Africa|Copper|Energy|Environment|Exploration|Innovation|Mineral Processing|Mining|Platinum|Resources|Sensor|Technology|Waste|Environmental|Waste|Operations
Africa|Copper|Energy|Environment|Exploration|Innovation|Mineral Processing|Mining|Platinum|Resources|Sensor|Technology|Waste|Environmental|Waste|Operations

Pursuing critical minerals in discard, tailings

An image of Sean Browne and Geoff Linnell

SEAN BROWNE & GEOFF LINNELL Reprocessing mine discard and tailings could create new mineral resources from which currently in-demand minerals could be easily sourced

1st September 2023


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The metals-intensive transition to a low-carbon economy has cast a spotlight on the mining sector’s ability to supply the large amounts of raw materials required for the energy transition, explain commodity resource specialist Acrux Resources executive directors Sean Browne and Geoff Linnell.

The past few years of under investment in new supply for many metals, combined with rising demand, has led to a minerals shortfall, most specifically the critical minerals needed for the energy transition including copper, cobalt, lithium, vanadium, nickel and others.

They say it is imperative that alternative ways to meet this demand are found, and quickly.

Browne and Linnell explain that, according to the International Energy Agency, to meet the goals of the Paris Agreement, sectors contributing to the energy transition will be responsible for over 45% of total copper demand, 61% of nickel demand, 69% of cobalt demand, and 92% of lithium demand, by 2040.

Being aware of the gap created between the future demand for critical minerals and the speed at which the mining industry can supply these minerals, Browne and Linnell state that new mineral recovery technology innovation can supplement mineral exploration in unlocking additional sources of mineral resources.

As an alternative to the 10 to 15 years that it takes to find, prove, develop and ramp up most mines, which they say is incompatible with the speed at which demand for metals is increasing, Browne and Linnell believe that a significant amount of mineral resource opportunities exist in the form of discard dumps and tailings dams.

These “mega deposits” are rich in minerals and metals and are easy to economically exploit with the right technology, they say, which can be easily capitalised from to produce in-demand minerals, at short notice.

In mining, both discards and tailings materials are created as the final by-product of the mining process.

In terms of the remining or retreatment of mine discard or tailings, Browne and Linnell state that the advancement of related technologies could provide the “perfect opportunity” for resource owners to bring discarded ore bodies and tailings dams to account, even in a supressed commodity price environment.

In South Africa, the world's foremost producer of platinum-group metals (PGMs), a significant amount of minerals can be obtained from the country’s vast amounts of PGMs tailings, that are found in the Bushveld Complex in the Limpopo and North West provinces.

As a result of the way that PGM-rich tailings have been historically processed in South Africa – by grinding ore down to an ultrafine size of below 100 μm – the residual material is too fine to recover any of the remaining chrome-rich co-product from the tailings material, thereby effectively sterilising this chrome material.

However, Browne and Linnell point out that the inability to recover this chrome-rich co-product has meant that several large-scale tailings dams – containing hundreds of millions of tonnes of ultrafine chrome, grading as high as 34% contained chrome – have been left sterilised.

“We therefore believe that implementing a mineral processing solution to recover this valuable material from the tailings would have the same effect as discovering the largest chrome discovery of this century,” states Browne and Linnell.

They explain that Acrux Resources has undertaken the necessary research, development and innovation to develop and support new technologies capable of unlocking the value of discard dumps and tailing dams, enabling them to address the current supply side squeeze for the metals needed in the energy transition.

Transforming Liabilities into Value

Mineral recovery technology company FineTech Minerals, in which Acrux Resources is a shareholder, specialises in the recovery of fine and ultrafine oxide mineral particles.

Through its unique and scalable mineral recovery process, which can be easily integrated into existing mineral processing operations, large volumes of valuable metallic oxide ore mineral content, in the form of fine and ultrafine particles, can be recovered from historic or current arising tailings waste, across multiple commodities and geographies.

By making use of this mineral recovery process, FineTech Minerals has been able to effectively “discover” a sizeable chrome mineral reserve from the Upper Group, Middle Group and Lower Group chromite reef discards and tailings in South Africa.

FineTech Minerals has successfully recovered a significant amount of chromite material of 100 μm and finer from tailings material that has already been processed.

The use of this innovative technology has turned what was once uneconomical, unviable PGMs- and chrome-rich waste material into a mega mineral reserve, highlight Browne and Linnell.

Similarly, Acrux Resources’ sensor-based sorting technology subsidiary Acrux Sorting Technology, is able to use separation technology to economically recover manganese from low grade discard dumps.

The company has undertaken a comprehensive testwork study to separate manganese from gangue material through its multi-sensor technology.

The net effect for miners, say Browne and Linnell, would be an increase both in bottom line performance as well as an increase in mineral reserves as lower grade material becomes economical to mine and process.

Innovative processing technologies can turn these environmental liabilities into significant mineral reserves, thereby providing a meaningful addition to exploration, in turn creating value from something that was once valueless.

This technology inadvertently reduces a resource owner’s environmental liabilities and risks and, in turn, improves their environmental, social and governance scorecards.

Edited by Donna Slater
Features Deputy Editor and Chief Photographer



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