <br />area and interconnecting haul road and conveyor system will increase the disturbed area <br />by 87 acres. The central facilities area will consist of a coal stockpile azea, wash plant <br />and product piles, office, shop and wazehouse, storage yard, parking lot, slurry ponds, <br />fresh water ponds, topsoil stockpile sediment pond and access road. All of these facilities <br />will be constructed on the alluvitun of East Salt Creek at the confluence of Munger <br />Canyon. These facilities aze shown on Figure 2.2-2S of Volume VII of the application. <br />Unconsolidated alluvial deposits were mapped by the applicant in the lower reaches of <br />Munger Canyon. The proposed underground development waste pile and associated <br />features aze located at the edge of these deposits. Exploratory drilling in the Munger <br />Canyon alluvium by the applicant indicates that ground water is greater than 40 feet <br />below the surface of the valley floor. Also, the absence of mottling in test pits PT-1, <br />TP-2, and TP-3 indicate the lack of natural subirrigation in the Munger Creek alluvium. <br />Mean annual. dischazges in Munger Canyon were estimated by the applicant to range <br />from 0.02 c£> to 0.48 cfs, with an average of 0.17 cfs. Mean monthly flows were <br />estimated at 0 during winter months and 1 cfs maximum in May. Flow in Munger Creek <br />occurs mainly in response to snowmelt and storm events. <br />The Division has determined that Munger Canyon does not contain an alluvial valley <br />floor. The depth to ground water precludes subirrigation and surface water flows are <br />prohibitively low for use in successful irrigated agriculture without a means of retaining <br />the flows. <br />Grand Valley Coal Company has not supplied information with respect to the presence of <br />an alluvial valley floor in the Big Salt Wash. Therefore, for the purpose of this findings <br />document, th.e Division will assume that there is a potential alluvia( valley floor in the <br />Big Salt Wa~oh. The following analysis will consider potential effects of the operation <br />under this assumption: <br />st <br />