Laserfiche WebLink
Huddleston -Berry <br />I rynminlA I. v.-y, I.Lt <br />The referenced reports also indicate that angles of internal friction ( +') of between <br />33.5° and 34° have been used in various analyses for drained conditions. However, the <br />majority of the analyses used a value of 34 °. <br />Based upon the available data, the following parameters were utilized for the <br />compacted gob. <br />• y = 104.6 pcf <br />• c' =0psf <br />• +' = 34° <br />Native Foundation Soils <br />In general, the soil parameters utilized for the native foundation soils have been <br />fairly consistent within the reviewed documentation. As a result, based upon the <br />available data, the following parameters were utilized for the native foundation soils. <br />• y = 125 pcf <br />• c' = 100 psf <br />• 0' = 34° <br />Cover ill <br />Based upon information provided to HBET, the coverfill consists of native <br />overburden soils. As indicated above, the in -place native soils have a moist unit weight <br />of 125 pcf. However, the in -place native soils are anticipated to generally be normally <br />consolidated. The coverfill stockpiles will not be compacted and as a result, a lower unit <br />weight is likely. The following parameter was utilized for the coverfill soils. <br />• y = 115 pcf <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, the pore pressures recorded by the vibrating wire piezometers are not zero. As <br />a result, the pore pressure data from the piezometers was used to generate a piezometric <br />surface consistent with that data in order to evaluate the impacts of the pore pressures on <br />the stability of the gob. HBET utilized data from VWP -05, VWP -06, and VWP -08 to <br />generate the piezometric surface along Section B -B'. It is important to note that VWP -10 <br />is at a similar elevation to VWP -05; however, the pore pressures in VWP -10 are negative. <br />Therefore, the use of the VWP -05 data for Section B -B' is conservative. For Section C- <br />C', pore pressure data from VWP -06, VWP -08, and VWP -09 was used. <br />Beyond the limits of the available piezometer data, HBET assumed a phreatic <br />surface for the area of gob pile #2 below VWP -05 and VWP -09. Beyond the toe, the <br />phreatic surface was assumed to intersect and follow the ground surface. This is a <br />conservative assumption. <br />.X:\2008 ALL PROJECTS \01349 -Bowie Resources, LLC \01349 -0001 Bowie Mine\200 - Geo \Gob 2 \Coverfill Stability\01349 -0001 R091914R2.doc 3 <br />