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• COAL <br />FLOWS <br />Plots of the measured discharges for the two #5 Mine discharge points are presented <br />in Figures 16 and 17. The flows are measured at the discharges by totalizing flow <br />meters on the dewatering sump pumps. The mean flow rate did not exceed the mine <br />inflow predictions from the Probable Hydrologic Consequences (PHC) evaluation. The <br />water produced in the No. 6 Mine is pumped underground to the No. 5 Mine sump and <br />where it then is pumped out of the No. 5 Mine Discharge point. The combined mean <br />discharge of approximately 600 gpm for the #5 Mine in 1995 was within the range of <br />487 to 830 gpm that has been experienced since 1989. The short term flluctuations in <br />weekly discharge rates are a function of pump capacity, periods of pump shutdown or <br />• failure and the fact that the pumps operate periodically based upon water levels in the <br />underground sumps. <br />WATER QUALITY <br />Summaries of the water quality data for the mine discharge are presented in Tables <br />17 through 20. The #5 Mine sump discharge is NPDES discharge point #003. The 7 <br />North Angle Discharge is NPDES discharge point #024. The #5 Mine discharge water <br />quality indicates a slight increase in dissolved solids concentrations over time which <br />has now stabillized at just under 1000 mg/L . The plot of dissolved solids presented in <br />Figure 18 shows that the average dissolved solids in the #5 Mine discharge water <br />have increased from about 800 mg/I in 1982 and 1983 to almost 1000 mg/I in 1995. <br />u <br />C-B1-044 1995 AHR Page 6 <br />