Mr. Daniel Wilton reports

FIRST MINING ANNOUNCES $50 MILLION BOUGHT-DEAL OFFERING OF COMMON SHARES

First Mining Gold Corp. has entered into an agreement with Haywood Securities Inc., ATB Cormark Capital Markets and National Bank Financial Inc., acting as co-lead underwriters and joint bookrunners, on behalf of a syndicate of underwriters, pursuant to which the underwriters have agreed to purchase, on a bought-deal basis, 59.53 million common shares of the company at a price of 84 cents per common share for aggregate gross proceeds to the company of $50,005,200. The underwriters have been granted an option to purchase up to an additional 15 per cent of the number of common shares issuable under the offering at the offering price, exercisable in whole or in part up to 30 days following the closing of the offering, which may be exercised to cover overallotments, if any, and for market stabilization purposes.

The net proceeds from the offering will be used to advance First Mining's Springpole and Duparquet gold projects, as well as for general working capital and corporate purposes.

The common shares will be offered by way of a prospectus supplement to the company's base shelf prospectus dated Feb. 23, 2026, in each of the provinces and territories of Canada (excluding Quebec). The common shares may also be offered by way of private placement in the United States and in offshore jurisdictions in accordance with applicable securities laws, and where doing so would not require a prospectus, registration statement, offering memorandum or similar document, or create reporting or other obligations for the company. The offering is expected to close on or about Sept. 24, 2026, and is subject to customary closing conditions, including, but not limited to, the company receiving all necessary regulatory approvals, including the approval of the Toronto Stock Exchange.

Access to the base shelf prospectus, the supplement and any amendments to such documents are provided in accordance with securities legislation relating to procedures for providing access to a base shelf prospectus, a shelf prospectus supplement and any amendment to such documents. The shelf prospectus is accessible, and the supplement will be accessible within two business days from the date hereof, under the company's profile on SEDAR+. Copies of the base shelf prospectus, the supplement and any amendment to such documents may be obtained, without charge, from: (i) Haywood Securities Inc., by phone at 604-697-7126 or by e-mail at ecm@haywood.com; (ii) ATB Cormark Capital Markets, by phone at 416-943-6701 or by e-mail at ecm@atb.ca; or (iii) National Bank Financial Inc., by phone at 416-869-8414 or by e-mail at NBF-Syndication@bnc.ca. Before investing, prospective investors should read the base shelf prospectus, the supplement, when available, and the documents incorporated by reference therein.

About First Mining Gold Corp.

First Mining is a gold developer advancing two of the largest gold projects in Canada, the Springpole gold project in Northwestern Ontario, where the federal environmental assessment for the Springpole project was approved in June, 2026, and the Duparquet gold project in Quebec, a PEA-stage (preliminary economic assessment) development project located on the Destor-Porcupine fault zone in the prolific Abitibi region. First Mining also owns a 20-per-cent project interest in the Pickle Crow gold project in Ontario and large equity interest in Seva Mining Corp.

First Mining was established in 2015 by Keith Neumeyer, founder and chief executive officer of First Majestic Silver.

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