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27. Response Accepted. Colowyo's changes to the post-mining topography have adequately <br />addressed this question. Please note that the Division still has concerns regarding the <br />swell factor, as detailed in question 2 above. <br />Comments Regarding Shannon and Wilson Report <br />28. The Division's original adequacy question is as follows: In the process of conducting the <br />TR-81 adequacy review, the Division revisited the earlier Shannon and Wilson Study and <br />Addenda Nos. 1 and 2. A discrepancy was noted in the transcription and utilization of <br />data, as follows: Table B-1 in Appendix B presents a "Summary of Laboratory Test <br />Results by Boring". Data in the Direct Shear "Cohesion" and "Friction Angle" columns, <br />for Borings CO-3 and LW-1, appears to have been incorrectly transcribed from Figures <br />B-4 and B-5, the original reports prepared by Knight-Piesold Consulting. Corrected <br />friction angles for CO-3 and LW-1 would be 24 and 33 degrees, respectively. Similarly, <br />the tabulated cohesion values for these two samples should actually have been 370 and 40 <br />psf. The incorrect numbers shown in Table B-1 appear to have been used in the <br />development of the Average Friction Angle and Cohesion values reported in Table C-1 <br />for "Soil", which parameters were in turn used for input into the Slope/W program. <br />Inclusion of these erroneous values may have resulted in Factors of Safety that were <br />inaccurate (too high). Please review the information presented in Appendices B and <br />C of the original Study, and revise as appropriate, including any conclusions or <br />recommendations that may change as a result of the review. (We note that <br />corrected friction angle and cohesion values from Boring CO-3 appear to have been <br />used in the Shannon and Wilson study submitted with TR-81.) <br />Colowyo responds that the new Shannon and Wilson Report Addendum No. 3 effectively <br />supersedes all previous geotechnical studies, including tabulated material strengths and <br />computer based slope stability analyses. While this may be true, the tabulated data <br />should be accurate to the extent possible. The Division withdraws its request to re-run <br />the Slope/W models, but reiterates the requirement to update the data in Tables B-1 and <br />C-1. Additionally, there is no notation on the cover page of the Shannon Wilson report <br />that Addendum 3 supersedes all previous studies and addendums. Please review the <br />information presented in Tables B-1 and C-1 and revise as appropriate. Please <br />update the cover page of the Shannon Wilson report to indicate that Addendum 3 is <br />the final report and supersedes all previous reports and addendums. <br />29. Response Accepted. Addendum 3 of the Shannon and Wilson Report has been revised as <br />requested. <br />30. Response Accepted. Table A-1 of the Shannon Wilson report has been renamed Table <br />D-1 and the entries have been revised as requested. <br />31. Response Accepted. The entries in Table A-3 of the Shannon Wilson report (now Table <br />D-3) have been revised as requested.