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• WATER QUALITY <br />The summary of the water quality data for the spring is presented in Tables 31 and 32. <br />A plot of dissolved solids for the #1 Strip Pit is presented in Figure 27 and iron <br />concentrations are presented on Figure 28. Figure 27 indicates that the dissolved solids <br />level of the discharge has increased from an average of approximately 900 mg/I in 1982 <br />and 1983 to almost 1,400 mg/I in 1986, and then decreased to approximately 1,100 mg/I <br />since 1987. The decreasing trend was noted to continue in 1997. Figure 28 illustrates <br />the variable nature of total recoverable iron concentrations in the Strip Pit discharge. <br />During 1997, these levels occurred within normal ranges established for this site. <br />PONDS <br />There were no discharges from the sediment ponds in 1997. <br />• <br />HYDROLOGIC IMPACTS <br />No significant unpredicted adverse impacts were detected during 1997. The continued <br />drawdown in the Middle Sandstone unit, which appears to be stabilizing, is determined <br />to be the most significant impact related to mining operations associated with Mines 5 <br />and 6. Drawdown effects in the Twentymile Sandstone unit were evident in the 1997 <br />data as well. The Probable Hydrologic Consequences section of the Permit predicted <br />drawdown in the Middle Sandstone unit associated with mining the F and E coal seams <br />at Mines 5 and 6, although the extent and magnitude of the drawdown were not <br />quantified. A worst case evaluation was, however, prepared for the overlying <br />Twentymile Sandstone. The drawdown in Middle Sandstone Well TRH attributable to <br />• the longwall mining in the E and F seams at a distance of approximately one mile has <br />C-81-044 1997 AHR Page 12 <br />