The growing demand for clean energy technologies is anticipated to drive an increase in production of minerals, such as graphite, lithium and cobalt, with a portion of this demand being able to be met through the remining of tailings dumps, reports mine modelling solutions company IMDEX.
International financial institution the World Bank estimates that more than three-billion tonnes of minerals and metals will be needed for the wind, solar, geothermal power and energy storage requirements of projects to be built to meet carbon reduction targets.
With existing resources either depleted or declining in quality, and new resources proving hard to find and mine, tailings serve as an attractive minerals source.
The value of precious, critical and strategic metals contained in tailings globally is estimated to exceed $3.4-trillion, according to the Minerals Research Institute of Western Australia.
IMDEX chief geoscientist Dr Dave Lawie emphasises the role of technology in assessing and extracting valuable materials from tailings, noting that there is a shifting sentiment, particularly in Europe, towards reviving old mines to meet the growing demand for metals.
“You could probably bring these mines back with much less local community and environmental impact and much better environmental, social and governance credentials,” Lawie says.
Lawie acknowledges that to remine tailings, the materials need to be analysed because some tailings are old stock, having been in place for many years and therefore records of their composition are poor.
Reprocessing offers value by recovering valuable material in tailings left behind by past and inefficient mining practices, with modern processing methods being used to find new uses for the tailings, and by creating value from an asset that would otherwise be carried as a liability by mining companies, Lawie explains.
“Some of the older processing plants and processes weren’t that efficient compared to today’s technology and the recovery might have been [between] 70% to 80%, which means 20% to 30% of the valuable material is still sitting in the tailings,” he elaborates.
Lawie also notes the value presented by tailings material itself, highlighting research done by various groups, such as restoration and remining enterprise Regeneration Enterprise, to determine alternative ways to use tailings.
“Reprocessing the tailings means you can potentially turn it into something valuable,” he adds.
Acknowledging that it is challenging to start remining waste initiatives, Regeneration chief innovation officer John Thompson emphasises the importance of technologies and partners in addressing challenges associated with pursuing remining waste.
Diversified miner Rio Tinto was Regeneration’s first investor and is a site and technology partner.
“There are hundreds of thousands of sites – a huge amount of material to work on; legacy messes that we as an industry have left. How can society like us when we leave these scars, so we have to address them,” Thompson concludes.