1993-11-15_GENERAL DOCUMENTS - C1981017 (2)

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Mid-Continent Report; Nov. 15, 1993 Steve Renner/Harry Posey Page 8 Coal Creek at Station #20 has recorded exceedences for SO4 (>250 mg/L) on just 3 occasions: Date Value Data Source 1978 --320 Crystal River Drainage Study 10/13/88 572 Mid-Continent AHR 10/24/88 282 Mid-Continent AHR 3. The Crystal River Drainage Study (author unknown) indicates that some of the area downstream of Coal Creek had high metals concentrations (no values reported), but that the area immediately below Coal Creek did not. The only metals data collected by Mid- Continent are nickel, and none of those are above aquatic life standards. The USGS data show the following: Crystal River below Carbondale; no metals problems. Crystal River above Coal Creek; As = 1 ug/L; no other problems. Coal Creek; detectable Cu, Pb, As, Mo, Ni, Zn, but none above aquatic life standards. The USGS data on Coal Creek were collected in 1972 and 1976, long before any sediment controls were installed. Yet even then, the metals concentrations were at very low levels. It is therefore highly unlikely that metals from Coal-Creek have had an adverse impact on aquatic life in the Crystal River. 4. The high TDS from the Mid-Continent area must be comprised mostly of Na and Ca sulfates plus dissolved clays. In these concentrations, they would not be harmful to aquatic life. CONCLUSIONS Water quality at station #20 has improved with regard to sediment load, but has deteriorated with regard to dissolved solids. Most of the improvement in TSS occurred after 1984. Most of the deterioration with TDS occurred after 1986. Driving of the "Rock Tunnel" adit in 1984 led to changes in mining practices in ways that caused TSS to fall. How this happened might be discerned from a review of the mining practices over that period. The adit apparently became operational in 1987, according to the