First Mining Gold Corp. — Capital/Financing Update 2025

Jul 16, 2025

FIRST MINING GOLD CORP.

UPSIZED TERM SHEET

Public Offering of Units

JULY 15, 2025

A final base shelf prospectus dated January 23, 2024 (the “final base shelf prospectus”) containing important information relating to the securities described in this document has been filed with the securities regulatory authorities in each of the provinces of Canada.

A copy of the final base shelf prospectus, any amendment to the final base shelf prospectus and any applicable shelf prospectus supplement that has been filed, is required to be delivered with this document and are accessible through SEDAR+.

This document does not provide full disclosure of all material facts relating to the securities offered. Investors should read the final base shelf prospectus, any amendment and any applicable shelf prospectus supplement for disclosure of those facts, especially risk factors relating to the securities offered, before making an investment decision.

Investing in the Units (as defined herein) involves risk. See “Risk Factors” in the final base shelf prospectus and in the prospectus supplement.

ISSUER:	First Mining Gold Corp. (“First Mining” or the “Company”).
PROSPECTUS OFFERING:	Public offering (the “Prospectus Offering”) of Units (as hereinafter defined) of the Company.
OFFERING:	Up to 66,670,000 units (the “Units”) in the capital of the Company.
	Each Unit shall consist of one common share (a “Common Share”) and one-half of one common share purchase warrant (each whole such purchase warrant, a “Warrant” of the Company).
ISSUE PRICE:	$0.18 per Unit (the “Issue Price”).
AMOUNT:	Aggregate gross proceeds of $12,000,600 million.
PURCHASE WARRANTY:	Each Warrant shall be exercisable to acquire one common share (a “Warrant Share”) at a price per Warrant Share of $0.27 for a period of 36 months from the Closing Date (as defined below).
	The Warrants will not be listed.
OFFERING BASIS:	Public offering by way of supplement to the Company’s base shelf prospectus dated January 23, 2024, on a commercially reasonable efforts agency basis, subject to a mutually acceptable agency agreement containing “disaster out”, “regulatory out”, “breach of agreement out” “market out” and “material adverse change out” clauses, in each of the Provinces of Canada (other than Quebec) and by private placement to eligible purchasers resident in jurisdictions other than Canada that are mutually agreed to by the Company and Haywood, each acting reasonably, provided that no prospectus filing or comparable obligation arises and the Company does not thereafter become subject to continuous disclosure obligations in such jurisdictions.

Offers for sale and sales of the Units to, or for the account or benefit of, persons in the "United States" and "U.S. persons" (as such terms are defined in Regulation S under the United States Securities Act of 1933 (the "1933 Act")) may only be made to (i) "qualified institutional buyers" (as defined in Rule 144A under the 1933 Act); and (ii) "accredited investors" (as defined in Rule 501(a) of Regulation D under the 1933 Act) by way of private placement) in reliance upon Section 4(a)(2) of the 1933 Act and/or Rule 506(b) of Regulation D thereunder, and similar exemptions from the registration requirements of applicable state securities laws. Resales of the Units and any securities comprising or underlying the Units will be permitted in the United States pursuant to an available

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exemption from the registration requirements of the 1933 Act and applicable state securities laws, or outside the United States pursuant to Regulation S under the 1933.

USE OF PROCEEDS: The net proceeds from the Offering will be used to advance the Company’s projects in Ontario and Québec and for working capital and general corporate purposes.

TSX LISTING: The Company shall obtain the necessary approvals to list the Common Shares, and the Warrant Shares issuable upon exercise of the Warrants, on the Toronto Stock Exchange, which listing shall be conditionally approved prior to the Closing Date.

LEAD AGENT: Haywood Securities Inc. (“Haywood”) on behalf of a syndicate of agents (collectively, the “Agents”).

CLOSING: On July 22, 2025 or such other date as agreed between the Company and the Agents (the “Closing Date”), each acting reasonably.

CONCURRENT OFFERING: Concurrent with the Prospectus Offering, the Company intends to undertake a non-brokered private placement offering of up to 22,730,000 flow-through units at a price per flow-through unit of $0.22 and up to 55,600,000 Units at the Issue Price for total additional proceeds of up to $15,008,600 million (the “NBPP”). The NBPP is expected to close on or about August 5, 2025.

ELIGIBILITY: The Common Shares and the Warrants are eligible for RRSPs, RRIFs, RESPs, DPSPs, RDSPs, TFSAs and FHSAs in Canada, subject to customary qualifications.

U.S. NOTICE: The securities offered hereby have not and will not be registered under the 1933 Act and may not be offered or sold in the United States or to U.S. persons (as defined in Regulation S under the 1933 Act) unless the securities have been registered under the 1933 Act, or are otherwise exempt from such registration.

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