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• u NL•dro(ogic Monironng AaTil•irirt Water from the freshwater pond(s) is used in two ways. It can be treated to meet potable and sanitary water requiremenu, used, and then treated as sanitary waste water. Or, it can be withdrawn for dust suppression in the mine, in which case it then becomes mine water. Sanitary Waste Water The sanitary waste water treatment plant has been operating since the fall of 1982. Dur- ing WY 1993, discharge from the plant averaged 12 gpm, when discharging. Discharge monitoring resulu from the waste water treatment plant, conducted under NPDES Permit No. CO-0038776, are in- cluded in Appendix J. Groundwater Inflows Groundwater appears to be contained within fractures, roof joints, minor faulu, or rock spars. Except for azeas near the under- ground mine portals, dripping and water inflow generally subsided within 24 hours. Areas of damp top persisted locally along the more pronounced fracture trends. Water inflows were greatest along the more highly fractured zones. Initial water inflows were estimated as high as 20 gallons per minute (gpm). After fractures were dewatered, inflows dropped substantially. No locations produced sustained flows of water. Some groundwater inflows in azeas near the por- tals of the mine continue to reflect climatic precipitation cycles (heavy rains or snow melt). "f"Seam No new mitring occurred in the F seam. Inflows in areas still accessible were moni- toted by occasional visiu. No new inflows were observed. The 1 West, 1 East, and 1 Northwest Submains were sealed off at the Southwest and South Main Intakes and no further monitoring of these areas can be conducted. Existing inflows in the Main Intakes were similaz to the last two years. Inflows are indicated on "F Seam Mine Map -Hydrologic Conditions - WY 1991" (1991 AHR>. `B" Seam All mining activity was accomplished in the "B" Seam during WY 1993. Exhibit 3 shows locations of inflows in the "B" seam. No seasonal variation in flows was ob- served. Table 5 characterizes the water quality of the mine inflows as represented by the discharge from MB-1. This pond also treau surface water runoff. The water is saline, alkaline, with moderate levels of total iron. 'table 6 Quality of Mine Water Discharge at the West Elk Mine During the 1993 Water Year (MB-I effluent) a.e. n.g. pH T55 TDS Total Fe Date (milts) (mg/L) (m`!L) (mg/L) 1st Q '93 8.6 5.2 1730 0.00 2nd Q '93 8.2 28.9 1160 0.58 3rd Q '93 8.4 20.2 2250 0.67 Water Balance An allowance of 5 acre feet was estimated as a reasonable contribution to the water balance of the mine. In addition, some of the fresh water pumped into the mine in 8