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drains are covered with a protective layer of tailing, the effluent should <br />clear up. At this time, the valve assemblies should be removed and replaced <br />with 12 -inch CiP. The valves will probably be removed In the first one or <br />two years of operation, probably in the fall of 1977. <br />The second part of the seepwater system is that of returning the <br />collected seepage to the pond. This will be accomplished using three pimps <br />discharging Into an 18 -inch rubber -lined steel return line. <br />The three pumps are Gould, vertical turbine pumps VIT 12 x 16 equiFped <br />with 2 stages and 300 H.P. motors. Each pump is rated at 3,000 gpm discharge <br />against a head of 380 feet. Pump specifications and rating curves are con- <br />tained in the Appendix. The seepwater pumps are automatically controlled <br />at the pumphouse by probes In the sump. <br />Because, the seepwater discharge line will be extended with time, the <br />total dynamic head of the pumps will also increase. Therefore the pump! <br />are designed such that extra stages can be added to them. A third stag( <br />will be necessary when the pressure reaches about 81 psig, a fourth stacie <br />at 112 psig and a fifth stage at 149 psig. These values are all based on <br />a total discharge of about 7,500 gpm for the three pumps. The horsepower <br />of the motors will also have to be increased, probably to about 500 horse- <br />power when the fifth stage Is added (about 150 psig). Again, it should be <br />noted that the seepage rates are unknown, and any combination of pumpinu <br />capabilities will have to be determined in the future. <br />The pipeline Is an 18 -inch rubber -lined steel pipe connected with <br />vlctaulic couplings. The rubber lining has been used because of the unknown <br />pH value of the seepwater, which after several years could possibly be cis <br />I6 <br />