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Daniels Sand Pit 2,Permit M-1973-007-SG; <br /> Response to"Approval Succession of Operators, Revision SO-2,with Stipulations" <br /> Page 4 <br /> APPENDIX A <br /> Slope stability analysis was completed to assess the potential for failure along the Fountain <br /> Mutual Ditch. Figures 4 and 5 present the requested Fountain Mutual Ditch cross sections based <br /> on surveyed topography provided by the owner. The slopes analyzed were associated with the <br /> Fountain Mutual Ditch located on the Daniels Sand site within a 30' Prescribed Ditch Easement. <br /> According to the MLRB policies revised May 2018 a factor of safety of 1.5 is required for <br /> critical structures with generalized, assumed, or single test strength measurements and 1.3 for <br /> structures with strength measurements resulting from multiple tests in the table"Recommended <br /> Minimum Factors of Safety for Slope Stability Analyses for Operations and Reclamation". Due <br /> to the extent of information collected in previous investigations and 37 strength values <br /> determined multiple tests have been conducted. <br /> A slope stability computer simulation analysis was performed to assess the global stability of the <br /> slopes within the coarse alluvium. Slope stability was analyzed using the computer program <br /> SlopeWTM, developed by GEO-SLOPE International (Geostudio 2012). SLOPE/W utilizes limit <br /> equilibrium principles to analyze potential failure surfaces within a user defined two-dimensional <br /> geometry. Slip surface ranges can be defined using a variety of methods; scenarios analyzed in <br /> this report defined failure surface locations over a range of slip surfaces. The Spencer Method <br /> was used to calculate critical slip surfaces and associated safety factors. From numerous trial <br /> surfaces, the slip surface with the lowest FOS is described as the critical section representing the <br /> estimated slope stability for the defined conditions. <br /> Mohr-Coulomb strength criteria was utilized to define soil strengths. The properties used in each <br /> analysis are based on the subsurface data gathered to date, field penetration tests,the laboratory <br /> test results and engineering judgement and experience. Geotechnical information collected <br /> during previous investigations are presented in Appendix B. The properties are summarized in <br /> the table below. <br /> Table 1 Slo a Stability Analysis Parameters <br /> Moist Effective Stress Analysis Total Stress Analysis <br /> Material Unit Cohesion Friction Cohesion Friction <br /> Weight Angle, T Angle,(p <br /> (pc� C' (Psi (degrees) C (Psi (degrees) <br /> Coarse Alluvium 1 115 1 0 33 1 50 - <br /> Each figure presents the results of the analysis for the cross section and conditions modeled as <br /> shown in the following images. The colored contours on the grid indicate a factor of safety <br /> associated with the centroids of the slip surfaces (see legend for corresponding value). This <br /> gives a good indication of the prevalence of the respective factor of safety. The white curve is <br /> the critical slip surface for the model associated with the red dot and factor of safety. <br /> BRIERLEY <br /> ASSOCIATES <br /> Creating Space Underground <br />