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Wes[ Elk Mine 2001 Annual Hydrology Report 22 4.5 Mine Water Inflows No major mine inflows occurred in WY2001. Some small inflows were encountered during mine development with the continuous miners. The small flows occurred as roof drips, rib seeps, and small flows (< 15 gpm) from some fault zones. Total mine inflows during WY2001 were estimated at 95 gpm (154 ac-fUyear) (MCC, 2002). 4.5.1 NW Panels Sealed Sump During WY2001, MCC water from the NW Panels Sealed Sump was drained through a borehole to the NE Panels Sealed Sump. There was no dischazge from the NW Panels Sealed Sump to the Lone Pine Pipeline (MCC, 2002). 4.5.2 NE Panels Sealed Sump During WY2001, water collected in the NE Panels Sealed Sump was pumped out of the sump using the mine water pumping facility (MWPF) up the vertical well and dischazged to Sylvester Gulch. A clarifying pond and energy dissipater system is located at this discharge paint. 4.5.3 Mine Water Sampling • During WY2001 as in WY200Q, sampling of mine water inflows was hampered by the locations of the inflows. Fault inflows occur in low places on the mine floor, which allows mixing of belt wash-down water, process water, road maintenance (road watering mixed with magnesium chloride), and rock dusfing operations. No representative samples of the mine water inflows were obtained in WY2001. 4.6 Mine Water Balance A mine water balance was developed as a tool for water management to quantify the water entering and leaving the mine. The WY2001 mine water balance is summarized below and illustrated on Figure 3. Inflows (water entering the mine) include: • Raw water intake (North Fork diversion, 572 ac-ft) • Mine Inflows (faults, coal outcrops, and drips, 166 ac-ft) • Total Inflow = 738 ac-ft Outflows (water exiting the mine) include: • Water in produced coal and GOB (150 ac-ft) • Mine sump dischazge and drilling water (323 ac-ft) Project n 00301 HydroGeo, Inc.