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London Mine Portals <br /> Page 2 <br /> Description- Cont <br /> 2) Adequate rock compressive strength for structural stability. <br /> 3) A length of the tunnel with minimal faulting or other geologic features that could serve <br /> as a leakage pathway. <br /> 4) Adequate ground cover over the potential site to resist the hydrostatic forces from the <br /> potential maximum head. <br /> If an acceptable location can be found, SGC will design and install hydraulic seals. After <br /> sealing is complete, the seals will be contact grouted and the diversion pipes, if necessary for <br /> construction, grouted. The near surface fracture flows typically found will be diverted to avoid <br /> contact with waste material and the portal closed. See attached paper on hydraulic seals. <br /> Analysis <br /> Diversion and isolation of the mine dumps(including pH stabilization)will isolate this material <br /> from direct contact with rainwater, snowmelt and portal flows. These Best Management Practices <br /> may improve Burrows Creek as well as the headwaters of the Animas River. <br /> The hydraulic seals proposed for the London Mine will reduce the unsaturated zone by <br /> removing the drain. This will result in minimizing the oxygen available for reaction with the sulfide <br /> materials in the area. The hydrological conditions will be restored to an approximation of premining <br /> conditions and should improve the water quality in the area. <br /> Monitoring <br /> Monitoring points for this project will consist of upstream and downstream as well as flows <br /> from adits and dumps. Monitoring will start prior to remediation work and continue until two years <br /> after the project is completed. Monitoring will occur four times yearly, once in early summer and fall <br /> and will be submitted annually at the same time of SWs Mined Land Reclamation submittal. A copy <br /> will also be sent to the Water Quality Control Division. All samples taken will be analyzed for <br /> dissolved and total recoverable metals for Pb, Cu, Zn, Cd, Mn and Fe. A field pH will be taken as <br /> well as field measurements for flow. <br /> Reporting <br /> SGC will submit annual reports for this project starting with finalized engineering drawings <br /> prior to starting onsite work. Once all reclamation activities are complete, a final report will be <br /> submitted. Reports will be sent to the Division of Minerals and <br /> T <br />