1996-06-12_HYDROLOGY - M1977378 - Laserfiche WebLink

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COLORADO DEPARTMENT OF LIC HEALTH AND ENVIRONMENT, Wate, ality Control Division Rationale - Page 8, CO- 0027529 F. Permit Termination The permittee will be released from further permit responsibilities in accordance with conditions specified in the consent agreement. VII. CHANGES MADE AFTER PUBLIC NOTICE Three Sunnyside Gold Corporation permits were sent to public notice - CO- 0027529, which is for the American Tunnel discharge, CO- 0036056, which is for the Terry Tunnel discharge, and CO- 0044768, which is for mine remediation projects in the Upper Animas basin. In addition, a related draft Consent Decree that has been negotiated between the Division and the mining company was in the same public notice. Responses to the public notice were received from private citizens, a committee of members of the Animas River Stakeholders group, several environmental and mining industry oriented groups, several governmental agencies, and the Sunnyside Gold Corporation itself Most of the comments received were related to the consent decree, which is being dealt with separately from the discharge permits. With respect to this discharge permit, the following issues were raised: 1) Comment: The CDPS permits must function as stand alone documents, regardless of the existence of the consent decree. Response: The permits were reviewed to find any terms or conditions that through reference were dependent upon the contents of the consent decree. Where such permit conditions were found, they were revised to more explicitly describe the intended permit requirements. However, there is one exception to this that should be noted Each draft permit included a termination clause which referred directly back to the consent decree. While this clause was modified to additionally require compliance with State permit regulations, it was determined that it would not be practical to include the consent decree's conditions related to permit termination within the permits themselves. Also, the termination clauses do not affect the enforceability of the permits. For these reasons, the termination clauses' references to the consent decree were retained. 2) Comment: For the American Tunnel permit, until it can be shown that there has been a substantial reduction in the toxicity of Cement Creek downstream of the tunnel discharge over present conditions, Whole Effluent Toxicity (WET) monitoring and limits should apply to the Discharge. Response: Cement Creek is not classified for aquatic life use. Therefore, it would be inappropriate to perform instream WET testing for Cement Creek. The first downstream segment classified for aquatic life is the Animas River. While the Division is concerned about controlling the toxic effects of the American Tunnel upon the Animas River, it would also be inappropriate to perform any instream WET testing there, due to the large number of other pollutant sources that may also be contributing toxicity. Instead, the Division has relied upon calculations involving flows and pollutant concentrations to show that treatment of Cement Creek will reduce significant pollutant concentrations at the mouth of Cement Creek. Since toxicity is most often demonstrated, and may be defined by the presence of a concentration vs toxicity relationship, where an increase in concentration results in an increase in toxicity, it can be argued that a reduction in pollutant concentrations at the mouth of Cement Creek is likely to also produce a reduction in toxicity. However, in order to maintain consistency with other permits, the permit will require continued WET monitoring and limits until the treatment of Cement Creek begins. This will be accomplished through the addition of a separate ou fall for WET testing. Rich Horstmann May 2, 1996