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Mid-Term Apex No. 2 Mine -2- November 19, 1985 A re-evaluation of this issue revealed that the springs are low flowing with a probable source being perched aquifers. The springs are non-adjudicated and are three quarters of a mile away from the mine permit boundary. In doing the probable hydrologic consequences assessment contained in our Apex Findings Document, it was clear that MLRD assumed worst case in the assessment. It is stated that even if the springs go dry, the resultant reduction in stream flow would not be significant. Under these circumstances MLRD sees no reason to require monitoring of these springs. If in the future an extension of the mine workings to the northwest is requested or, if significant mine inflows are encountered, MLRD may require monitoring of the springs at that time. B. The annual mine inflow study and sump water analysis should be continued by the operator. The Division recommends that Apex delete the following parameters from the sump analysis: Dissolved Oxygen Phosphate Aluminum Selenium These parameters have consistently been below EPA water quality criteria and Colorado Receiving Stream Standards for Trout Creek. The Division requests Apex add total alkalinity and silver to the sump monitoring list. Alkalinity is a measure of the buffering capacity of the water. An elevated level of alkalinity is beneficial since it may complex with metals and remove them from solution. We request silver be added since it is a receiving stream standard and has recently been identified at elevated levels at other mines in the Twentymile Park Basin. If it is undetected in the sump water it can be deleted in the future. C. A review of the monitoring data on alluvial and stream quality was conducted by MLRD for data collected from 1980-1985. The data does not show any significant trends or adverse impacts that could be related to the Apex Mine. The alluvial well does show some anomalous levels of zinc, mercury, cadmium, and aluminum (at or slightly below standards), however, the levels are not significantly above standards, nor are they consistent. Due to the lower levels encountered and the dilution effects of the stream, MLRD recommends that laboratory analysis of both the stream and alluvial well be suspended. Sufficient data exists to correlate field pH and conductivity to any effects caused by major ions or metals leached from the mine. Since the operation has been essentially unchanged for five years, any effects from the mine should have been identified by now. If discharges from the mine occur in the future the laboratory analysis should be continued.