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METHODOLOGY <br /> The mining embankment configuration shown in the computer analysis represents the <br /> estimated conditions for this site. If mining conditions differ from the estimated <br /> conditions, the slope stability will need to be re-evaluated on a case by case basis. The <br /> Bishop Method was used in the computer analysis for determining safety factors. The <br /> procedure searches for circular shear failures and automatically searches for the lowest <br /> safety factor. 2,000 separate failure surfaces were analyzed for each case. The required <br /> minimum safety factors are based on the current standards used by the Colorado State <br /> Engineer's Office (SEO) in evaluating embankment dams, and industry accepted <br /> standards for the evaluation of temporary structures during construction. <br /> SLOPE STABILITY RESULTS <br /> The SEO requires minimum safety factors of 1.25 for static condition analyses and 1.0 <br /> for pseudo-static (earthquake loading) condition analyses for Class I (high hazard) <br /> embankment dams. This design criteria was used to establish the desired minimum <br /> safety factors for this project and should be considered as highly conservative for <br /> evaluating alluvial mining slopes. The calculated factors of safety are within the design <br /> criteria specified for this project and can be considered indicators of the mining slope <br /> performance under the various conditions. The results of the static condition and <br /> pseudo-static condition slope stability analyses are presented in Table 2 and Table 3. <br /> Table 2 - Static Condition Slope Stability Analysis Results <br /> Description Calculated Required Minimum <br /> Factor Factor Of Safety <br /> Of Safety <br /> Case 1 — South Property Line 1.30 1.25 <br /> Case 2 — Existing Balsam Avenue ROW 1.30 1.25 <br /> Case 3 — North Property Line 1.30 1.25 <br /> Case 4 — Existing Gas Well 1.46 1.25 <br /> Table 3 - Pseudo-Static Condition Slope Stability Analysis Results <br /> Description Calculated Required Minimum <br /> Factor Factor Of Safety <br /> Of Safety <br /> Case 1 E — South Property Line 1.02 1.0 <br /> Case 2E — Existing Balsam Avenue ROW 1.03 1.0 <br /> Case 3E — North Property Line 1.02 1.0 <br /> Case 4E — Existing Gas Well 1.16 1.0 <br /> Broken Arrow Investments,LLC-Derr Pit Project <br /> J&T Consulting, Inc. Slope Stability Analysis <br /> Page 4 <br />