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0 Huddlrseom-Bcrty <br />1,nf 1.11 Tc kj, LLC <br />With regard to shear strength, previous stability analyses for gob 92 and gob 93 <br />did not include cohesion. However, the WESTEC and Lambert laboratory testing data <br />indicates fairly large cohesion values. In general, using a large cohesion value is not <br />conservative. In addition, as discussed above, HBET understands that the material at gob <br />41 is coarser than at gob 92 and gob 93. Gob 91 has been undisturbed for many years <br />and consolidation of the mass under its own weight has likely been completed. Therefore, <br />for conservatism, HBET believes that a friction angle of 36° and cohesion of 0 psf is <br />appropriate for gob #1. <br />Based upon the available data, the following parameters were utilized for the <br />compacted gob at pile 91. <br />• y = 93.5 pcf <br />• c' = 0 psf <br />• �' = 36° <br />Native Foundation Soils <br />In general, the soil parameters utilized for the native foundation soils have been <br />fairly consistent over time. As a result, based upon the available data, the following <br />parameters were utilized for the native foundation soils. <br />• y = 125 pcf <br />• c' = 100 psf <br />• �' = 34° <br />3.3 Piezometric Surface <br />In general, based upon our review of the available data, HBET does not believe <br />that there is a free water surface, such as a static groundwater table, within the gob pile. <br />However, there are no piezometers installed in gob pile #1 to accurately define pore <br />water pressure conditions within the mass. <br />In general, HBET anticipates that pore pressures in gob 91 will be very small due <br />to the fact that no filling has occurred at this location for several years. It is likely that <br />any excess pore pressures have dissipated. However, for conservatism, HBET evaluated <br />the piezometric surface elevation at VWP-05 and VWP-09 installed near the toe of gob <br />pile 92. Based upon the 3rd quarter 2014 instrumentation monitoring, the piezometric <br />surface at VWP-05 is at approximate elevation 5994. At VWP-09, the piezometric <br />surface is at approximate elevation 5989. <br />Using the above elevations at gob pile 41, the piezometric surface exists below <br />the gob in the native foundation soils. However, for conservatism in the analysis, HBET <br />assumed that the piezometric surface exists at the base ground surface elevation at gob <br />pile #1. <br />X:\2008 ALL PROJECTS\01349 -Bowie Resources, LLC\01349-0001 Bowie Mine\200 - Geo\Gob 1\01349-0001 R112114.doe 3 <br />