Phase 2 bench-scale testwork program demonstrates a compelling opportunity for a more simplified and selective processing pathway to produce a variety of high purity caesium based chemical products from Shaakichiuwaanaan'spollucite concentrate.

MONTREAL, Sept. 22, 2026 /PRNewswire/ -- September 23, 2026 – Sydney, Australia

The Company continues to work with Koch Technology Solutions ("KTS"), part of Koch Inc., in evaluating downstream processing pathways to produce value-added caesium chemical products.

The results of the recent Phase 2 testwork program have successfully demonstrated a pathway for the production of multiple caesium products.

KTS's proprietary technology could significantly simplify and lower the costs of producing a wide variety of high-purity caesium products from pollucite.

Follow-up testwork program is now being designed and is anticipated to be expanded to include a complete bench-scale proof-of-concept with production of marketable samples.

Pollucite concentrate generated from the ongoing BerryPick Program will underpin the next phase of the testwork with KTS (see press release, September 8, 2026).

The Company continues to advance discussions with strategic caesium players downstream, including deepening its existing relationship with KTS, for future chemical processing opportunities.

Caesium and tantalum are anticipated co-products at Shaakichiuwaanaan, with the potential for future revenue to be credited against the cost of lithium production. A Preliminary Economic Assessment, targeted for Q4 2026, will provide the first economic evaluation of the caesium credit.

PMET Resources Inc. (the "Company" or "PMET") (TSX: PMET) (ASX: PMT) (OTCQX: PMETF) (FSE: R9GA) is pleased to report results from its Phase 2 bench-scale caesium testwork program completed by Koch Technology Solutions ("KTS"), part of Koch Inc., on pollucite concentrate from its Shaakichiuwaanaan Project, host to the world's largest pollucite-hosted caesium pegmatite Mineral Resource and one of the world's largest lithium pegmatite Mineral Reserves1.

The Company continues to evaluate downstream opportunities beyond pollucite concentrate production at site to potential "value-added" caesium chemicals, produced with strategic partners with chemical expertise to maximize value from its globally significant caesium resource. The KTS proprietary process offers an attractive and compelling process route for caesium extraction from pollucite concentrate into marketable chemical products, potentially capturing more economic value from the caesium resource. This program further develops the potential process pathway.

Koch Technology Solutions Caesium Extraction Testwork Program

The program was carried out under a testwork arrangement with KTS, announced on April 15, 2026. KTS, part of Koch Inc., one of the largest privately held companies in the world, develops, commercializes, and licenses critical minerals extraction technologies. The arrangement with KTS allows the Company's testwork program to leverage demonstrated capabilities in engineering, development, and commercialization of critical minerals extraction technologies.

Following completion of Phase 1 (see news release dated July 12, 2026), the Phase 2 bench-scale program advanced by KTS was designed to assess the application of their proprietary flowsheet technology that uses highly selective media. The approach targets simplification of the existing, more conventional caesium recovery methodology by significantly increasing selectivity for caesium, which would allow for much of the impurity removal stage(s) to be bypassed. In contrast, existing approaches require additional stages to obtain the desired caesium product purity. If successful, the approach using KTS's proprietary flowsheet offers an opportunity to significantly lower the cost of recovery into a final high-purity caesium product.

Theresults of the recent bench-scale testwork have successfully established the potential for a wide variety of caesium end-products to be produced by the KTS process, demonstrating high selectivity for caesium and a much-reduced impurity profile. Further work is required to validate the process through to marketable samples; however, the confirmation of high selectivity for caesium using Shaakichiuwaanaan pollucite concentrate, is a significant milestone.

The pollucite concentrate (~6 kg) used as feed for the KTS caesium extraction testwork program 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 (Figure 1)

Next Steps

A follow-up testwork program is now being designed and is anticipated to comprise a complete bench-scale proof-of-concept for the processing of pollucite concentrate from Shaakichiuwaanaan through to gram quantities of marketable caesium products (e.g., caesium formate, caesium carbonate), as well as an initial assessment of OPEX-CAPEX. This program will utilize a larger quantity of concentrate, which is currently targeted to be produced from the ongoing BerryPick Program (see news release dated September 8, 2026).

The pollucite sample collection methodology undertaken in the BerryPick program is designed to produce >500 kg to potentially >1 tonne of pollucite concentrate to support ongoing development and downstream caesium chemical testwork initiatives. This includes future chemical testwork programs with Koch Technology Solutions, as well as with others as the Company furthers its engagement with strategic partners in the caesium industry downstream (see news release dated April 15, 2026).

In addition to being one of the largest lithium-tantalum pegmatite Mineral Resources2 and lithium pegmatite Mineral Reserves3 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.

About Caesium

Mineral deposits of pollucite-hosted caesium are very rare globally and represent the most fractionated component of LCT pegmatite systems, which are effectively the only known primary economic source of caesium supply. Economic deposits of caesium pegmatite are typically on a smaller scale of 10 kt to 350 kt in size compared to deposits of lithium pegmatite that typically range in the millions of tonnes in size (10 Mt to over 100 Mt).

The market for caesium compounds and metals is niche and largely opaque because it is not publicly traded like copper or gold, but rather through private bi-lateral and term contracts. Further, product prices vary depending on their contained caesium form, purity, and end-product use. As an example, caesium carbonate (Cs2CO3≥99%) as an indicative spot price currently trades at around US$250/kg (excluding VAT, Price Sourcing – Shanghai Metal Markets (SMM)4

Caesium is currently supply constrained, with only limited sources supplying the global market. A discovery at the size, grade, and scale of Shaakichiuwaanaan has the potential to be a primary source of supply for global markets over the long-term. This includes existing applications for caesium in oil/gas drilling, medical imaging, emissions reduction, atomic clocks and precision GPS navigation, as well as new and potentially growing applications in the terrestrial solar panel industry. Caesium has been found to play a vital role in significantly improving next generation solar panel efficiency, stability, and life span. Additionally, the use of caesium in lithium-ion batteries to improve performance is actively being explored through use as an additive in certain cathode, anode, and electrolyte chemistries.

About Koch Technology Solutions.

Koch Technology Solutions (KTS) is a global leader in technology development, commercialization and licensing. KTS works with owners, developers, and investors in the process, manufacturing and critical minerals sectors to solve complex technical and investment challenges before large capital is committed, helping clients make confident decisions from early concept through EPC-ready design. With a global network and rich history of domain experience and expertise, KTS gains additional strength from its position within Koch Engineered Solutions (KES). This backing enhances our ability to partner with companies developing chemical process technologies, create attractive licensing solutions for commercial deployment, and bring the next generation of technologies to the market.

For further information, please contact us at [email protected] or by calling +1 (604) 279-8709, or visit www.pmet.ca. Please also refer to the Company's continuous disclosure filings, available under its profile at www.sedarplus.ca and www.asx.com.au, for available exploration data.

Qualified/Competent Person

The technical and scientific information in this news release that relates to the Mineral Resource Estimate, exploration, and metallurgical results for the Company's properties is based on, and fairly represents, information compiled by Mr. Darren L. Smith, M.Sc., P.Geo., who is a Qualified Person as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects ("NI 43-101"), and member in good standing with the Ordre des Géologues du Québec (Geologist Permit number 01968), and with the Association of Professional Engineers and Geoscientists of Alberta (member number 87868). Mr. Smith has reviewed and approved the related technical information in this news release.

Mr. Smith is an Executive and Vice President of Exploration for PMET Resources Inc.