Sconi cobalt-nickel-scandium project is being developed in Greenvale, Queensland, Australia.
Australian Mines fully owns and is developing the project with an estimated investment of A$1.35bn ($974m). The project was acquired from the company’s joint venture partner Metallica in September 2018.
Bankable feasibility study (BFS) of the project was completed in November 2018 and construction works are anticipated to begin in 2019 and last until 2021. Mining activities are anticipated to begin in October 2020, with commissioning of the processing plant scheduled for July 2021.
The mine is expected to produce 53,300 tonnes per annum (tpa) of nickel sulphate, 89t of scandium oxide, and 8,500tpa of cobalt sulphate during its mine life of 18 years. It is expected to create 500 construction jobs and 300 operational jobs.
Sconi project geology and mineralization
The Sconi project is located near the town of Greenvale, approximately 250km west of the port of Townsville, northern Queensland.
The historic project is made up of Greenvale, Lucknow, and Kokomo deposits, which span in three mining license areas - ML 10368, ML 10366, and ML 10342.
Mineral resources at the deposits are hosted within laterites on the ultramafic rocks formed by weathering process. The ultramafic rocks comprise serpentinites, meta-gabbros, and pyroxenites rich in iron, magnesium, nickel, and cobalt.
Nickel mineralization is hosted in relatively thin and laterally extensive limonitic and saprolitic profiles.
As of November 2018, the Sconi mine was estimated to hold 33.89Mt of probable and proven ore reserves grading 0.67% nickel, 0.10% cobalt, and 42 parts per million (ppm) of scandium.
Ore mining at Sconi cobalt-nickel-scandium project
Conventional open-pit mining methods will be used at the Sconi project. Greenvale and Lucknow deposits are proposed to be operated as a single mine as part of the mine plan, while Kokomo will be a separate mine. Both areas will be split and operated simultaneously by using two mining fleets.
Ore from the Greenvale deposit will be delivered to a run-of-mine (ROM) pad adjacent to the primary crushing circuit. Ore from both the Lucknow and Kokomo deposits will be delivered to local ROM pads, loaded into road trains, and transported to the Greenvale site.
Processing of ore at Sconi project
The processing plant at Sconi nickel-cobalt-scandanium project is a 2Mtpa plant, which will use hydrometallurgical methods for processing the nickel, cobalt, and scandium. It will produce battery-grade nickel sulphate and cobalt sulphate in four stages.
In the first stage, the material will pass through aqueous pressure leaching to dissolve the base metals and scandium while minimizing dissolution of the iron and silica gangue. The second stage will remove impurities and recover nickel/cobalt sulphide.
The filtered pregnant leach solution will proceed to neutralization for removal of the free acid, iron, and aluminium. The resultant solution is then subjected to sulphide precipitation to recover a high-grade nickel/cobalt sulphide product.
In the third stage, nickel and cobalt oxidative will be oxidised and re-leached under medium pressure and temperature before processing for secondary impurity removal.
High-purity nickel sulphate and cobalt sulphate will undergo crystallization process in the fourth stage. Solvent extraction is used to separate the nickel and cobalt. The separate nickel and cobalt sulphate streams are concentrated to saturation point via thermal and mechanical energy input.
The final nickel and cobalt sulphate produced will be packed and shipped to customers through the port of Townsville.
In March 2018, Australian Mines signed a binding off-take agreement with SK Innovation for the off-take of cobalt sulphate and nickel sulphate.
The agreement was made for an initial period of seven years, which can be further extended to another six years.
Infrastructure facilities at Sconi cobalt-nickel-scandium project
The Greenvale mining area is accessed through a dual-lane sealed road except a 10km section located approximately 20km from Greenvale, while the Lucknow is located approximately 10km from Greenvale and will be accessed through the Gregory Highway.
The Kokomo mine will be accessed through an unsealed haulage road and a ford crossing of the Burdekin River.
Water will be collected from Burdekin River during floods and stored for usage during operations.
Power for the Sconi cobalt-nickel-scandium project will be supplied from the existing 60kV power line grid along with a transformer.
An accommodation village for the employees will be constructed at Greenvale.
Ausenco compiled the BFS of Sconi project for Australian Mines, while CSA Global conducted the geological studies and estimated the mineral resources.
Orelogy prepared the mine plan and mining cost inputs, while Simulus Engineers developed capital cost estimates for the processing plant as part of the feasibility study.
Golder was engaged by the JV of Australian Mines and Metallica for preparing the mineral resources in 2012.