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discussed in the Report and associated with the Mine. The Division has no additional comment and this <br /> Item has been satisfied. <br /> • Division: While not discussed in this Memo or in the Report, RAM is approvedfor blasting per <br /> the permit. Please have RMR orKUE address thepotential impact blasting may have on the <br /> stability of the Mine and have it modeled within the provided active mining and post-mining <br /> analyses. <br /> KUE:Section 7Blasting Impacts to Stability has been added to address thepo ten tial impact <br /> blasting may have on the stability of the Mine. <br /> To address the associated Division comment, KUE included a new section, Section 7 - Blasting Impacts <br /> to Stability, to the Report.In Section 7,KUE analyzes potential seismic loading to the slope from blasting <br /> operations based on the results of a study performed by the U.S.Department of Interior, Office of Surface <br /> Mining -Structure Response and Damage Produced by Ground Vibrations from Surface Blasting <br /> (Blasting Study). This Blasting Study evaluated direct measurements of ground-vibration-produced <br /> structure responses and damage from blasting. Using the evaluation of the Blasting Study along with the <br /> assumption of proper blast design and site conditions, a design seismic coefficient can be determined. <br /> From this, a design seismic coefficient from blasting using site conditions was calculated by KUE and <br /> resulted in a value of 0.12 as discussed in the Report. This design seismic coefficient from blasting can <br /> be compared to the design seismic coefficient from the peak gravitational acceleration of an applicable <br /> maximum considered earthquake. As discussed in Section 7 of the Report,the seismic load resulting <br /> from a blast at the Mine is less than that from an applicable maximum considered earthquake. This means <br /> that the seismic coefficient from the maximum considered earthquake for a 1,000-year return period will <br /> apply a greater seismic load which is a more conservative value to use within the stability analysis for <br /> seismic conditions. For more discussion regarding the design seismic coefficient used in the stability <br /> analyses within the Report,please refer to discussions associated with the following Item from the <br /> Divisions 2023 Memo. The Division has no additional comment and this Item has been satisfied. <br /> • Division: When reviewing the associatedstability analysis with mechanical stabilization under <br /> Appendix G, it was observed that none of the scenarios provided met the minimum FOS of 1.5 as <br /> stated in the Report. Per Section 8.1 of the Report, "[p]otential slope heights... <br /> ...were modeled to determine the resistingforce required to reach a factor ofsafety of 1.5. " The <br /> West section resultant FOS is 1.45 and resultant FOS for the East section for 10 feet and 15 feet <br /> are].4 and].41 respectively as provided in Appendix G. In order to ensure the minimum criteria <br /> of the Division's Section 30 is met,please have KUE provide updated mechanical stabilization <br /> recommendations and associated analyses that meets or exceeds the minimum FOS requirements <br /> of 1.5 forstatic conditions. <br /> KUE:Stability models in Appendix G have been revised to achieve a FOS of].5 static and 1.3 <br /> seismic. <br /> Based on the Division's comment, KUE has provided updated analyses for mine stabilization under static <br /> and seismic conditions. Discussions regarding the applied seismic coefficient is provided under Section 7 <br /> of the Report. When reviewing Section 7, it was observed that the value of the peak ground acceleration <br /> for a 1,000-year return period was provided (0.196)however,the actual value of the applied seismic <br /> coefficient was not provided along with the methodology in which it was derived from. <br /> While reviewing Appendices D and G, the applied seismic coefficient can be observed within the models <br /> as 0.126. Based on the discussed return period, it appears to the Division that KUE used AASHTO <br /> LRFD Specifications in determining the appropriate seismic coefficient. AASHTO LRFD Specifications <br /> for seismic applications is a widely used and accepted engineering methodology. With this assumption, <br /> the Division was able to corroborate the peak gravitational acceleration,site adjustment factors and <br /> resulting seismic coefficient provided under Appendices D and G with published information from the <br /> USGS Seismic Design Map Web Services. With the applied design seismic coefficient of 0.126, the <br /> Mid Cortinent Limestone Quarry Geotechnical Review Memo February 6,2024 <br />