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SHANNON t~WII.SON, INC. <br /> <br />the west and east fills are shown on Figure 8. The locations of these cross-sections are shown on <br />Figure 2. <br />As shown on Figures 2 and 8, the west fill is the larger of the two planned fills. Sections A-B <br />and A-C extend along the centerlines of the existing valley forks. A portion of the fill has a <br />slope of about 3H:1 V, which is cut by section D-E. This slope is located above the mine and is <br />technically not excess spoil; however, because it was a steeper section an analysis was <br />performed. <br />The east fill has a maximum slope of about 4H:1 V with a relatively flat top planned. A <br />temporary spoil fill is planned above this area that will be removed as mining and reclamation <br />proceeds. Another temporary spoil fill is plannedjust east of the east fill (Figure 2). <br />3.0 SUMMARY OF PREVIOUS WORK <br />CTL/Thompson, Inc. (CTL) and Shannon & Wilson, Inc. (S&W) have performed previous <br />geologic/geotechnical studies at the site that included subsurface explorations and/or evaluation <br />• of excess spoil fill. The locations of the previous explorations and references to the previous <br />projects are shown on Figure 3. As part of our current scope of work, we reviewed these <br />previous reports. <br />The results of the explorations and laboratory data (Section 4.0 and Appendices A and B) <br />associated with our current scope of work indicate that the subsurface conditions at the South <br />Taylor excess spoil sites are similar to the previous studies. Therefore, we considered the <br />previous subsurface information and Laboratory data to develop the parameters used in our <br />stability analyses. The results of the April 9, 2003 Geotechnical Investigation for South Taylor <br />Excess Spoil Fill (Reference 17) indicate that valley fills with out-slopes of about 3H:1 V and <br />subsurface conditions similar to the current investigation had a factor of safety (FS) of at least <br />1.4. <br />We reviewed a seep and spring survey by Greystone Environmental Consultants, Inc. (Reference <br />20). This report indicates that three seeps/springs are located within the proposed footprint of the <br />west excess spoil fill and one seep/spring within the proposed footprint of the east excess spoil <br />fill. The locations of the mapped seeps and springs are shown on Figure 5. <br />• <br />23.1-01105-200-Rl.doc <br />23-1-01105-200 <br />2 <br />