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Alluvial waters adjacent to the disturbed areas will show <br />• evidence of diminished water quality associated with mine waste piles, <br />sedimentation ponds and other direct recharge from surface waters <br />running across the facilities area. The quality will improve with <br />time, in conjunction with flooding of the alluvium which will result <br />both from leaching of the salts and dilution. <br />The elevation changes associated with subsidence may have long- <br />term consequences for surface water flow patterns at the site. Much <br />subsidence occurs within six months following mining. Changed <br />conditions within the mine can modify the potential for future <br />subsidence. Saturation of the coal through flooding can weaken the <br />pillars. Stoping of the workings with coal fines can limit the <br />potential for subsidence. No detrimental impacts have been observed <br />since mining commenced in 1952. <br />Room and pillar mining was utilized in over 90°s of the mine <br />workings. Secondary extraction was employed in the main workings. <br />Coal was produced using a longwall in a small section of the mine. <br />Longwall subsidence typically results in subsidence the thickness of <br />the coal seam down the center of the panel, with less change in <br />elevation along the edges of each panel. These impacts are lessened <br />• with increasing overburden thickness. This could cause ponding and <br />depressions within stream channels or irrigation ditches, or may <br />damage water storage structures. Long-term surface water quality <br />impacts will probably not be detectable. <br />Water Rights. The rights of users of surface and groundwater <br />present in the area of the New Elk Mine are reviewed in Section 2.04 <br />of this application. No significant amounts of ground water were <br />encountered in this area. Therefore, the New Elk Mine's effect on <br />groundwater users is not expected to be significant. Also, <br />projections have been conducted which show insignificant effects on <br />downstream surface water quality and quantity beneficial uses. <br />Water Monitoring Program. A monthly surface and ground water <br />monitoring program was initiated in February 1984 to gather baseline <br />and operational hydrologic data to assess potential effects of mining. <br />This program was based on stipulations placed on the permit and has <br />been revised multiple times in the interim period. Requirements of <br />the monitoring program are contained in Table 27, Hydrology Monitoring <br />Requirements and Table 28, Water Quality Parameter Sample Suites. <br />~ ~,a~la <br />2.05-90a (revised 08/29/97) g~~0 <br />