TORONTO, ON / ACCESS Newswire / September 17, 2026 / NiobiumX Mining Inc. (CSE:NIOX)(OTCQB:NIOXF)(FSE:O7D0) ("NiobiumX" or the "Company") announces the appointment of Erik Sehn, P.Geo., as a director of the Company, effective September 17, 2026.

Background

Mr. Sehn is a professional geologist with nearly ten years of experience in mineral exploration, project management and the advancement of exploration projects in Canada. He has served as Vice President, Exploration of F4 Uranium Corp. since September 2025 and previously served as Senior Project Manager with F3 Uranium Corp., where he held senior technical and management roles and contributed to the discovery and advancement of the JR Zone and the Tetra Zone at the Patterson Lake North project in the Athabasca Basin of Saskatchewan. His earlier work in the Athabasca Basin included the Triple R deposit. He brings experience in exploration strategy, drill program design and execution, geological interpretation, technical team leadership, and the evaluation and advancement of early-stage mineral exploration projects.

Shipshaw and the Program

The Shipshaw Property comprises 48 mineral claims totalling approximately 2,686 hectares in the Saint-Honoré carbonatite district of Quebec. The nearest claim boundary lies less than two kilometres from the mining-lease boundary of the producing Niobec mine. The most recent geophysical survey in the assessment record is a heliborne magnetic survey flown in May 2010. The Company's current technical report, prepared by Bertrand Brassard, M.Sc., P.Geo., with an effective date of February 17, 2026 and available under the Company's profile on SEDAR+, recommends a two-phase program: relocation and re-assay of historical drill core for total rare earth elements together with magnetic modelling, followed by drill testing. Mr. Sehn will advise the Board on the design and execution of that program. The Shipshaw Property does not host a mineral resource or mineral reserve estimate.

"Erik has taken targets from geophysics through drilling to discovery in the Athabasca Basin. That is the sequence in front of us at Shipshaw: a carbonatite system with no airborne geophysics in more than fifteen years, a technical report that tells us where to start, and now a director who has run that program through to a discovery. We welcome him to the Board," said Kirby Renton, President and Chief Executive Officer.

The Company also announces that Dr. Terrance G. Owen has resigned as a director of the Company, effective September 17, 2026. Dr. Owen served as an independent director through the acquisition of the Shipshaw Property and the Company's transition from Arctic Fox Lithium Corp. to NiobiumX Mining Inc. He brought more than thirty years of public company, corporate finance and capital markets experience to the Board, and his judgment and steady counsel were valued throughout. The Board thanks Dr. Owen for his service and wishes him every success.

Qualified Person

The scientific and technical information in this news release has been reviewed and approved by Babak V. Azar, M.Sc., P.Geo. (OGQ #10876), a Qualified Person as defined by National Instrument 43-101.

About NiobiumX Mining Inc.

NiobiumX Mining Inc. (CSE:NIOX)(OTCQB:NIOXF)(FSE:O7D0) is a Canadian mineral exploration company focused on niobium and rare earth elements. The Company's principal asset is the Shipshaw Property, a package of 48 mineral claims totalling approximately 2,686 hectares in the Saguenay region of Quebec, situated within the Saguenay Graben of the Grenville Geological Province and characterized by a swarm of carbonatite and lamprophyre dykes. The Shipshaw Property does not host a mineral resource or mineral reserve estimate.

For Further Information

Kirby Renton, President, Chief Executive Officer and Director

Telephone: (604) 689-2646 | Email: contact@niobiumx.com | Website: niobiumx.com

On behalf of the Board of Directors, Kirby Renton, President and Chief Executive Officer, NiobiumX Mining Inc.

Forward-Looking Information

Except for statements of historic fact this news release contains certain "forward-looking information" within the meaning of applicable securities law. Forward-looking information in this news release includes, without limitation, statements regarding the anticipated contribution of the appointee; the grant and vesting of any securities issued in connection with the appointment; the scope, sequence and timing of the two-phase program recommended in the Company's technical report; and the Company's exploration plans and programs. Forward-looking information is based on assumptions management considers reasonable as of the date hereof and is subject to known and unknown risks and uncertainties that may cause actual results to differ materially, including that no mineral resource or mineral reserve estimate exists for the Shipshaw Property and none may ever be established; that geophysical, geochemical or model-derived anomalies may not reflect mineralization; that interpreted targets may not be confirmed by drilling; that historical or third party information may not be verified or replicated; that the Company may be unable to obtain financing, permits, contractors or title on acceptable terms; and changes in commodity prices, demand and critical minerals policy. Readers are cautioned not to place undue reliance on forward-looking information. The Company undertakes no obligation to update forward-looking information except as required by law. Additional information on risks is available in the Company's filings at www.sedarplus.ca.

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

NiobiumX Mining Inc. | Unit 401, 90 Adelaide St W, Toronto, ON M5H 3V9 | niobiumx.com | contact@niobiumx.com

SOURCE: NiobiumX Mining Inc.