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intercepted). Furthermore, a 16" HDPE pipe (slotted in the seepage area) was installed in a shallow <br />trench along the upslope (south) edge of the drainage blanket adjacent to the bedrock face. This pipe <br />was sloped downward to the east until it reached the 12" HDPE (solid wall) coming down from the <br />upper interceptor trench further east. These pipes then extended parallel to each other down the <br />hillside to discharge into the main sediment ditch as shown in Figure 4. <br />2.3 Construction Observation <br />Representatives from Barr and a subconsultant (Rock Logic Consulting) were present on a part-time <br />basis to observe the removal of material and the construction of the design elements described above <br />as the work progressed. Nuclear moisture - density testing was performed by Lambert & Associates <br />periodically during construction activities. Construction moisture - density test results and particle <br />size gradations are provided in Appendix A. <br />It is Barr's opinion that the construction activities and quality control measures performed as part of <br />the project are in general accordance with the recommendations provided by Barr to West Elk Mine <br />personnel. <br />2.4 Final Conditions <br />As -built survey shots of key locations on the repaired slope were received by Barr on May 3, 2012. <br />The seepage and slope stability models were updated to reflect the as -built conditions. A <br />topographic map that incorporates the survey information is shown on Figure 13. <br />2.4.1 Geometry <br />A cross - section through the East Slide was used for the seepage and stability analysis. This cross - <br />section, shown on Figure 5, was selected to be at the same cross - section location used for the <br />modeling performed as part of the design phase. As before, the granular drainage blanket and the <br />layer of Carbonaceous Shale at the top of the bedrock bench were both included in the model, though <br />they were present at a lower elevation. <br />2.4.2 Modeling <br />Seepage parameters were identical to those used during the design phase. <br />Unit weight and shear strength parameters were also identical to the design phase modeling except <br />for the Carbonaceous Shale layer in the exposed bedrock bench. For this material, fully softened and <br />residual shear strength testing was performed in the laboratory. The fully softened envelope was used <br />in the modeling using the non - linear shear strength envelope shown below in Table 4. <br />P Mpls 06 CO 26 06261003 Haul Road Slide Repair WorkFiles Report MCC_ Slump Repair- Instrumentation- DrainRe._ 2012 -05 -25 doe), <br />9 <br />