Bonterra Provides Exploration and Corporate Updates

Val-d'Or, Quebec--(Newsfile Corp. - August 28, 2025) - Bonterra Resources Inc. (TSXV: BTR) (OTCQX: BONXF) (FSE: 9BR2) ("Bonterra" or the "Company") is pleased to provide exploration updates at its 100% owned Desmaraisville South and at the Phoenix JV Projects. Exploration work at Phoenix JV (the "Project") is being led by a 100% indirect subsidiary of Gold Fields Ltd ("Gold Fields" or the "Operator"). The Project is under a definitive earn-in and joint venture agreement (the "JV Agreement") with Gold Fields. Under the JV Agreement, Gold Fields has the right to acquire a 70% interest in the Project by spending C$30 million in work expenditures, with a minimum spending commitment of C$10 million per year over a three-year period (see press release dated November 28, 2023, for more details). To date, over 65,000 meters ("m") have been drilled, with approximately C$20 million invested in the Project under the JV Agreement.

Marc-André Pelletier, President and CEO commented: "The exploration program, led by our joint venture partner Gold Fields, is progressing well and has provided several valuable insights ahead of the 15,000 m drilling campaign, which is set to begin this week with a drill rig mobilized on the Duke NE target. Prospecting work conducted to date has allowed for the mapping and sampling of several areas, including outcrops, boulders, and a historical trench located on the Gladiator SW target. In addition, a B-horizon soil sampling campaign was completed to the east and west of the Gladiator deposit, alongside an airborne gravimetric survey covering the entire JV property.

At the Desmaraisville South property, drilling is currently underway. Prospecting work is also scheduled to begin on the Property this week. We are pleased with the progress achieved this year through the Phoenix JV and excited to advance both campaigns as drilling programs are now underway."

Exploration Updates at Phoenix JV

The exploration program, which began in May 2025 on the JV Property, includes two gravimetric surveys-one airborne and one ground-based-as well as field activities such as B-horizon soil sampling, prospecting, mapping of outcrops, and reviewing historical trenches.

The airborne gravimetric survey is now completed. The ground survey might resume once the airborne data has been compiled and analyzed. Prospecting activities to date have focused on the Gladiator SW outcrops, Titan target, and areas near Lac-aux-Loutres. Mapping work will continue at Panache target. B-horizon soil samples were also collected at these targets.

The drilling campaign will start with one drill rig on the Duke NE target, and Gold Fields plans to deploy up to three drill rigs for a total of 15,000 m of drilling (see Figure 1). Several targets will be tested including the Gladiator NE and Titan targets along the Barry shear zone.

Figure 1 - Phoenix JV Project - Surface Plan View with Completed Drill holes, Historical Drill Hole Assay Results and 2025 Drill Target Areas

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Exploration Updates at Desmaraisville South

At Desmaraisville South, the 2025 drill campaign started with one drill rig. To date, approximately 2,500 m have been drilled at Hewfran and Mistik targets. The Company is planning a 10,000 to 12,000 m drill program expected to be completed by year-end and includes targets selected with the assistance of the VRIFY's AI-Assisted Mineral Discovery Platform known as DORA (See Figure 2). Field work is expected starting soon on the Property.

Figure 2 - Desmaraisville South Project - Historical Drill Hole Assay Results and 2025 Drill Target Areas

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Corporate Updates

Following the closing of its upsized brokered private placement for proceeds of $10.5 million, announced on June 30, 2025, the Company would like to clarify the number of non-transferable broker warrants issued in connection with this financing. The correct number of broker warrants issued is 2,509,109, not 2,509,108 as previously disclosed in the June 30, 2025 press release (see the June 30^th press release for more information).

Qualified Person

M. Donald Trudel, P.Geo. (OGQ # 813), Director Geology for the Company, has reviewed and approved the technical information contained in this press release. Mr. Trudel is a qualified person as defined by National Instrument 43-101 on standards of disclosure for mineral projects.

ABOUT BONTERRA

Bonterra is a Canadian gold exploration company with a portfolio of advanced exploration assets anchored by a central milling facility in Quebec, Canada. The Company's assets include the Gladiator, Barry, Moroy, and Bachelor gold deposits, which collectively hold 1.24 million ounces in Measured and Indicated categories and 1.78 million ounces in the Inferred category.

In November 2023, the Company entered into an earn-in and joint venture agreement with Osisko Mining Inc. for the Urban-Barry properties (the "JV Agreement"), which include the Gladiator and Barry deposits. In October 2024, Gold Fields Ltd, through a wholly owned Canadian subsidiary, completed the acquisition of Osisko Mining for C$2.16 billion. Gold Fields is now the counterparty to the JV Agreement and can continue to earn a 70% interest in the joint venture by incurring C$30 million in work expenditures until November 2026 (including expenditures incurred by Osisko Mining prior to October 2024). This strategic transaction highlights Bonterra's dedication to advancing its exploration assets, marking a significant step towards development.

FOR ADDITIONAL INFORMATION

Marc-André Pelletier, President & CEO
ir@btrgold.com

2872 Sullivan Road, Suite 2, Val d'Or, Quebec J9P 0B9
819-825-8678 | Website: www.btrgold.com

Neither 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.

Caution regarding forward-looking statements

This news release contains forward‐looking statements and forward‐looking information within the meaning of applicable securities laws. All statements other than statements of historical fact may be forward‐looking statements or information. Forward-looking statements are frequently identified by such words as "may", "will", "plan", "expect", "anticipate", "estimate", "intend" and similar words referring to future events and results. The forward‐looking statements and information are based on certain key expectations and assumptions made by management of the Company. Although management of the Company believes that the expectations and assumptions on which such forward-looking statements and information are based are reasonable, undue reliance should not be placed on the forward‐looking statements and information since no assurance can be given that they will prove to be correct.

Forward-looking statements and information are provided for the purpose of providing information about the current expectations and plans of management of the Company relating to the future. Readers are cautioned that reliance on such statements and information may not be appropriate for other purposes, such as making investment decisions. Actual results could differ materially from those currently anticipated due to a number of factors and risks, including the ability and timing of the parties to complete the Joint Venture (if at all), whether the work expenditures would be incurred as contemplated in the Agreement (or at all), the speculative nature of mineral exploration and development, fluctuating commodity prices, competitive risks and the availability of financing, as described in more detail in the Company's recent securities filings available at www.sedarplus.ca. Accordingly, readers should not place undue reliance on the forward‐looking statements and information contained in this news release. Readers are cautioned that the foregoing list of factors is not exhaustive. The forward‐looking statements and information contained in this news release are made as of the date hereof and no undertaking is given to update publicly or revise any forward‐looking statements or information, whether as a result of new information, future events or otherwise, unless so required by applicable securities laws. The forward-looking statements or information contained in this news release are expressly qualified by this cautionary statement.

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