2008-01-08_REPORT - C1980007 - Laserfiche WebLink

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West Elk Mine 2006 Annual Hydrology Report 30 very slow recharge rates. Field water quality parameters are recorded and water samples are • processed and sent to the laboratory for analysis, as described above. 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. MCC conducted the mine water sampling for the 9 inflow sites, discharge 004 and 017, influent 007, and effluent 007. SGS Commercial Testing and Engineering Company in Denver did the laboratory analyses of these sites. 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, 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 2006 mine water balance (MCC, 2007) is summarized below and illustrated on Figure 8. Inflows (water entering the mine) include: Raw water intake (North Fork diversion, 327.39 ac-ft) • Temporary River Pumping, (North Fork diversion, 404.35 ac-ft) • Mine Inflows (faults, coal outcrops, and drips, 105.65 ac-ft) Total Inflow = 837.39 ac-ft Outflows (water exiting the mine) include: Water in produced coal and GOB (538 ac-ft) Mine sump discharge and drilling water (340 ac-ft) • Mine ventilation moisture (50 ac-ft) Miscellaneous mine seepage and evaporation (20 ac-ft) • Pond evaporation (22 ac-ft) • Runoff from surface operations\pond discharge (281.5 ac-ft) Total Outflow = 1,251.50 ac-ft The total volume of water entering the mine during WY 2006 was 837.39 ac-ft versus a total • outflow of 1,251.50 ac-ft, a net difference of 414.11 ac-ft (surface operations discharge). December 2007 HydroGeo, Inc.