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possible mechanical failure of the casing and loss of the well seal or increased porosity resulting in a <br />lowering of the water level. Monitoring well 006-82-48A was installed in a borehole that had originally been <br />• drilled through the Twentymile Sandstone to the Wadge Seam. Although subsidence may have precipitated the <br />destruction of this well, no impacts on the ground water quality in the Foidel and Middle Creek alluviums are <br />anticipated. This conclusion concurs with the 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 IS years of <br />monitoring of alluvial wells and bedrock wells (see Annual Hydrologic Reports), no impacts to the water quality of <br />the Trout Creek Sandstone, Twentymile Sandstone, or overlying alluvial aquifers has been found. The only <br />impacts to subsurface water quality has been an increase in TDS and iron in the water stored in the mine. In <br />addition, high TDS water from the adjacent surface mine has moved into the underground workings (see in Effects <br />on Ground Water Ouality of 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 <br />area for the Foidel Creek Mine is located within the Foidel Creek and Fish Creek surface water drainages. <br />Therefore, any mining impacts on surface water systems will be confined to these streams and their receiving <br />streams. <br />Potential Minine Related lmpacls on Surface Water Ouantitv and Oualitv <br />The planned underground mining activities have the potential of creating changes in the existing surface water <br />.quantity in terms of runoff volumes, Flow rates, direction and location of surface water drainage. The potential <br />mechanisms of impact are: <br />I) Discharge of mine inflow water [o surface water drainages via sedimentation ponds; <br />2) Detention of surface runoff in sedimentation ponds and related evaporation loss; <br />3) Diversion of overland flow with ditches; and <br />4) Induced recharge or discharge by underground mine dewatering. <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 diverted to <br />sedimentation ponds or treatment facilities. The relatively continuous inflows discharged to Foidel Creek make up <br />a significant proportion of the total creek flow, particularly during the period of low Flow from September to <br />February. Due to its higher instream Flows, changes to Fish Creek water quality from discharges from Site 1 ] 5 will <br />generally be less 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. <br />ming activities in the permit area will create changes in surface water quality. Mining practices such as <br />removing and stockpiling topsoil, clearing vegetation, road construction, and vehicular travel in disturbed areas <br />have provided <br />APPRfl9~'~ n.IN 2 2000 <br />PR 99-OS 2.05-150 03/28/00 <br />