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11111 <br />portions of the rubble material from the original failure and the scarp face (cliff) <br />have lower factors of safety than those shown. <br />CONCLUSIONS <br />• The large potential failures that are likely to affect the bottom of the pit <br />have calculated factors of safety of about 1.06 or greater assuming <br />weaker material properties and about 1.3 assuming more likely material <br />properties. <br />• The slide appears to have been triggered by an increase in ground water <br />levels about three and a half to four months after heavy rains in August <br />and September of 2008. <br />• The ground water levels have likely declined since the slide occurred by <br />draining out through the slide rubble or fractures in the based of the slide <br />material. <br />• The base of the slide may have moved along an unidentified thin clay <br />layer within the limestone, or along the interface of the sandstone and <br />the limestone, or a weak zone within the sandstone. <br />• •. Likely the safest way to further stabilize the slope will be to remove <br />material from the top of the slope downward in benches to expose <br />undisturbed material below the slide. <br />• The safety of the cliff portion of the scarp face can probably be improved <br />by blasting with explosives set into the upper scarp fractures. <br />RECOMMENDED FUTURE WORK <br />Based on the results of this investigation, we recommend the following <br />additional work be performed. <br />1. Additional stability analysis to determine safe design slopes for the final <br />pit reclamation. <br />2. Additional stability analysis to determine a safe means of improving the <br />stability of the slope so that the pit can safely be brought to the final <br />reclamation configuration. <br />TRANSIT MIX AGGREGATES 20 <br />PIKEVIEW QUARRY SLOPE <br />CTLIT PROJECT NO. CS17341-125 <br />S:1CS17000-174991CS17341.000112512. Reports1CS17341-125-R1-Final.doc