News | July 12, 2026

PMET Demonstrates >97% Caesium Extraction From Pollucite Concentrate

Multiple pathways to value-add caesium chemicals identified during bench-scale extraction testwork at SGS Lakefield and through Koch Technology Solutions Phase 1 program

Highlights
SGS Canada Caesium Extraction Test Program

  • Leaching of pollucite concentrate using sulphuric acid was highly successful with >97% recovery of the caesium (Cs) into solution achieved.
  • Bench-scale testwork on impurity removal was also successful, demonstrating efficient removal of key impurities such as aluminum.
  • Opportunity identified to potentially recover a rubidium by-product.
  • Primary objective of program was fully realized – that being to identify a preliminary set of conditions to extract caesium from pollucite concentrate (produced from the Vega Zone) at high recovery while characterizing (and limiting) the impurity profile.
  • Next steps will build upon this extraction phase of work with a primary objective to produce gram quantities of high-purity Cs-sulphate, Cs-carbonate, Cs-formate, and potentially Rb-carbonate.

Koch Technology Solutions Caesium Extraction Test Program

  • PMET is working with Koch Technology Solutions, part of Koch Inc., evaluating advanced processing pathways to value-added caesium products.
  • Preliminary results from Phase 1 indicate both synthetic and live Pregnant Leaching Solution yield very selective high loading factors of caesium recovery using Koch's proprietary flow sheet.

PMET Resources Inc. (the "Company" or "PMET") is pleased to provide an update on two parallel bench-scale testwork programs focused on caesium (Cs) extraction from pollucite samples from the Shaakichiuwaanaan Project. Both approaches – conventional by SGS Canada, and proprietary by Koch Technology Solutions – offer attractive process routes for caesium extraction from pollucite concentrate into marketable chemical products. The Company is motivated to consider caesium value-added chemical production (with key partners) to unlock maximum value from its globally significant caesium resource and its pollucite concentrates produced at site.

In addition to being one of the largest lithium-tantalum pegmatite Mineral Resources[1] and lithium pegmatite Mineral Reserves[2] globally, the Property also hosts the world's largest in-situ pollucite-hosted caesium pegmatite Mineral Resource, comprising 0.69 Mt at 4.40% Cs2O (Indicated) and 1.70 Mt at 2.40% Cs2O (Inferred). The CV13 Pegmatite, host to the caesium Mineral Resource, is located <3 km along trend from the CV5 Pegmatite, which is situated approximately 13 km south of the regional Trans-Taiga Road and powerline infrastructure corridor, and is accessible year-round by road.

The pollucite concentrate used as feed for both extraction testwork programs was produced by X-Ray Transmission (XRT) ore sorting of drill core material from the Vega Caesium Zone at the CV13 Pegmatite (see news release dated October 9, 2025) and assayed 12% Cs2O.

SGS Canada Caesium Extraction Testwork Program
At SGS Lakefield, a conventual process approach for caesium extraction from pollucite concentrate is being advanced using sulphuric acid digestion (H2SO4) and subsequent impurity removal. The primary objective of this initial bench-scale test program is to identify a preliminary set of conditions to extract caesium at high recovery while characterizing (and limiting) the impurity profile.

The pollucite concentrate sample (~15 kg) was ground to varying sizes (P80 of 75 µm to 212 µm) and a portion (<4 kg) subjected to sulphuric acid (H2SO4) leaching at varying temperatures (up to 120°C). The program was highly successful with the testwork achieving consistently high extractions of 97-98% Cs while maintaining significantly lower extractions of key impurities (e.g., Al). Further, subsequent impurity tests successfully removed the remaining aluminum (Al) and a majority of the sulphur (S) with negligible caesium (Cs) losses.

Additionally, the program also identified a potential opportunity to recover a rubidium by-product from one of the waste streams. Further characterization of this opportunity was not undertaken during this initial bench-scale caesium extraction test phase and will be investigated as a secondary objective in future work.

The testwork was completed at SGS Canada's Lakefield, Ontario, facility with support from Primero Group Americas and a Company-retained Subject Matter Expert ("SME") specializing in caesium extraction and recovery from pollucite. These three parties, in addition to TOMRA Mining, are also key contributors to the design and execution of the Company's ore sorting programs.

Next steps will build upon this bench-scale testwork with a primary "proof-of-concept" objective to produce gram quantity samples of high-purity Cs-sulphate, Cs-carbonate, Cs-formate, and potentially Rb-carbonate. This test program is currently underway at SGS Canada's facility in Lakefield, Ontario, with results expected circa Q4 2026.

Koch Technology Solutions Caesium Extraction Testwork Program
The testwork program with Koch Technology Solutions ("KTS") has been developed as part of a strategic relationship that has evolved following the Company's investigations of the caesium industry, commercial engagement, and research. The program will leverage KTS's demonstrated capabilities in engineering, development and commercialization of critical minerals extraction technologies to produce a range of value-added caesium chemical compounds.

The bench-scale test program being advanced by KTS is designed to assess the application of their proprietary flowsheet technology, to produce a range of value-added caesium chemical compounds. Approximately 6 kg of pollucite concentrate is being used to support the testwork.

Preliminary results from Phase 1 of the program indicate a strong and selective caesium recovery. The testwork will now move onto Phase 2 and the Company anticipates expanding the mandate to produce gram quantities of caesium derivative products as a complete bench-scale proof-of-concept.

Study Work Underway
A Preliminary Economic Assessment ("PEA") for the broader Project, incorporating lithium, caesium, and tantalum, is scheduled for completion in Q4 2026. The PEA will complement the Feasibility Study for the CV5 Pegmatite (lithium and tantalum), which is also scheduled for completion in Q4 2026, and will provide the first economic assessment of the Project's caesium potential.

1 Consolidated MRE (CV5 + CV13 pegmatites) totals 108.0 Mt at 1.40% Li2O and 166 ppm Ta2O5 (Indicated), and 33.4 Mt at 1.33% Li2O and 155 ppm Ta2O5 (Inferred), at an Li2O cut-off grade of 0.40% (open-pit), 0.60% (underground CV5), and 0.70% (underground CV13). A grade constraint of 0.50% Cs2O was used to model the Rigel and Vega caesium zones, contained entirely within CV13, with a MRE of 0.69 Mt at 4.40% Cs2O (Indicated), and 1.70 Mt at 2.40% Cs2O (Inferred). The Effective Date is June 20, 2025. Mineral Resources are not Mineral Reserves as they do not have demonstrated economic viability. Mineral Resources are inclusive of Mineral Reserves.

2 Probable Mineral Reserve of 84.3 Mt at 1.26% Li2O at the CV5 Pegmatite with a cut-off grade is 0.40% Li2O (open-pit) and 0.70% Li2O (underground). Underground development and open-pit marginal tonnage containing material above 0.37% Li2O are also included in the statement. The Effective Date is September 11, 2025. See Feasibility Study news release dated October 20, 2025.

Source: PMET Resources Inc.