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iii iiiiiiiiiiiii iii 999 STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Depanment of Natural Resources 1313 Sherman 51., Room ? 15 Denver, CO 80203 Phone: (3031 866-3567 FAX: (3031 832-8106 TO: Janet Binns FROM: Dag Boothe RE: 1992 AHR Review .f or Eagle Mines #5 and #6. (C-81-044) Surface and Groundwater review. DATE: 07/12/93 1) Surface Water. OF' COQ ~`~ 4 ~~~` ~~ ~ r8 i6 Ruy Romer Governor Michael B. Long Division Direclur The Eagle Mine is in compliance with the surface water monitoring plan. Monitoring stations Y-1, Y-2, WF-1, WF-2, and the #1 strip pit discharge are included in the plan. There a:re no noticeable exceedences of the Colorado Department of Health water quality standards or increasing trends throughout the permit area. No significant adverse hydrologic impacts to the surface water quality have resulted from mining operations. 2) Groundwater. The Eagle Mine is in compliance with the groundwater monitoring plan. Bedrock wells, alluvial wells, and mine discharges are monitored. The alluvial wells have readings that indicate high levels of total dissolved solids. Alluvial wells AVF-3, AVF-5, and AVF-6 have TDS's of 1500 mg/1, 1890 mg/1, and 1708 mg/1 respectively. The 7 North Angle discharge and i:he #5 discharge areas are also experiencing high TDS's of 1474 mg/1 and 1178 mg/1 respectively. Another area of concern is the lowering water elevation in the Middle Sandstone formation. The Twentymile Sandstone and the Trout Creek Sandstone show no evidence of adverse impacts from mining operations. In summary, the surface water quality in the permit area shows no adverse effects from the mining operations. However, there are a few areas of concern for the groundwater. The high levels of TDS's in the above mentioned wells and the lowered water elevation in the Middle Sandstone need to be looked at in more detail for possible explanations.