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3-6 <br />impellers. Two pumps were installed to provide a standby system in case of <br />pump breakdown. The two pumps were bolted to two 6 inch high steel beams <br />which were in turn bolted to the concrete slab. Clearance between the bottom <br />of the pump's metal strainer and the bottom of the sump is 1.8 feet. The <br />pumps were selected to pump 200 gallons per minute (gpm) against 120 feet of <br />head. The existing pumps can be altered to increase the pumping capacity to <br />350 gpm at 120 feet of head utilizing a 15 hp motor and M -type impellers, if <br />needed. Field tests show that with butterfly valves wide open, the pumping <br />capacity of each pump is approximately 170 gpm. When both pumps are operating <br />1 at the same time, a flow rate of approximately 270 gpm is, observed. The water <br />being pumped is clear, and therefore minimum pump wear is anticipated. <br />Four inch steel pipe with Victaulic fittings was used to connect each pump to <br />the discharge pipe which exits from the pumphouse through the concrete <br />floor. A system of 3 check valves and 3 butterfly valves was used in the <br />fitting arrangement to facilitate automatic pumping by one or both of the <br />pumps, as required. A schematic of the types and arrangement of the pumps, <br />valves and fittings is shown in Figure 3. <br />Six inch diameter Driscopipe (5.5 inch inside diameter) was laid along the <br />j east side of the stream channel to carry the collected seepage water from the <br />pump station back to the tailings pond. Design and construction of this <br />discharge line was handled by Homestake personnel. The location of the <br />discharge line is shown in Figure 2. The reducer from the 4 inch steel line <br />from the pumps to the 6 inch Driscopipe is located 40 feet east of where the 4 <br />inch line enters the pumphouse. The Driscopipe was buried a minimum of 5 feet <br />below grade along its entire length. The pipe passes through the embankment <br />approximately 8 feet below the crest on the east abutment, then empties into <br />the tailings pond. <br />A Haliburton flowmeter including a flow totalizer was installed on the <br />discharge line in the pumphouse to determine and record the flow of seepage <br />Ed IML <br />