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• can be accomplished using the mine scales and the known volume of a front end <br />Five Year Waste Pile <br />loader bucket. This information can then be used in establishing the bond <br />estimate. In addition to the physical properties, a chemical analysis of the topsoil <br />must be performed to determine the quantity of fertilizer that will be needed to <br />assure successful growth of vegetation during final reclamation. <br />A revised estimate of 5000 cubic yards of waste rock production annually was <br />used in estimating the elevation of the 5-year waste pile. Beginning with the <br />existing waste rock volume, approximately 25,000 cubic yards, and adding the <br />annual increment, results in a required 5-year volume of 50,000 cubic yards. This <br />corresponds to a pile height of 75 feet (elevation 7490). The boundary of the 5- <br />year pile is shown on the accompanying design drawing. In addition, the volume <br />of cover material (fill and topsoil) for the 5-year pile was estimated at 7000 cubic <br />yards. Of this, the mine operator estimated that they currently have enough cover <br />stockpiled to accommodate the existing pile (about 4800 cubic yards of cover). A <br />location for the 5-year cover storage pile (7000 cubic yards) is shown on the plan <br />drawing. <br />Drainage Features <br />• Enlargement of the waste pile will require modification of the drainage <br />intercept ditches on both the north and south side of the pile. In addition the <br />sedimentation ponds will be altered to accommodate the increased contaminated <br />runoff volumes. All ditches and pipes are sized for the 100 year event and the <br />ponds for the 10 year event. Please refer to the drainage report (revised July <br />1997), and the accompanying design drawings for details. <br />The Eastside drainage channel will be moved from its existing location, to the <br />north against the natural hill slope. As the waste bank increases in elevation the <br />ditch will move up the hillside. At the top of the sloping pile faced the channel will <br />intersect an armored channel that will flow down the front face of the waste pile. <br />These two ditches will route uncontaminated water to the clear water diversion <br />system. <br />A similar set of intercept ditches on the south side of the pile will collect <br />contaminated runoff from the pile and some clear water from the adjacent hillside <br />and route it to the sedimentation ponds. Please refer to the design drawings and <br />the drainage report for details. <br />Underdrain <br />An underdrain system for the waste pile is required by the regulations. The <br />purpose is to intercept water which originates either form precipitation infiltration <br />. through the waste pile surface or from the interception of groundwater at the pile- <br />January 1998 <br />