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<br />• 1. Preliminary plan of disposal area locations and topography (Fig. 1). <br />2. Geology and Soils Baseline Technical Reports (October 1996, draft <br />copies), and <br />3. Water Resources Map. <br />We also considered CTLrfhompson, Inc, experience at the nearby New <br />Elk/Golden Eagle Mine sites, and other spoil/waste fill designs in sedimentary rock <br />areas along with technical publications to develop our opinions. A list of references <br />is provided at the end of this report. <br />PROPOSED DISPOSAL AREAS <br />To accommodate excess spoil generated from proposed surface mining at the <br />Lorencito Mine, 21 disposal areas have been identified. Mine plans are preliminary <br />and the number, location and configuration could vary. The proposed locations as <br />• provided by Greystone are shown on Fig. 1. To characterize the spoil fills we <br />estimated elevation and slope information as shown on Table 1 (Fig. 1). The fill <br />heights range from about 50 feet to 250 feet (toe to crest) with the maximum <br />thickness of fill below the crest ranging from about 50 to 170 feet. <br />The proposed geometry of the fill slopes is a 2.5:1 (horizontal:vertical) slope <br />face, with 20•foot wide benches at 40-foot vertical intervals. This results in an overall <br />slope on the order of 3:1. <br />We estimated the average valley slope and maximum side slopes to compare <br />to the CDMG definition of Valley Fills. A Valley Fill is subject to specific underdrain <br />size requirements and is defined by CDMG regulations as "a fill structure consisting <br />of any material other than coal waste and organic material that is placed in a valley <br />where side slopes of the existing valley measured at the steepest point are greater <br />than 20' or the average slope of the profile of the valley from the toe of <br />the fill to the top of the fill is greater than 10•." Based on our estimates the <br />• <br />LORENOITO COAL COMPANY <br />cTLrT zs,zsi 3 <br />