PMET Resources has increased contained caesium oxide at its Shaakichiuwaanaan project by 55% and added maiden rubidium and CV4 lithium resources. The update is designed to feed an updated feasibility study and broader economic assessment due before year end, but the new resources are not yet reserves.
- Contained caesium oxide rises to 110,600 tonnes
- Maiden rubidium resources added within the Caesium Zone
- Consolidated lithium resource reaches 113.9Mt Indicated and 33.8Mt Inferred
- CV4 adds 1.75Mt of Inferred lithium resources
- Updated feasibility study and broader PEA due before year end
Caesium Resource Expands at CV13
PMET Resources Inc. (ASX:PMT) has made its already outsized caesium inventory larger, higher-grade and more strategically interesting. The company’s updated resource estimate for the Shaakichiuwaanaan property in Quebec lifts contained caesium oxide in the Caesium Zone by 55% to 110,600 tonnes, across 1.844 million tonnes at 4.40% Cs2O in the Indicated category and 981,000 tonnes at 3.00% Cs2O in Inferred.
The estimate covers the Rigel, Vega and newly included Helios zones, all hosted within the CV13 pegmatite. PMET says the resource remains the world’s largest pollucite-hosted caesium pegmatite resource. It has also declared maiden rubidium resources within the same zone, grading 0.46% Rb2O Indicated and 0.37% Rb2O Inferred, although no rubidium tonnage has been separately reported.
The result lands as PMET builds out the infrastructure and development case around Shaakichiuwaanaan. The project’s access story recently gained C$1.215 million road funding, with the federal contribution earmarked for upgrades to about 20 kilometres of road. That funding does not represent mine approval or a construction decision, but the property’s all-season access and proximity to power infrastructure remain part of the project’s stated development advantages.
Lithium and Tantalum Base Continues to Grow
The broader consolidated estimate, covering CV5, CV13 and CV4, now contains 113.9 million tonnes at 1.43% Li2O and 164 parts per million Ta2O5 in Indicated resources, equivalent to 4.03 million tonnes of lithium carbonate equivalent and 18.7 kilotonnes of contained Ta2O5. The Inferred category adds 33.8 million tonnes at 1.24% Li2O and 150 parts per million Ta2O5, or 1.03 million tonnes of LCE and 5.1 kilotonnes of Ta2O5.
Relative to the previous consolidated estimate, PMET reports a 4% increase in tonnage, a 0.2% increase in lithium grade and a 5% increase in contained LCE. The update also introduces 1.75 million tonnes at 1.24% Li2O as a maiden Inferred resource at CV4, roughly 1.5 kilometres east of CV5. The company interprets the gap between the two pegmatites as a potential extension, though that corridor still requires drilling.
PMET highlighted the resource’s high-grade subsets rather than relying only on the headline tonnage. At a 1.5% Li2O cut-off, the estimate outlines 36.5 million tonnes at 2.04% Li2O Indicated and 4.1 million tonnes at 2.01% Li2O Inferred, alongside a smaller, higher-grade set of 5.9 million tonnes at 2.77% Li2O Indicated and 4.2 million tonnes at 2.24% Li2O Inferred. A single principal dyke at CV5 accounts for 87.4 million tonnes of Indicated and 2.2 million tonnes of Inferred resources, a geometry the company says could limit external dilution and simplify mining.
Economic Studies Must Convert Optionality
The next test is less geological than commercial. PMET intends to use the estimate to underpin an updated CV5 lithium-tantalum Feasibility Study and a Preliminary Economic Assessment covering lithium, caesium and tantalum across CV5 and CV13, both scheduled before the end of 2026. Caesium processing has already produced a 97% caesium extraction result, while a separate bench-scale program has examined pathways to high-purity caesium chemicals.
Those results provide technical support, not a completed business case. The company describes caesium and rubidium markets as small, opaque and dominated by private bilateral or term contracts. The resource estimate also uses conceptual mining shapes and a 0.50% Cs2O reporting constraint, while Mineral Resources are not Mineral Reserves and have not demonstrated economic viability. No new drilling results were reported in this announcement; the estimate is based on drilling completed through 2025.
PMET says drilling completed during 2026 will feed a future resource update expected in 2027, with further work also planned between CV5 and CV4. The immediate valuation question is therefore whether the year-end studies can attach credible recovery, pricing, mining and processing assumptions to the newly enlarged critical-minerals inventory. Until then, Shaakichiuwaanaan has more geological scale than economic definition.
Bottom Line?
The resource growth is substantial, but the year-end studies must show whether caesium and rubidium can become saleable credits rather than simply impressive additions to the geology.
Questions in the middle?
- What recovery rates, product specifications and pricing assumptions will the broader PEA assign to caesium and rubidium?
- How much of the enlarged lithium-tantalum resource can ultimately convert from Indicated or Inferred material into reserves?
- Will further drilling between CV5 and CV4 confirm the interpreted pegmatite connection and support additional resource growth?