21 May 2026

Guardian Metal Resources plc

('Guardian Metal' or the 'Company')

Dr. Mark Thorpe appointed to the Board

Guardian Metal Resources plc (NYSE.A: GMTL, LON:GMET, OTCQB:GMTLF), a strategic exploration company focused on tungsten in Nevada, USA, is pleased to announce that Dr. Mark Thorpe is to be appointed to the Board as an Independent Non-Executive Director, subject to completion of the required AIM due diligence process.

Dr. Thorpe brings to Guardian Metal decades of experience as a senior mining executive. He is a sustainability specialist with more than 30 years of experience working for major mining companies, focussed on environmental, permitting and community engagement initiatives, across the global mining sector. His experience covers the entire mine life cycle from greenfield exploration through to mine closure and post-closure management, which makes him well qualified to support Guardian Metal as it advances its Nevada-based tungsten projects through key development phases and into production. He holds a Ph.D. in mine land rehabilitation from the University of Saskatchewan and was the Chair of the Board of Directors of the Canada Mining Innovation Council.

Dr. Thorpe is replacing Mr. Mark Burnett, who steps down from his role as Non-Executive Director on 21 May 2026. The Board would like to thank Mark Burnett for his significant contribution as an original director of Guardian Metal and for helping to build the Company from a small private company into a notable dual-listed business in London and New York over the past five years. He steps down to focus on other business interests.

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

"Dr. Mark Thorpe's appointment to the Board as Independent Non-Executive Director is an exciting and important step in Guardian Metal's evolution as we look to reshore U.S. mined tungsten supply for the first time in over a decade. Mark is widely recognised as a leader in his field, setting best practice industry standards for global mining companies in responsible mining, environmental, permitting and stakeholder relations. We are delighted to appoint someone of his calibre and welcome his leadership and expertise as we approach important development milestones to deliver on our strategy of establishing our tungsten projects as cornerstones of U.S. tungsten supply.

"I would like to thank Mark Burnett for his dedicated service and the significant contribution he has made to the Board of Directors and Guardian Metal over the last five years. He is leaving the Company with our best wishes for the future."

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

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

About Guardian Metal Resources 

Guardian Metal Resources PLC (NYSE.A: GMTL, LON:GMET, OTCQB:GMTLF) is a strategic mineral exploration company driving the revival of U.S. mined tungsten production and strengthening America's defense metal independence. The Company is advancing two 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 United States.

In July 2025, the U.S. Department of War (DoW) under Title III of the Defense Production Act of 1950, as amended, invested U.S. $6.2M in Golden Metal Resources (USA) LLC, a wholly-owned subsidiary of Guardian Metal Resources PLC, to support the Pilot Mountain PFS. The Company completed a U.S. listing on the NYSE American on March 20, 2026. 

Tungsten is a strategic metal critical to the defense, energy transition, technology, and industrial sectors. In the context of shifting geopolitical dynamics and tightening Chinese export restrictions, Guardian Metal is well positioned to play a leading role in re-establishing a secure, domestically mined U.S. supply chain for this vital defense metal.