2024-03-12_REVISION - C1981022 (18)

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techniques with the same conventional equipment as previously discussed, except that conveyors were used in place of rail cars. Annual production of this addition of the mine was projected to be approximately 750,000 tons per year. Upon opening the portals, coal was first trucked to the tipple at the Elk Creek yard. A conveyor system was constructed while developing the first part of the Sanborn Creek addition. The conveyor system was used instead of haul trucks to convey coal from the Sanborn Creek portals to the tipple at the Elk Creek yard. The Sanborn Creek East Tract and the East Tract modification are located adjacent to the original Sanborn Creek addition on the eastern boundary and is an underground continuation of the Sanborn workings. No additional surface disturbance was required. Method of operations and production rate projections remained the same. With the approval of Technical Revision No. 24 (TR-24) on February 15, 1995, the coal production level at the mine was increased to 1.3 million tons per year. The production level at the loadout was increased to 1.6 million tons per year. The mine plan was also revised to accommodate the increase in production. Continuous mining remained the mining method. With the approval of Technical Revision No. 29 (TR-29) on July 15, 1997, Oxbow Mining, Inc. (now Oxbow Mining, LLC.)began longwall mining. The anticipated annual coal production was increased from 1.3 million tons per year to 4 million tons per year. To handle this increase in production, TR-29 also approved Oxbow Mining, Inc.'s plans to improve the coal handling facilities, increase the coal stockpile size, construct a new coal waste disposal site, move existing or build new support facilities and modify the train loadout for the new production rate. The West Valley Fill coal refuse area was permitted through TR-29 for use when the East Yard waste pile was filled to capacity. The operator began using the West Valley Fill coal refuse area during the third quarter of 2000. TR-43 approved the new II West Coal Refuse Facility in October 2003. On January 26, 1999, Oxbow Mining, Inc. evacuated the Sanborn Creek Mine due to elevated levels of carbon monoxide. The concern was that the elevated levels may have indicated a mine fire. The Mine Safety and Health Administration (MSHA) and the Division were notified. Emergency measures were taken to seal the mine openings. Two days after the sealing of the mine openings, there was an explosion in the mine, presumably due to a buildup of methane. MSHA directed Oxbow Mining, Inc. to drill emergency boreholes into the mine, for water injection and for gas monitoring. In February of 1999, Oxbow Mining, Inc. pumped approximately 88 acre-feet of water from the North Fork of the Gunnison River through one of the emergency boreholes and into the Sanborn Creek Mine in the longwall area where the spontaneous combustion event was suspected. In April of 1999, Oxbow Mining, Inc. concluded that additional inflow was entering the mine workings and had the potential to flood the longwall equipment. The source of the additional inflow was not known and had an approximate inflow rate of 200 gpm. With the Division's approval, through Technical Revision No. 34 (TR-34), Oxbow Mining pumped out mine water to the North Fork of the Gunnison at a rate of about 2,000 gpm. The pumping occurred from July 1999 to the first week of October 1999. Oxbow Mining made a decision to dewater only half of 8