2012-07-02_REPORT - C1980007 (3)

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West Elk Mine 2011 Annual Hydrology Report 41 4.0 MINE WATER MANAGEMENT ACTIVITIES The mine water management activities (water balance) pertains to the water flows into and out of the mine and mine site, and include fresh water intake (appropriated diversions) from the North Fork of the Gunnison River, and discharges of treated sanitary wastewater, sedimentation ponds, and mine water inflows. The individual components associated with the mine water balance are discussed below and illustrated in Figure 9. 4.1 Mine Water Balance The mine water balance was developed as a tool for management to quantify the water entering and leaving the mine and mine site. The WY 2011 mine water balance (MCC, 2012) is summarized below and illustrated on Figure 9. Inflows (water entering the mine site and mine) include: • Raw water intake from North Fork diversion (including 3.4 ac -ft to the CPP and 241.9 to the 1.2 MG raw water tank into the mine): 286.9 ac -ft; • Mine Inflows (from faults, coal partings, roof, etc.): 37 ac -ft • Total Inflows = 323.9 ac -ft Outflows (water exiting the mine and mine site) include: • Water in mined coal and gob: 89 ac -ft • Water used in CPP: 3.9 ac -ft • Mine sump discharge via MWPF: 0 ac -ft • WWTP discharges: 10.13 ac -ft • Miscellaneous mine seepage and evaporation: 10 ac -ft • Evaporation from all ponds: 30 ac -ft • Moisture taken into ventilation air: 80 ac -ft • Treated water usage: 11.6 ac -ft • Runoff from surface operations \pond discharge: (0.13 +8.9 +1.72) = 10.75 ac -ft • Total Outflows: 245.38 ac -ft The total inflows entering the mine and mine site during WY 2011 were 323.90 ac -ft versus total outflows of 245.38 ac -ft, resulting in a net difference of 78.52 ac -ft. For the most part, fault water inflows accumulated in the sealed sumps and northern- most mined B -seam panels. June 2012 HydroGeo, Inc.