Mineral Resource Estimate (November 2024)
| Columbia Gold-Silver Project 2024 Mineral Resource Estimate | |||||||
|---|---|---|---|---|---|---|---|
| Classification | Tonnes | Au | Au | Ag | Ag | AuEq | AuEq |
| (Mt) | (g/t) | (koz) | (g/t) | (koz) | (g/t) | (koz) | |
| Inferred | 21.4 | 1.34 | 920 | 4.6 | 3,140 | 1.4 | 960 |
AuEq (g/t) = Au (g/t) + Ag (g/t) × (US$30 ÷ US$2,200) × (77% ÷ 96%). Figures may not sum due to rounding.¹
Mineral Resources and Exploration Results. The information on this website relating to Mineral Resources and Exploration Results for the Columbia Gold-Silver Project and the Big Springs Gold Project is extracted from the ASX announcements “[title]” dated [date] and “[title]” dated [date], available at www.sentinelmetals.com and www.asx.com.au. Sentinel Metals confirms that it is not aware of any new information or data that materially affects the information included in the original market announcements and, in the case of Mineral Resources, that all material assumptions and technical parameters underpinning the estimates continue to apply and have not materially changed. Sentinel Metals confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcements.
Forward-looking statements. This website may contain forward-looking statements that are subject to risks and uncertainties, many of which are outside Sentinel Metals’ control. Actual results may differ materially. Any restart of mining at Big Springs is subject to studies, permitting and funding.
¹Columbia MRE (Prospectus, Oct 2025)
The reported November 2024 Mineral Resource Estimate (MRE) has been constrained within a US$2,200 gold value shell using an AuEq lower cut-off of 0.4865 g/t AuEq. Mineral Resources have been classified as Inferred based on drill spacing and confidence in geological and grade continuity.
- The deposit model comprises 11 subvertical host structures within a 350m wide corridor over a 2km strike zone.
- The host structures extend to nearly 220m vertical depth and have been capped near the surface by a late-stage andesitic unmineralised flow in the Columbia Flat area. For the most part however, there is no overburden.
- Individual structures vary in width from several metres to 60 m. The structures are near vertical and dip slightly west and converge to the north while becoming more divergent in the southern part of the deposit.
Information regarding metal equivalents
- The MRE has been optimised and reported using a gold equivalent value based on the following formula: AuEq (g/t) = Au (g/t) + Ag (g/t) × (US$30 ÷ US$2,200) × (77% ÷ 96%).
- A gold price of US$2,200 and Silver price of US$30 have been assumed for the metal equivalents calculation.
- It is the Company’s opinion that all of the elements included in the metal equivalents calculation have a reasonable potential to be recovered and sold.
- Recoveries of 96% gold and 77% silver have been applied to the metal equivalents calculation. These assumed recoveries have been derived from metallurgical testing conducted by Canyon Resources Corporation in 2006. The study yielded gravity concentration up to 56% gold and 18% silver from the bulk sample. Gravity tail flotation increased gold recovery to 96% gold and 77% silver.
