Mt. Margaret
A road-accessible copper-gold-molybdenum-silver porphyry deposit located in Randle Washington, USA.
Project Overview
Cambria Gold Mines holds mineral interest jointly with the US government in the Mt. Margaret Property.
The Mt. Margaret project is a road-accessible copper-gold-molybdenum-silver porphyry deposit located 22.5 km southwest of Randle Washington in Skamania County. The deposit was discovered by the Duval Corporation in 1969 and was actively explored from 1971-1980. By 1980, a total of 105 diamond drill holes totaling 20,729 meters had been completed. The project was put on hold following the eruption of Mt. St. Helens in 1980.
In 2010 Ascot Resources drilled 4,880 metres over 11 infill holes at the Mt. Margaret project. Drilling was successful in confirming previous copper, gold, molybdenum, and silver results in nearby drilling from Duval, and the deposit was also shown to be open to expansion laterally and at depth.
A historical resource estimate was completed by Duval for the Mt. Margaret deposit, with 577Mt grading 0.36% Cu, 0.24 g/t Au, 0.011% Mo, and 1.58 g/t Ag (Taylor, 1980 & Derkley et al, 1990).1,2 This historic estimation work predates the implementation of National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI-43-101”) guidelines and was not classified based on currently accepted reserve and resource classifications as set forth by the Canadian Institute of Mining and Metallurgy, August 20, 2000 (CIM Guidelines) or the United States Securities and Exchange Commission’s Regulation Subpart 1300 of Regulation S-K (“S-K 1300”).
Cambria cautions it is not treating the historic Duval work as a current mineral resource estimate, and there has been insufficient work completed by a Qualified Person to do so at any point in the project’s history. Furthermore, uncertainty regarding cut off grade, metal prices, modelling methodology, or other parameters and assumptions used in the Duval work could impact the reliability of the historic estimation. Cambria still considers the Duval work relevant given the number of supporting historical drillholes, many of which were confirmed by subsequent Ascot drilling in 2010. Further work including additional infill drilling, geological modelling, and assay certificate and collar validation by a Qualified Person pursuant to NI 43-101 would be required to produce a NI-43-101 or an S-K 1300 compliant resource. There are no guarantees that this additional work would confirm the historical resource estimate defined by Duval.
1 Derkey et al (1990). P. 338. Metal Mines of Washington – Preliminary Report; Open File Report 90-18; https://dnr.wa.gov/sites/default/files/2025-03/ger_ofr90-18_metal_mines_pt2.pdf
2 Taylor, J.D., 1980, Margaret project status report: Duval Corporation report (unpublished). Available in the Washington Department of National Resources Archives
Project Highlights
Red Mountain is a high-grade, bulk-mineable underground gold deposit with a substantial Measured resource, existing underground development, and prior federal and provincial environmental approvals.
With favourable geometry supporting efficient longhole mining and resources open for expansion, it forms the cornerstone of Cambria’s development strategy and the primary focus of near-term advancement.
High-Confidence, High-Grade Resource
Hosts approximately 543,800 ounces of Measured gold grading 8.81 g/t Au, with the Marc Zone averaging approximately 10.5 g/t Au, providing a strong foundation for near-term mine planning.
Favourable Geometry for Bulk Underground Mining
Broad, laterally continuous mineralized zones with an average thickness of ~25 metres, locally exceeding 40 metres, supporting low-risk, bulk underground mining methods.
Advanced Underground Access
Approximately 2,000 metres of production-sized underground development completed, with mineralization accessed within ~200 metres of surface.
Efficient Development Profile
Only approximately 1,600 metres of additional development required to support the first year of stoping, enabling a capital-efficient path to production.
Fully Permitted
Provincial and Federal Environmental Assessment Certificates in place, significantly reducing permitting risk and development uncertainty.
Geological Upside Through Improved Interpretation
Revised geological model, including the identification of high-amplitude folding, enhances understanding of mineral continuity and opens additional exploration potential.
Resources Open for Expansion
Mineralization remains open in multiple directions, with opportunities to expand resources through future drilling once access is established.
Strategic Role in Cambria’s Development Plan
Positioned as the primary source of early mill feed, providing the grade, confidence, and continuity required to support a disciplined restart.
Mineral Resource Estimate
| Classification | Tonnes |
Average Grades Au (g/t) |
Average Grades Ag (g/t) |
Contained Ounces Au |
Contained Ounces Ag |
|---|---|---|---|---|---|
| Measured | 1,920,000 | 8.81 | 28.30 | 544,000 | 1,747,000 |
| Indicated | 1,271,000 | 5.85 | 10.00 | 239,000 | 409,000 |
| Measured + Indicated | 3,191,000 | 7.63 | 24.52 | 783,000 | 2,516,000 |
| Inferred | 405,000 | 5.32 | 7.30 | 69,000 | 96,000 |
- The Red Mountain mineral resource estimate is reported at a 3.0 g/t Au cut-off grade and is summarized below.
- Resource estimates are derived from the NI 43-101 Technical Report with an effective date of August 30, 2019, authored by Gilles Arsenault, P.Geo., a Qualified Person as defined by NI 43-101. Numbers may not sum due to rounding.
- Measured, Indicated, and Inferred resources are presented on a project basis.
- Full details, assumptions, and sensitivities are available in the Company’s technical disclosures.
Development Timeline
A Clear, Three-Year Execution Path
Cambria’s Red Mountain development plan follows a defined critical path designed to unlock the highest-confidence orebody first, align infrastructure, and position the operation for sustainable production.
2026–2027: Red Mountain Access Road (Critical Path)
Unlocks physical access to Cambria’s highest-confidence orebody.
- Initiate construction of the Red Mountain access roadConstruction expected to begin in Q1 2026, with completion targeted for Q3 2027
- Enables ore haulage and underground mining operations
- Physically unlocks Red Mountain, the primary source of early mill feed
2026: Updated Feasibility Study
Validates the revised, Red Mountain–led development strategy.
- Updated feasibility study targeted for completion
in 2026. Reflects:- Red Mountain as the primary feed source
- Revised development sequencing
- Updated operating and capital assumptions
- Accompanied by updated resource and reserve estimates
2026–2027: Mill Care & Maintenance / Optimization
Preserves infrastructure while preparing for restart in 2027/2028.
- Premier mine and mill placed on care and maintenance during Red Mountain development
- Maintain regulatory compliance while reducing operating costs
- Advance engineering and optimization planning aligned with Red Mountain ore characteristics
2026–2027: Long-Lead Equipment Procurement
- Ensures the processing facility is properly configured before restart, reducing execution risk.
- Order long-lead items for mill upgrades, including a fine-grinding (Vertimill) circuit
- Upgrades designed to improve gold recoveries from Red Mountain ore and increase operational flexibility and throughput
2027–2028: Restart Readiness & Commissioning
Transitions the project from development to production readiness.
- Complete access road construction
- Finalize mill upgrades and commissioning plans
- Position operations for restart aligned with Red Mountain ore supply