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• Water was noted during excavation of TP-3B irectly above the bedrock at a <br />depth of 11 feet. In bori TH-3 ater was first encountered near the bedrock layer <br />GII a ~~,~ and quickly rose to a depth of 1 foot. One day after drilling water was at a depth of <br />G~l~~ 0.5 feet (Elev. 6850) in boring TH-3. Water was found perched in a gravel layer <br />~~(~/ above the bedrock in bori TH-5 t 23 feet during drilling and one day after drilling. <br />The remaining borings in the area of the revised RDA were dry. <br />The water found in boring TH-3 was at an elevation very close to the water <br />surface elevation in Sedimentation Pond D at the time of drilling. The lowest and <br />closest portion of the proposed RDA is located about 150 feet west of TH-3 and at <br />an elevation of about 6865. This is about 15 feet above the water elevation <br />measured in the boring and pits near TH-3. We do not anticipate that groundwater <br />• will affect the excavation for the lower portions of the revised RDA. <br />REFUSE DISPOSAL AREA ANALYSIS AND DESIGN <br /> <br />Our analysis and design of the waste pile included geotechnical aspects <br />related to stability, drainage and construction. Analysis of the potential acid or toxic <br />properties of the waste rock was not within the scope of this investigation. <br />1 <br />Volume and Configuration <br />The RDA will be constructed of waste derived from processing of low quality <br /> <br />coal. The proposed configuration of the RDA is shown on Fig. 2, with typical <br />sections on Figs. 3 through 5. The revised RDA is approximately 3500 feet in length, <br />500 to 800 feet in width, with a maximum slope height on the east face on the order <br /> <br />of 125. The toe is located about 100 feet from the valley centerline to allow for <br />• access road construction without disturbing the valley bottom. The top will extend <br />7 <br /> <br />