The NiWest nickel-cobalt project is a high-quality nickel (Ni)-cobalt (Co) mine being developed in the North Eastern Goldfields region of Western Australia.
GME Resources is developing the project, which is considered as one of the biggest undeveloped Ni-Co projects in Australia.
The pre-feasibility study of the project, with a focus on the Mt Kilkenny, Eucalyptus, and Hepi deposits, was completed in August 2018.
The project is expected to produce an average of 19,200t of nickel and 1,400t of cobalt over the first 15 years of the initial 27-year operating life. It is forecasted to produce approximately 456,000t of nickel sulphate and 31,400t of cobalt sulphate.
NiWest nickel-cobalt project location, geology, and mineralisation
Located in the West Australian Nickel belt, the NiWest nickel-cobalt project lies in close proximity to Glencore’s Murrin Murrin Nickel-Cobalt project. The NiWest is made up of seven deposits, namely Mt Kilkenny, Eucalyptus, Hepi, Mertondale, Waite Kauri, Murrin North, and Wanbanna.
The project is located within the Murrin Domain of the Kurnalpi Terrane, which is part of the Eastern Goldfields Superterrane in Yilgarn Craton, Western Australia. The Yilgarn Craton hosts metamorphosed Archaean granite and greenstone rocks and is known to be a world-class mineral province containing high-quality nickel and gold mineralisation.
Most of the Ni-Co mineralisation within the Murrin Domain is believed to have formed as supergene, blanket-style deposits. The mineralisation extends for up to 7km and has a width of 750m, while the thickness ranges between 5m to 30m.
Lateritic nickel ore mineralisation is identified within the smectite, upper saprolite, and lower ferruginous zones while cobalt mineralisation is majorly found in the lower ferruginous and upper smectite zones.
NiWest nickel-cobalt project reserves
The proven and probable ore reserves at NiWest project are estimated to be 64.9Mt, grading 0.91% Ni and 0.06% Co. The mine is estimated to contain 592,000t of nickel and 38,000t of cobalt.
The project is expected to contain mineral resources of 85.2Mt graded at 1.03% Ni and 0.065% Co.
Mining at NiWest project
The NiWest project proposes to employ conventional open-pit mining method using an excavator, loader, and truck fleet with minimal blasting. The drilling and blasting will be conducted only to remove ferruginous capping.
Mining activity for the first six years will be focused on the Mt Kilkenny deposit, while the Eucalyptus and Hepi orebodies will be mined from the seventh year onwards. Ore from the latter two will be transported by trucks to the Mt Kilkenny plant site, which is located approximately 40km and 22km from Eucalyptus and Hepi, respectively.
The processing plant will have a capacity of 2.4Mtpa and is expected to recover 79% of nickel and 85% of cobalt. The ore will undergo two-stage crushing to produce a -50mm product, followed by agglomeration and heap leaching.
Calcrete will be added to the pregnant leach solution (PLS) from heap leaching in order to remove residual acid and precipitate 99.9% of the Fe and Al.
The PLS will be processed in a solution neutralisation and Fe/Al removal circuit in two stages through pre-heating to between 50°C and 70°C. The resulting product will be conveyed to the direct solvent extraction plant, which comprises two separate solvent extraction circuits to produce purified Ni and Co sulphate solutions.
The nickel sulphate solution will be cooled to produce high-purity nickel sulphate hexahydrate crystals, which will be recovered by centrifugation and subsequently lightly washed, dried and packed into 1t bulka-bags.
The cobalt sulphate solution will be contacted with a reductant chemical to produce a pure solid cobalt sulphide, which will be filtered and refined using pressure leaching and crystallisation to produce cobalt sulphate heptahydrate.
The regional rail infrastructure near the project includes the Malcolm siding near Leonora, which has been supporting the Murrin Murrin operation for two decades.
The project proposes to use the existing commercial airstrip at Leonora for the transportation of personnel to and from the operation.
The project will host a single-train, 3,300tpd sulphur burning acid plant, which will feature a heat recovery system to recover excess heat. The recovered heat will be used to generate power (using steam turbines) and steam.
The power and steam required by the project will be provided by the acid plant operation, which is expected to generate approximately 21MW. Diesel generators are expected to supply power in the event of an emergency.
Water for the project will be sourced from a combination of dewatering of the Mt Kilkenny deposit, in addition to the proposed groundwater bores and local extraction system.
Golder Associates updated the geology and mineral resource estimates, while Perth Mining Consultants completed the mining study for the Mt Kilkenny, Eucalyptus, and Hepi deposits of the NiWest project.
Australia-based environmental consultant Sustainability is responsible for the review and preparation of environmental baseline studies while Prudentia Process Consulting was engaged to undertake the PFS for the NiWest nickel-cobalt project.