Name of the Project
Mallina gold project.

Location
Pilbara region of Western Australia.

Project Owner/s
De Grey Mining.

Project Description
Mallina gold project refers to the Hemi plus regional deposits. Hemi is a top-three global undeveloped gold development project, based on average yearly gold production rates. Once Hemi is in production, it will rank in the top five Australian gold mines.

The project is expected to average total gold production of 540 000 oz/y over the first ten years of operation. In years 1 to 5, the operation is expected to produce 550 000 oz/y and 637 000 oz/y at peak production.

Total production of 6.4-million ounces is estimated over a 13.6-year life-of-mine (LoM).

The processing plant will have a nameplate capacity of ten-million tonnes a year for the comminution, flotation and carbon-in-leach circuits, with pressure oxidation circuit throughput of 800 000 t/y.

Average processing recovery of 93.6% over the LoM from extensive testwork demonstrates excellent amenability of mineralisation to the flowsheet developed for the project.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a pretax net present value, at a 5% discount rate, of about $3.9-billion and internal rate of return of about 51%, with payback of about 1.6 years.

Capital Expenditure
Capital costs for the ten-million-tonne-a-year plant and site infrastructure are estimated at $985-million, inclusive of $100-million in growth allowance. Additional mine preproduction prestrip capital is estimated at $68-million.

Planned Start/End Date
Not stated.

Latest Developments
De Grey Mining is confident that it will be able to fund the Mallina gold project.

Financially, the company’s market capitalisation and the quality of the asset will attract sufficient debt and equity funding to develop the project, according to De Grey MD Glenn Jardine beleves.

De Grey is undertaking a definitive feasibility study (DFS), which is due for release in the September quarter of this year. The DFS will update the openpit design for Mallina, and will include an updated flowsheet and a mining and processing schedule for the Hemi deposit, as well as material takeoffs for capital cost estimates and quotations for mine operating costs.

A final investment decision is expected by mid-2023, subject to statutory approvals. However, this timeline will be updated in the DFS.

Key Contracts, Suppliers and Consultants
Majesso Consulting (independent mining cost estimate, based on a contractor mining strategy) and GR Engineering (independent assessment of the processing cost estimate at a throughput rate of 7.5-million tonnes a year).

Contact Details for Project Information
De Grey Mining, tel +61 8 6117 9328 or email admin@degreymining.com.au.