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The results in Table 1.0 indicate that all four methods produced a resulting global minimum <br />factor of safety of 1.686 for the as -built slope. Since all of the factors of safety are <br />significantly greater than 1.50, which is used a basis for long -term stability, in our opinion, <br />the slope of the Gob Pile #4 is stable as constructed. Figure 1 below presents the results of <br />the analysis showing the slope as constructed and with the Janbu Method results. <br />Figure 1. Analysis results for Janbu simplified method which resulted in the lowest and <br />therefore most conservative Factor of Safety for the Gob Pile #4 slope as- constructed. <br />CONCLUSIONS <br />Since the analyses presented in this letter represent the CWDA #4 pile in its current <br />condition including moisture and grade, we recommend that the as -built condition be <br />accepted as is and that re- vegetation proceed as outlined in the mine's re- vegetataion plan. <br />That re- vegetation should result in continued increase in slope stability as long as surface <br />drainage is controlled and re- vegetation of the slope begins to take effect. <br />Thank you for the opportunity to work with you on this long -term project at the Bowie Mine <br />#2. If you have any questions about this analysis, please contact me at (970) 497 -8852 or <br />dan@buckhorngeo.com. <br />Respectfully submitted, •� �;`G /0 �( <br />Daniel C. Quigley, PE, PG 38334 <br />Buckhorn Geotech, Inc. <br />NAL <br />Bowie Mine #2 — CWDA Pile # 4 PN 05- 126 -GEO <br />REVISED As -Built Stability Analysis <br />_MW <br />?�U,1)3 <br />Satety Fwtoc <br />0.000 <br />0.500 <br />, tr 05- 126 -GEO Bonne Mine9ile t.1 -2012 Stability <br />1.000 <br />i.. <br />�y ,. 1.686 Material: Native <br />1.500 <br />Strength Type: Mohr - Coulomb <br />125 lb103 <br />2.000 <br />Cohesion: 100 psf <br />` Friction Angle: 34 degrees <br />2.$00 <br />Water Surface. None <br />a <br />3.000 <br />Material: Gob <br />3.500 <br />Strength Type Mohr - Coulomb <br />Unit Weight: 110.5lbA3 <br />4.000 <br />Cohesion 0 psf <br />Friction Angle: 34 degrees <br />4.500 <br />Water Surface- None <br />4 <br />F <br />5.000 <br />Method )anbu simplified <br />5.50o <br />FS: 1686330 <br />Gob <br />6.000h <br />Native Sod <br />27 4(10 +000 rmo <br />CONCLUSIONS <br />Since the analyses presented in this letter represent the CWDA #4 pile in its current <br />condition including moisture and grade, we recommend that the as -built condition be <br />accepted as is and that re- vegetation proceed as outlined in the mine's re- vegetataion plan. <br />That re- vegetation should result in continued increase in slope stability as long as surface <br />drainage is controlled and re- vegetation of the slope begins to take effect. <br />Thank you for the opportunity to work with you on this long -term project at the Bowie Mine <br />#2. If you have any questions about this analysis, please contact me at (970) 497 -8852 or <br />dan@buckhorngeo.com. <br />Respectfully submitted, •� �;`G /0 �( <br />Daniel C. Quigley, PE, PG 38334 <br />Buckhorn Geotech, Inc. <br />NAL <br />Bowie Mine #2 — CWDA Pile # 4 PN 05- 126 -GEO <br />REVISED As -Built Stability Analysis <br />_MW <br />?�U,1)3 <br />