2009-07-01_REPORT - C1980007 (6)

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West Elk Mine 2008 Annual Hydrology Report 40 • are recorded and water samples are processed and sent to the certified laboratory for analysis, as described above. The underdrain monitoring program includes measuring and recording flow and field water quality (pH, EC, and temperature), and collecting laboratory samples for analysis. Flow rates are measured using the timed volumetric method described above. The protocols for recording field water quality and processing the underdrain samples for laboratory analysis are the same as described above for surface water monitoring. The temperature monitoring program includes monthly visits to the data logger monitoring stations to verify that the loggers are functioning properly, to download data, and to ensure that the loggers are submerged and in the shade when possible. The temperature data loggers are downloaded to a laptop computer monthly or whenever access is not prevented by excessive snow/ice or by dangerously high flows in the North Fork of the Gunnison River. 4.0 MINE WATER MANAGEMENT ACTIVITIES The mine water management activities or 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 2008 mine water balance (MCC, 2009) 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 346.96 ac-ft to the 1.2 MM gal. raw water tank into the mine): 382.24 ac-ft; • Mine Inflows (from faults, coal partings, roof, etc.): 58.4 ac-ft • Total Inflow = 440.64 ac-ft Outflows (water exiting the mine and mine site) include: • Water in mined coal and gob: 93.2 ac-ft • Mine sump discharge: 444.61 ac-ft • Miscellaneous mine seepage and evaporation: 5 ac-ft • Evaporation from all ponds: 22 ac-ft • Moisture taken into ventilation air: 50 ac-ft • Treated water usage: 13.28 ac-ft • Runoff from surface operations\pond discharge: 156.46 ac-ft • Total Outflow: 784.55 ac-ft June 2009 HydroGeo, Inc.