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the hydrologic system, and since oxidation of sulfides is the chief <br /> source of contamination in mineralized areas, mine flooding would have a <br /> beneficial impact on water quality for groundwater passing over mined <br /> surfaces. An assessment of mine flooding on drainages surrounding the <br /> mine has been, and will continue to be, a component of Sunnyside's <br /> reclamation plan. The highest elevation that could be reached by the <br /> impounded mine pool is approximately 12,200 feet, and the most likely <br /> direction of groundwater flow from the flooded workings is toward Cement <br /> Creek. There are several intervening drainages between Boulder Creek and <br /> the mine workings; it is most likely that these drainages would intercept <br /> any groundwater flow toward Boulder Creek. In addition, Sunnyside Gold <br /> will maintain the capability of drawing down the mine pool, and returning <br /> to present conditions, if unforseen problems develop. <br /> Item c) <br /> It is likely that hydraulic seals in the Sunnyside Mine will have the <br /> short-term impact of reducing flows in Cement Creek. The Colorado <br /> Division of Water Resources has reviewed this impact and has indicated <br /> that there would be no problems in terms of water rights. Once the mine <br /> pool reaches an equilibrium condition, Cement Creek flows should return <br /> to approximately the current levels. The hydraulic seals would have no <br /> effect on downstream flooding. <br /> Item d) <br /> The concept of flooding the Sunnyside workings has been a part of the <br /> approved reclamation plan for the mine since 1987. This technical <br /> revision was submitted by Sunnyside Gold to provide technical details for <br /> the hydraulic seals, or bulkheads. The plan to flood the underground <br /> workings as part of reclamation was originated by Sunnyside Gold, and is <br /> not a specific requirement of the Colorado Mined Land Reclamation Act or <br /> the Board. The main goal of the hydraulic seals is to relieve the <br /> company of the difficulty and expense of treating the mine discharge as <br /> required under Federal Clean Water Laws, and to allow the company to move <br /> forward with reclamation of the site. The Division and the Board share <br /> your concern with the loss of potentially valuable mining properties <br /> under this sort of reclamation scheme, however, requiring mining <br /> companies to treat water at inactive mine sites in perpetuity would, in <br /> the long term, be more damaging to the mining industry than allowing <br /> companies to complete final reclamation, and be released from their <br /> obligations at specific sites. <br /> If you have any questions, please contact myself at the letterhead <br /> address or phone number, or Larry Perino or Bill Goodhard at the <br /> Sunnyside Mine. <br /> Sincer y, <br /> / J <br /> Allen C. Sorenson <br /> Reclamation Specialist <br /> enclosure(s) <br />