Bonterra Resources (TSXV: BTR) has released a preliminary economic assessment for its Barry gold project, outlining a combined open pit and underground operation with an after tax net present value of C$665 million and an after tax internal rate of return of 54%.
Those figures are based on a long-term gold price of US$3,500 per ounce and an exchange rate of US$0.74 to the Canadian dollar, using a 5% discount rate. Payback is estimated at 2.5 years. At a spot gold price of US$4,100 per ounce, the after-tax NPV climbs to C$976 million and the IRR to 77%.
The study, prepared by BBA Consultants, outlines a 7.2 year mine life processing 8.4 million tonnes grading 2.79 g/t gold. With recoveries of 93.0%, the plan yields 696,772 ounces of payable gold, or an average of 87,097 ounces per year.
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Most of that production is weighted to underground mining The underground plan calls for 3.4 million tonnes at 4.05 g/t gold, containing roughly 448,000 ounces, mined through a mix of long-hole and modified cut-and-fill methods. The open pit would contribute 4.9 million tonnes at 1.9 g/t gold at a strip ratio of 6.7:1.
Rather than building a plant, Bonterra plans to send material to a nearby toll milling facility. That approach keeps initial capital at C$118.7 million, including a 25% contingency, with power and electrical infrastructure accounting for most of the C$42.4 million infrastructure budget. Sustaining capital totals C$354.3 million, the bulk of it tied to underground development.
Life-of-mine cash costs are estimated at US$1,786 per ounce, while all in sustaining costs come in at US$2,235 per ounce, a comfortable margin against both the base case and current spot pricing.
The study represents a sharp change in scope from the company’s earlier PEA, which covered only the open pit and returned an after-tax NPV of C$48.3 million on production of about 30,000 ounces per year. The updated assessment draws on the February 2026 mineral resource estimate and brings the underground resource into the mine plan for the first time.
Executive Chairman and Interim CEO Cesar Gonzalez pointed to further upside, noting the mine plan uses “only approximately 40% of the contained gold ounces in the February 2026 MRE.” He added that the deposit remains open at depth, with mineralization identified more than 100 metres beyond the resource boundary.
Barry sits within the Phoenix joint venture, under which Gold Fields can earn a 70% interest by spending C$30 million on the project by November 2026. Bonterra noted that Gold Fields did not participate in or endorse the PEA.
Bonterra Resources last traded at $0.125 on the TSX Venture.
