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Cripple Creek & Victor Gold Mine <br />Valley Leach Facility Expansions <br />Detailed Design for Permitting <br />NewFields Project No. 475.0106.064 <br />September 2025 <br /> <br /> <br /> <br />Page 17 <br />leach facility, leak detection trench alignment and leak detection sumps with spot <br />elevations surveyed along the alignment to demonstrate the leak detection trench will <br />flow towards the sump and a survey frequency less than 100-feet between points.” <br /> <br />5. GEOTECHNICAL EVALUATION <br />A geotechnical evaluation was completed to assess the global stability and potential settlement <br />of the proposed VLF Expansion Phase 4 and 6 slopes and facility. The results of the evaluations <br />are discussed in the following sections. <br />5.1. Stability Evaluation <br />Stability analysis was completed using the computer program SLIDE2 v.9. The results of <br />Morgenstern-Price and Spencer method of slices were implemented within SLIDE2 to evaluate <br />the factor of safety, confirm convergence within the model, and ensure accuracy of results. <br />Circular and non-circular failure forms were evaluated. Non-circular failure forms were found to <br />produce more conservative results and are presented herein. <br />Minimum acceptable factors of safety for static and pseudostatic conditions are 1.40 and 1.15, <br />respectively. This acceptance criterion meets the requirements of both the Colorado Division of <br />Reclamation Mining and Safety (DRMS) guidelines and the Newmont Tailings and Heap Leach <br />Facility Management Standard and remains consistent with previous evaluations. The model <br />development, material properties, and results of the stability analyses are expanded on in the <br />following sections and presented in Appendix E. <br />5.1.1. Model Development <br />A total of five cross sections were evaluated for the VLF Expansion. The cross sections depict the <br />regions with the greatest elevation difference between the stacked ore and base grade. The <br />specific locations were selected to represent the most critical conditions where the VLF reaches <br />its highest point along both outward and inward facing foundation contours. The stability <br />sections were created by superimposing the as-built liner surfaces, existing VLF surface, and <br />proposed VLF Expansion surfaces. <br />Subsurface conditions beneath the VLF Expansion were discussed in Section 2.5. In general, <br />existing boreholes and test pit logs, geophysical velocity profiles, as well as the geologic model <br />provided by CC&V were used to develop the subsurface stratigraphy. Groundwater under the <br />VLF was not modeled as it is very deep and is not expected to influence the facilities stability. <br />Phreatic conditions within the facility were modeled at approximately 0.5 feet above the LLDPE <br />liner, representing a fully drained VLF with minor accumulation of solution along the base <br />geomembrane.