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Mine, there was very little inflow. <br />Because there is the potential that subsidence could cause fracturing of the <br />interburden between the B seam and the flooded workings of the Oliver Mine, <br />Oxbow Mining, LLC has committed to limited extraction in the Sanborn Creek <br />Tracts under those areas known to be flooded. This would avoid catastrophic <br />inundation. The mine has supplied the Division with a geotechnica] analysis of <br />the mine plan, demonstrating that it 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 believed 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 standards, but it is expected that <br />the discharge will have an elevated TDS for which there are no discharge standards. <br />From water quality analyses of the flooded old Somerset Mine, TDS values of 3,200 <br />mg/1 For the discharge can be expected. During the emergency mine water dischazge <br />of the Sanborn 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 floor <br />to the level of the river, which is below the 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 azea 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 aze 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 discharges aze regulated under the National Pollution Discharge <br />Elimination System (NPDES). Specific details regazding the sediment and drainage <br />control systems are found in the Sanborn Creek Mine Permit, pages 2.05-34 through <br />38 and Map 2.05-M4 (sheets 1 through 4). <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 />22 <br />