Stillwater Mobilizes for Largest Exploration and Resource Expansion Program to Date at Stillwater West, Montana, USA

VANCOUVER, BC / ACCESS Newswire / June 15, 2026 / Stillwater Critical Minerals Corp. (TSXV:PGE)(OTCQB:PGEZF)(FSE:J0G) (the "Company", or "Stillwater") is pleased to announce that contractors have been retained and mobilization of drill rigs is expected in short order for the Company's largest exploration and resource expansion campaign to date at its flagship Stillwater West Ni-PGE-Cu-Co-Cr + Au project in Montana, USA.

The 2026 drill program is designed to build upon the successful 2025 program and the upcoming updated Mineral Resource Estimate, with a focus on expanding mid- to high-grade polymetallic sulphide mineralization within and adjacent to existing resource areas.

The program follows significant advancements achieved over the past year, including the expansion of the Company's geological model across more than 20 kilometres of strike length, completion of resource growth drilling, and continued refinement of multiple large-scale polymetallic sulphide targets identified through the Company's district-scale geological and geophysical programs.

Primary objectives of the 2026 field program include:

• Expansion of existing near-surface resources at Chrome Mountain and Iron Mountain, the Company's primary resource growth areas, and other priority areas;

• Continued delineation of higher-grade nickel-copper-PGE sulphide and polymetallic mineralization within the existing resource footprint;

• Follow-up drilling on priority geophysical and geological targets identified through the Company's district-scale targeting programs;

• Completion of ground geophysical surveys to refine existing deposit expansion targets and generate additional exploration drill targets across the project area;

• Testing new zones of sulphide mineralization within the lower Stillwater Igneous Complex; and

• Supporting future technical and economic studies through continued resource growth and geological de-risking.

Michael Rowley, President and CEO of Stillwater Critical Minerals, commented "We are excited to begin another important field season at Stillwater West as we continue advancing a large-scale domestic source of ten critical minerals in Montana. With strong support from our strategic partner Glencore plc, a growing U.S. focus on critical mineral security, and an upcoming updated Mineral Resource Estimate expected shortly, we believe 2026 will mark another significant step in advancing the project. Our objective remains clear: to continue growing and advancing the resource base while demonstrating the strategic importance of the Stillwater district to U.S. critical mineral supply chains."

Dr. Danie Grobler, Vice-President Exploration, commented "The successful completion of our 2025 drilling program has significantly advanced our understanding of the scale and potential of the Stillwater West project. The combination of resource expansion opportunities and multiple district-scale near-surface exploration targets provide an exceptional platform for continued growth as we advance one of the most significant undeveloped critical mineral systems in the United States.

Having spent much of my career working on large-scale polymetallic magmatic sulphide systems in South Africa's Bushveld Complex, including the Platreef deposit, I continue to be impressed by the geological similarities we are seeing at Stillwater West. While each project is unique, the scale of the mineralized system, the presence of extensive bulk-tonnage nickel-copper-PGE sulphide mineralization, and the opportunity for continued resource growth across a large district-scale land package underscore the significant long-term potential of the project."

Strategic Positioning

The Company believes that Stillwater West represents one of the largest undeveloped polymetallic critical mineral systems in the United States. The project hosts large-scale resources containing ten minerals identified as critical by the U.S. government and benefits from excellent infrastructure, access to power, water, rail and skilled labour within an established mining district. Results from the 2026 program are expected to contribute to ongoing resource growth, further definition of higher-grade mineralization, and the advancement of future development studies aimed at evaluating potential mining scenarios within the district.

Stillwater West hosts mineralization containing 1.6 billion pounds ("Blbs") of nickel, copper, and cobalt, 3.8 million ounces of platinum, palladium, rhodium, and gold, 2.3 Blbs of defined chromium plus undefined quantities of ruthenium and iridium. The project is located adjacent to Sibanye-Stillwater's producing operations in Montana's historic Stillwater mining district, providing access to established infrastructure, workforce, and mining expertise.

The Company expects to provide regular updates throughout the 2026 field season and looks forward to the release of the updated Mineral Resource Estimate in the near-term.

Upcoming Events

Company representatives will be attending the following events to discuss upcoming catalysts:

1. Fastmarkets Global Battery and Critical Materials Conference - Las Vegas, NV, June 22-25, 2026.

2. Montana Mining Association Annual Meeting 2026 - Butte, MT, USA, July 13-15, 2026.

3. Precious Metals Summit - Beaver Creek, CO, USA, September 22-25, 2026.

About Stillwater Critical Minerals Corp.

Stillwater Critical Minerals (TSXV:PGE)(OTCQB:PGEZF)(FSE:J0G) is a mineral exploration and development company advancing its 100%-owned Stillwater West Ni-PGE-Cu-Co-Cr + Au project in the Stillwater mining district of Montana, USA. Stillwater West is directly adjacent to Sibanye-Stillwater's operating Stillwater mines and processing infrastructure, the only primary platinum group element-producing complex in the United States. An NI 43-101 Mineral Resource Estimate released in January 2023 positions Stillwater West as one of the largest nickel and platinum group element resources in the United States and contains ten minerals currently listed as critical in the United States. With strategic investments by Glencore and an experienced technical team with expertise in Bushveld- and Platreef-style systems, the Company is advancing Stillwater West through ongoing resource expansion and technical studies.

Stillwater also holds a 49% interest in the high-grade Drayton-Black Lake-gold project adjacent to Nexgold Mining's development-stage Goliath Gold Complex in northwest Ontario, currently under an earn-in agreement with Heritage Mining, and the Kluane PGE-Ni-Cu-Co critical minerals project on trend with Nickel Creek Platinum's Wellgreen deposit in Canada's Yukon Territory. The Company also holds the Duke Island Cu-Ni-PGE property in Alaska and maintains a back-in right on the high-grade past-producing Yankee-Dundee in BC, following its sale in 2013.

FOR FURTHER INFORMATION, PLEASE CONTACT:
Michael Rowley, President, CEO & Director - Stillwater Critical Minerals
Email: info@criticalminerals.com Phone: (604) 357 4790
Web: http://criticalminerals.com Toll Free: (888) 432 0075

Forward-Looking Statements

This news release includes certain statements that may be deemed "forward-looking statements" or "forward-looking information". In particular, this press release contains forward-looking information relating to, among other things, the interpretation of exploration results, the potential for resource expansion, the timing and results of future resource estimates (including the targeted H1 2026 updated MRE), the timing and success of exploration activities, permitting timelines, and future plans and objectives of the Company. All statements in this release, other than statements of historical facts, are forward-looking statements that involve various risks and uncertainties. Although Stillwater Critical Minerals believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in the forward-looking statements. For more information on Stillwater Critical Minerals and the risks and challenges of their businesses, investors should review their annual filings that are available at www.sedarplus.ca.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

SOURCE: Stillwater Critical Minerals Corp.