The Sconi deposits are hosted in laterites which have formed on ultramafic rocks that include serpentinites, meta-gabbros and pyroxenites. These occur as lower crustal material rich in iron, magnesium and nickel. It is likely that these laterites formed following a period of prolonged weathering post the Cretaceous era.

Ultramafic rocks have a high background level of nickel and cobalt and the process of lateritisation has concentrated the nickel and cobalt to grades which have the potential to be exploited economically.

The laterite profiles are well preserved with the drill holes intersecting a complete laterite profile, from natural surface soil cover down to poorly mineralised bedrock. Each deposit varies with respect to geological profile and mineralisation, with Kokomo and Lucknow enriched in scandium, while Greenvale appears less enriched in scandium.

The Sconi Project spans three Mining Licence areas (ML 10368, ML 10366, and ML 10342) which are Greenvale, Lucknow and Kokomo respectively. The mining operation will be centred at the Greenvale site. Lucknow is located approximately 10 kilometres to the south-east with access via the Gregory Highway, while Kokomo is located approximately 60 kilometres to the north-northeast of Greenvale.

An unsealed haulage road will be constructed to connect Kokomo to the processing facility at Greenvale. Conventional open pit mining is planned for the operation at the three sites utilising a mining contractor model. The ore production schedule assumes Greenvale and Lucknow are operated as one mining area and Kokomo as a separate area. The schedule indicates that mining will be split between both areas and operated simultaneously, thereby requiring two mining fleets.

At Greenvale, ore will be delivered from the pits to a Run-of-Mine (ROM) pad adjacent to the primary crushing circuit. Ore from both Lucknow and Kokomo will be delivered to local ROM pads from where it will be loaded into road trains and transported to the Greenvale site.

The road trains will discharge their load into a purpose-built hopper bin where the ore will be crushed and processed directly or diverted to a storage stockpile on the upper level of the Greenvale ROM pad for rehandling.

Economic recovery of valuable metals requires optimised acid dosing in the Sconi project and to enable consistent acid-dosing and recovery a consistent feed blend of ore is desirable, which will be managed through stockpiling and ore blending. Operationally, the Project will use a stockpile finger blend strategy, where the ore is fed to the crusher from multiple fingers on a ROM stockpile using a front-end loader for material from Greenvale and a road train schedule for ore from Lucknow and Kokomo.

Waste material from the mine will generally be dumped onto designed waste rock dumps or backfilled into pits with a proportion of the waste mined at Greenvale used to construct embankments for the dry stacked tailings storage facilities.

Rehabilitation works will be carried out on an ongoing basis as part of the mining operation.

The Sconi Project uses a hydrometallurgical route for processing nickel and cobalt ore through to battery-grade nickel sulphate and cobalt sulphate with scandium recovery and production of high-purity scandium oxide.

The proposed process flow comprises the following key unit processes:

• Stage 1 – Leaching. Aqueous pressure leach in an acidic sulphate medium to dissolve the base metals while minimizing dissolution of the iron and silica gangue. The conditions used are typical for base metal dissolution from lateritic ores sources, with rapid leach kinetics resulting in autoclave residence times of ~60 minutes for near complete nickel and cobalt extraction. The leach discharge slurry proceeds to neutralization for removal of the free acid, iron and aluminium. The neutralised slurry is filtered and washed to separate the valuable metal in solution from the residue solids. The solids are conveyed for dry stacking.

• Stage 2 – Sulphide Precipitation. The filtered PLS solution is then subjected to sulphide precipitation to recover a high-grade nickel/cobalt sulphide product with minimal impurities.

• Stage 3 – Nickel and cobalt oxidative re-leach and secondary impurity removal. The nickel and cobalt rich sulphide intermediate is oxidised and re-leached under medium pressure and temperature to provide a high concentration, small volume stream. Solvent extraction is used to separate the nickel and cobalt.

• Stage 4 – Crystallisation of high-purity nickel sulphate and cobalt sulphate. 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. This causes the metals to begin crystallising from solution as metal sulphate hydrates. The specific form of crystal is manipulated by controlling the temperature of crystallisation. The crystals are dried and packed for shipping.

In addition to the key stages outlined, the proposed process plant also includes:
• a sulphuric acid plant for generation of acid, steam and power
• an oxygen plant
• reagent preparation facility
• water treatment plant
• plant air and cooling system.

The process comprises four basic sequential steps, all of which are well proven and commonly used in the wider metallurgical industry and provide high recoveries of base metals.