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West Elk Mrne mine area. The quantity of effluent dischazged from the sedimentation ponds is described in the quarterly NPDES discharge monitoring reports and in the Annual Hydrology Reports. • Underground Water Management Historically (prior to 1996), mine process water runoff and groundwater inflows flowed down- dip in the B-Seam workings, and were collected in vazious sized open sumps, pumped to the sump at the bottom of the slopes, and then pumped to one of the sedimentation ponds on the surface (MB-1 or MB-2R). After the water daylighted at the mine portals, a chemical coagulant and/or flocculent was added to the flow prior to entering the sedimentation ponds. After typical residence times of a few days, the pond water was discharged in accordance with MCC's NPDES permit. Prior to 1996, MCC had a strong history of NPDES permit compliance. Two key events occurred in 1996 that caused MCC to alter this historic practice. The first was the unprecedented inflows from the B East Mains fault. The second was the presence of a new colloid in the mine water that would not settle out in the ponds. As a result of these events, MCC changed both the way it manages water underground and the way it treats the water. The current mine water management practices (as of December 1998) aze shown schematically in Figure 22. In general, the schematic represents three key components: mine inflows, mine outflows, and in-mine water transfers. In order to better keep track of the quantities of water coming into the mine, leaving the thine, and being stored in the various sealed sumps, MCC ;, ~ has installed and will install numerous totalizing flow meters. These flow meters will enable a more accurate computation of the mine water balance. Mine Inflows -Mine inflows consist of imported water from the North Fork for mining uses, various, smaller groundwater inflows, and significant groundwater inflows, such as the B East Mains fault. The large groundwater inflows are shown separately since they require special management. Estimates for the various mine inflows for 1996, for instance, are as follows: Imported water from the North Fork = 260 AF (160 gpm) Miscellaneous groundwater inflows = 19 AF ( 12 gpm) B East Mains fault inflows = 300 AF (185 gpm) Mfne Outflows -There are numerous ways for water to leave the mine. Mine outflows could consist of the following: water pumped from a sump in the mine to the sedimentation ponds, duect discharge of fault water, dtrect dischazge of F-Seam colluvial water, discharge from the sealed panels sumps, to Lone Pine Gulch, and/or to Sylvester Gulch, minor groundwater seepage from the sealed panels sumps, water retained in the product and gob, and miscellaneous losses. 2.05-187 RevisedJrm. 1995 PR06; RevisedNw. 1998 TR80: 1/98 PR08