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RAG, Empire Corporation 1999 AHR <br />• in the PHC for the overlying Twentymile Sandstone at a distance of one mile from the <br />location of mine subsidence. The impacts observed in the Middle Sandstone are <br />comparable to the worst case projections developed for the Twentymile Sandstone. <br />The increased TDS in the 7 North Angle Discharge seen in 1991 has decreased to <br />approximately 975 mg/L. The increase in TDS was due to the accumulation of water in <br />the North Angle Sump location that was able to equilibrate with oxidized rock within <br />old workings and rubbelized rock within subsidence panels. The maximum <br />concentrations of 1474 mg/I probably represent this equilibrium concentration. Flow <br />from the #1 Strip Pit spring discharge was within the range observed during 1982 <br />through 1986. Flow from this spring is influenced by both snowmelt and ditch seepage <br />associated with the 7 North Angle discharge. Flows from the 5 mine workings were, <br />• of course, notably lower than previous years. <br />Page 13 <br />