2019-05-29_REVISION - C1981018 (11)

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31 The impact of the proposed mine on ground water will be very localized, with no significant impact expected on a regional basis. This is due primarily to the small quantity of ground water in the area. Water encountered within the mine will be utilized underground for dust suppression. As a result, only those inflows that temporarily exceed storage capacities and mine use requirements would potentially be discharged to the surface and lost from the ground water system. Pumping from approved mine water discharge locations ceased upon sealing of the “D” seam northern longwall district in 1996. With the approval of TR-68, the Deserado Mine is approved for dewatering within the workings of the “B” seam. Excess water entering the mine workings is pumped to the surface where it is allowed to settle out or discharge through a series of sediment ponds and artificial wetlands known as the “B” seam dewatering pond system. To the date of this findings document, no water has discharged from the “B” seam dewatering pond system. Water pumped to the surface is allowed to percolate through the soil of the ponds and artificial wetlands remaining in the same hydrologic system. Groundwater in the area is tributary to the White River. Since January, 1997, prep plant thickener water has been disposed underground within down-dip, sealed sections of the “D” seam mine. No discernible effects on surface water or ground water quality are anticipated, although water levels will be reestablished sooner than would otherwise have been the case. Subsidence effects include fracturing of the material overlying the coal for a vertical distance of 30 to 40 feet due to caving of the roof material and surface subsidence and possible development of tension cracks on the surface due to differential settling. Observed ground water inflows during mining have been approximately 50 gpm. In fractured areas, increased flows of 100 to 300 gpm may be encountered for a short period of time. These flows will diminish as equilibrium is reestablished. Due to the low transmissivities of the aquifers, if caving should create a hydraulic connection from the mine to an aquifer within 30 to 40 feet of the coal, the additional inflow will be minimal. It is not probable that fracturing from the mine to the surface will occur as a result of subsidence and cause the flow of surface water to the mine. Subsequent to completion of mining, the ground water will slowly reestablish its pre-mining water levels. Due to the caving of the roof materials into the mine, an area of increased permeability will exist within the mine that will act as a "sump area" until equilibrium is established. However, due to the small quantity of water in the aquifers being discharged to the White River and its tributaries, the lack of ground water usage in the area, and the poor quality of ground water, potential impacts to flow in the White River will be minimal. The possibility exists for water to discharge from the portals once the mine workings have become completely flooded. The portals are updip in the mine