Guardian Metal Resources PLC Announces Board Changes

Rhea-AI Summary

Guardian Metal Resources (OTCQB:GMTLF / LON:GMET) announced on November 3, 2025 that Michael X. Schlumpberger, PE MBA will be appointed as a Non-Executive Director, subject to completion of the required AIM due diligence process.

Michael brings almost 40 years of mining experience, including 20 years at PotashCorp and a tenure as CEO of American Pacific Borates where he helped grow market cap from AUS$20M to AUS$900M. He replaces Mick Billing, who will retire after a four-year tenure. The board says Michael's operational and ESG experience will support advancement of the Pilot Mountain and Tempiute tungsten projects. A further announcement with regulatory disclosures will follow.

Positive

• Appointed Michael X. Schlumpberger as Non-Executive Director (Nov 3, 2025)
• Director's track record: grew American Pacific Borates market cap from AUS$20M to AUS$900M
• Board guidance: support for advancing Pilot Mountain and Tempiute toward development

Negative

• Appointment is conditional on completing AIM due diligence
• New director is non-executive—no immediate operational authority
• Outgoing director retires, creating a board transition during project advancement

Mr. Michael X. Schlumpberger appointment to the Board

LONDON, GB / ACCESS Newswire / November 3, 2025 / Guardian Metal Resources plc (LON:GMET)(OTCQB:GMTLF), a strategic mineral exploration and development company focused on tungsten in Nevada, U.S., is pleased to announce that Mr. Michael X. Schlumpberger, PE MBA, is to be appointed to the Board as a Non-Executive Director, subject to completion of the required AIM due diligence process.

Michael's extensive operational and executive experience in the critical minerals space is uniquely suited to Guardian Metal as it progresses its co-flagship projects to help reshore U.S. tungsten production. During Michael's 20 years at PotashCorp, the world's largest potash producer prior to its merger to form Nutrien, he held a myriad of senior operational roles, refining his skillset in mine development and maintenance, downstream operations, and ESG compliance. Since then, he has gone on to hold a series of operational and executive positions, including most recently Managing Director and Chief Executive Officer at ASX-listed American Pacific Borates Ltd, where, during his tenure, he grew the company from a market cap of AUS$20M to over AUS$900M. Michael currently acts as non-executive director for Rapid Critical Metals, a critical mineral exploration company focused on Australia and North America, and as the President of mining and management consultancy Schlumpberger Inc.. Michael is an American citizen based in New Mexico, U.S.

Michael is replacing Mr. Mick Billing, who will step down from his role as Non-Executive Director upon Michael's appointment to the Board. Mick is retiring following a four year tenure with Guardian Metal. The Board sincerely thanks Mick for his significant contribution to the Company and wishes him the best for his retirement.

J.T. Starzecki, Executive Chairman of Guardian Metal, commented:

"It brings me great pleasure to welcome Michael to the Board. Michael's record of achievements in his almost 40 years in the industry speaks to his distinguished skillset in mining operations, development and management, and will be particularly well-suited to guide Guardian Metal as it advances Pilot Mountain and Tempiute through to development, to ultimately become the cornerstone of U.S. tungsten supply. I look forward to working closely with him as we transform Guardian Metal into the leading producer of American-made tungsten.

"On behalf of the Board, I would like to sincerely thank Mick for his commitment and service to Guardian Metal, during which the Company established itself as a critical component in U.S. efforts to strengthen defence supply chain resilience. He has been instrumental in the rapid advancement of the Company's offering and focus to date, and we wish him all the best for his retirement."

A further announcement, including regulatory disclosures, will be made in due course.

For further information visit www.guardianmetalresources.com or contact the following:

Guardian Metal Resources plc Oliver Friesen (CEO)	Tel: +44 (0) 20 7583 8304
Cairn Financial Advisers LLP (Nominated Adviser) Sandy Jamieson/Jo Turner/Louise O'Driscoll	Tel: +44 (0) 20 7213 0880
Tamesis Partners LLP (Lead Broker) Charlie Bendon/ Richard Greenfield	Tel: +44 (0) 20 3882 2868
Tavistock (Financial PR) Emily Moss/Josephine Clerkin	Tel: +44 (0) 7920 3150/ +44 (0) 7788 554035 guardianmetal@tavistock.co.uk

About Guardian Metal Resources

Guardian Metal Resources PLC (LON: GMET, OTCQX: GMTLF) is a strategic mineral exploration and development company driving the revival of U.S. tungsten production and strengthening America's independence in defense metals. The Company is advancing two co-flagship tungsten projects, Pilot Mountain, one of the largest undeveloped tungsten deposits in the U.S. and Tempiute, formerly America's largest producing tungsten operation, both located in Nevada, one of the top-rated mining jurisdictions in the U.S.

In July 2025, Golden Metal Resources (USA) LLC, a wholly-owned subsidiary of Guardian Metal, was awarded US$6.2M from the U.S. Department of War under Title III of the Defense Production Act of 1950 to support the rapid advancement and pre-feasibility study for the Pilot Mountain tungsten Project. Guardian Metal Resources joined both the Defense Industrial Base Consortium and the Cornerstone Program. The Company has also announced plans to pursue a U.S. listing in the first half of 2026.

Tungsten is a strategic mineral essential to the defense, energy transition, technology, and industrial sectors. Against the backdrop of evolving geopolitical dynamics and Chinese export restrictions on tungsten, Guardian is positioned to play the leading role in rebuilding a reliable domestic supply chain for this critical metal.

To learn more, please visit www.guardianmetalresources.com.

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SOURCE: Guardian Metal Resources PLC

View the original press release on ACCESS Newswire

FAQ

Who was appointed to the Guardian Metal board on November 3, 2025 (GMTLF)?

Michael X. Schlumpberger, PE MBA, was named as a Non-Executive Director, subject to AIM due diligence.

Which director is leaving Guardian Metal following the November 3, 2025 board change (GMTLF)?

Mick Billing will step down and retire after a four-year tenure once Michael's appointment is complete.

What experience does Michael X. Schlumpberger bring to Guardian Metal (GMTLF)?

He has ~40 years in mining, 20 years at PotashCorp, and grew American Pacific Borates from AUS$20M to AUS$900M.

How will the board change affect Guardian Metal's Pilot Mountain and Tempiute projects (GMTLF)?

The board says Michael's operational and ESG experience will help advance Pilot Mountain and Tempiute toward development.

Is Michael Schlumpberger's Guardian Metal appointment final (GMTLF)?

No; the appointment is subject to completion of the required AIM due diligence process.