2009-01-23_REVISION - C1980007 (3)

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the following stratigraphic units (in ascending order): the B • Seam, the E Seam, a stratigraphic interval between the E and F seams, the F Seam, the Barren Member, and Quaternary alluvium. More than one well is completed in most of the stratigraphic units. Sampling occurs seasonally (three times a year). Parameters monitored include: water level, pH, conductivity, temperature, total dissolved solids, total suspended solids, total iron, and total manganese. Underground or mine water is permitted for discharge at the following locations: Sylvester Gulch fan site, sediment pond MB-1, the Sylvester Gulch mine water treatment facility, Lone Pine Gulch and Minnesota Creek. The Lone Pine discharge has been discontinued, and the portals have been sealed. Mine water is discharged through the main portals to MB-1 and from the mine water treatment facility to Sylvester Gulch. Quality parameters appear to be such that B seam mine water will be suitable for treatment and discharge under current NPDES/CDPS permit requirements to the North Fork of the Gunnison River. The quality of mine water from the E seam workings can be expected to be similar to water from the B seam workings, based on the similar depositional origin of these two seams. • The rate of mine water discharge from West Elk's underground workings ranges from 0 to 2,000 gpm. The average over a year has been about 100 gpm. Water discharged from the mine has met NPDES criteria with periodic excursions of high alkalinity and iron. The high alkalinity caused some WET test failures in past years. MCC has worked with the WQCD and the Division to develop a solution for eliminating the alkalinity problem. As of October 8, 2008, Colorado Water Quality Control Division is reviewing past exceedances of discharge limitations for iron (potentially dissolved and total recoverable) at outfall 017. MCC has ceased mine water pumping at Outfall 017 and is investigating potential corrective measures to ensure future discharges at Outfall 017 comply with effluent limitations specified in CDPS Permit No. CO-0038776. MCC monitors twenty-four springs in the area. In 1998, Mountain Coal Company performed an extensive study of the springs in the vicinity of the West Elk Mine. The study showed that nearly all the springs tapped shallow meteoric groundwater in the colluvial deposits, rather than bedrock sources. As a result of • the study, a revision was made in the monitoring program, with the eighteen springs monitored to include all decreed springs and those which might have some bedrock groundwater component. 36