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These standards and discharge analyses are contained in Exhibit 22, NPDES permit and in the <br />Annual Hydrology Reports. <br />Long term Hvdrolo2ic Impacts. Following the completion of mining, the underground working <br />will flood and the potentiometric surface in the coal seams will rebound to near the pre - mining level. <br />Physically the overburden and coal will have increased inter connection and transmissivity for a distance <br />of up to 195 feet above the highest mined seam and will act as an integrated hydrologic unit because of <br />increased fracturing. The 1980 WWL Report estimated that the potentiometric surface will recover to the <br />original level of water in the coal (page 56) Hole LA 221 had a water level in 1976 located 304 feet <br />above the top of the Maxwell seam of coal (1994 supplement to Exhibit 8 Table 3A). The elevation of <br />the Allen seam of coal in the approximate center of the New Elk Mine is 7,150. If the 1976 water level <br />information is representative of the original potentiometric surface then the anticipated equilibrium level <br />of water in the coal seam at New Elk Mine would be about 7,450 feet elevation. Given the approximate <br />nature of the water level estimation and the proximity of the predicted elevation to the elevation to the <br />East Portal (7,460 feet) NECC will install a 6 PVC pipe to discharge groundwater from the portal in the <br />event that surface discharge occurs. <br />The water quality of the water filling the mine will reflect a mixture of five years of pumping of <br />thickener into the mine with inflow from the coal seam and other sources. This will not materially change <br />the beneficial uses which can be acquired from the Allen and Apache seams as they are not acceptable for <br />use as a domestic water source or a flood irrigation source due to salinity levels. In addition, the coal <br />seam aquifers exceeds MLRD suspect levels for stock watering for iron manganese and fluoride. <br />Water quality along the Middle Fork of the Purgatoire will experience a diminished water quality <br />following the discharge of water from the flooded workings. Salinity, sulfate, and SAR levels will <br />increase, but projections of water quality during low flow show that beneficial uses will not be <br />compromised. Ammonia concentrations in the river have historically exceeded chronic aquatic life <br />receiving stream standards. The discharge of water from the flooded workings is projected to improve the <br />water slightly, but not enough to meet the standards. Table 26C delineates loading of parameters which <br />potentially could impair uses. <br />TR -56 2.05 -88 Revised 4/11 <br />