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Cheechoo Gold Project: Mineral Resource Estimate Update Underway Based on New Model

Resource Estimates

TSX-V: SOI

Cheechoo Gold Project: Mineral Resource Estimate Update

Underway Based on New Model

May 28, 2025

Montréal (Québec) - Sirios Resources Inc. (TSX-V: SOI; OTCQB: SIREF) (“Sirios”) is pleased to

announce that an update of the Mineral Resource Estimate (MRE) for its flagship Cheechoo Gold

Project in Eeyou Istchee James Bay, Québec, is well underway, with results anticipated as soon as

this summer. This update is driven by the adoption of a new game-changing geological and structural

model that significantly redefines the deposit’s potential.

A Transformative Geological Model

Developed in collaboration with leading consultants in resource modeling and applied structural

geology, the new model is grounded in a comprehensive analysis of drilling data and geological

structures. This work has uncovered previously unrecognized struc tural controls on gold

mineralization, resulting in a redefinition of key mineralized zones and corridors. An interactive 3D

viewer of the new model will be made available on Sirios’ website upon publication of the updated

MRE.

Key Anticipated Impacts

For the first time, the forthcoming resource estimate is expected to include an underground

component—representing a major advancement over the December 2022 estimate. This addition

paves the way for expanded resource development through future drilling initiatives.

“Our team’s dedication over the past year is coming to fruition as we integrate new insights and data

into the upcoming Mineral Resource Estimate,” stated Dominique Doucet, President and CEO of

Sirios Resources. “We are confident that the new estimate will showcase Cheechoo’s substantial

resource development potential and reinforce its status as a premier gold project in Québec.”

The MRE update is being conducted by PLR Resources Inc., a trusted geological consulting firm

founded by Pierre Luc Richard, a recognized expert in mineral resource estimation who has authored

and coordinated more than 100 technical reports under National Instrument 43-101.

Livestream Event: May 28

To provide further details on developments at the Cheechoo Gold Project and the ongoing resource

estimate update, Sirios will host a livestream event later today.

Attendees will have the opportunity to ask questions following the presentation. The livestream will

be held on Zoom, with sessions offered in both French and English:

Webinar in French: 1:00 p.m. (EDT)

https://us06web.zoom.us/j/83341809688?pwd=3d2f1f1WmzfDP7zF0FyeNpazoNXzra.1

Webinar in English: 2:00 p.m. (EDT)

https://us06web.zoom.us/j/88567968164?pwd=dwORJwp39XomdTZ25QMqycbm9baiWB.1

About the Cheechoo Project

Located less than 15 km from Dhilmar Ltd.’s Éléonore gold mine in Quebec’s Eeyou Istchee James

Bay territory, the Cheechoo Project —100% owned by Sirios —hosts an untapped gold deposit with

outstanding potential for expansion and development.

The 2022 Mineral Resource Estimate (MRE) reported, for an open-pit model:

• Indicated resources: 1.4 million ounces at an average grade of 0.94 g/t Au;

• Inferred resources: 500,000 ounces at an average grade of 0.73 g/t Au.

Underground mining scenarios have not been evaluated in this MRE.

Source: BBA, Mineral Resource Estimate Update for the Cheechoo Project, 23/12/2022

Learn more about Cheechoo at sirios.com/en/cheechoo

About Sirios

Sirios Resources Inc. (TSX -V: SOI; OTCQB: SIREF) is a Quebec -based mineral exploration company

focused on developing its 100% -owned Cheechoo Gold Project , located in Eeyou Istchee James Bay,

Canada.

About PLR Resources

PLR Resources specializes in mineral resource estimates and project evaluations and offers a wide

variety of services, from grassroots exploration planning to feasibility studies and mining operation

optimization, serving clients that include juniors, majo r operators as well as financial experts

seeking reliable and realistic advice.

For more information, please contact:

Dominique Doucet, P.Eng., CEO

450-482-0603

[email protected]

www.sirios.com

Cautionary note regarding forward-looking statements

This news release contains “forward -looking information” within the meaning of applicable Canadian

securities legislation based on expectations. estimates and projections as at the date of this news release.

Forward-looking information involves risks, uncertainties and other factors that could cause actual events,

results. Performance, prospects and opportunities to differ materially from those expressed or implied by

such forward-looking information. Factors that could cause actual results to differ materially from such

forward-looking information include, but are not limited to, capital and operating costs varying

significantly from estimates; the preliminary nature o f metallurgical test results; delays in obtaining or

failures to obtain required governmental, environmental or other project approvals; uncertainties relating

to the availability and costs of financing needed in the future; changes in equity markets; infl ation;

fluctuations in commodity prices; delays in the development of projects; the other risks involved in the

mineral exploration and development industry; and those risks set out in the Company’s public documents

filed on SEDAR at www.sedar.com. Although the Company believes that the assumptions and factors used

in preparing the forward-looking information in this news release are reasonable, undue reliance should

not be placed on such information, which only applies as of the date of this news release, and no assurance

can be given that such events will occur in the disclosed time frames or at all. The Company disclaims any

intention or obligation to update or revise any forward -looking information, whether as a result of new

information, future events or otherwise, other than as required by law.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies

of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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