Green Technology Metals Announces Large, High-Grade Rubidium Resource at Seymour Project, Ontario

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TORONTO and PERTH, Australia, July 24, 2025 (GLOBE NEWSWIRE) -- Green Technology Metals Ltd (ASX: GT1) ("GT1” or "the Company”), a Canadian-focused multi-asset lithium business, is pleased to announce a significant milestone at its Seymour Project in Ontario, Canada, with the release of a maiden Rubidium Mineral Resource.

Hosted within the same pegmatite system as the company’s lithium resource at North Aubry, this Rubidium discovery has the potential to convert material previously considered waste into a valuable by-product stream. Recognised as a critical mineral by both the United States and Japan, Rubidium plays a key role in advanced electronics, aerospace, quantum computing, and defence applications.

GT1’s vertically integrated strategy now offers exposure to multiple high-value markets through this exciting new resource.

Maiden Rubidium Mineral Resource Estimate - Seymour Project

8.3 million tonnes @ 0.27% Rb₂O, for ~23,000 tonnes of contained Rb₂O Includes high-grade component of 3.4 million tonnes @ 0.40% Rb₂O, for ~13,600 tonnes of contained Rb₂O Hosted within the existing 2023 North Aubry Lithium Resource (6.2 Mt Indicated, 2.1 Mt Inferred)

Strategic and Market Context

Rubidium is a high-value critical mineral, trading at approximately USD $1,060 per kilogram for high-purity material. Globally recognized as essential to defence, aerospace, quantum computing, and advanced electronics, Rubidium is included on critical minerals lists in the United States and Japan.

Historic metallurgical test work confirmed Rubidium grades of up to 1.3% Rb in mica-rich waste streams at Seymour. This mica, already removed as part of GT1’s lithium processing flowsheet, presents a compelling low-cost by-product opportunity.

GT1 is among the few companies globally to actively explore the recovery of Rubidium from lithium operations. This aligns with the Company’s strategy to maximise resource value and support a sustainable, diversified critical minerals supply chain.

Managing Director Cameron Henry commented:

"The discovery of significant Rubidium mineralisation at Seymour adds an exciting new dimension to our project’s strategic value. As one of the largest high-grade Rubidium resources on the ASX and the most substantial in Canada, Seymour is well positioned to play a critical role in the global supply of this high-value specialty metal. Rubidium’s importance in advanced technologies and its recognition as a critical mineral by the US and Japan highlight the growing demand and strategic relevance of this metal.

By investigating Rubidium products as a low-cost by-product alongside our core lithium operations, we can unlock additional value, enhance project sustainability, and provide diversified exposure for investors. We look forward to progressing targeted test work to better understand Rubidium’s recovery potential and to further integrate this opportunity within our broader strategy and government engagement initiatives.”

To view the full announcement: https://wcsecure.weblink.com.au/pdf/GT1/02970492.pdf

KEY CONTACTS

For further information please visit www.greentm.com.au or contact

Investors

Cameron Henry

Managing Director

[email protected]

+61 8 6557 6825Media

Jacinta Martino

Investor Relations Manager

[email protected]

+61 8 6557 6825