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was due to the failure of the pump. The discharge from the sump generally ranges from 250 to 450 gpm <br />• when the pump is working. <br />WATER QUALITY <br />Summaries of the water quality data for the mine discharge are presented in Tables 19 through 22. The #5 <br />Mine sump discharge Is NPDEs discharge point #003. The 7 North Angle Discharge is NPDES discharge <br />point #024. The #5 Mine discharge water quality indicates a slight increase in dissolved solids <br />concentrations over time. The plot of dissolved solids presented in Figure 21 shows that the average <br />dissolved solids (n the #5 Mine discharge water have increased from about 790 mg/1 in 1982 and 1983 to <br />approximately 940 mg/1 in 1991. This increase in dissolved solids appear to have leveled off since 1986 <br />other than one relatively high reading in 1987. <br />The average dissolved solids concentration for the 7 North Angle discharge increased considerably in 1997 <br />from about 875 mg/1 in prior years to 1280 in year 1991. This trend is related to the accumulation of water <br />• in the NoRh Angle Sump location while the pump was out of order from December 1990 to May 1991. This <br />water was allowed to equilibrate within old workings and rubbelized subsidence panels. The maximum <br />concentrations of 1474 mg/1 represents this equilibrium concentration and also provides an indication of <br />the expected post mining TDS concentrations In rubbelized zone and underground mine workings. <br />ALLUVIUM <br />Sediments in the Williams Fork River Alluvium are monitored. Three wells are in the general area of the <br />loadout facilities and underground discharge sediment ponds. <br />WATER LEVELS <br />Groundwater levels in the alluvium have remained faidy regular, with normal seasonal fluctuations, apparently <br />related to changes In river levels. Groundwater levels in the alluvium are plotted in Figure 22. A piezometric <br />• 6 <br />