First Mining Gold Corp. — Capital/Financing Update 2025

Jul 17, 2025

Blakes

Blake, Cassels & Graydon LLP
Barristers & Solicitors
Patent & Trademark Agents
1133 Melville Street
Suite 3500, The Stack
Vancouver, B.C. V6E 4E5 Canada
Tel: 604-631-3300 Fax: 604-631-3309

July 16, 2025

VIA SEDAR+

TO: British Columbia Securities Commission (as Principal Regulator)

AND TO: Alberta Securities Commission
Financial and Consumer Affairs Authority of Saskatchewan
Manitoba Securities Commission
Ontario Securities Commission
Autorité des Marchés Financiers
Nova Scotia Securities Commission
Financial and Consumer Services Commission (New Brunswick)
Prince Edward Island Securities Office
Securities Commission of Newfoundland and Labrador

Dear Sirs/Mesdames:

Re: First Mining Gold Corp. (the "Company") – Prospectus Supplement dated July 16, 2025 (the "Prospectus Supplement")

We refer to the Prospectus Supplement to the short form base shelf prospectus of the Company dated January 23, 2024 relating to an offering of units of the Company (the "Units"), with each Unit consisting of (i) one (1) common share in the capital of the Company and (ii) one half of one (1/2) common share purchase warrant of the Company exercisable for a period of 36 months from the issuance date thereof.

We consent to the reference to our name on the cover page of the Prospectus Supplement and under the heading "Legal Matters", and to reference to our name and the inclusion and use of our opinion under the heading "Eligibility for Investment" and "Certain Canadian Federal Income Tax Considerations".

We confirm that we have read the Prospectus Supplement and have no reason to believe that there are any misrepresentations in the information contained therein that are derived from our legal opinions referred to above or that are within our knowledge as a result of the services that we performed in connection with such opinion.

Yours truly,

(signed) "Blake, Cassels & Graydon LLP"

Blake, Cassels & Graydon LLP

TORONTO
CALGARY
VANCOUVER
MONTRÉAL
OTTAWA
NEW YORK
LONDON
Blake, Cassels & Graydon LLP | blakes.com