Laserfiche WebLink
GEOTECHNICAL STABILITY EXHIBIT <br /> The slopes at the Birdseye Pit will be excavated to the final reclamation condition of 3H:1 V to <br /> the bottom of the pit. This plan will ensure stable slopes and successful revegetation. As mining <br /> and reclaimed slopes are the same, only one set of slope conditions is evaluated for stability. <br /> 1. Slope Stability Analysis <br /> The material used in the analysis are sand and gravel, mixed grain size for the aggregate deposit. <br /> The material properties are outlined in the table below and are derived from the SME Mining <br /> Reference Handbook(2002 edition)5. The water level is assumed to be 30 feet below the starting <br /> grade. <br /> Table 1 —Material Properties <br /> Aggregate <br /> sand and gravel,mixed grain size <br /> Unit Weight(Ibs/ft3) 110 <br /> Frk*m arq0e(") 45 <br /> Cohesion 0 <br /> 1.1 Reclaimed Slope <br /> Reclaimed slopes will consist of sand and gravel, as described above, that is topsoiled and <br /> revegetated according to the reclamation plan. Analysis of the stability of said slope involves <br /> building a model of the slope in GALENA slope stability software and conducting a search for <br /> the failure circle using Bishop's method of slices. A circular failure slope is most likely for a <br /> slope excavated in native alluvium material. Slope stability is governed by the physical <br /> properties of the material as described in Table 1. <br /> Multiple failure circles were generated by GALENA to determine the lowest Factor of Safety <br /> (FS). The results of the software iterations are attached to this exhibit. <br /> s Table 2.5;Originally from Houk and Bray, 1977 <br /> Birdseye Pit Gnqg lx%id.i and%ssociate. PI F <br /> June 2019 GS-1 <br />