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possible mechanical failure of the casing and loss of the well seal, or increased porosity resulting in a lowering of the water level. Monitoring Well 006-82-48A was installed in a borehole that had originally been drilled through the Twentymile Sandstone to the Wadge Seam. Although subsidence may have resulted in the loss of this well, no impacts on the ground water quality in the Foide] and Middle Creek alluviums are anticipated. This conclusion is consistent with experience in other coal fields. Most of the studies of subsidence effects of surface and ground water quality in the Appalachian coal fields concluded that no significant long-term effects on water quality were observed, which confirms observations from the Foidel Creek Mine (Owili-Eger, 1987; Moebs and Barton, 1985; Schultz, 1988). After over 15 years of monitoring of alluvial and bedrock wells (see Annual Hydrologic Reports), no impacts to the water quality of the Trout Creek Sandstone, Twentymile Sandstone, or overlying alluvial aquifers has been found. The only impacts to sub-surface water quality has been an increase in TDS and iron in the water stored in the mine. In addition, high TDS water from the adjacent surface mine has moved into the underground workings (see in Effects on Ground Water Ouality of Aauifersl. SURFACE WATER SYSTEM A detailed discussion of surface water hydrology is presented under Rule 2.04.7(2). The proposed life-of--mine azea for the Foidel Creek Mine is located within the Foidel Creek and Fish Creek surface water drainages. Therefore, any mining impacts on surface water systems will be confined to these drainages and their receiving streams. Potential Mining-Related Impacts on Surface Water Quantity and Quality The planned underground mining and associated activities have the potential of creating changes in the existing surface water quantity in terms of mnoff volumes, flow rates, and direction and location of surface water drainage. The potential mechanisms of impact aze: • 1) Direct disturbance of surface flow channels 2) Dischazge of mine inflow water to surface water drainages via sedimentation ponds 3) Detention of surface runoff in sedimentation ponds and related evaporation loss 4) Diversion of overland flow with ditches 5) Induced rechazge or dischazge by underground mine dewatering Direct disturbance of surface flow channels may occur through temporary disturbance for construction activities or long-term disturbance for road or railroad crossings. Examples would be the mine road, railroad, and pipeline crossings of Foidel and Fish Creeks. The greatest potential impact to surface flows from this operation is the discharge of mine inflow water. Ground water that flows into the mine is collected in sumps and pumped to the surface, where it is diverted to sedimentation ponds or treatment facilities. The relatively continuous inflows discharged to Foidel Creek make up a significant proportion of the total creek flow, particulazly during the period of low flow from September to Febmary. Due to its higher in-stream flows, changes to Fish Creek water quality from discharges from Site 115 will generally be less than those to Foidel Creek. Detention of surface runoff in sedimentation ponds decreases peak flow rates, and reduces the amount of water available downstream. Diversions of overland flow will deprive small azeas of water, but will not reduce the amount of water downstream. The quality of surface and ground water could possibly be affected by water handling and treatment methods under the planned operations of the Foidel Creek Mine. Impacts of mining on water quality can be measured by analyzing the data of indicator parameters such as conductivity, total dissolved solids (TDS), total suspended solids ~TSS), sodium adsorption ration (SAR), and pH. Mining activities in the permit area will create changes in surface ater quality. Mining practices such as removing and stockpiling topsoil, clearing vegetation, road construction, and vehicular travel in disturbed areas may result in MR07-223 2.05-150 10/03/07