PMET Resources Lifts Contained Caesium 55% at Quebec Project

PMET Resources (PMET.TO ) announced its fifth consolidated mineral resource estimate for the wholly owned Shaakichiuwaanaan project in Quebec’s Eeyou Istchee James Bay region on November 3, 2026, reporting a 55% increase in contained caesium. The update adds the newly estimated Helios zone to Vega and Rigel, declares maiden rubidium resources and gives CV4 its first resource estimate.

The CV13 Caesium Zone now contains 1.844 million tonnes at 4.40% caesium oxide (Cs2O) in the Indicated category and 981,000 tonnes at 3.00% Cs2O Inferred. Those categories contain 81,200 tonnes and 29,400 tonnes of Cs2O, respectively. Total contained Cs2O rises from 71,000 tonnes to 110,600 tonnes, while grade increases 31% and tonnage 18% from the preceding estimate. PMET ranks the deposit as the world’s largest pollucite-hosted caesium pegmatite mineral resource, based on other issuers’ public disclosures through October 23, 2026.

Alongside the caesium increase, the update adds rubidium to the resource base. Maiden grades within the Caesium Zone are 0.46% rubidium oxide (Rb2O) Indicated and 0.37% Rb2O Inferred. Pollucite, the primary caesium host at Shaakichiuwaanaan, is the target recovery mineral for both elements.

Lithium Growth Is More Modest

Across CV5, CV13 and CV4, Indicated resources total 113.9 million tonnes at 1.43% lithium oxide (Li2O) and 164 parts per million tantalum pentoxide (Ta2O5), containing 4.03 million tonnes of lithium carbonate equivalent. Inferred resources total 33.8 million tonnes at 1.24% Li2O and 150 ppm Ta2O5, containing 1.03 million tonnes of lithium carbonate equivalent.

Contained lithium carbonate equivalent increases 5% from the previous consolidated estimate, effective June 20, 2025, reflecting 4% higher tonnage and a 0.2% grade improvement. CV4 contributes a maiden 1.75 million tonnes at 1.24% Li2O, all Inferred. PMET interprets CV4, approximately 1.5 kilometres east of CV5, as a potential extension of the principal CV5 dyke, but the corridor between them remains untested by drilling.

At CV5, a single principal dyke contains 87.4 million tonnes Indicated and 2.2 million tonnes Inferred. It extends nearly 5 kilometres and reaches true widths of up to about 125 metres. PMET expects that geometry to limit external dilution and simplify mining.

Resource Basis and Economic Limits

MRE-5 has an effective date of July 10, 2026 and draws on 857 diamond drill holes totaling 263,424 metres completed through 2025, plus 614 metres of outcrop channels. The Caesium Zone work includes 64 holes totaling 13,940 metres completed across the 2022–2025 programs. Todd McCracken of BBA Consultants is the independent Qualified Person and Competent Person for the estimate, prepared under NI 43-101, CIM Definition Standards and the JORC Code.

For the consolidated estimate, cut-off grades and mining shapes are based on Li2O alone; other elements are non-paid in those assumptions and reported for reference. The Caesium Zone is reported at a 0.50% Cs2O cut-off within CV13’s conceptual open-pit shape. The conceptual mining constraints assume a US$1,500-per-tonne price for 6% spodumene concentrate FOB Bécancour and approximately 70% average recovery into a 5.5% Li2O concentrate. These are estimation inputs, not achieved commercial results. Mineral Resources are not Mineral Reserves and lack demonstrated economic viability; the estimate also contains no Measured-category blocks.

PMET describes caesium formate as a premium high-density drilling fluid used in high-pressure, high-temperature oil and gas wells, with historically limited and concentrated supply constraining broader adoption. The market is niche and opaque, with sales through private bilateral and term contracts rather than public trading. Any potential for Shaakichiuwaanaan to diversify supply remains subject to further market analysis and assessment.

Economic Studies Are the Next Test

The update does not materially change the current mineral reserve or the existing economic conclusions for lithium-only development at CV5. MRE-5 is instead intended to underpin an updated feasibility study for lithium and tantalum at CV5 and a preliminary economic assessment covering lithium, caesium and tantalum across CV5 and CV13. Both are scheduled for announcement before the end of 2026, and the assessment is expected to provide the project’s first preliminary economic evaluation of caesium. Drilling completed during 2026 will be held for a future resource update anticipated in 2027.

The announcement therefore expands the inventory without yet establishing a caesium business case. CV5’s lithium-only case already has a reserve and economic conclusions; caesium has a larger, higher-grade resource but no demonstrated economic viability. The forthcoming assessment is the next material test of whether that resource can support a saleable product alongside lithium and tantalum.