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6.4.21(13)Climate <br /> The mill does not have liquid containment systems open to the environment. Climate information is <br /> provided in Exhibit K and Appendix I.The exhibit includes weather data from the local weather station in <br /> Canon City, CO. The mountain foothills are typically a degree or two cooler than in town temperatures. <br /> Site specific wind data is not available. <br /> 6.4.21(14)Geochemical Data and Analysis <br /> The seepage from the FTSF will comprise of filtrate introduced to the facility with the tailings and <br /> infiltration water that contacts the tailings and the support buttresses (development rock). During <br /> mining operations, infiltration water contacting the tailings will likely take on the filtrate quality, due to <br /> continuing additions of fresh tailings and entrained filtrate. The shake flask extraction results, adjusted <br /> for dilution affects (please see Appendix B for a description of how the test results were adjusted), were <br /> assumed to represent the quality of infiltration water contacting the development rock. The FTSF <br /> seepage quality was estimated by combining the contributions from development rock and tailings on a <br /> mass balance basis. <br /> The predicted FTSF seepage quality, compared with background groundwater quality and groundwater <br /> quality standards, is presented in Table 1. For details regarding the calculations and the assumptions <br /> made,the reader is directed to Appendix B. The predicted seepage quality is dominated by the tailings <br /> contact water quality. Seepage is predicted to meet the groundwater quality standard, with the <br /> exception for manganese. However,the predicted manganese concentration (0.071 mg/L) is less than <br /> the background groundwater concentration (0.14 mg/Q. The groundwater quality standard is 0.05 <br /> mg/L. <br /> The predicted seepage quality presented herein would be reflective of short term and operating <br /> conditions. The seepage quality estimates for the long term will be developed once the kinetic tests on <br /> tailings are complete. However, based on humidity cell data to date, it is expected the seepage quality <br /> will improve overtime. <br /> Implications for Contact Water Management <br /> The contact water pond will be comprised of FTSF seepage and surface runoff water from the FTSF. As <br /> discussed above,the seepage quality is expected to meet groundwater quality standards. The surface <br /> runoff quality will at worst be similar to the tailings filtrate quality. Given that runoff water will likely <br /> have a shorter contact time with tailings compared to infiltration water, it is reasonable to expect runoff <br /> quality to better than filtrate quality. As noted in Section 1 above,tailings filtrate meets the <br /> groundwater quality standard and is less than the background groundwater quality. Contact water in <br /> the contact water pond is expected to meet groundwater quality standards and,therefore,will not <br /> require treatment prior to discharge. <br /> Based on the seepage quality estimate, contact water can be discharged from the contact water pond <br /> through one or a combination of the following: <br /> 1. Recycle to the mineral process plant <br /> 2. Direct discharge via an exfiltration pond <br /> Evaporation within the contact pond.The report is provided in Appendix B. �' <br /> 7 / <br />