Bonterra files NI 43-101 Technical Report for the Bachelor and Moroy Deposits

Press Release

Val-d’Or, QC – May 19, 2026 – Bonterra Resources Inc. (TSX-V: BTR, OTCQX: BONXF, FSE: 9BR2) (“Bonterra” or the “Company”) is pleased to announce that it has filed the NI 43-101 Technical Report (the “Report”) supporting the Mineral Resource Estimates for the Bachelor and Moroy Deposits.

The Report is titled “Updated Mineral Resource Estimate and Technical Report of The Bachelor and Moroy Deposits, Desmaraisville South Project, Northern Québec, Canada”. The Report was prepared by Antoine Yassa, P. Geo, OGQ, of P&E Mining Consultants Inc. (“P&E”) based in Brampton, Ontario, Canada. The Report was independently prepared by P&E on behalf of the Company in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and is effective as of February 18, 2026.

The Report is available on the Company’s website at www.btrgold.com and on SEDAR+ (www.sedarplus.ca) under the Company’s Issuer profile.

Qualified Person

M. Donald Trudel, P. Geo. (OGQ # 813), Director of 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 P&E MINING CONSULTANTS INC.

P&E, established in 2004, provides geological and mine engineering consulting reports, Mineral Resources Estimate technical reports, Preliminary Economic Assessments and Pre-Feasibility Studies. In addition, we are affiliated with major consulting firms for the purposes of joint venturing on Feasibility Studies. Our experience covers over 490 technical reports on diamonds, most metallic deposits including gold, silver, base metals, PGM and iron for both open pit and underground deposits. Software packages utilized include Gemcom, Leapfrog, Whittle, NPV Scheduler, Vulcan, Ventsim, AutoCAD and Deswik. P&E’s 22 associates have experience in geological interpretation, 3D geological modelling, technical report writing, Mineral Resources and Mineral Reserves Estimates, property evaluations, mine design, production scheduling, operating and capital cost estimates, and metallurgical engineering.

ABOUT BONTERRA

Bonterra is a Canadian gold exploration company with a portfolio of advanced exploration assets anchored by a central milling facility in Québec, Canada. The Company’s assets include the Gladiator, Barry(1), Moroy, and Bachelor(2),  gold deposits, which collectively hold 16.8 million tonnes (“Mt”) at an average grade of 3.02 g/t Au for 1.63 million ounces (“Moz”) of Measured and Indicated Mineral Resources, plus 15.6 Mt at an average grade of 4.32 g/t Au for 2.17 Moz Au of Inferred Mineral Resources.

In November 2023, the Company entered into an earn-in and joint venture agreement with Osisko Mining Inc. (“Osisko Mining”) 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 on or before 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.

(1) See our press release from February 23, 2026, titled “Bonterra Reports Significant Mineral Resources Growth at Barry and Gladiator Deposits” for further details.

(2) See our press release from April 1, 2026, titled “Bonterra Reports Significant Mineral Resource Growth at Bachelor and Moroy, 100% owned Deposits and Provides Corporate Updates” for further details.

FOR ADDITIONAL INFORMATION

Cesar Gonzalez, Executive Chairman & Interim CEO
ir@btrgold.com

2872 Sullivan Road, Suite 2, Val d’Or, Québec J9P 0B9

819-825-8678 | Website: www.btrgold.com

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