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Draft West Elk Mine 2005 Annual Hydrology Report 34 effluent discharge (outfall 017). Testing included whole effluent toxicity or "WET" tests. Static toxicity tests for acute (48-hour) and chronic (96 hour) were completed in WY 2005. The test organisms included the daphnid (Daphnia magna) and the fathead minnow (Pimephales promelas). The test results indicated that the effluent from outfall 017 was acutely toxic to daphnid in the 2nd 3`d, and 4d' quarters of 2005 as detailed in the quarterly Discharge Monitoring Report (DMR) submittals. MCC established that high alkalinity is the cause of the Daphnid mortality. 4.5 Mine Water Inflows In WY 2005, only one significant ground water inflow occurred during mining in Panel 9 headgate, Entry 3, crosscut 39 to 42. The flows originated from the BEM Fault Zone with total flow between 140 to 160 gpm. In addition, some small inflows (<15 gpm) were encountered during mine development and longwall mining. These flows and drips occurred as roof drips, rib seeps, and ,.. minor fault zones. Total mmeintlows during tiUL' 2005 were`esfimated.af'_ ac-ft fr'dm faults; ,_ , , ac=ft froze P Seam inflows, and ~ ae=ft fi'om;misbellaneous-ground water for:?a 1ota1 of,_'ac-ft (MCC, 2006x)' Inflorvsaze illii'sfrated on_Ivtap'1 aiid ttewater'balance:is'showiionFigure:8 • 4.5.1 NW Panels Sealed Sump During WY 2005, 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, 2006x). 4.5.2 NE Panels Sealed Sump During WY 2005, 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 point. 4.5.3 Mine Water Sampling During WY 2005 representative mine water samples were collected and analyzed at 9 locations including the following: • lE 32 crosscut 24 headgate • Pane124 headgate roof water • Box Canyon Main E2 crosscut 63 • Pane] 24 headgate E3 crosscut 36 • Box Canyon Main crosscut 66 E-7 Sump • Panel 19 headgate E3 crosscut 14 • Panel Z2 taiIgate Sump September 2006 HydrOCieo, Inc.