(via TheNewswire)

THETFORD MINES, QUEBEC, June 4, 2026 - TheNewswire – Dundee Sustainable Technologies Inc. (“DST ” or the “Corporation ”) (CSE: DST) is pleased to announce that its shareholders have approved the previously announced amalgamation under Section 181 of the Canada Business Corporations Act (the “Amalgamation ”) involving the Corporation and 17799799 Canada Inc. (the “Purchaser ”), a newly-incorporated and wholly-owned subsidiary of Dundee Corporation (“Dundee ”), the Corporation’s parent company.

At the annual and special meeting of the shareholders of DST held earlier today, the special resolution approving the Amalgamation (the “Amalgamation Resolution ”) was passed by 99.7% of the votes cast on the Amalgamation Resolution by the holders of subordinate voting shares and multiple voting shares of the Corporation, voting together as a single class, present in person or represented by proxy at the meeting, and by 97.5% of the votes cast on the Amalgamation Resolution by the holders of subordinate voting shares and multiple voting shares present in person or represented by proxy at the m eeting, excluding votes attached to subordinate voting shares and multiple voting shares held by Dundee and its affiliates and any other votes required to be excluded pursuant to Multilateral Instrument 61-101 – Protection of Minority Security Holders in Special Transactions .

The parties expect to close the transaction in the first half of 2026, subject to the satisfaction of certain customary closing conditions. Following completion of the transaction, the Corporation will become a privately held company and the Corporation intends to apply to cease to be a reporting issuer under Canadian securities laws and to have the subordinate voting shares voluntarily delisted from the CSE.

About Dundee Sustainable Technologies

The Corporation is engaged in the development and commercialisation of environment-friendly technologies for the treatment of materials in the mining industry. Through the development of patented, proprietary processes, DST extracts precious and base metals from mineralised material, concentrates and tailings, while stabilising contaminants such as arsenic, which could not otherwise be extracted or stabilised with conventional processes because of metallurgical issues or environmental considerations.

DST has filed, published and was granted patents for the GlassLock Process™ and CLEVR Process™ in numerous countries.

FOR FURTHER INFORMATION PLEASE CONTACT:

Dundee Sustainable Technologies Inc.

Mr. Jean-Philippe Mai President and CEO

Dundee Sustainable Technologies Inc. Tel: (514) 866-6001 # 228

info@dundeetechnologies.com

FORWARD LOOKING STATEMENTS

This news release contains forward-looking information and forward-looking statements (collectively referred to hereinafter as, “ forward-looking information ”) within the meaning of applicable Canadian securities legislation. Forward-looking information is not representative of historical facts or information or current conditions, but instead represent only the beliefs of the management of DST regarding future events, plans or objectives, many of which, by their nature, are inherently uncertain and outside of the control of DST. Generally, such forward-looking information can be identified by the use of forward-looking terminology such as “plans”, “expects” or “does not expect”, “is expected”, “budget”, “scheduled”, “estimates”, “forecasts”, “intends”, “anticipates” or “does not anticipate”, or “believes”, or variations of such words and phrases or may contain statements that certain actions, events or results “may”, “could”, “would”, “might” or “will be taken”, “will continue”, “will occur” or “will be achieved”. The forward-looking information contained herein may include, but are not limited to, information concerning: (i) the transaction, including, the timing for the completion of the transaction, the manner in which the transaction will be completed, and the anticipated benefits therefrom; and (ii) the Corporation’s intention to apply to cease to be a reporting issuer under Canadian securities laws and to have the subordinate voting shares voluntarily delisted from the CSE.

By identifying such information and statements in this manner, DST is alerting the reader that such information and statements are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such information and statements. In addition, in connection with the forward-looking information contained in this news release, DST has made certain assumptions. Among the key factors that could cause actual results to differ materially from those projected in the forward-looking information are the following: (i) any inability to consummate the transaction on the terms proposed and described herein, or at all; (ii) any inability to obtain, in whole or in part, any requisite regulatory, third party and shareholder approvals and/or to satisfy any of the other conditions to the consummation of the Transaction on the terms proposed, or at all; (iii) any adverse impact of the announcement or consummation of the Transaction on the relationships of DST; (iv) changes in general economic, business and political conditions, including changes in the financial markets; (v) changes in applicable laws; (vi) any difficulty or inability in complying with extensive government regulation; and (vii) the diversion of management time on the transaction. Should one or more of these risks, uncertainties or other factors materialize, or should assumptions underlying the forward-looking information prove incorrect, actual results may vary materially from those described herein as intended, planned, anticipated, believed, estimated or expected.

Although management of DST believes that the assumptions and factors used in preparing, and the expectations contained in, the forward-looking information are reasonable, undue reliance should not be placed on such information and statements, and no assurance or guarantee can be given that such forward-looking information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such information and statements. The forward-looking information contained in this news release is made as of the date of this news release, and DST does not undertake to update any forward- looking information contained or referenced herein, except as required by applicable securities laws.

This news release shall not constitute an offer to sell or the solicitation of an offer to buy any securities in any jurisdiction.

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

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