Osisko Mining Obtains Interim Order for Plan of Arrangement; Update on Special Meeting for Gold Fields Transaction

Osisko Mining Inc. ("

Osisko

") (TSX:OSK) is pleased to announce that it has obtained an interim order ("

Interim Order

") from the Ontario Superior Court of Justice (Commercial List) (the "

Court

") in respect of the acquisition by Gold Fields Limited, through a 100% owned Canadian subsidiary (the "

Purchaser

"), of Osisko by way of plan of arrangement under the Business Corporations Act (Ontario) (the "

Arrangement

").

The Interim Order, among other things, authorizes Osisko to call and hold a special meeting of shareholders of Osisko (the "Special Meeting") to approve the Arrangement. In accordance with the Interim Order, the Special Meeting is schedule to be held at 10:00 a.m. (Toronto time) on Thursday, October 17, 2024, at the offices of Bennett Jones LLP, Suite 3400, One First Canadian Place, Toronto, Ontario, Canada.

Under the terms of the Arrangement, the Purchaser has agreed to acquire all of the issued and outstanding common shares of Osisko (the "Shares") at a price of C$4.90 per Share (the "Consideration"). The Consideration represents a premium of approximately 55% to the 20-day volume weighted average trading price per Share on the Toronto Stock Exchange for the period ending August 9, 2024, being the last trading day prior to the announcement of the Arrangement.

Shareholders of Osisko as of August 30, 2024, being the record date of the Special Meeting, will receive notice of, and be entitled to vote at, the Special Meeting. A management information circular of Osisko (the "Circular"), which will provide further information about the Arrangement, will be mailed to shareholders of Osisko in due course.

The Circular will include the unanimous recommendation of the Board of Directors of Osisko for Osisko's shareholders to vote FOR the Arrangement. The Circular will be available in due course on SEDAR+ (www.sedarplus.ca) under Osisko's issuer profile.

The hearing date for the application for the Final Order of the Court is scheduled for October 22, 2024. The Arrangement is anticipated to become effective on or about October 25, 2024, subject to obtaining the required approvals from the shareholders of Osisko, the final order from the Court, the receipt of all approvals under the Competition Act (Canada) and the satisfaction or waiver of all other closing conditions.

Shareholder Questions

For shareholder inquiries regarding the Arrangement, please contact Laurel Hill Advisory Group:

North America Toll Free: 1-877-452-7184 Calls Outside North America: 416-304-0211Email: [e-mail]

About Osisko

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 50% interest in the high-grade Windfall gold deposit located between Val-d'Or and Chibougamau in Québec and holds a 50% interest in a large area of claims in the surrounding Urban Barry area and nearby Quévillon area (over 2,300 square kilometers).

Cautionary Statement Regarding Forward-Looking Statements

This news release may contain forward-looking statements (within the meaning of applicable securities laws) which reflect Osisko's current expectations regarding future events. Forward-looking statements are identified by words such as "believe", "anticipate", "project", "expect", "intend", "plan", "will", "may", "estimate" and other similar expressions. The forward-looking statements in this news release include statements regarding the proposed acquisition by the Purchaser of all of the Shares of Osisko and the terms thereof, the anticipated date of the Special Meeting, the anticipated filing of materials on SEDAR+, the expected date of completion of the Arrangement, the receipt of all required regulatory approvals and other statements that are not historical fact.

The forward-looking statements in this news release are based on a number of key expectations and assumptions made by Osisko including, without limitation: the Arrangement will be completed on the terms currently contemplated; the Arrangement will be completed in accordance with the timing currently expected; and all conditions to the completion of the Arrangement will be satisfied or waived. Although the forward-looking statements contained in this news release are based on what Osisko's management believes to be reasonable assumptions, Osisko cannot assure investors that actual results will be consistent with such statements.

The forward-looking statements in this news release are not guarantees of future performance and involve risks and uncertainties that are difficult to control or predict. Several factors could cause actual results to differ materially from the results discussed in the forward-looking statements. Such factors include, among others: the Arrangement not being completed in accordance with the terms currently contemplated or the timing currently expected, or at all; expenses incurred by Osisko in connection with the Arrangement that must be paid by Osisko in whole or in part regardless of whether or not the Arrangement is completed; the conditions to the Arrangement not being satisfied by Osisko and the Purchaser; currency fluctuations; disruptions or changes in the credit or security markets; results of operations; and general developments, market and industry conditions. Additional factors are identified in Osisko's annual information form for the year ended December 31, 2023 and most recent Management's Discussion and Analysis, each of which is available on SEDAR+ (www.sedarplus.ca) under Osisko's issuer profile.

Readers, therefore, should not place undue reliance on any such forward-looking statements. There can be no assurance that the Arrangement will be completed or that it will be completed on the terms and conditions contemplated in this news release. The proposed Arrangement could be modified or terminated in accordance with its terms. Further, these forward-looking statements are made as of the date of this news release and, except as expressly required by applicable law, Osisko assumes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.

Contact Information:

John BurzynskiChairman & Chief Executive Officer(416) 363-8563