2009-05-12_PERMIT FILE - C1980007

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Mountain Coal Company Exhibit 69 West Elk Mine Sylvester Gulch Facilities • During batch flow operation, mine water will be pumped into the first pond (existing Pond 017) at 400 gpm with the mine pump turned off when the pond water surface reaches El. 6825.0 ft MSL. Flow from Pond 017 to the Second Pond will be via a 12-inch diameter pipe at an inlet invert elevation of 6820.0 ft MSL. The volume of the existing pond between El. 6820 and 6825 ft MSL is approximately 230,000 gallons. Therefore, inflow at 400 gpm can occur for approximately 9.6 hours during which time aeration will continue. Flow through the pipe will be controlled with a full-port motor controlled valve connected to a time switch, which will open the valve 6 to 15 hours after the pond water surface reaches El. 6825.0 ft MSL and the mine pump is turned off. Thus, under this scenario, the total aeration time would be at least 15 to 24 hours prior to discharge to the Second Pond. The aeration time requirements will likely vary depending upon the iron concentrations in the influent, and the controls can be adjusted by the pond operator to allow more or less aeration time. The automatically-controlled valve will be placed in a 48-inch diameter manhole for maintenance access as necessary. An emergency overflow spillway will also be installed in the first pond (Pond 017) with an inlet invert El. 6825.5 ft MSL, with outfall to the Second Pond, to prevent direct discharge from Pond 017 into Sylvester Gulch. This will provide flow from Pond 017 to the Second Pond in the event that the mine water pump continues beyond its normal cycle time or the valve between Pond 017 and the Second Pond malfunctions. The Second Pond will have an operating capacity of approximately 1.2 million gallons (3.7 acre feet). This will provide a detention time in excess of 48 hours at the design flow rate of 400 gpm assuming a maximum sediment depth of 2 feet. The pond invert (top of liner) will be approximately El. 6804. ft MSL at the south and north ends, increasing to El. 6805.0 ft MSL in the middle of the pond where a geomembrane baffle will be located. This will provide for sediment accumulation at the north and south ends of the pond. A geomembrane baffle, with a flow-through window, will divide the pond into two cells at the approximate mid-point to prevent short-circuiting through the pond. The normal operating water surface will be El. 6818.0 ft MSL. Both ponds will accommodate the precipitation from a 10-year, 24-hour storm event. Because neither pond receives drainage from adjacent areas, this storm event would raise pond water surfaces a maximum of only 0.2 feet. Following detention and sedimentation in the Second Pond, normal discharge from the Second Pond will be via gravity flow from a 12-inch diameter overflow pipe located at the northwest corner of the pond with an inlet invert elevation of 6817.4 ft MSL. A low-level 12-inch diameter pipe having an invert elevation of 6806.0 ft MSL will be located near the overflow pipe at the northwest corner of the pond. A mid-level discharge pipe will also be installed to increase operational flexibility. These pipes will have valves in a 48-inch diameter manhole that will normally be closed. Flow from either the overflow pipe, mid-level pipe or low-level pipe will proceed to a weir and gate structure on the northwest bank of the Second Pond. This structure will contain a V-notch weir with a pressure transducer and data logger to record the discharge flow rate. A lower-level gate will be installed in the weir wall to provide pond drawdown when necessary. This lower- 6 Rev. 10197-TR83, Rev. 04109-TR116