2008-06-27_REPORT - C1980007 (4)

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West Elk Mine 2007 Annual Hydrology Report 32 • The underdrain monitoring program includes measuring and recording flow, recording 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. 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 include fresh water intake (appropriated diversions) from the North Fork of the Gunnison River, mine discharge of treated sanitary wastewater, sedimentation ponds, and mine water inflow. The individual components associated with the mine water balance are discussed below and illustrated in Figure 8. 4.1 Mine Water Balance The mine water balance was developed as a tool for water management to quantify the water entering and leaving the mine. The WY 2007 mine water balance (MCC, 2008) is summarized • below and illustrated on Figure 8. Inflows (water entering the mine) include: • Raw water intake (North Fork diversion, 456.26 ac-ft) • Mine Inflows (faults, coal outcrops, and drips, (32.26+10+64.52=106.78 ac-ft) • Total Inflow = 563.04 ac-ft Outflows (water exiting the mine) include: • Water in Project and GOB (94 ac-ft) • Mine sump discharge and drilling water (470.64+10.54 = 481.18 ac-ft) • Miscellaneous mine seepage and evaporation (5 ac-ft) • Pond evaporation (22 ac-ft) • Runoff from surface operations\pond discharge (103.6+95+2.3+14.8=215.7 ac-ft) • Total Outflow = 817.88 ac-ft The total volume of water entering the mine during WY 2007 was 563.04 ac-ft versus a total outflow of 817.88 ac-ft, a net difference of 254.84 ac-ft (surface operations discharge). 0 June 2008 HydroGeo, Inc.