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pcf, a cohesion value of 500 psf and an effective phi angle of 0 were used for the natural clays underlying <br />• the proposed embankment; whereas, a unit weight (soil density) of 114 pcf, a cohesion value of 250 psf and <br />a phi angle of 0 were used for the remolded clays to be used in construction of the embankment. <br />Based on our calculations and analysis, the minimum calculated theoretical factor of safety for a failure of <br />the maximum embankment fill slope section, with the Cuttings Pond full, will be 1.62 under static <br />conditions. The slope stability analysis data and a cross section showing the slip (failure) surface are <br />presented in Appendix B. <br />Sedimentation Pond 1 - Embankment Fill Slope (Station 1+50): A slope stability analysis was <br />completed for the largest section of the proposed embankment fill slope to be constructed at the southern <br />end of Pond 1, which appears to be located at approximately Station 1+50. It appears that the proposed <br />embankment fill slope will be constructed with the upstream face being approximately 8 feet in height and <br />constructed to a 2 (horizontal) to 1 (vertical) slope configuration; whereas, the downstream face will be <br />approximately 11 feet in height and constructed to approximately a 3.0 (horizontal) to 1 (vertical) slope <br />configuration. <br />A phreatic surface has also been added to this model to analyze the embankment under a full reservoir <br />condition with steady state seepage, which is considered to be the worst case scenario. Therefore, a failure <br />i of the downstream face of the embankment during peak water storage was analyzed. <br />For this evaluation a unit weight (soil density) of 135 pcf, a cohesion value of 1,000 psf and a phi angle of <br />0 were used for the underlying, natural claystone bedrock materials. A unit weight (soil density) of 127 <br />pcf, a cohesion value of 500 psf and an effective phi angle of 0 were used for the natural clays underlying <br />the proposed embankment; whereas, a unit weight (soil density) of 114 pcf, a cohesion value of 250 psf and <br />a phi angle of 0 were used for the remolded clays to be used in construction of the embankment. <br />Based on our calculations and analysis, the minimum calculated theoretical factor of safety for a failure of <br />the maximum embankment fill slope section, with Pond 1 full, will be 2.19 under static conditions. The <br />slope stability analysis data and a cross section showing the slip (failure) surface are presented in Appendix <br />B. <br />Sedimentation Pond 2 - Embankment Fill Slope (Station 2+00): A slope stability analysis was <br />completed for the largest section of the proposed embankment fill slope to be constructed at the southern <br />end of Pond 2, which appears to be located at approximately Station 2+00. It appears that the proposed <br />embankment fill slope will be constructed with the upstream face being approximately 4 feet in height and <br />constructed to a 2 (horizontal) to 1 (vertical) slope configuration; whereas, the downstream face will be <br /> <br />Job Number: 08-8241 NWCC, Inc. Page 11