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EXHIBT C - paragraph 9 (continued) <br />Initially, this can be achieved by building a zoned starter dike, <br />which has an upstream gradation from compacted borrow material <br />into a course sand zone around the interior of the dike. <br />The successive dikes should be built over the underlying course <br />sand zones, rather than on top of the previously deposited, <br />unconsolidated tailings. This variation of the upstream method <br />of tailings sam construction is preferred, because it keeps the <br />slimes, and the free water surface, away from the upstream face <br />of the impoundment dam. This prevents the failings from piping <br />through the starter dike, allows the slimes to consolidate, <br />promotes ideal stratification of the tailings and creates a <br />relatively impervious seal in the bottom of the tailings pond. <br />Seepage can ba controlled, because the phreatic line, or water <br />surface is lowered on both the upstream and downstream faces of <br />the tailings dam. A refinement of the upstream method of <br />tailings dam construction employs a hydrocyclone to separate the <br />sand from the slimes. This classified product is then used to <br />achieve a broader sand zone, and to raise the successive dikes. <br />Since cyclones recover more dam building material from very <br />finely ground tailings, this permits faster sam construction. If <br />these design features are adhered to during the construction and <br />operation of the tailings pond, a horizontal to vertical slope <br />gradient of 1.5 to 1 can be maintained on the downstream face of <br />the impoundment dam. The supernatant, or floating, water is <br />removed by settling in the tailings pond, followed by <br />decantation. This type of tailings dam construction is well <br />suited for milling operations which have relatively low tonnage <br />rates, utilize a course grinding circuit, and allow the tailings <br />to become well compacted before slowly raising the level of the <br />impoundment dam. <br />The tailings dam has been designed to provide a storage site with <br />the capacity to retain the mill tailings that will result from <br />processing. At the projected mill rate of 2.08 tons of ore par <br />hour, 1.88 tons of tailings will be produced hourly; at the <br />maximum milling rate of 50 tons or ore per day, 45 tons of <br />tailings will be produced per day. Based upon the anticipated <br />milling schedule, and tailings discharge volumes, the tailings <br />impoundment area will have a life of approximately 4 years. If <br />the tailings can be used as brick making material, they will be <br />removed and transported from this site; then the tailings <br />impoundment process will be tepee+,ed by utilizing the starter <br />