2008-01-11_PERMIT FILE - C1982056A (2)

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water to the surface facilities. A second centrifugal pump delivers water to the mine for dust control and fire protection. A second sowce is a water-line, which runs from a Colorado Yampa Coal Company manhole station 220 feet to a borehole approximately 170 feet deep, constmcted of 4- inch PCV pipe, as shown on Map 24, Surface Facilities. This • line will provide water to the TCC/CYCC water system. TCC proposes to install an additional waterline between CYCC and TCC. The line will be installed between CYCC's wash bay and TCC's pumphouse. The approximate location of the water line is shown on Map 24, Surface Facilities. A 40-foot corridor will be disturbed during installation. TCC is adding an 8-inch HDPE, 400-foot long waterline between Location 6 Inspection manhole and the freshwater borehole. A 40-foot corridor will be distwbed during installation. Mine Water Discharge System (Revised - MR07-2161 Discharge of mine water can occw at three stations, the Portal Borehole (Site 109) the Fish Creek Borehole (Site 115), and the EMD Dewatering Borehole. In addition, there is a very limited potential for production mine water to discharge at the Northwest Mains Ventilation Shaft through a presswe relief/accumulator pipe for the production mine water system. Although discharge occurred in mid-2005 due to catastrophic failwe of both the primary and back-up presswe relief valves, TCC has taken positive steps to asswe that this site will not dischazge in the futwe. Water discharged from the portal site is routed to Sedimentation Pond D or Sedimentation Pond F prior to discharging to Foidel Creek. Mine dischazge water from the Fish Creek Borehole is treated prior to either transfer to the mine water system or dischazge to Fish Creek. A treatment system for the EMD Dewatering Borehole has not been constructed to date, and the water is pumped from this site either to the mine water system or back underground. At the Fish Creek Borehole location, submersible pumps draw from an underground sump where mine water inflows, that have been intercepted and routed underground, as shown on Map 16 (Mine Water Balance Map), collect, Prior to entering the sump, the mine water passes through an network of abandoned and sealed mine workings which facilitate • settling of any suspended solids prior to collection and pumping of mine water to the surface. At the Fish Creek Borehole Site, pumped mine water from the 6-inch Fish Creek North Dewatering Borehole and fl- inch (maximum) Fish Creek Ventilation Shaft Dewatering Site is transferred to buried 8-inch HDPE cormector lines and a distribution point. At the distribution point, the flow is metered and regulated to discharge a desired quantity of water to the electro-coagulation system and treatment ponds, and to return any excess flow to the mine through the fl- inch HDPE recirculation line that dischazges into the Fish Creek Vent Shaft. Formerly, mine water dischazge at the Fish Creek Borehole Site was treated by injecting caustic soda (NaOFI) to increase pH, promoting precipitation of soluble iron in the treatment ponds. Dependent on water quality in the last pond, it was sometimes necessary to add dilute sulfuric acid (HZSO4) to adjust water pH prior to either dischazge or transfer to the mine water system. In 2006 (MR06-207), the caustic soda treatment system was replaced by anelectro-coagulation system, which uses an electrical charge to induce precipitation of the excess iron. The discharge from the electro-coagulation system is routed through the ponds to asswe adequate retention time before discharge. After treatment, water can flow from the treatment ponds through a discharge ditch to Fish Creek, or can be transferred by a pumping system to the mine water system. 1n 2007, (MR07-216) the Fish Creek Ventilation Shaft was converted to a dewatering well to replace the Fish Creek South Dewatering Borehole, where a defective dewatering pump became stuck down-hole in the well and could not be retrieved for repair or replacement. The Fish Creek Borehole Dewatering System consists of two adjacent dewatering installations. Each of the two 12.75- inch O.D. Fish Creek North and South boreholes houses a 6-inch dischazge pipe, electrical cable, and a 300-600 gpm capacity submersible pump. Electrical power is supplied by the distribution powerline depicted on Map 39, Foidel Creek Mine Powerline Location. The substation location for the dewatering boreholes is shown on Maps 26 and 39. At the substation location, after topsoil removal, a fence was constructed around the perimeter of the site, enclosing an area of approximately 48 x 24 feet. Within the fenced azea, a 12 x 12 x 1.5 foot concrete pad was powed and a fow- oole stmctwe was constructed. The general layout of this site is shown on Figure 18. A gravel blanket, approximately inches deep, has been placed azound the concrete pad and extends to the fence. During the life of the facility, weeds will be controlled within the fence using selective herbicides. As previously noted, the Fish Creek South Borehole has been replaced by the Fish Creek Ventilation Shaft Dewatering System. MR07-216 2.05-50 05/28/07