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Serime - 2.05.6 <br />completed mine development waste pile areas. Additional information on potential water quality <br />• impacts from mine development waste and coal materials is provided under the disctsssion of <br />Protection of Ground Water Resources. <br />Operation of the sedimentation ponds for both the mine development waste pile areas and coal <br />stockpile area under OMI's CDPS pertniu will assure compliance with applicable water quality <br />regulations and effectively mitigate any potential surface water quality impacu. Reclamation of mine <br />development waste stockpile areas will occur on an ongoing basis with individual benches being <br />progressively reclaimed az soon az stockpile construction in that area reaches the bench design <br />elevation and the design outslope configuration is established. Coal stockpile areaz will be reclaimed <br />az soon az operationally practical after they are no longer required to support ongoing mining and <br />related operations. The initial step in reclamation of coal stockpile areas will involve removal of any <br />re~*+~~~+~g stockpiled coal materials and azsoua[ed stmctures. Subsequent reclamation of both <br />development waste and coal stockpile areas will involve regrading the disturbance areas to the final <br />design configuration, replacement of soil and substitute materials, and revegetation. 'These activities <br />are designed to establish effective surface drainage, stabilize the effected areas, and develop aself- <br />sustaining vegetative comrrn,~;ty. <br />Generally, ground water inflows to active mine workings are captured and routed to large <br />underground sumps which serve az operational water supplies for underground operations. Under <br />normal operations, any accumulations of mine water which exceed the available capacity of <br />underground sumps and cannot be recycled to the mine water system are pumped to the surface for <br />discharge through an approved CDPS discharge point. There are, however certain exceptions to this <br />nomral operating practice, including emergency flooding of a portion of the Sanbom Creek mine <br />workings in 1999 and subsequent mine water discharge, discharge of any large-volume inflows from <br />abandoned mine areas, and initial dewatering in conjunttion with mine development activities. As <br />• necessary, the water used to flood the area of the possible mine fire, large-volume flows from flooded <br />mine areas, or initial development dewatenng discharge flows have been or maybe discharged directly <br />to the approved surface CDPS discharge points}. Although large-volume discharges are not <br />common or likely, for any such discharges OMI would contact and obtain required CDPHE and <br />DMG approvak prior to discharge. Such discharges could impact stream flow volumes and water <br />quality downsveam from the point of discharge. <br />In January 1999, after gas readings indicated a possible underground mine fire in the Sanbom Creek <br />Mme, the mine was temporarily sealed and the area of the possible fire was flooded to extinguish any <br />attive fire, eliminate the potential for further ignition hazard, and allow subsequent reentry and <br />recoveryof the mute. Errtergencq•discharge of a portion of the water from the flooded workings was <br />necessary to prevent damage to the longwall mining system and was approved under Technical <br />Revision TR-33 and accomplished by pumping water from vertical boreholes drilled into the flooded <br />workings to a temporary mine water discharge pond prior to releaze to the North Fork The <br />temporary pond was designed to provide adequate detention tune for settlement of suspended solids <br />and allow for sampling of mute discharge prior to release to the North Fork Due to oxidation within <br />the mine workings, there was the potential that the water used to flood the area of the potential mitre <br />fire could exhibit lower pH and elevated levels of TDS and various chemical constituenu. Sampling <br />and full-suite analysis of this water indicated similarities in water chemistry and constituenu between <br />the discharge from the flooded workings and groundwater associated with the coal seams. It is <br />important to note, however, discharge water quality was consistent with all applicable discharge <br />effluent limitations under OMI's existing CDPS permit. <br />It should be noted that discharges of up to 2,000 gpm occurred over a short period of time for <br />• removal of the rem~~~~~g water from the area of the potential mine fire in the Sanbom Cmek Mute <br />workings. This discharge was routed through the existing underground mine water sump pnor to <br />transfer to the surface and discharge through the existing CDPS discharge point. Given that mine <br />water discharge requiremenu were limited in both duration and volume, and the specific control and <br />sampling measures inherent in operation of both the underground mine water sumps and surface <br />PR04 2.05-81 Revised May 2001 <br />