St Barbara Limited (ASX: SBM) has taken major steps to advance its Simberi Gold Project, confirming the project as a high-quality, long-life, low-cost asset while securing strategic partnerships with Kumul Mineral Holdings Limited and Lingbao Gold Group.
The company released the results of its Feasibility Study for the Simberi Expansion Project, which incorporates updated Mineral Resource and Ore Reserve estimates and forms the basis of the latest Life of Mine Plan (LOMP).
The study indicates total gold production of 2.1 million ounces from the second quarter of FY26 to FY39, with annual production rising above 200,000 ounces from FY29. All-in Sustaining Costs (AISC) are expected to fall to between US$1,100 and US$1,400 per ounce from FY29 to FY36, reflecting proposed enhanced royalty payments to landowners and communities.
“The study shows gold production averaging above 200,000 ounces per annum over nine years, with a mine life extending to 13 years – without including any mineral resource conversion or exploration targets,” Managing Director and CEO Andrew Strelein said.
“Our Feasibility work demonstrates that the Simberi Expansion Project is developing into a highly compelling opportunity to generate real value for St Barbara shareholders. Simberi will be a low capital intensity brownfields development, taking advantage of existing infrastructure to realise the value from this high-quality resource at a globally competitive operating cost," Strelein added.
The Feasibility Study estimates initial project capital of US$275 million across FY26 to FY28, with additional pre-expansion growth capital of US$50–70 million planned for FY26 to FY27. Mining throughput will increase to approximately 20 million tonnes per annum from the current 10 million tonnes, transitioning from oxidised ore processed via the existing Carbon-in-Leach circuit to fresh sulphide ore treated through an upgraded comminution circuit and a new flotation circuit to produce gold-bearing concentrate. Flotation tailings will continue to be treated through the CIL circuit to recover remaining gold.
At an assumed gold price of US$3,000 per ounce and silver price of US$30 per ounce, the project delivers a post-tax net present value (NPV) at 8% of US$1,023 million and an internal rate of return (IRR) of 79%. At US$4,000 per ounce gold and US$50 per ounce silver, the NPV rises to US$1,811 million with an IRR of 243%.
The Feasibility Study was led by Pitch Black Group, with mine planning and Ore Reserve estimation by AMC Consultants. Klohn Crippen Berger completed waste rock dump designs, and Engeny developed water management plans, including surface water, water balance, and water quality. Designs informed the cost estimates for waste rock construction and sediment and process water ponds.
In a related development, St Barbara has signed binding agreements with Kumul and Lingbao to secure funding and strategic support for the Simberi Expansion Project. Kumul will acquire a 20% interest in Simberi for A$100 million, forming an unincorporated joint venture with Simberi Gold Company Limited, which will retain 80% and act as manager. The parties are also finalising documentation for Kumul to farm in to earn up to 20% of the Tabar Islands Exploration Licences.
“St Barbara welcomes Kumul as a joint venture partner at Simberi. We share a commitment with the PNG Government, that the value of the nation’s resources are to be shared equitably for the benefit of PNG’s people,” Strelein said.
“Kumul’s participation in Simberi aligns the interests of St Barbara and our key stakeholders. We look forward to a long and productive joint development of the Simberi Expansion Project with Kumul, and Simberi’s development partner Lingbao Gold Group also announced," he added.
Separately, Lingbao will pay A$370 million to acquire a 50% stake in St Barbara Mining Pty Limited (SBML), which will hold 80% of the Simberi Gold Project following completion of Kumul’s transaction. St Barbara will retain the other 50% of SBML, ensuring it is fully funded for its share of development costs.
“The investments by Lingbao and Kumul in Simberi will help us accelerate the development of the Simberi Expansion Project and the delivery of its value to our shareholders and key stakeholders in PNG,” Strelein said. “With Lingbao we have a committed, experienced and well-funded partner. In addition, we welcome Kumul to the project as a co-investor.”
Lingbao chairman Wang Pinran said: “We are very pleased to be making this key strategic investment in the Simberi Gold Project and to have the opportunity to develop the Simberi Expansion Project with St Barbara and Kumul. Our confidence is solid not only because of this high-quality project, which contains 2.5 Moz in reserve and 5.8 Moz in resource of gold, but also because of St Barbara’s world standard development proposal and the participation by Kumul demonstrating to the world the PNG government’s support and encouragement for overseas investors.”
Key next steps for the project include confirmation of the Mining Lease Extension, completion of Early Works Packages and pre-expansion growth capital projects, and a Final Investment Decision (FID) based on an updated Life of Mine Plan and construction work programme. The FID is now anticipated in the third quarter of FY26, with ball mill commissioning projected for late Q3 FY27 and flotation plant commissioning in Q4 FY28.
SBML will be jointly managed by St Barbara and Lingbao, with an incorporated 50:50 governance structure, while the Simberi Joint Venture with Kumul will be managed by SGCL, with Kumul holding two of six committee positions. Financial advisory for St Barbara is provided by Macquarie Capital (Australia) Limited and legal advisory by King & Wood Mallesons.
