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near the site of the soil stockpiles, other water <br /> quality monitoring stations on Sylvester- Gulch, and <br /> sites above and below the mine on the North Fork of <br /> the Gunnison, provide sufficient baseline water <br /> quality information to evaluate the changes in water <br /> quality that could result from the impacts of this <br /> refuse stockpile. Conductivity and TDS from samples <br /> of monitoring well GP-1 showed slightly higher levels <br /> in 1986. However, this does not appear to be a <br /> continuing problem. Concentrations of iron during <br /> 3.991 were higher than the baseline monitoring data, <br /> which the operator believes may be associated with <br /> B development waste. Concentrations of iron will be <br /> monitored to see if the elevated levels continue. <br /> A leachate study of the F seam refuse was conducted <br /> and included in the application for the permanent <br /> refuse disposal site in Exhibit 51 of the permit <br /> application. In addition, the effects of B seam <br /> refuse on leachate were also evaluated and can be <br /> found in Exhibit 56. The permeability contrast found <br /> in the pile will cause most of the leachate water to <br /> perch within the refuse pile and above the native <br /> sioils. A shallow water mound will build within the <br /> pile and cause the water to migrate laterally to <br /> small seepage area at the edge site. During 1991, <br /> there were no visible flows from the pile toe and <br /> midsection underdrain. <br /> Upper Refuse Disposal Area - The upper waste rock <br /> pile was approved, with stipulations on June 14, <br /> 1.986. This pile has not been constructed and <br /> construction is not proposed for this permit term. <br /> The final pile will cover approximately 40 acres and <br /> contain five million tons of coal reject and <br /> developmental waste rock. The primary predicted <br /> impact to ground water is the development of leachate <br /> from precipitation infiltration through the pile. <br /> The approved plan calls for the installation of five <br /> lateral subdrains to collect this leachate. The <br /> drains will help prevent the formation of a large <br /> perched leachate aquifer that may effect the <br /> stability of the pile. Additionally, the drains will <br /> intercept most of the leachate and prevent it from <br /> entering the shallow colluvial aquifers. The <br /> s.ubdrains will daylight into surface channels where <br /> the leachate will flow to a sediment pond. As this <br /> pile is constructed, spoil wells will be installed. <br /> There are a number of stipulations which must be <br /> addressed prior to beginning the construction of the <br /> upper refuse pile. <br /> ii. Mitigation of Ground Water Impacts - <br /> The applicant anticipates no degradation of ground <br /> water quality during mining. The applicant will <br /> treat any mine water effluent as necessary to meet <br /> water quality standards prior to discharge and there <br /> will be no uncontrolled mine water discharge after <br /> mining is complete which might otherwise degrade <br /> surface streams or ground water. The operation plan <br /> indicates most water used for dust control will be <br /> absorbed on the coal and carried from the mine, <br /> thereby minimizing the quantity to be treated. Any <br /> discharge will be delivered and treated in the <br /> 32 <br />