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<br /> <br />www.NewFields.com 9540 Maroon Cir, Suite 300, Englewood, CO 80112 T. 720.508.3300 <br /> <br />Date: 05/07/2025 NewFields Project 475.0106.071 <br /> <br /> <br />Cripple Creek & Victor Gold Mining Company <br />100 N. 3rd St. <br />Victor, CO 80860 <br /> <br /> <br />Attention: Kristyn Suto <br /> Interim Projects Manager <br />CC&V <br /> <br /> Johnna Gonzalez <br /> Environmental Superintendent <br /> CC&V <br /> <br />RE: Drain Cover Fill with Lime Addition Physical Properties <br /> <br />Dear Kristyn, <br /> <br />Cripple Creek and Victor Gold Mining Company (CC&V) requested NewFields review physical <br />property risks for potential lime addition to Drain Cover Fill (DCF) material to be placed during <br />the construction of Valley Leach Facility 2 Phase 3 Stage B (VLF2 3B). CC&V is proposing using <br />fresh crushed ore, with lime added before placement. CC&V utilizes lime to balance the pH <br />levels of the process solution within VLF2. <br />CC&V utilizes pebble lime (quick lime) provided by Lhoist for the lime addition onsite to crushed <br />ore and ROM at a maximum application rate of 15 pounds per 2000 pounds of crushed ore. <br />Considering the DCF ore specification states the percentage passing by dry weight on the No. <br />200 Sieve shall be between 0-8%, the addition of 0.75% of fines is negligible to a 2000-pound <br />sample. In previous testing, the lime partially to mostly washes out of the sample during <br />testing over the #200 sieve (0.075 microns). Additionally, lime is also utilized in other soils <br />applications to decrease the plasticity of soils providing additional benefit to the DCF. <br />Prior to the placement of any DCF material, with or without lime, NewFields will complete a <br />Particle Size Distribution (PSD) testing (ASTM D6913) to verify the proposed material is within <br />the technical specifications. In the event the addition of lime has pushed the DCF outside the <br />approved specifications, additional testing, such as Rigid Wall Permeability USBR5600, will be <br />conducted to verify the high permeability and suitability of the material placed as DCF. A <br />project deviation letter and the additional testing results will be provided as part of the Record <br />of Construction report provided by the Engineer of Record. <br />