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~~I ~~~II~~I~I~~~~~~ STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY D rt (N l R oF~c~ epa ment o alura esources 1313 Sherman Sl., Room 215 Nf~ ~~ q~ • • Denver, CO 80203 • Phone: 1303) 866J567 ~ reis ~ fAX: (303)832-8106 Roy Romer Governor Se tember 10 1993 P Michael B. Long Drvrsion Director Mr. Joe Shoemaker Cyprus Empire Corporation P.O. Box 68 Craig, CO 81625 RE: Eagle 5 & 9 Mines, (C-81-044), Permit Renewal No. 2 Dear Mr. Shoemaker: The Division has reviewed the adequacy responses received from Cyprus-Empire on August 24, 1993. Our comments follow: I. Outstanding Midterm Concerns A. CECs explanation for hydroxide reporting practices is acceptable. The explanation should be incorporated into the permit, and hydroxide levels in future water quality reports should be reported as zero where appropriate. B. Exhibit 29 does, indeed, show zinc as a bimonthly sample. II. 1991 Annual Hydrology Review A. Referring to the Annual Hydrology Report (ANR), Figure 10 is a plot of water level data for Well 83-03 which is completed in the Middle Sandstone. The linear regression line shows an overall water level decrease from an elevation of approximately 6255 feet in 1984 to approximately 6245 feet in 1992. This indicates an overall decline in. Well 83-03 of 10 feet rather than 15 feet as reported i^ the AHR. CEC should submit the appropriate correction for clarity. B. The Division expressed a concern about the usefulness of water level data reported for the Trout Creek Sandstone, because all of the wells used for water level measurements are pumping wells. Water levels measured in a pumping well are influenced by drawdown within the cone of depression in the aquifer and additional drawdown due to frictional losses within the pumping well itself. Therefore, the water levels reported do not reflect static water levels in the aquifer, either inside or out of the cone of depression.