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• • J.0 Hyd~ologi[ Monitoring Atfivitits Headgate Section, and approximately 80% of the Lone Pine Gulch development section. The B West Mains were developed and advanced approximately 2700' using continuous mining methods. This included the recovery room development for the 6th Northwest Headgate Panel, the 7th Northwest Headgate Panel, and the access to the 7th Northwest Headgate Section. The longwall completed mining in the 2nd Northwest Headgate Panel, the 3rd Northwest Panel, the 4th Northwest Headgate Panel and completed approximately 20%p of the 5th Northwest Headgate Panel. miscellaneous surface activities. In WY 2994, no water was transferred from MB-1 to FW-1. Some amount of water placed into pond FW-1 is lost due to seepage from the pond and evaporation from the water surface. Water is taken from the underground mine workings by pumping of excess free water, as added moisture to the coal product and waste (gob), as added moisture to exhaust ventilation air, and perhaps by some seepage (recharge) into the surrounding formations. Mine water pumped from the mine workings is discharged into pond MB-1, or MB-2R and, if not recycled back to FW-1, is released back into the North Fork of the Gunnison River upon meeting NPDES discharge requirements. Figure 3 shows locations of inflows in the "B" seam. No seasonal variation in flows was observed. Table 1.5-1 characterizes the water quality of the mine inflows as represented by the discharge from MB-1. This pond also treats surface water runoff. The water is saline, alkaline, with modera[e Levels of total iron. 1.6 WATER BALANCE An accounting of water use in the West Elk Mine is presented in Table 1.6-1. Sources of water introduced into the mine are the North Fork of the Gunnison River (at the Raw Water Intake Gallery) from which water is withdrawn and placed in fresh water pond FW-1; recycled water from pond MB-1 (water pumped from the mine is discharged into pond MB-I) into pond FW- 1; and seepage into the mine workings. Not all of the water placed into pond FW-1 is pumped into the mine. Water is withdrawn from pond FW-1 to backwash the Raw Water Intake Gallery (returned to the River), for domestic use (returned to the River after being processed through the sewage treatment plant), and for R3.210/IOA/OS/OS/91(B:Odam) Table 1.5-1 Quality of Mine Water Discharge at the West Elk Miae During the 1994 Water Year (MB-1 and MB- 2R effluent) DW An. Ary. 70.5 A.e. p8 7'55 (msJLl iaml Fe (~,) t~ul.) (tit MB-1 4th Q '93 8.3 17 2370 0.33 1st Q '94 8.3 29 1740 0.29 2nd Q '94 8.3 t5 1430 0.31 Std Q '94 8.7 33.6 2163 0.88 MB-2R 4th Q '93 7.4 23.4 1240 0.61 1stQ'94 7.4 19 416 0.70 ltd Q '9d 7.6 2a 1910 0.90 Std Q '94 7.6 29.7 2090 1.18 1.7 MINE WATER QUALITY During WY 1994, mine water was dis- charged into sedimentation ponds MB-1 and MB-2R during every quarter of the year. 15 REVISED 10/02/96