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CONCLUSIONS <br /> Water quality at station #20 has improved with regard to sediment <br /> load, but has deteriorated with regard to dissolved solids . Most <br /> of the improvement in TSS occurred after 1984 . Most of the <br /> deterioration with TDS occurred after 1986 . <br /> Driving of the adit in 1984 led to changes in mining practices in <br /> ways that caused TSS to fall . How this happened might be discerned <br /> from a review of the mining practices over that period. The adit <br /> apparently became operational in 1987, according to the 1988 AHR. <br /> Road use probably decreased, and the combination of decreased road <br /> use and installation of sediment collection ponds likely caused the <br /> drop in TSS. <br /> There is no discernable indication that flooding of the adit and <br /> the subsequent "natural" discharge has caused water quality to <br /> deteriorate with Dissolved Solids beyond that caused by discharge <br /> by pumping. However, there does appear to be an excursion toward <br /> poorer TDS quality water after the adit was constructed and in <br /> operation. Higher dissolved solids appear to consist of Na and Ca <br /> sulfates and dissolved clays, as deduced from the pre-existing <br /> water quality information and the known composition of the local <br /> rocks . <br /> Overall, water quality from the mine area has improved in some <br /> respects but has deteriorated in others . Unless the adit <br /> intersected base metal sulfide veins that are now weathering and <br /> contributing to poor water quality (high TDS) it is highly unlikely <br /> that the parameters that have diminished water quality are of the <br /> type that would injure wildlife. It would be appropriate to <br /> collect water quality monitoring samples at station #20 over the <br /> next year, analyze them for a full suite of base metals, and from <br /> that determine whether the mine water discharge is of a different <br /> composition than that of the general water quality prior to <br /> construction of the adit. <br /> Attachments: <br /> The Crystal River Drainage Study August 1978 - May 1979 <br /> USGS Multiple station analyses (Processed 11-10-93) <br /> Water quality data exerpts; Mid-Continent Annual Hydro Reps . <br /> Graphs showing flow, TDS, TSS, and Conductivity <br /> cc: Mike Long <br /> Jim Pendleton <br /> Larry Routten <br /> Tony Waldron <br /> m:min\hhp\midcont. rep <br />