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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 5 <br />Table 2.1-: Seismic Design Criteria <br />Return Period PGA (g) <br />2,475-Year 0.13 <br /> <br />2.5. Subsurface Conditions <br />Generally, the site of the VLF Expansion is in an area of relatively shallow bedrock with a thin <br />veneer of colluvial soils. Existing topsoil and ore stockpiles are the only areas within the footprint <br />that have a relatively thick package of soils over bedrock. Generally, colluvial soils consist of sands <br />and gravels formed by slope wash of weathered in place bedrock. The geotechnical <br />characterization program that was used to refine the geologic model provided by CC&V for <br />subsurface conditions is described in Section 3. <br />3. GEOTECHNICAL CHARACTERIZATION <br />Geotechnical investigations were completed during the design and development of the VLF <br />Expansions, as shown on Drawing A007. A summary of the investigations is described in the <br />following sections. <br />3.1. VLF2 Phase 3 Expansion Site Investigation (NewFields, 2020) <br />Six boreholes in the proposed footprint of the VLF2 Phase 3 Expansion were completed. The <br />boreholes were drilled using a CME 550X ATV mounted drill equipped with 5.5-inch (outer <br />diameter) ODEX down-hole air hammer. <br />Based on conditions encountered in the boreholes, the general subsurface profile consists of 26 <br />to 62 feet of gravel and sands over phonolite bedrock. Bedrock was encountered in borings BH- <br />03 and BH-05 at 45 and 30 feet, respectively. Groundwater was encountered in boring BH-05 at <br />a depth of 35 feet. <br />3.2. Valley Leach Facility Expansion Test Pit Program (Newmont, 2023) <br />Test pits were excavated within the VLF Expansion footprint to characterize near surface soil <br />conditions. Excavations were completed with a John Deere 210G hydraulic excavator operated <br />by Conley Construction to depths between 2.5 and 13 feet below ground surface (bgs). The <br />excavation depth was limited by the machine reach and refusal on boulders and bedrock. <br />Descriptions of materials encountered, and excavation depths were recorded in the field. Large, <br />disturbed samples of soil and rock were obtained for laboratory testing. After completion, test <br />pits were backfilled with excavated materials and recompacted to the original ground surface <br />elevation. Test pit logs are presented in Appendix A.