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• Analyses of additional cross sections for the Co Rd(perpendicular to Section WH-3 and GH-4) and SGVLF (south of Section SI-2). RESPONSE: Two new cross sections (WH-4 and GH-6) have been analyzed and are shown in plan view on the revised Figure 6-1 (Attachment 8). Cross section WH-4 is on the northwest wall of the WHEX mine and cross section GH-6 is in the northwest corner of the proposed Globe Hill mine. Cross section WH-4 resulted in a FOS of 2.28 (Figure 6-31,Attachment 8). Cross section GH-6 resulted in a FOS of 2.22 (Figure 6-32). Both of these cross sections meet the FOS criterion of 1.5. The far southern slope of the Schist Island portion of the mine will be located beneath the SGVLF. However, this north facing slope is only 200 feet high, is designed at an overall slope angle of 36 degrees, and has a rock quality designation (RQD) of 70 percent. Therefore, due to the low slope height, relatively shallow interramp angle, and high rock quality, it is reasonable to surmise that the FOS of this highwall design is significantly greater than 1.5. • Justification for claiming high confidence in strength parameters if using an FOS = 1.3. RESPONSE: CNI agrees that the FOS criterion for failure mechanisms that may interact with critical structures should be 1.5 in this area of the mine. 35. Appendix 5 Section 6.3.5, Figures 6-1 and 6-18. Based on Figure 6-1, it appears Section GH-4 (northeast side of the Globe Hill mine) may include a portion of Teller Co Rd 82. The Division considers this road a critical structure and requires the road be shown on Figures 6-1 (in plan view) and 6-18 (in section). Section 6.3.5 references Figures 6-16 and 6-17 for the GH-4 geology. The reference to Figure 6-16 is incorrect as that is for GH-3. This Section 6.3.5 narrative is unclear as to whether it is potentially stable with an FOS = 1.52 (line one of 2nd paragraph), unstable with an FOS = 0.96 (line two of 2nd paragraph) or whether it is advocating lowering the interramp slope angel to 39 degrees to achieve an FOS = 1.20 (last line of 2nd paragraph). Please provide the following: • Assurance that the appropriate FOS at the edge of the Co Rd Right-of-Way is achievable (reference DRMS Table 1 above), RESPONSE: See response to question 34 (first bullet point) above. • Show Teller Co Rd 82 on Figures 6-1, 6-17 and 6-18, RESPONSE: See response to question 34 (first bullet point) above. • Clarification on the different FOS's in the second paragraph. RESPONSE: See response to question 34 (first bullet point) above. 36. Appendix 5 Section 6.3.9, Figures 6-1 and 6-26. Based on Figure 6-1, it appears Section WH-1 (south side of the WHEX mine) extends to the ECOSA. The Division considers ECOSA a critical structure and requires the facility be shown on Figure 6-1 (in plan view) and labeled in Figure 6-30(in section). Section 6.3.9 references Figures 6-24 and 6-25 for the WH-1 geology. The reference to Figure 6-24 is incorrect as that is for SI-2. Please provide the following: • Assurance that the appropriate FOS at least 50 feet from the toe of the ECOSA is achievable (reference DRMS Table I above), Page 16 of 30