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<br />The 1998 field parameter data for the two Twentymile Sandstone wells (No. 9 Mine Well <br />and Well 259), do not suggest significant impact or trend. Water quality data for the <br />Twentymile Sandstone wells are summarized in Tables 13 through 16. Plots of field <br />conductivity over time are presented in Figure 15. Measurements during 1998 <br />appeared normal. <br />In summary, the water quality of all three sandstone aquifers does not indicate any <br />significant trends or adverse impacts related to mining at Mines 5 and 6. <br />COAL <br />FLOWS <br />Plots of the measured discharges for the two #5 Mine discharge points are presented in <br />Figure 16. Figure 17 is a monthly tabulation of meter readings for 1998. While in <br />temporary cessation, the mine is being flooded and pumps are being run only <br />periodically for preventive maintenace. The minimal discharges recorded for 1998 do <br />not reflect changes of inflow into the mine. <br />WATER QUALITY <br />Summaries of the water quality data for the mine discharge are presented in Tables 17 <br />through 20. The #5 Mine sump discharge is NPDES discharge point #003. The 7 North <br />Angle Discharge is NPDES discharge point #024. The #5 Mine discharge water quality <br />indicates a slight increase in dissolved solids concentrations over time which has now <br />• C-81.a, 1999AHR Page 6 <br />