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• historically been determined to be between 50 and 60 feet. This is comparable to the <br />60 foot drawdowns projected in the PHC for the overlying Twentymile Sandstone at a <br />distance of one mile from the location of mine subsidence. The impacts observed in the <br />Middle Sandstone are comparable to the worst case projections developed for the <br />Twentymile Sandstone. A small increase in the dissolved solids in Williams Fork <br />Alluvium Well AVF-3 appears to be fluctuating around 2100 mg/L. The cause of this <br />recent relative increase is unknown; however, the data indicates that it is not from the <br />mine discharge or from the waste water lagoon. In addition, these levels are consistent <br />with measurements recorded earlier in the well's data set. The increased TDS in the 7 <br />North Angle Discharge seen in 1991 has decreased to approximately 850 mg/L. The <br />increase in TDS was due to the accumulation of water in the North Angle Sump location <br />• which was able to equilibrate with oxidized rock within old workings and rubbelized rock <br />within subsidence panels. The maximum concentrations of 1474 mg/I probably <br />represents this equilibrium concentration. Flow from the #1 Strip Pit spring discharge <br />was within the range observed during 1982 through 1986. Flow from this spring is <br />influenced by both snowmelt and ditch seepage associated with the 7 North Angle <br />discharge. Flows from the 5 Mine workings were, of course, notably lower than <br />previous years. <br />• C-81-044 1997AHR Page 13 <br />