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Peabojq <br />Twentymile Coal Company ?ryy 29515 Routt County Road #27 <br />RECEIVED Oak Creek, CO 80467 <br />1~ 970.879.3800 <br />Mrs. Janet Binns SEP 17 September 15, 2008 <br />Environmental Protection Specialist Division of Reclamation, <br />Mining and Safety <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />(303) 866-4933 <br />RE: Twentymile Coal Company - Foidel Creek Mine (Permit No. C-82-056), Minor Revision <br />(MR08-230) for Mine Dewatering Modifications <br />Dear Mrs. Binns: <br />Twentymile Coal Company (TCC) requests CDRMS approval of a Minor Revision (MR08-230) to our <br />approved Mining and Reclamation Permit, for several permit modifications necessary to address increases <br />in mine dewatering volumes and related discharges. The proposed increases in dewatering volumes and <br />discharges are necessary to reduce water levels in sealed mine areas. <br />TCC currently has the capability to dewater sealed mine areas using the existing Fish Creek Borehole and <br />associated Fish Creek electro-coagulation system and 3-cell treatment ponds (Southwest Mining District), <br />and the existing IORT Dewatering Borehole (Eastern Mining District). These existing dewatering <br />installations discharge to the mine water system via pipelines from both the Fish Creek water treatment <br />ponds and the IORT Dewatering Borehole to the Barricade Chamber and FCM-2 Well Casing. From <br />these connections to the mine water system, water is transferred to the Area 1 Pit via existing underground <br />pipelines, with the option of discharging from the Area 1 pit through Sedimentation Pond D at CDPS <br />Outfall 005. The option also exists to discharge from the Fish Creek water treatment ponds directly to <br />Fish Creek at CDPS Outfall 115. <br />TCC has also permitted additional dewatering installations for the Fish Creek Ventilation Shaft (MR07- <br />216) and the TORT Dewatering Borehole No. 2 (MR08-228), with the original intent of providing <br />supplemental dewatering capacity and backup capabilities for the existing dewatering installations. <br />Given, however, a rapid and unanticipated rise in water levels in the sealed mine workings, TCC is <br />looking at all reasonable options to increase mine dewatering volumes in order to reduce water levels in <br />the sealed mine areas to provide an adequate safety buffer. The following summarize the actions and <br />modifications TCC is proposing to address both immediate and longer-term mine dewatering and <br />discharge needs: <br />(Action/Modification) Discharge at capacity (approximately 500 gpm) from the Fish Creek water <br />treatment ponds to Fish Creek through CDPS permitted Outfall 115, initially on an emergency <br />basis, and subsequently in compliance with applicable CDPS effluent limitations. Treated <br />discharge water from the Fish Creek water treatment ponds can also be routed to the Barricade <br />Chamber/FCM-2 location via the existing transfer pipeline, for mine water use. <br />(Action/Modification) Install pump in existing inactive Fish Creek Ventilation Shaft (MR07-216) <br />and discharge through either CDPS permitted Outfall 115, initially on an emergency basis, and <br />G:\Environmental\REVISION\MINOR-RV\MR08-230 Mine Dewatering Modifications\MR08-230 Mine Dewatering <br />Modifications TL.doc