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Mr. Mark Johnson <br /> January 2 , 2014 <br /> Page 5 <br /> Soil-Bentonite Slurry <br /> The proposed slurry wall will consist of a mix of the overburden clay and imported bentonite. The resulting mix will <br /> produce a non-Newtonian fluid with some shear strength characteristics based on a reduced friction angle of the <br /> overlying clay overburden. Based on engineering judgment,we modeled the slung wall as follows: <br /> Dry Unit Moist Unit Saturated <br /> Weight(pcQ Weight(pco Unit Weight Cohesion C'psf Friction Angle 0"' <br /> NA 112 115 0 0 <br /> STAB►UTYANALYSES RESULTS <br /> Stability analysis included three conditions: <br /> 1. Proposed dry mining slopes with a slung wall. <br /> 2. Seismic loads from an estimated earthquake bad with a mine full of water. <br /> 3. Rapid draw down of water levels within the mine. <br /> Setbacks listed in Table 1 indicate the minimal setback from the structure to the mining limits. The setback <br /> distance can be increased as needed to address other restrictions. <br /> The factor of safety shown below is the minimum factor of safety of the three conditions listed above. <br /> TABLE 1 •SLOPE STABILITY RESULTS AND SETBACKS <br /> Section Location Critical Structure Modeled Surcharge Slurry Wall Factor of <br /> (pso Setback ft Safety <br /> AA' West Phase 1 Ditch/House 2000 25 from Ditch 1.133(rapid <br /> drawdown <br /> BB' North Phase 1 Ditches/Road/Utilit 250 25 from Ditch 1.226 <br /> (earthquake) <br /> CC' West Phase 2 Ditches NA 25 from Ditch 1.262 <br /> (earthquake) <br /> DD' Phase 1/Phase 2 Oil Well 500 75 from Well 1.072 <br /> (earthquake) <br /> EE' South Phase 2 Ditch/Utilities 300 25 from Property 1.131 <br /> Line (earthquake) <br /> FF' South Phase 1 Farm Structures 1400 25 from Property 1.010 <br /> Line (earthquake <br /> The mining setback will be the slurry wall setback plus twelve feet. <br /> CONCLUSIONS <br /> The minimum distances proposed in this report will likely be increased more for construction and maintenance than <br /> for stability. <br />