Sirios Launches Drilling Campaign at Cheechoo

Execution of the first 25,000-metre drilling phase at Cheechoo begins with the mobilization of two drill rigs

Sirios Resources Inc. (TSXV: SOI,OTC:SIREF) (OTCQB: SIREF) ("Sirios" or "the Company") announces that it has received all required permits, including the Authorization for Impact-Causing Exploration Work (ATI), for the execution of Phase 1 of the drilling campaign at Cheechoo, as announced in a press release dated April 1. In addition, the Company has mobilized the first two drill rigs to the project site. A third drill rig will be added at the end of June.

The Sirios team is also mobilizing a LIBS (Laser-Induced Breakdown Spectroscopy) unit to analyze drill core samples directly on site, improve the accuracy of core logging, and enhance the understanding of the deposit and its metallurgy. In addition to the drill cores generated during the summer campaign, a review program of existing core samples will also be carried out.

"Our project management team has done an excellent job, enabling us to begin drilling in early June as planned," commented Jean-Félix Lepage, President and Chief Executive Officer of Sirios.

Dominique Doucet, Head of Exploration, added: "Site preparation work has been completed as scheduled. The installation of the LIBS system in modules designed by Sirios has also been completed, and we are very excited to use this cutting-edge technology to improve the accuracy of the project's geological and metallurgical data."

In addition, Sirios confirms that a helicopter-borne magnetic survey has been completed at the Fagnant gold project. This survey, combined with historical data, will enable Sirios to establish its field exploration strategy.

About Sirios
Sirios Resources is a Quebec-based mineral exploration company focused on developing its Cheechoo gold deposit, as well as exploring and advancing its other high-potential gold projects in the Eeyou Istchee James Bay region of Canada. On December 11, 2025, Sirios announced the details of the acquisition of OVI Mining, a milestone in the company's history.

Cautionary Note Regarding Forward-Looking Statements
This press release contains "forward-looking statements" within the meaning of applicable Canadian securities laws, based on expectations, estimates, and projections as of the date of this press release. Forward-looking statements involve risks, uncertainties, and other factors that could cause actual events, results, performance, expectations, and opportunities to differ materially from those expressed or implied in such forward-looking statements. Factors that could cause actual results to differ materially from those indicated in these forward-looking statements include, but are not limited to: capital and operating costs that differ materially from estimates; the preliminary nature of metallurgical test results; delays or failures in obtaining required governmental, environmental, or other approvals; uncertainties regarding the availability and cost of necessary future financing; changes in financial markets; inflation; fluctuations in metal prices; delays in project development; other risks associated with the mineral exploration and development industry; and the risks disclosed in the Company's public filings on SEDAR+ at www.sedarplus.ca. Although the Company believes that the assumptions and factors used to prepare the forward-looking statements contained in this press release are reasonable, readers should not place undue reliance on this information, which is valid only as of the date of this press release, and there is no guarantee that these events will occur or occur within the timeframes indicated. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as required by applicable law.

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