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maximum velocity of 11 feet per year, a slower velocity than predicted for the <br /> nearby Foidel Creek Mine in the previously mentioned U.S. Geological <br /> Survey report of Robson and Stewart. PSC predicts that seepage of <br /> underground mine water from the workings up dip into Grassy Creek <br /> alluvium after postmining recovery of the Wadge seam potentiometric surface <br /> will be less than 1 gallon per minute and will be too small to have a significant <br /> effect on alluvial ground water quality. <br /> Section 2.03.5 of the PSC permit provides updated information in relation to <br /> selenium both naturally occurring and in the reclaimed mine spoils from the <br /> previous Seneca II mining operations. Additional factors related to the PHC <br /> include current effluent limitations and existing wetland passive treatment <br /> systems which are effective in reducing selenium. The PHC has been <br /> updated to reflect current information. <br /> IV. Topsoil <br /> Baseline soils information is provided in Exhibit 2.04.9E-1 and on Map 2.04.9-M1 in <br /> the permit application. Exhibit 2.04.13-E2 shows the thicknesses of topsoil replaced <br /> on the lands that have been transferred from the Seneca II Mine permit area to the PSC <br /> permit area. The average depth was 15.6 inches as indicated by 933 samples taken <br /> over 1,793 acres (one sample per 1.9 acres). <br /> During mining operations at the PSC, available soil or suitable growth materials will be <br /> salvaged prior to disturbing lands. Section 2.04.9 and Exhibit 2.04.9-E1 identify target <br /> topsoil salvage depths. Large shrubs will be removed prior to soil removal. Smaller <br /> vegetation will be removed during soil salvage and will be incorporated into the topsoil <br /> as organic matter. Heavy clay soils will be recovered only if there are sufficient non- <br /> clay soils loams and sandy soils for blending. <br /> Approximately 140,000 cubic yards of topsoil have been salvaged during construction <br /> of the PSC portal facilities and associated roads. The salvaged topsoil has been <br /> stockpiled near the PeCoCo pond in the stockpile area shown on Map 2.05.3M1A. The <br /> stockpile will be seeded for erosion control with a temporary reclamation seed mix that <br /> is listed in Table 24.05.4-T1. <br /> Following final grading during reclamation operations,approximately 12 inches of soil <br /> will be placed on disturbed areas. The surface of the replaced topsoil will be left in a <br /> roughened condition to promote infiltration, minimize runoff, and provide a good <br /> seedbed for revegetation. Replaced topsoil will be stabilized by contour tilling, <br /> seeding, and establishing vegetative cover soon after topsoil replacement. Replaced <br /> soil will be sampled following the soil testing plan described in Section <br /> 2.05.4(2)(e)(vii) of the permit application. <br /> Page 19 of 27 <br />