Ardea Resources’ high-tech mineral processing technique has boosted the nickel-cobalt inventory at its Goongarrie Hub project near Kalgoorlie in Western Australia and earned it a healthy Federal Government grant of $1.1 million.
It comes less than two months after a giant Japanese consortium committed to backing the development of the project described by the Federal Government as “globally significant”. Sumitomo Metal Mining and Mitsubishi Corporation have agreed to jointly fund a $98.5 million definitive feasibility study (DFS) for Goongarrie Hub, which is part of Ardea’s wider Kalgoorlie Nickel Project (KNP).
Ardea Resources rust-coloured goethite and whitish magnesite saprock is helping reduce costs at its Goongarrie Hub nickel project in WA.
The company’s “mineralised neutraliser” (MN) process is protected by an international patent application and has been proven by metallurgical testwork, resulting in significant savings to the company and a reduced carbon emissions footprint at Goongarrie Hub.
The method uses the magnesite saprock that occurs within and most commonly at the base of the nickel-cobalt laterite profile at the site. Once it has been mined, the target magnesite neutraliser is sourced by a simple wet screen separation of the magnesite-goethite-serpentine clay saprock into separate “fines” and “scats”.
The goethite-serpentine mineral comprises the “fines” with the oversized “scats” material of magnesite used to neutralise the sulphuric acid discharged from the high-pressure acid leach (HPAL) or atmospheric leach (AL) circuits. Scats material contains elevated nickel-cobalt grades and results in a 16 per cent boost to the project’s metal inventory.
Ardea says it gleans several benefits from the MN process, ranging from not having to purchase and transport considerable quantities of a limestone-calcium-type neutraliser to site and the resulting reduction in carbon emissions, in addition to the extra nickel-cobalt production from the scats material.
The company has calculated a significant cost reduction in using less sulphuric acid due to the amount of magnesite neutraliser it will produce. It estimates a sulphuric acid cost of about $290 per tonne of nickel, compared to its peers’ costs that it believes are closer to $500 per tonne due largely to their need to purchase limestone.
Ardea’s massive KNP consists of an 854 million-tonne resource at 0.71 per cent nickel and 0.045 per cent cobalt for a total of 6.1 million tonnes of contained nickel and 386,000 tonnes of contained cobalt. Goongarrie Hub comprises the bulk of the resource, with 584 million tonnes going 0.69 per cent nickel and 0.043 per cent cobalt.
The three main deposits at the Hub are Goongarrie, Highway and Siberia North. All three sit within granted mining leases and ground that is 100 per cent controlled by the company.