Name of the Project
Sulphur Springs copper/silver/zinc project.

Location
Pilbara region of Western Australia.

Project Owner/s
Australian base metal developer Develop Global, through its wholly-owned subsidiary Venturex Sulphur Springs.

Project Description
The project hosts a volcanogenic massive sulphide deposit containing copper, silver and zinc mineralisation. The current ore reserve is 8.8-million tonnes at 5.4% zinc, 1.1% copper, 0.2% lead, 21 g/t silver and 0.1 g/t gold, reported at June 30, 2025.

An updated definitive feasibility study (DFS) has shown that Sulphur Springs will be technically and economically robust, with the new proposed bottom-up mining approach resulting in Sulphur Springs’ developing as an underground mine from the outset. This will allow for substantial flexibility in the mine plan and scheduling sequence.

Develop’s June 2026 final investment decision (FID) is based on underground mining and treatment through a process plant with a nameplate capacity of 1.5-million tonnes a year to produce separate copper, silver and zinc concentrates.

The FID physicals indicate total ore mined and processed of 9.716-million tonnes over an estimated eight-year mine life, with concentrate production of 1.037-million tonnes of zinc concentrate and 337 000 t of copper concentrate. Contained metal in concentrates is estimated at 480 000 t of zinc, 73 000 t of copper and 2.699-million ounces of silver.

Infrastructure proposed includes a power station; communications systems; a processing plant and ancillaries; plant buildings; an upgrade to the site access road; an accommodation village; raw and potable water supply and mine water treatment; fuel storage; a tailings storage facility, evaporation and run-off ponds; mobile equipment; concentrate transport and mining offices.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The June 2026 FID outcomes, using spot commodity prices as at June 8, 2026, estimate a pretax net present value (NPV), at an 8% discount rate, of A$811-million and an internal rate of return (IRR) of 37%, with payback of about 23 months. The October 2025 updated DFS had estimated a pretax NPV, at an 8% discount rate, of A$921-million and a pretax IRR of 59%.

Capital Expenditure
Develop Global has committed capital expenditure (capex) of A$450-million.

The June 2026 FID estimate reflects all preproduction capital required to achieve first production. It comprises A$390-million in direct costs, A$22-million in indirect costs, A$18-million in owner’s costs and A$20-million in contingency. 

Planned Start/End Date
Remaining long-lead procurement is targeted for the June 2026 quarter, major contract awards for the June to September 2026 quarter, GR Engineering Services mobilisation for the September 2026 quarter, process plant cold commissioning for the March 2028 quarter and first saleable concentrate production for the June 2028 quarter.

Latest Developments
On June 10, 2026, Develop announced FIDs for Sulphur Springs and Pioneer Dome and a binding $400-million financing arrangement with Trafigura. The package comprises a $350-million senior secured loan facility and a $50-million warrant package, and is accompanied by binding offtake agreements.

Develop has approved A$450-million in capex to advance Sulphur Springs through construction and into production. The company has also said the project is to be renamed Yitirrti by the Nyamal First Nations people, at Develop’s invitation.

Early works to date include the identification and procurement of long-lead items, including the ball mill, concentrate filters and electrical infrastructure, which are in transit to site. Surface works are advancing, with site establishment and box cut construction complete, bulk earthworks and construction of the site access/haul road started, and about 2 050 m of lateral development completed in the twin declines, 26% above the 2026 financial year budget schedule.

Project-readiness workstreams are progressing in parallel with construction activity, including key management appointments, negotiation of power supply and site services agreements, and finalisation of concentrate haulage and logistics arrangements to Port Hedland.

Key Contracts, Suppliers and Consultants
Trafigura and Trafigura Asia Trading (offtake for 100% of Sulphur Springs copper and zinc concentrates not sold under separate Toho arrangements, for a minimum 1.25-million dry metric tonnes across copper and zinc concentrates); Trafigura (financing); GR Engineering Services (preferred engineering, procurement and construction contractor and May 2026 front-end engineering design study); Develop Mining Services (owner-operator underground development and production); Toho Zinc Co (separate offtake arrangements); Develop, ALS Metallurgy and Auralia Metallurgy (metallurgical testwork); Develop and Entech (geology, resources, geotechnical, mining, mine design, ore reserves and financial modelling); and CMW Geoscience and Knight Piésold (tailings management facility and geotechnical studies).

Contact Details for Project Information
Develop Global, tel +61 8 6389 7400 or email hello@develop.com.au.