Simberi Expansion Project: 2.1 Million Ounces Gold, $275M Capital, and $1,023M NPV Confirmed

Simberi Expansion Project, Confirming a High-Quality Asset

St Barbara Limited has delivered a comprehensive Feasibility Study for its Simberi Expansion Project, reinforcing the operation’s status as a high-quality, long-life, and low-cost gold and silver mining asset. The study outlines a 13-year Life of Mine Plan (LOMP) with total gold production of approximately 2.1 million ounces, supported by an updated Mineral Resource Estimate that adds 0.9 million ounces of gold and 2.8 million ounces of silver.

The project’s economics are compelling, with a post-tax Net Present Value (NPV) at an 8% discount rate of US$1,023 million and an Internal Rate of Return (IRR) of 79% based on a conservative gold price of US$3,000 per ounce. These figures improve significantly under higher gold price scenarios, highlighting the project’s sensitivity to market conditions.

Capital and Operating Cost Profile

The expansion requires an initial capital investment estimated at US$275 million, with an additional US$50 to 70 million allocated for pre-expansion growth capital. This investment will fund critical upgrades including a new flotation circuit to process fresh sulphide ore, enhancements to the comminution circuit, additional power generation capacity, and construction of a new wharf to handle larger concentrate shipments.

Operating costs are projected to be competitive, with All-in Sustaining Costs (AISC) expected to decline to a range of US$1,100 to US$1,400 per ounce from FY29 through FY36. This cost efficiency is underpinned by the project’s low capital intensity and the use of existing infrastructure, which reduces upfront expenditure and operational complexity.

Technical and Environmental Considerations

The Feasibility Study incorporates advanced AI-based weathering models developed in partnership with Stratum AI, improving the classification of ore types and enhancing resource estimation accuracy. Metallurgical testwork confirms the suitability of the flotation circuit for sulphide ore processing, with expected gold recoveries of around 90% for sulphide material and 74% for oxide and transitional ores.

Environmental management remains a priority, with all operations conducted under valid permits and ongoing compliance with Papua New Guinea’s Conservation and Environmental Protection Authority. The project includes plans for progressive rehabilitation of waste rock dumps and tailings management via deep sea tailings placement.

Project Timeline and Risks

The Final Investment Decision (FID) is targeted for the third quarter of FY26, contingent on the approval of the Mining Lease extension. While the project remains on track, St Barbara acknowledges risks including sovereign and regulatory uncertainties in Papua New Guinea, delays in tax assessment resolutions, and potential capital cost variations during construction.

Despite these challenges, the company has advanced key early works such as the procurement of a new ball mill and expansion of camp facilities, positioning the project for timely execution once approvals are secured.

Outlook

St Barbara’s Simberi Expansion Project stands out as a robust and strategically important asset, offering significant value creation potential for shareholders. With a solid foundation of updated resources, proven processing technology, and a clear development pathway, the project is poised to contribute meaningfully to the company’s production profile and financial performance over the next decade and beyond.