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M03086GE 1~ I movements. If the driving forces are equal to or greater than the resisting forces then failure is imminent. A theoretical calculat- ed factor of safety of 1.5 is considered by the geotechnical engineering industry as a minimum factor of safety for a slope to be considered as stable. A calculated factor of safety of 1.0 or less indicates that slope movement is imminent or in process. Failure can occur as slow deformation, creep, or as a somewhat spontaneous failure. Factors that have an adverse influence on slope stability can• generally be classified as those that increase the stress (driving force) on the system or decrease the strength (resisting forces) of the soil. Our stability analyses of the proposed excavation cut and fill slopes was based on the Bishops method of slices. This method is based on the assumption that the slope soil mass will fail in a rotation mode on a circular arc plane. In this method of analysis the mass of soil is divided into vertical slices. The forces acting on each slice are evaluated from the equilibrium of the slices; that is, the forces that tend to drive the slice downhill and the forces that tend to resist the movement of the slice. The equilibrium of the entire mass is determined by summing the driving and summing the resisting forces acting on all slices and comparing these forces. Our slope stability analysis was performed using "Slope Stability Analysis" program by Geosoft computer software. Our slope stabil- ity analysis considered three (3) different cross sections deter- mined by Mr. Stover with a total of about 1,500 separate possible failure surface iterations for each cross section to help identify the potential theoretical slope stability. Our discussions and data presentation is based only on the calculated critical circle which presented the lowest factor of safety against failure. Our presentation does not include the results of all of the iterations which resulted in a theoretical factor of safety greater than the lowest factor of safety and therefore were not critical. The cross sections included in our stability analyses are A-A, B- B, and C-C as presented on Drawing C-96-083, Mine Facilities, as provided by Mr. Stover. We assume that the drawings showing the location of the cross sections are available through Mr. Stover's office therefore these are not reproduced and included in this report. Our Stability analyses assumed that the foundation soils supporting the proposed portal bench fill and the stock pile fills had equal or greater strength characteristics than the proposed fill material. If the natural on site foundation soil materials 4 3iLambert ana ~,o,~ociateo CONSULTING GEOTECM NICAL ENGINEERS ANO MATERIAL TESTING