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Longfellow Koehler Project <br /> Page 3 <br /> The remaining sources of water will be collected and put through the passive bio treatment <br /> system described under Mine Drainage Treatment. All ditches will be constructed according to Mined <br /> Land Reclamation Standards. <br /> Mine Waste Remediation <br /> The waste dumps need to be moved and isolated from portal flows, intermittent flows and the <br /> pond. SGC proposes removal and consolidation with pH adjusted to near neutral by addition of lime <br /> or limestone. <br /> Preferably an isolation site can be found onsite. As an alternative, the dumps will be relocated <br /> to Tailings Pond #4. Prior to consolidation either onsite or offsite, the pH will be adjusted to near <br /> neutral. Once removal and consolidation is completed,the material will be capped with 14-16" of soil, <br /> provided that amount of soil is available, and planted in order to prevent direct contact with <br /> water. <br /> Surface disturbances will be pH adjusted with the use of limestone addition and planted. <br /> SGC will apply for a 404 permit from the Army Corp. of Engineers for the work in the stream. <br /> Removal of buildings will be required on the South(Koehler)dump. This will require working <br /> with the San Juan County Historical Society. Planned activities would include historical recordation <br /> prior to removal. <br /> Mine Drainage Treatment <br /> Improvement in quality in the flows from the adits, natural seeps and the stormwater runoff <br /> poses a difficult problem due to the combination of low pH and high metals content. At this time it <br /> appears that the best solution is a passive bio treatment system. SGC will collect waters from the <br /> underground sources to be treated. The water will be bench tested for a passive bio treatment system <br /> to be designed to increase pH and reduce base metal concentrations. See attached paper on the <br /> passive bio treatment system. <br /> Passive bio treatment Desian Criteria <br /> Bench scale test results will provide design parameters that will utilize the space occupied by <br /> the current pond. The design will focus on establishing the longest practicable life for the installation. <br /> During the design stage SGC will collect additional background information monthly, when <br /> the site is accessible. Information collected will include flow, pH, temperature, dissolved metals and <br /> hardness. Dissolved metals will be limited to Zn,Fe, Al,Mn, Cd, Cu and sulfate. These and any other <br />