1994-10-21_GENERAL DOCUMENTS - C1980007

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sedimentation ponds and discharged as specified in the NPDES permit. To monitor the changes in water quantity and quality, the west Elk Mine has an extensive ongoing Hydrologic Monitoring Plan. Twenty-three wells are currently being monitored in the alluvium, the Rollins Sandstone, the Barren member, the F seam, the B seam and E seam. Two wells, which has been completed to the B seam and the Rollins Sandstone, have been added to the monitoring program in Jumbo Mountain. 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. The quality of mine water discharges from the B seam is expected to be similar to the F seam. Underground or mine water is permitted to be discharged at the following locations: Sylvester Gulch fan site, sediment pond MB-1, and Minnesota Creek. Mine water is usually discharged through the main portals to MB-1. Quality parameters appear to be such that B seam mine water will be suitable for treatment and discharge under current NPDES/CPDES permit requirements to the North Fork of the Gunnison River. The quantity of ground water flows which would be potentially discharged is low. Testing to date indicates the permeabilities in and near the B seam to be low. Water in storage, based on testing in the B seam and experience in the F seam, is of low quality. Fractures, from existing data, appear to be less extensive and less open with increased depth and contact the B seam in localized areas. All of these parameters indicate low groundwater flow potential in the B seam. Because there is a unit downward gradient, and MCC monitors the B seam which is 20 feet above the Rollins Sandstone, mining is not expected to impact the Rollins Sandstone. Springs in West Elk Mine area are also monitored. Seven springs that potentially could be impacted by mining are monitored. Nine other springs have been added to the monitoring program on Jumbo Mountain. Several decreed springs on the West Elk Mine lease area have the potential of impairment as a result of mining the F seam. Springs are also monitored three times a year for pH, conductivity, temperature, total dissolved solids, total suspended solids, total iron and total manganese. The springs, to date, show no significant trends or changes which can be associated with mining activity. Most springs are responsive to spring runoff, but flow rates are sporadic and many times do not correlate well with other seasonal parameters such as snowpack, precipitation, or streamflow. b. Surface Water Effects The West Elk Mine plan is designed to minimize the impacts of the project on the surface water hydrology of the region. Disturbed area drainage is collected and treated 33