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inundation. The mine has supplied the Division with a geotechnical analysis of <br />the mine plan, demonstrating that i[ would avoid subsidence-caused fracturing <br />of the interburden. <br />4. The abandoned Hawk's Nest Mine has several drill holes that were drilled down <br />from the active mine into lower seams. These holes are not be]ieved to be <br />sealed and could provide a conduit through which water could flow into the <br />active mine; however, as reported in the PHC, there is no indication that the <br />mine is flooded. <br />Mine inflow, except that used in the mining process, will be treated and discharged <br />to the North Fork. The discharge will meet NPDES standazds, but it is expected that <br />the discharge will have an elevated TDS for which there are no discharge standazds. <br />From water quality analyses of the flooded old Somerset Mine, TDS values of 3,200 <br />mg/l for the discharge can be expected. During the emergency mine water discharge <br />of the Sanbom Creek Mine in 1999, water quality analyses of the discharge water <br />showed TDS ranging from a low of 2668 mg/1 to a high of 4785 mg/1. <br />Post-mining impacts are expected to be small. The mine is expected to slowly flood <br />[o the level of the river, which is below [he elevation of the portal. Discharge from <br />the portal is unlikely. The water quality of the flooded workings is anticipated to be <br />the same as that of the old Somerset Mine. After mine closure, the proposed <br />Sanborn Creek area is not expected to contribute additional dissolved solids to the <br />river. <br />Effects on Surface Water <br />The areas of surface disturbance at the Somerset Mine are protected by sediment <br />control systems including diversion and containment ditches, sediment ponds, and <br />other alternate sediment control features such as rock, vegetation and straw filters. <br />All point source dischazges are regulated under the National Pollution Discharge <br />Elimination System (NPDES). Specific details regarding the sediment and drainage <br />control systems are found in the Sanbom Creek Mine Permit, volume 1, pages <br />2.05-15, 2.05-16, and 2.05-41 through 2.05-48. Map S-035 also contains pertinent <br />information. Drainage and sediment control information specific to [he Sanborn <br />Creek Tracts permit azea is located in the Permit Revision No. 1 and Permit <br />Revision No. 2 binders, pages 2.05-15i, 2.05-15ii, 2.05-16, 2.05-43 through 48, and <br />Appendix B. Drawings 5-002, 003 and 004 also contain pertinent information. <br />Drainage from disturbed areas can contribute additional suspended solids to offsite <br />stream systems; however, the above-referenced sediment control systems will <br />effectively control sediment yield to offsite areas. Other applicable effluent <br />limitations will also be met, as required by the NPDES permit. There is no evidence <br />of acid-forming or toxic-producing materials. <br />2l <br />