Bonterra Releases Robust Preliminary Economic Assessment for the Barry Project, Highlighted by After-Tax NPV of C$665 Million and IRR of 54% at US$3,500/oz Long-Term Gold Price

Bonterra Resources Inc. released an independent Preliminary Economic Assessment (PEA) for its Barry open pit and underground project in Quebec, prepared by BBA Consultants. The assessment outlines an economic case using a toll-milling operating model, projecting an after-tax net present value (NPV) of C$665 million and an after-tax internal rate of return (IRR) of 54% at a long-term gold price of US$3,500/oz.

Life-of-mine production is estimated at 696,772 oz of gold payable, representing a 93.0% recovery, over a 7.2-year mine life that averages 87,097 oz annually. LOM cash costs are projected at C$2,411/oz ($1,786/oz), with all-in sustaining costs (AISC) at C$3,017/oz ($2,235/oz). Total capital costs are C$480.3 million, comprising C$118.7 million in initial capital and C$354.3 million in sustaining capital, with a payback period of 2.5 years.

The project is under a definitive earn-in and joint venture agreement with Gold Fields Limited (via Windfall Mining), which holds the right to acquire a 70% interest by spending C$30 million over three years. Gold Fields has not reviewed, verified, or endorsed the PEA or the news release. Sensitivity analysis shows significant leverage to gold prices, with an after-tax NPV of C$976 million and IRR of 77% at US$4,100/oz.

Bonterra Resources Inc. (BTR) released a Preliminary Economic Assessment (PEA) for the Barry project, presenting a strong conceptual economic case that validates the viability of a toll-milling strategy. The study demonstrates rapid payback and high margins at current gold price levels. This release follows the February 2026 updated Mineral Resource Estimates, the May 2026 inclusion of the Barry Mining Lease into the Phoenix Joint Venture, and the ongoing 2026 deep drilling campaign.

The PEA is a conceptual-stage study, and Gold Fields has not reviewed or endorsed the work. Consequently, the release does not trigger a development decision or change the joint venture earn-in terms. The news aligns with prior expectations of advancing the Barry project toward a restart, with the strong economics of the toll-mill model reducing execution risk and enhancing the asset's strategic value for the joint venture partner.

Bonterra Resources Inc. is a Quebec-based gold exploration and development company focused on the Urban-Barry Camp in the Abitibi Greenstone Belt. Its flagship assets include the Phoenix Joint Venture, which encompasses the Barry and Gladiator deposits and is partnered with Gold Fields, as well as the 100% owned Bachelor-Moroy and Desmaraisville South projects.

The company is pursuing a toll-milling strategy, leveraging the permitted Bachelor Mill, which has a capacity of 800 TPD and is expanding to 1,800 TPD, and the nearby Windfall Mill, which has 3,400 TPD capacity and is in late-stage permitting, to minimize upfront capital expenditure. Historical production at Barry, which yielded approximately 44,000 oz Au between 2008 and 2010, and Bachelor, which produced over 350,000 oz Au, provides a proven mining district context characterized by existing infrastructure, underground ramps, and active mining leases.