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and 60 feet. This is comparable to the 60-foot drawdowns projected in the PHC for the overlying <br />• Twentymile Sandstone at a distance of one mile from the location of mine subsidence. The impacts observed <br />in the Middle Sandstone are compazable to the worst case projections developed for the Twentymile <br />Sandstone. <br />The increased TDS in the 7 North Angle Discharge seen in 1991 has decreased to approximately 970 mg/L in <br />2001. The increase in TDS was due to the accumulation of water in the North Angle Sump location that was <br />able to equilibrate with oxidized rock within old workings and rabble-ized rock within subsidence panels. <br />The maximum concentrations of 1474 mg/I, seen in 1991, probably represent this equilibrium concentration. <br />Flow from the No. 1 Strip Pit spring dischazge was within historic ranges observed in recent years. Flow from <br />this spring is influenced by both snowmelt and ditch seepage associated with the 7 North Angle dischazge. <br />Flows from the No. 5 Mine workings were somewhat lower than previous years. <br /> <br />• <br />I:\Env\Empire\AHR\2001 \Text\Empire2001 AHR.doc <br />