St Barbara Limited (ASX: SBM) has announced the results of its Simberi Process Plant Layout and Design AACE Class 4 Study (“Plant Study”), which confirms the strong economic potential of its Simberi Expansion Project in Papua New Guinea.
The update given on 30 April this year, after the plant study, also includes revised Mineral Resource and Ore Reserve estimates that support a significantly enhanced Life of Mine Plan (LOMP).
Managing Director and CEO Andrew Strelein described the findings as clear validation of the company’s strategy.
“Our current work shows a project with significantly higher production averaging 220 kozpa over eight years, a lower operating cost and a mine life extending to 13 years without including any exploration targets,” CEO Strelein said.
“At an assumed gold price of only US$2500/oz that delivers a Post-Tax NPV (8%) of US$717 million and a Post-Tax IRR of 62%.”
“Our focus now is on the completion of the Feasibility Study to support a Financial Investment Decision, which we are targeting for H1 FY 2026. In the meantime, we continue to advance early works to allow a seamless transition into full-scale development,” he added.
The new LOMP outlines average gold production of 220,000 ounces per annum over eight years, with total production reaching 2.2 million ounces between Fiscal Years 2026 (FY26) and 2038 (FY38).
The mine’s life now extends to 13 years based solely on Proved and Probable Ore Reserves, excluding any exploration upside, the company said.
The project’s economic case is compelling, with a post-tax Net Present Value (NPV) of US$717 million and an internal rate of return (IRR) of 62%, based on a conservative gold price of US$2,500/oz, St. Barbara said.
Key Highlights of the Expansion Plan include:
- Annual gold output: Expected to ramp up from approximately 90,000 oz in FY27 to over 220,000 oz from FY28 onward.
- All-in Sustaining Cost (AISC): Forecasted to decrease to US$1,200–$1,300/oz from FY29 to FY36.
- Initial capital investment: Estimated at US$235 million over FY26–FY28, with an additional US$48 million in pre-expansion growth capital.
- Ore Reserves: Updated to 2.61 Moz of gold and 4.68 Moz of silver, with a new silver Ore Reserve reported for the first time.
- Project infrastructure: Includes a new 5.8MW ball mill, a flotation circuit for sulphide processing, a new wharf to support concentrate shipment, and expanded power generation.
The Plant Study, completed by Pitch Black Group, confirms the technical readiness of the project and outlines a transition from oxide to sulphide ore processing using flotation to produce a gold concentrate.
St. Barbara has already initiated early works, including camp expansion, new haul roads, and detailed engineering for the process plant upgrades.
The final investment decision or FID is anticipated in late Q2 or early Q3 of FY2026, pending the resolution of an ongoing tax assessment with PNG authorities. Meanwhile, long-lead items such as the ball mill and environmental compliance efforts are progressing, the company added.
The expanded LOMP estimates a total capital spend of US$458 million, including sustaining and closure costs, with robust sensitivity to gold price upside, potentially exceeding US$1.1 billion in post-tax NPV at US$3,000/oz, it said.
Further updates are expected upon completion of the Feasibility Study and progression toward project financing, the company said.
