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• <br />• <br />• <br />March 2000 ~- 993-2099.150 <br />The Phase N design will consist of an additional 7.8 million square feet (surface area <br />corrected for slope) of lined leach area. Phase N provides additional area for both ore <br />storage and construction of an internal PSSA. Each of these areas will include composite <br />liner systems. Within the Ore Storage Area, the composite liner will be comprised of a <br />12-inch thick Soil Liner Fill (SLF) with a 1 x 10-6 cm/sec or lower permeability overlain <br />by an 80-mil single-sided textured linear low density polyethylene (LLDPE) geomembrane, <br />which is overlain by 2 feet of Drain Cover Fill (DCF). Within the PSSA, the liner system <br />on native ground will consist of 12-inch thick SLF with a 1 x 10'6 cm/sec or lower <br />permeability, overlain by a 100-mil textured LLDPE geomembrane, overlain by 3 feet of <br />Low Volume Solution Collection Fill (LVSCF), overlain by a 100-mil smooth LLDPE <br />geomembrane, overlain by 2 feet of DCF. <br />Native ground recontouring and regrading within the limits of Phase N were developed <br />such that the foundation slopes would be 2.SH:1V or shallower, with the exception of one <br />side of the PSSA solution collection sump. The side of the Phase N PSSA solution <br />collection sump to be developed with slopes of 2H:1V, is explained in Section 4.6.2. The <br />Phase N design has been developed to provide for a total VLF storage volume of <br />approximately 262.5 million tons of ore, using an in-place ore dry density of 96 pcf. The <br />Phase IV VLF ore topography is shown on Drawing No. 25, and cross-sections through <br />the VLF are shown on Drawing No. 6. <br />The majority of pregnant solution generated during operation of Phase IV will be contained <br />within the Phase N internal PSSA. Some of the solution applied to Phase IV will report to <br />the Phase I and II internal PSSA's. The Phase N PSSA will be constructed on native ground <br />and compacted ore. The southern edge of the PSSA will be conswcted along the Phase III <br />ore slope while the eastern and western ends of the PSSA will be constructed on berms <br />consisting of ore material over a liner system. Further details on the PSSA liner system are <br />provided in Section 4.6.2 of this report. <br />I:\99\HH9\FINAL REPORT2099MAIN1.000 Golder Associates <br />