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far potable use without treatment. Discharge from the No. 6 Mine is expected to be similar to the No. 5 Mine <br />Discharge from natural springs in the permit area and discharges from the Williams Fork Strip Pit are relatively poor <br />in quality. Average values for dissolved solids of these waters exceed EPA drinking water standards. EPA drinking <br />water standards for dissolved metals are exceeded in several instances by averages of these parameters. Water <br />discharged at the North Spring exhibits relatively high concentrations of nitrates and sulfates, suggesting possible <br />surface contamination by agricultural sources. <br />EC monitors both surface and ground water within its permit boundary. The location of all monitoring points are <br />shown on the Hydrologic Monitoring Program Location Map (Map 11) and a summary of all monitoring points are <br />presented on Table 3, Summary of Hydrologic Monitoring Stations. The historic summary of hydrologic monitoring <br />sites are identified in Table 3, Parts 1 through 3, while the current summary of hydrologic monitoring sites are <br />identified in Table 3A, Parts 1 through 3. A detailed discussion of the monitoring implemented by EC is presented in <br />Section 2.04.7, Hydrological Information and Section 2.05 Mining and Reclamation Plan. <br />A more detailed discussion of the regional hydrology for both surface and ground water has been included in [he <br />permit as Exhibit 7, Regional Hydrology Information. <br />Regional Ground Water Quality <br />EC has researched publications from the United States Geological Survey (USGS), Water Resources Division, to <br />obtain available information describing ground water quality near the mine site. It was found that [here are 22 USGS <br />ground water sampling sites located close to the mine. The water samples were collected by the USGS from 21 wells <br />and one (1) spring from aquifers in the alluvium, the Williams Fork and Iles Formations, and the Mancos and Lewis <br />Shales. However, there was not enough information available from the USGS publications to determine which <br />sandstones in the Williams Fork and Iles Formations produced the water. Sampling site locations are shown on Figure <br />2, USGS Sample Sites. The chemical analyses of water samples collected at the sites are presented on Table 5, <br />Specific Conductance and pH of Ground Water Near Mine Site, Table 5, Specific Conductance and pH of Ground <br />Water at a Distance from the Mine Site. Table 6, Ground Water Quality Data Near Mine Si[e, and Table 7, Ground <br />Water Quality Data at a Distance from Mine Site. Upon review of the tables, it is apparent that not all the ground <br />water samples were analyzed for chemical constituents. Specific conductance and pH measurements were taken at <br />approximately 15 sites. The remaining seven (7) sites were sampled and analyzed for total dissolved solids, pH, iron, <br />and manganese. The sampling sites were visited by the USGS once, and only one (1) water sample was collected at <br />each site. Measurement of the spring discharge was not taken at the time USGS personnel collected the water sample. <br />In general, the regional water quality is similar to the mine site water quality. Specific conductance ranges from 525 <br />to as much as 7,000 microhms; total dissolved solids can be as high as a 6,000 milligrams per liter (mg/L). The pH of <br />ground water analyzed in the field and laboratory ranges from 7.Ito 8.9. <br />Dissolved iron and maganese concentrations in ground water samples are available from Williams Fork Formation <br />and the Lewis Shale. Examination of [he data reveals that iron concentrations from the Williams Fork Formation and <br />Lewis Shale are variable and range from zero to as much as 90 micrograms per liter (ug/L); many of the samples had <br />iron concentrations of approximately 100 ug/L. <br />The quality of water in the aquifers is variable, even within a single geologic unit. The quality of water from the <br />Williams Fork and Iles Formations near the mine site is more uniform than the quality of water from other geologic <br />units. The quality of water from Lewis and Mancos Shales is generally poor. <br />Permit Revision 04-34 2.04-5 Revised 7/2/04 <br />