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Potential impacts of replaced spoil on groundwater quality. The analysis of geochemical <br />controls on groundwater quality suggests that the water chemistry and concentrations of most <br />elements of concern are controlled by mineralogic reactions that will resist changes in water <br />chemistry. Production of acid may occur in very local settings and is probably most prevalent in <br />the coal which will be mined. Calculations indicate that neutralization of the acid will occur rapidly <br />with mixing of water, orwith movement of acidicwater into calcite-bearing rocks. Also, the analysis <br />conducted indicates that chemical changes are not likely to occur. <br />Effects of mining on the local geomorphology. Impacts from mining on the local <br />geomorphology will be long term, but appear to be of minimal significance. The reestablished <br />reach of the drainage which will be mined will result in a shorter, slightly steeper stream channel. <br />The potential for increased sediment loads in the drainage (once pond 007 is removed) should be <br />offset by the stable banksides and the relatively small change in overall gradient. The increased <br />runoff and consequent erosion potential on disturbed basins in the mining area due to the <br />temporary loss of topsoil stricture should be of minimal significance. Contour ripping, mulching and <br />revegetation have been demonstrated to minimize soil erosion and will be used to mitigate the <br />increased runoff potential until the topsoil structure is developed. <br />Effects of sediment ponds on channel characteristics and downstream users. Potential <br />impacts of sediment pond 007 on downstream users will involve possible reductions in flow due to <br />impounded water. The water augmentation plan discusses the available water which will be used <br />should impacts be identified. WFC currently has rights to a sufficient quantity of water to supply <br />all users associated with the mining activities, plus an additional quantity of water that can be used <br />to mitigate any impact to downstream users. <br />Effects of sediment pond discharge on surface water quality. The effects of sediment pond <br />diversions on surface water quality will be negligible because the structure has been designed to <br />minimize impacts to the hydrologic balance. The diversion involves such minor areas of <br />disturbance that chemical and sediment changes in the flows will be unmeasurable. <br />Effects of runoff from reclaimed areas on the quality of streamflow. Due to the relatively small <br />area of disturbance in the New Horizon 2 mining area, any reductions in runoff will have only a <br />(REVISED 25 Jul 2002) 2.04.7-49 <br />