Name of the Project
Dolphin tungsten project.

Location
King Island, Tasmania, Australia.

Project Owner/s
Tungsten developer Group 6 Metals.

Project Description
The project has a probable reserve of 4.43-million tons grading 0.92% tungsten trioxide.

Group 6 proposes to extend the historical Dolphin opencut mine eastward to a depth of –140 m RL to recover remnant ore from the historic underground operation using an eight-year opencut mine. On completion of the proposed Dolphin opencut, a further six years of underground mining is planned from ore resources between –140 m RL to –300 m RL, extending the total project life to 14 years.

It is planned that the opencut operation will mine and process about 400 000 t/y of ore for eight years to produce about 26 800 t of tungsten concentrate. The underground mine will be accessed from a portal established at –120 m RL and a new southern decline developed to re-access and rehabilitate historic mine infrastructure below –150 m RL, including production drives and ventilation return airways. 

The underground production schedule and mining equipment list have been calculated, based on the mine design and production rates of about 300 000 t/y of ore producing an additional 24 500 t/y of tungsten concentrate. The project also requires the construction of a gravity process plant capable of producing more than 400 000 t/y, supplemented by a concentrate dressing circuit, together with mine infrastructure.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
A review has resulted in a 24% increase in the Dolphin project’s estimated net present value, increasing from A$241-million to A$300-million, while the internal rate of return has declined from 43% to 38%. The capital payback has increased slightly from 2.25 years to just under three years.

Capital Expenditure
Group 6 Metals flagged another cost increase at the mine in January 2023, with the capital costs of the project having increased from A$129.2-million to A$153.9-million.

Planned Start/End Date
Group 6 is working to ensure that the project remains on schedule to come on line in the first quarter of 2023.

Latest Developments
The project has produced its first tungsten concentrate, with Group 6 Metals now focusing on completing the remaining commissioning activities and performance testing to ramp up throughput and tune performance.

The process plant has been running 24 hours a day for several days, processing lower-grade commissioning ore.

The team will now turn their focus to performance testing to increase throughput, grade and recovery.

Dolphin is expected to have an initial mine life of 14 years, with the project having a processing capacity of more than 400 000 t/y.

Key Contracts, Suppliers and Consultants
Polberro Consulting (underground mine plan and schedule); Resource and Exploration Geology (required personnel, equipment and quarterly operating expenditure for contract underground mining estimate); Group 6 Metals (update of Xenith Consulting’s estimated opencut mining costs); and Gekko Systems (processing plant design, based on a flowsheet developed by ALS Laboratories).

Contact Details for Project Information
Group 6 Metals, email info@g6m.com.au.