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Case SS-3 — Gas Line Northeast of Pit. <br /> The mining operation is adjacent to a gas line on the northeast side of the pit. The <br /> proposed setback for mining is 61 feet from the gas line. The mining depth was assumed <br /> to be 34 feet in this area based on bore log information. <br /> Case SS-4— Gas Line East of Pit. <br /> The mining operation is adjacent to a gas line on the east side of the pit. The proposed <br /> setback for mining is 46 feet from the gas line. The mining depth was assumed to be 35 <br /> feet in this area based on bore log information. <br /> Case SS-5 — Gas Line South of Pit <br /> The mining operation is adjacent to a gas line on the south side of the pit. The proposed <br /> setback for mining is 45 feet from the irrigation ditch bank. The mining depth was assumed <br /> to be 36 feet in this area based on bore log information. <br /> The cross-sections located in Appendix B show the estimated phreatic surface associated <br /> with each case, the geometry used in the mining/reclamation, and the locations of the <br /> man-made structures adjacent to the mining slopes. <br /> 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 conditions, <br /> the slope stability will need to be re-evaluated on a case-by-case basis. The Bishop <br /> Method was used in the computer analysis for determining safety factors. The procedure <br /> searches for circular shear failures and automatically searches for the lowest safety <br /> factor. 20,000 separate failure surfaces were analyzed for each case. The required <br /> minimum safety factors are based on the policy of the Mined Land Reclamation Board <br /> (MLRD) for Factors of Safety for Slope Stability/ Geotechnical Analyses. <br /> All cases were analyzed using mining condition geometry to determine the factor of safety <br /> for each case with the steeper mining slopes. Case SS-5, which is the location that is <br /> closest to a critical structure (45 feet from the gas line), was analyzed to determine the <br /> minimum factor of safety for all reclaimed slopes. <br /> IHC Scott, Inc.—Bernhardt Sand and Gravel Pit <br /> J&T Consulting, Inc. Slope Stability Analysis <br /> �� Page 3 <br />