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Sullivan Pit Engineering Second Revim Dlenio <br />Page 2 of 3 <br />October 6, 2015 <br />• The Applicant used a cohesion value of 480 psf for the native clayey gravel and 280 psf <br />for the backfill material <br />• The Division used a more conservative of 105 psf for the native clayey gravel and 0 psf <br />for the backfill material <br />• No laboratory strength tests were performed on soils at the site <br />• No borehole data was submitted by the Applicant <br />The Division verified the Applicant's stability analysis model using Clover Technology's Galena <br />v6.1 slope stability software. <br />Cross-section E -E' — Mining Slope <br />The Applicant's cross-section with Highway 9 and topsoil stockpile loading was duplicated for <br />verification. The factor of safety produced by Galena (1.41) is lower than the factor of safety <br />produced by the Applicant's calculation (1.85); however the factor of safety is greater than the <br />required factor of safety of 1.3. Therefore, the accuracy of the Applicant's analysis is <br />confirmed. A copy of the Galena model is attached. <br />Cross-section E -E' — Reclamation Slope <br />The Applicant's cross section with Highway 9 loading was duplicated for verification. The factor <br />of safety produced by Galena (1.41) is lower than the factor of safety produced by the <br />Applicant's calculation (1.95); however the factor of safety is greater than the required factor of <br />safety of 1.3. Therefore, the accuracy of the Applicant's analysis is confirmed. A copy of the <br />Galena model is attached. <br />Cross-section B -B' — Mining Slope <br />The Applicant's cross-section was duplicated for verification. The factor of safety produced by <br />Galena (1.41) is lower than the factor of safety produced by the Applicant's calculation (1.85); <br />however the factor of safety is greater than the required factor of safety of 1.3. Therefore, the <br />accuracy of the Applicant's analysis is confirmed. A copy of the Galena model is attached. <br />Cross-section B -B' — Reclamation Slope <br />The Applicant's cross section was duplicated for verification. The factor of safety produced by <br />Galena (1.52 is lower than the factor of safety produced by the Applicant's calculation (1.75); <br />however the factor of safety is greater than the required factor of safety of 1.3. Therefore, the <br />accuracy of the Applicant's analysis is confirmed. A copy of the Galena model is attached. <br />Conclusion <br />The Division agrees with the proposed setback and mining and reclamation slope angles for the <br />Sullivan Pit as presented in the stability analysis for the two (2) critical cross-sections. The <br />mining excavation must never exceed a slope of 2.5H:1V, groundwater must not be <br />