2008-03-31_PERMIT FILE - C1980007A (34)

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West Elk Mine • The streams in the Minnesota Creek basin exhibit water quality characteristics similar to the North Fork. Iron frequently reaches concentrations in excess of 1.0 mg/L, especially during spring runoff. TDS and TSS levels are usually low, but exhibit elevated levels during storm runoff or snowmelt. Surface water quality data are available from three locations in or very near the permit area (Map 34). High levels of total iron and suspended solids occur during snowmelt or storm flow and are due to natural sources since no mine-related activities occur in the area. In order to characterize the suspended solids in the streams not currently monitored, WWE and Mr. Pemberton prepared the sediment transport analysis included in Exhibit 55 and Exhibit 55A. A sediment yield rate of 0.03 acre-feet per square mile per year for the basins was adopted in the permit area. This results in mean annual sediment yield for the permit area basins being low, ranging from 5 to 50 cubic yards per year. When coupled with annual water yield, this results in an average annualized sediment concentration of approximately 70 mg/L, which is consistent with regional analyses for the North Fork. Water Quality of Springs The approximate locations of the known springs in the coal lease area are shown on Map 37. Water quality samples from springs in and near the permit area are summarized in Table 20. Spring waters are typically more saline than the surface waters in the area. TDS levels of the springs range from 78 to 2,400 mg/L, with most of the TDS observations being near or above the recommended drinking water standard of 500 mg/L. Spring water TDS is generally within the TDS range observed for the North Fork, but higher than the TDS range observed for the smaller drainages. Most of the springs located above the F Seam have TDS concentrations near or less than 500 milligrams per liter, indicating that the water source is probably local and that there is not a large continuous groundwater reservoir supplying these springs. In general, constituent concentrations in springs below the F-Seam are higher than those of springs from the Barren Member. Baseline Characterization of Water Quality - North Fork A baseline characterization of North Fork water quality was prepared in to evaluate the potential changes in North Fork water quality that could result from discharges at the West Elk Mine. The baseline characterization was performed downstream of the mine using data from the USGS water quality monitoring station on the North Fork near Somerset and from the MCC water quality monitoring station on the North Fork below the old Bear No. 2 Mine. Data collected after August 1981 for the two stations downstream of the mine facilities is compared with the baseline in order to evaluate possible impacts of mining and construction activities. Water quality parameters which were selected for evaluation of changes in this study include: pH, TSS, TDS, D.Q., ammonia/nitrogen, copper, cadmium, total iron, lead, total manganese; nitrate/nitrogen, and chloride. J 2.04-108 Revised November 2004 PRIG; Rev. April 2006 PRIG; Sep. 2007 PR12; Feb. 2008 PR12