At its core, the mining industry is cyclical, so it makes sense that new life can be found in the discarded remnants and forgotten waste piles of previous mining operations. Once dismissed as worthless and scraps, tailings and other mine waste are now increasingly emerging as an opportunity for industry to reclaim valuable minerals.
Around the world, governments and organisations are predicting that the rise in clean energy technology will supercharge demand for critical minerals. It is expected that to meet this critical minerals demand, new mines around Australia will need to be developed.
However, Geoscience Australia’s Jane Thorne said that with such long lead times in the creation of new mines, from discovery to development, meeting the predicted demand should also include recovery and recycling innovations.
Incorporating recovery and recycling innovations would include rethinking the value proposition of existing mine tailings and rock dumps, in a bid to unlock the potential of once discarded critical minerals and diversify supply chains.
Why waste?
“Mine waste potentially contains significant amounts of previously overlooked minerals and materials that are today considered critical and/or strategic.”
Ms Thorne said that reprocessing material previously excavated during mining operations could give new life to old mining towns, create jobs, rejuvenate local economies and potentially lead to improved environmental outcomes.
“With Australia’s long history in mining, our waste material could contain considerable quantities of valuable critical minerals and strategic materials that were previously of limited economic interest. This got us thinking, what are the opportunities for critical mineral recovery from mine waste and, importantly, how can Geoscience Australia support these opportunities?”
The lack of a national mine waste database is what spurred Geoscience Australia into action.
A comprehensive mine waste directory
Work began in 2021 and in May 2023 the Atlas of Australian Mine Waste was launched by Geoscience Australia as part of the Geoscience Australia-led Exploring for the Future program. The Atlas is an interactive, online spatial mapping tool that offers accurate information on known mine tailings, waste rock, smelter residues and other related mine waste materials in Australia.
“Geoscience Australia wanted to create a national Atlas that would support Australia’s commitment to net zero emissions by 2050 and contribute to Australia’s world-leading environmental, social and governance standards.”
Ms Thorne said the Atlas is intended to be a tool used to identify and support the sustainable and economic recovery of critical minerals from prospective mine waste sites and the management of their environmental legacy.
The interactive nature of the Atlas allows users to zoom in to see specific features and read a summary of publicly known information about a waste type, how it is stored and which mine, refinery or smelter it came from. Additional information for individual sites such as the associated mineral system and geochemistry will be added as it becomes available.
To create the Atlas and help industry realise the potential in mine waste, Geoscience Australia partnered with researchers at the School of Engineering at RMIT University and the Sustainable Minerals Institute at The University of Queensland. The partnership combined Geoscience Australia’s world-class mineral resource and mineral systems understanding with world-leading mine waste research conducted by the universities.
“Together, we set about building a comprehensive understanding of mine waste distribution across the nation to generate Australia’s first national inventory – the Atlas of Australian Mine Waste. This is one of the first national datasets in the world focussed on mineral resource potential in mine waste.
“The Atlas helps identify potential new opportunities for critical minerals supply from individual mine waste sites – whether that be reprocessing tailings or reassessing the viability of old waste rock dumps with new extraction techniques in mind.”
The Atlas currently includes more than 1,400 storage facilities across Australia.
Data collection processes
According to Ms Thorne, populating the Atlas with mine waste locations is just the first step in helping industry realise the potential for sourcing critical minerals and strategic materials from mine waste.
“Realising the potential value of Australia’s mine waste requires a thorough understanding of the chemical and mineral characteristics of the different types of waste from around the country.”
Together with its partners, Geoscience Australia undertook a nation-wide mine waste sampling and analysis campaign in partnership with the state and territory geological surveys.
“Building on an approach pioneered by The University of Queensland and the Geological Survey of Queensland, this project is assessing representative sites of different deposit and mineral system types to support mine waste recycling across Australia.
“As part of the Exploring for the Future program, the researchers have sampled waste at 19 sites across Australia in order to understand the geochemical and mineral composition of these sites and determine what strategic materials and critical minerals they may contain.
“With complementary state- and territory-funded programs, over 90 mine waste sites across Australia are being similarly assessed for their metal content, concentrations and composition.”
Ms Thorne said this national consistent approach allows the results to be incorporated into the Atlas and improves confidence in the data.
Overcoming complications
Prior to this undertaking, a national dataset recording Australia’s mine waste sites did not exist.
“No project is without its challenges. You can probably imagine the sheer number of datapoints and range of datasets we needed to bring together to create this.
“Together with our university, state and territory government partners, we gathered and standardised the existing information into a single national dataset. We then went about filling the knowledge gaps and populating previously unknown sites using publicly available information in conjunction with expertise from our researchers and our partners.”
Ms Thorne attributes the success of the on-ground, national sampling campaign to the support and willingness of mining companies who provided researchers with access to their mine waste.
“Fortunately, as this project and state and territory mine waste programs have built momentum, there is greater enthusiasm for the sampling campaign. This has also led to a broader national discussion about the potential valorisation of mine waste.”
Ms Thorne said that one of the most pleasing outcomes has been the way the project has brought together a diverse range of experts and stakeholders from industry, academia and government to help build the critical mass and national momentum needed to ensure that Australia can make the most of its mine waste opportunities as a nation.
“The work has also enabled Geoscience Australia to provide leadership internationally, engaging with partners through established programs – including the Critical Minerals Mapping Initiative with the US and Canada – to establish consistent approaches in sampling and mine waste data management and enabling us to develop a more rapid understanding of critical mineral and strategic materials potential in our tailings and rock dumps globally.”
Following its launch, industry is encouraged to make use of the dataset, and there are a number of ways it can do so.
“By providing detailed information about individual mine waste sites and their associated deposits, the Atlas can be used to investigate potential critical mineral associations and provide greater understanding of the current management status of the waste sites across Australia from one location.”
Ms Thorne said the results of the sampling and analysis campaign are being progressively released and will be incorporated into the Atlas over the next six months.
“When combined, the Atlas of Australian Mine Waste is a pre-competitive toolbox, provided by the Australian Government, seeking to support mineral recovery through mine waste recycling. It provides data, information and new thinking to help inform and de-risk further investigations and investment decisions.
“Our focus is now shifting to understanding the viability of reprocessing mine waste. This includes an assessment of potential environmental, social and governance outcomes as well as legislative considerations. Understanding mineral grade and character will be fundamental to determining how mine waste sites can be economically reprocessed.
“We are incredibly grateful to the mining community for getting involved and supporting this world-leading project.”
