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<br />1 foot cover of decomposed granite will be used to protect <br />the PVC liner from deteriorating because of exposure to ~Z. <br />sunlight and weathering. A construction certification by a~~ <br />qualified professional associated with the Denve \\NeJ ~;~^"' <br />Engineering Corporation of Golden, Colorado, will b GLjx, // <br />submitted to the Mined Land Reclamation Division within two <br />weeks following the installation of the geomembrane liner. <br />completely filling the impoundment area with mill / <br />tailings. <br />12. Any necessary repairs to the PVC liner will be ~'~ <br />patched with the liner material itself, and in the same fir <br />manner described above. <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. <br />Polyvinyl Chloride (PVC) plastic lining material was <br />selected to line 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 />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 pp <br />and quality of the ground water below the tailings cY <br />impoundment area. These wells will be installed prior to y <br />(eJ\~ <br />the disposal of any mill tailings in the tailings retention ,~ <br />structure, a nd the location will be plotted and submitted on <br />the revised Millsite and Tailings Pond Reclamation Plan Map. <br />Monitoring operations will follow a ua 1 ch no- <br />lnairal can++Pn~o, beginning with preoperational monitorin <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 during 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 />