Laserfiche WebLink
commences. Please commit to monitoring underground blasting as recommended by <br /> MMC. <br /> RESPONSE: Newmont is committed to monitoring underground blasting as <br /> recommended by MMC in its report. <br /> 30. Appendix 5 —Scope and Purpose Clarification. The division is unsure of the purpose of this <br /> appendix. <br /> • The inclusion of"NORTH AREA UNDERGROUND MINING AREAS" in the title <br /> implies the purpose is to provide recommendations for underground mining <br /> considerations. Yet, all the analyses are focused on surface mining activity. Is the <br /> purpose to provide recommendations for more stable surface mining benches to reduce <br /> the potential for slides that may disrupt underground mining, or is this limited to surface <br /> mining only and has nothing to do with the proposed underground mining? <br /> RESPONSE: Comment noted. At the time CNI was retained to complete its <br /> geotechnical analysis, Newmont was proposing to develop new portals and underground <br /> workings originating in the WHEX mine area. Due to several factors including highwall <br /> stability and future development of surface mining in the WHEX mine area, the scope of <br /> Amendment 11 was changed to focus underground workings from the Chicago Tunnel <br /> and the North Area Underground title was dropped. <br /> The CNI scope of work was to provide geotechnical slope design recommendations for <br /> the ongoing surface mining areas. This included updating the geotechnical database, <br /> determining geotechnically justifiable slope design angles for the proposed surface mine <br /> designs, and providing life-of-mine slope management recommendations. In Section <br /> 1.4.1, CNI recommends that additional geotechnical evaluations be performed before <br /> construction of underground begins to investigate the possibility of interaction between <br /> surface and underground operations. <br /> • It is also unclear as to the limits of potential highwall failure. The Division is tasked <br /> with regulating off-site damage and the potential damage to structures. This <br /> recommendations document appears to address optimal bench designs, impacts to mine <br /> operations, and slope management, as mentioned in the Executive Summary. The <br /> second paragraph of the Executive Summary mentions"global stability analyses", but <br /> of the 10 cross sections evaluated(reference Table 6-2 and Figure 6-1), only two (WH- <br /> 3 and GH-4) consider highwall stability near Teller Co Rd 82. Please comment on <br /> whether or not these recommendations are intended to satisfy the requirements of Rule <br /> 6.5. <br /> RESPONSE. The CNI slope recommendations report is intended to satisfy the portion <br /> of rule 6.5 that concerns slopes and highwalls within the surface mine designs. The <br /> cross sections WH-3 and GH-4 are located where Teller Co. road 82 will be nearest the <br /> proposed highwalls (see revised Figure 6-1 presented in Attachment 8). Two new cross <br /> sections have also been created for this document to evaluate the highwall stability near <br /> Teller Co. road 82 in two additional locations. The new cross sections are named WH- <br /> 4 and GH-6 and are described in response to question 34. <br /> 31. Appendix 5 —Factors of Safety. The implication from this report(Paragraph 1.3.4, Table 6- <br /> 2, and Figure 6-10) is that a factor of safety(FOS) of 1.2 is universally accepted. <br /> • If a slope failure has the potential for off-site impacts or damage to a structure (e.g., <br /> Teller Co Rd 82, Squaw Gulch VLF near the North Cresson Mine/Schist Island, and <br /> possibly the Mollie Kathleen tourist mine),the minimum FOS presented in DRMS <br /> Table 1 (reference Comment No. 20 above,then the Division requires a minimum FOS <br /> Page 13 of 30 <br />