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<br />completely filling the <br />tailings. <br /> <br />impoundment area with mill <br />12. Any necessary repairs to the PVC liner will b~ <br />patched with the liner material itself, and in the same Y ~ <br />manner described above. `'~, <br />~~ <br />13. When the tailings pond is expanded, the upper edge <br />of the geomembrane lining will be removed from the <br />anchor trench, and a previously rolled 1 foot section <br />of the lining will be used to seam an additional panel <br />to the old PVC lining. ~S~c <br />~~ ~ i,n~" <br />Polyvinyl Chloride~VC) plastic lining mm t~=-1 was. <br />'selecte o ine the tailings impoundment area because of <br />the relatively short time that the tailings pond will remain <br />empty. If the milling schedule is less than anticipated, a <br />1 foot cover of decomposed granite will be used to protect <br />the PVC liner from deteriorating because of exposure t <br />sunlight and weathering. A construction certification by <br />qualified professional associated with the Denver <br />Engineering Corporation of Golden, Colorado, will be <br />submitted to the Mined Land Reclamation Division within two <br />weeks following the installation of the geomembrane liner. <br />2. A field examination with the staff specialist from the <br />Mined Land Reclamation Division disclosed that the two sites <br />selected for drilling the monitoring wells downgradient from <br />the tailings pond were acceptable locations. Because of the <br />reduction in the length of the tailings embankment from 400 <br />feet to 275 feet, these two wells will be spaced 135 apart <br />rather than 200 feet, and will be drilled to a minimum depth <br />of 60 feet. The northeastern most of the U.S. Bureau of <br />Mines' test holes will also be used to monitor the amount <br />and quality of the ground water below the tailings <br />impoundment area. These wells will be installed prior to <br />the disposal of any mill tailings in the tailings retention <br />structure, and the location will be plotted and submitted on <br />the revised Millsite and Tailings Pond Reclamation Plan Map. <br />Monitoring operations will follow a quarterly chrono- <br />logical sequence, beginning with preoperational monitoring <br />to establish the baseline ground water conditions which <br />exist prior to the onset of milling activities. It will be <br />necessary to ensure that the monitoring wells are adequately <br />purged to eliminate water which is standing within the bore <br />holes. Pumping of the sample until stable values of pH and <br />conductivity are achieved will be done to assure that the <br />sample is truly representative. <br />Operational monitoring will be conducted ~uring the <br />life of the milling project on a quarterly basis unless it <br />can be demonstrated that potential ground water contaminants <br />are not migrating downgradient from the tailing impoundment <br />-3- <br />