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6. Project Design <br /> The Overland Ponds and Treiber Pits interconnect pipelines are intended to transfer water <br /> between Overland Ponds Pond 2, Treiber A, and Treiber B. The interconnect pipeline <br /> includes the following: <br /> 6.1 Interconnect Pipelines <br /> The Interconnect Pipelines consist of 379 feet of 48 inch diameter steel pipe installed at the <br /> Pond 2 to Treiber A interconnect, and 179 feet of 48 inch diameter steel pipe installed at the <br /> Treiber A to Treiber B interconnect. Both pipelines will be installed within the Pierre Shale <br /> bedrock using trenchless construction methods. Vertical alignments were selected to provide <br /> adequate cover beneath cutoff walls and slope liners and to avoid the potential of- <br /> encountering mixed face conditions during excavation. The annular space surrounding the <br /> tunnel excavation will be grouted after installation to prevent fluid migration along overcut <br /> areas and to evenly transfer loads onto the tunnel. <br /> 6.2 Interconnect Shaft Construction <br /> Construction shafts are positioned at the base of the slope for each interconnect. The shafts <br /> will be excavated into bedrock to allow for trenchless construction at the design line and <br /> grade. Following construction, the shafts will be backfilled with Controlled Low Strength <br /> Material (CLSM) to provide support for piping, intake/outlet structures, and to reduce the <br /> potential for seepage along the pipe and eliminate the need for mechanical compaction <br /> around the pipe. <br /> Details of anticipated ground behavior shaft excavation and tunnel construction are contained <br /> in the project Geotechnical Baseline Report (Brierley, 2014). <br /> G E I V Project Design 1 16 <br />