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possible mechanical failure of the casing and loss of the well seal, or increased porosity resulting in a lowering of <br />the water level. Monitoring We11006-82-48A was installed in a borehole that had originally been drilled through <br />the Twentymile Sandstone to the Wadge Seam. Although subsidence may have resulted in the loss of this well, no <br />• impacts on the ground water quality in the Foidel and Middle Creek alluviums are anticipated. This conclusion is <br />consistent with experience in other coal fields. <br />Most of the studies of subsidence effects of surface and ground water quality in the Appalachian coal fields <br />concluded that no significant long-term effects on water quality were observed, which confirms observations from <br />the Foidel Creek Mine (Owili-Eger, 1987; Moebs and Barton, 1985; Schultz, 1988). After over 15 years of <br />monitoring of alluvial and bedrock wells (see Annual Hydrologic Reports), no impacts to the water quality of the <br />Trout Creek Sandstone, Twentymile Sandstone, or overlying alluvial aquifers has been found. The only impacts to <br />sub-surface water quality has been an increase in TDS and iron in the water stored in the mine. In addition, high <br />TDS water from the adjacent surface mine has moved into the underground workings (see in Effects on Ground <br />Water OualitYof Aquifers). <br />SURFACE WATER SYSTEM <br />A detailed discussion of surface water hydrology is presented under Rule 2.04.7(2). The proposed life-of--mine area <br />for the Foidel Creek Mine is located within the Foidel Creek and Fish Creek surface water drainages. Therefore, <br />any mining impacts on surface water systems will be confined to these drainages and their receiving streams. <br />Potential M1ninE-Related Impacts on Surface Water Ouantity and Ouality <br />The planned underground mining and associated activities have the potential of creating changes in the existing <br />surface water quantity in terms of runoff volumes, flow rates, and direction and location of surface water drainage. <br />The potential mechanisms of impact are: <br />1) Direct disturbance of surface flow channels <br />2) Discharge of mine inflow water to surface water drainages via sedimentation ponds or direct discharge <br />3) Detention of surface runoff in sedimentation ponds and related evaporation loss <br />4) Diversion of overland flow with ditches <br />5) Induced recharge or discharge by underground mine dewatering <br />Direct disturbance of surface flow channels may occur through temporary disturbance for construction activities or <br />long-term disturbance for road or railroad crossings. Examples would be the mine road and railroad crossings of <br />Foidel and Fish Creeks. <br />The greatest potential impact to surface flows from this operation is the discharge of mine inflow water. Ground <br />water that flows into the mine is collected in sumps and pumped to the surface, where it is normally diverted to <br />sedimentation ponds or treatment facilities. The potential also exists for direct discharge to area drainages under <br />emergency conditions. The relatively continuous inflows discharged to Foidel Creek make up a significant <br />proportion of the total creek flow, particularly during the period of low flow from September to February. Due to <br />its higher in-stream flows, changes to Fish Creek water quality from discharges from Site 115 will generally be less <br />than those to Foidel Creek. <br />Detention of surface runoff in sedimentation ponds decreases peak flow rates, and reduces the amount of water <br />available downstream. Diversions of overland flow will deprive small areas of water, but will not reduce the <br />amount of water downstream. <br />The quality of surface and ground water could possibly be affected by water handling and treatment methods under <br />the planned operations of the Foidel Creek Mine. Impacts of mining on water quality can be measured by <br />• analyzing the data of indicator parameters such as conductivity, total dissolved solids (TDS), total suspended solids <br />(TSS), sodium adsorption ration (SAR), and pH. Mining activities in the permit area will create changes in surface <br />water quality. Mining practices such as removing and stockpiling topsoil, clearing vegetation, road construction, <br />and vehicular travel in disturbed areas may result in the potential for increased erosion. <br />MR08-230 2.05-150 09/05/08 <br />