With high-grade ore deposits depleting and demand for resources continuing to increase, the mining industry is looking for ways to extract greater value from low-grade ore deposits. Compared to high-grade ore deposits, low-grade ores are more difficult to extract economically. They require the mining, movement and processing of larger quantities of ore with a substantial proportion of waste rock (gangue), making it more costly and energy intensive.
However, if the gangue is removed early enough it can bring significant cost savings to miners. It can also reduce their environmental footprint with lower per tonne energy consumption and water losses, smaller tailings facilities and reduced greenhouse gas emissions.
While some technologies have been successful identifying and sorting high-value ore from waste – they can only tackle relatively low throughput rates. A solution that accurately sorts large throughput rates can deliver massive benefits to the industry and the environment.
Recognising these benefits, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) developed a cost-effective and sustainable analyser for large-scale ore sensing and sorting. To bring this next-generation bulk ore sorting technology to market, Advisian Digital, RCF Ambrian and the CSIRO have created the company, NextOre.
MRI for mining
Taking advantage of magnetic resonance technology, the CSIRO’s analyser rapidly identifies ore grade so large volumes of gangue can be rejected before entering the plant. This significantly reduces the amount of energy and water needed for processing.
By illuminating batches of ore with short pulses of radio waves, magnetic resonance penetrates through ores – much like medical MRI ‘sees into’ human bodies – to rapidly and accurately detect ore grade. This can ultimately be used to extend the life of current mines or get undeveloped, low-grade mines into production. While the productivity benefits vary depending on the characteristics of the ore body, the analyser has the potential to double the ore grade once sorted.
It has an advantage over other ore sorting analysers that can often only go ‘skin deep’ to detect mineral particles on the surface of ore, producing less reliable results. The magnetic resonance analyser can be applied to copper, gold and iron-bearing ores among others.