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Analytics,Inc. <br /> Engineering <br /> 1600 Specht Point Rd. Suite 209 Fort Collins,CO 80525 970.488.3111 www.EngAnalytics.com <br /> October 8, 2025 Project No. 2101.05.15 <br /> Mr. David Carino <br /> Battle Mountain Resources, Inc. t. <br /> P.O. Box 310 `"' ND <br /> San Luis, CO 81152-0310 OC1 L 2025 <br /> RE: San Luis Tailings Dam i.t �;;ilikl .��.rT` <br /> 2025 Annual Dam Safety Inspection Report <br /> CDRMS Permit No. M-1988-112 <br /> Dear Mr. Carino, <br /> Engineering Analytics, Inc. (EA)has conducted the 2025 annual dam safety inspection for the San <br /> Luis Tailings Dam. The inspection was conducted on July 21st by the Engineer of Record for the <br /> facility, Mark S. Abshire, P.E. Also present were Jonathan Gillen, PE (Newmont), yourself and <br /> Julio Madrid (BMRI), and Phillip Crouse, PE (Stantec). <br /> EA's inspection included review of the 2024 TSF inspection report. An overall site plan of the San <br /> Luis TSF and findings of the 2025 inspection are presented on Figures 1 and 2, respectively. <br /> Figures 3 to 8 present piezometer levels and underdrain flow measurements. Specific inspection <br /> results are detailed on the Tailing Dam Inspection Form (Attachment 1), which includes <br /> photographs taken during the inspection. <br /> PREVIOUS FINDINGS <br /> The primary issues identified in the 2024 annual inspection included surface erosion along the <br /> south side of the South Diversion Channel Drop Structure, and a blocked culvert at the lower end <br /> of the HDPE-lined channel at the downstream toe just south of the outlet pipes. <br /> INSTRUMENTATION <br /> Piezometers: It was discovered while evaluating the depth of water above the HDPE liner that <br /> the labeling of standpipe piezometers P6 through P15 was reversed from the labels SRK <br /> established after these piezometers were installed in 1993,as first presented in SRK's(1995)Phase <br /> 2, Raise 1 design report. According to EA's records, the first readings of piezometers P6 through <br /> P10 reported to DRMS were on May 5, 1995; the total piezometer depths for BMRI's readings <br /> match those of SRK's piezometers P6 through P10 in reverse order, and have been consistently <br /> measured and reported this way to the present. The piezometric levels presented on Figure 3 have <br /> been adjusted to reflect that actual as-constructed piezometer numbering.EA will work with BMRI <br /> to correct the order of the piezometers to reflect the as-built numbering. <br /> Standpipe piezometer readings from January 2010 to May 2025 are presented graphically on <br /> Figures 3 and 4,and piezometric levels from the eight vibrating wire piezometers(VWPs)installed <br /> in 2024 are presented on Figures 5 through 7. Readings for standpipe piezometers P6, P7, and P9 <br />