2020-08-20_REVISION - C1980007 (36)

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Power to the mine is supplied via existing lines of the Delta-Montrose Electric Association. Power is stepped down at a substation in the main mine facilities area for powering underground operations and the surface facilities. Ventilation in the mine is provided by a fan in Sylvester Gulch (PR-7), and a vent shaft in Deer Creek,just to the east of Minnesota Reservoir JR-109), as well as numerous Mine Ventilation Boreholes (MVBs) which are constructed in advance of mining and are operated so as to control the partial pressure of methane in the air inside the mine. Between 1995 and 2001 ventilation to the B-seam workings was provided by the Lone Pine Fan. Mining ceased in the Lone Pine portion of the mine in early 2001 and the workings served by the fan portal were sealed off underground. The Lone Pine Portals were sealed in 2001 (TR-93). MCC occasionally uses a relatively small quantity of explosives for blasting for underground construction. The explosives are stored in an explosives magazine located in the main facilities area of the mine. The West Elk Mine portals are located at an approximate elevation of 6,450 feet. Run-of-mine coal is transported from the production panels to the various surface facilities by a system of belt conveyors. A conveyor carries coal from inside the mine portal to the stacking tubes. From the stacking tubes, an underground conveyor reclaim system transports the coal to the two crushers. A conveyor then moves the coal from the crushers to the two storage silos. A stacktube located to the east of the silos provides additional storage for product coal. A loadout conveyor carries coal from the storage silos to the over-the-track loadout. A portion of this conveyor is completely enclosed where it crosses the North Fork of the Gunnison River and Highway 133. Coal is shipped from the West Elk Mine mainly by rail, although some coal is either trucked from the mine or is transferred to various handling or stockpile facilities on the mine site. Coal mine waste at the mine is generated during underground construction activities and mining. Other sources of coal mine waste are contaminated coal spillage, material cleaned out of sediment ponds, and soils contaminated with non-hazardous materials. These other sources of waste comprise only a small portion of the coal mine waste produced at the mine. Coal mine waste is currently being processed in a plant that MCC constructed on the Lower Refuse Pile (LRP). The processing plant and an adjacent coal stockpile and laboratory were approved in TR- 118. The refuse generated by the processing plant was initially disposed of in a permanent coal mine waste pile called the Refuse Pile Expansion area (RPE). This is a 20 acre site to the east of the LRP, and is east of Sylvester Gulch. The level area on top of the RPE is used as an equipment lay down area and the slopes have been topsoiled and seeded. As the RPE neared its design capacity, a new refuse pile, the Refuse Pile Expansion East (RPEE)was approved for construction with TR-120 (and re-designed with TR-127 and TR-133), in the drainage immediately east of the RPE. Material is transported to and from the RPEE by haul truck. An Upper Refuse Disposal Area has also been approved for construction, but has not been built. Although MCC has verbally indicated this pile will not be needed, Stipulation#7 requires MCC to complete a geotechnical investigation prior to constructing the pile. Surface runoff from the disturbed area is treated by six ponds (MB-3, MB-4, MB-5E,NSSA, RPE pond, and SG-1) and a number of small area exemptions (SAEs), two additional ponds (FW-1 and FW-2) are used for water storage. Surface water and sediment control structures are 26