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3.2 Treatment Plant The mine drainage will be pumped to the Untreated Water Pottd or duectly to the water treatment trailer, depending on the rate of mine dewatering. The treatment plant has been designed to operate at an average flow rate of 20 GPM, which is approximately three times the minimum size requirement for the estimated steady~tate flow wnditions when the mine is not operating. This will allow for sufficient flexibility to operate the plant on an as need basis and will not require weekend operation of the plant. The treatment plant, shown on Drawing 07004A-G-01, will include, reagent mix tanks, reaction tanks, and reagent storage. Water to be treated will be pumped into the trailer's head tank. Chemicals from the reagent mix tanks will then be added to the untreated water as it is pumped from the head tank to the two 220-gallon reaction tanks. The reaction tanks are sized to allow for at least ten minutes of retention time per tank. Design calculations indicate that only one tank is needed; the second tank provides flexibility of operation and the potential for treating higher flows if needed. The trailer will have two (2) reagent mix tanks of approximately 100 gallons each in volume fitted with an agitator to properly mix each reagent. The first tank is for barium chloride; the second tank is for ferric sulfate, and a third tank is included if required in the . future. The mix tanks will be filled with reagent make-up water and the operator will add the appropriate weight of reagent. The agitators within each tank will be operated constantly to ensure proper mixing or suspension of reagent. Reagents will be fed (metered) into the reaction tanks at the designed dose rate. The reagent dosing pumps are adjustable to provide more or less dosing depending on flow rates and water quality. The projected initial dose rate for each reagent is shown in table 3.2 below. To insure adequate contact with the water and the reagents, the reagents will be fed into an inline static mixer. The reaction will start in the static mixer and continue as the water and reagents mix in the reaction tanks. The reaction tanks are fed via the head tank pump; the first reaction tack is elevated and will overflow by gravity into the second tank. The fmal treated water will discharge from the second reaction tank by gravity and flow into the Settling Pond. 3.3 Settling Pond The treated water will discharge from the trailer via gravity flow into one or both of two (2}parallel settling ponds for collection of the precipitated sludge. The precipitate formed by the addition of barium chloride and ferric sulfide is an insoluble solid (sludge) that will naturally settle and separate from the treated water. To insure complete separation of the solids from the treated water, atwo-cell pond will be constructed with the sludge retained in the first cell and the treated water flowing into the second cell. Each of the two-cell ponds will have an overflow weir from the first cell to the second cell and from the second cell into a conveyance that will discharge into the natural drainage. 7