Australian scientists have tested digital soil mapping techniques usually used for spatial soil analysis to try to identify lithium reserves – with some success.
A team from Sydney University says the first map (Above) to be produced in this way has pinpointed the concentration and distribution of lithium (Li) across Australia, identifying potential areas for further exploration for the critical mineral.
Lead author of a paper recently published in the journal Earth System Science Data, Dr Wartini Ng, a Postdoctoral Research Fellow in Soil Security from the School of Life and Environmental Sciences, says: “Our research not only opens up new possibilities for Australia’s lithium industry but could also advance our path towards a low-carbon economy, a critical step in curbing greenhouse gas emissions.”
Ng told Cosmos the University has developed the digital soil mapping techniques to unveil soil distribution for some time, but this is the first time they’ve changed it to seek rare metals.
She says the team behind the research combined the Li point survey data from Geoscience Australia survey project and relevant environmental data in a machine learning model, to allow the model to identify potential Li presence around Australia.
Senior study author Professor Budiman Minasny, one of the leading international scientists in soil mapping and modelling, said that the findings could have significant implications for the lithium industry in Australia.
“We’ve developed the first map of lithium in Australian soils which identifies areas with elevated concentrations,” Professor Minasny said.
“The map agrees with existing mines and highlights areas that can be potential future lithium sources.”
The research paints a comprehensive overview of lithium distribution across the continent, which is influenced by a variety of environmental factors including climate, geology and vegetation.
The study indicates the highest lithium concentrations are found near the Mount Marion deposit of Western Australia, with elevated concentration across the central western region of Queensland, southern New South Wales and parts of Victoria.
Australia’s lithium exploration has predominantly centred in Western Australia, but this research indicates the potential of other Australian regions, including Queensland, New South Wales and Victoria, that display elevated predicted lithium densities.
Lithium demand is increasing for applications in batteries, phones, laptops and electric vehicles.
Higher concentrations of Li are often found in the deeper layers of soil profiles and typically, enters through the weathering of sedimentary minerals in the underlying saprolite and bedrock.
The National Geochemical Survey of collected samples at 1315 sites in most parts of the continent, but due to limitations to access, samples from some parts of South Australia and Western Australia could not be obtained.
Digital soil mapping was conducted at two depths – 0–10cm and approximately 60–80cm.
The paper says: “Overall, the model performance was on the low side, and the inclusion of the results into a prospectivity framework needs to consider the model uncertainties.
“This approach provides an estimate of the environmental background concentration of Li, which is reflecting a range of processes including source rock geochemistry from which the sediments were derived, weathering and geomorphic processes.
“The work provides a framework to better understand the processes controlling the Li concentration at the surface and the modelling effectively delineates regions with locally higher Li background.”
Despite the low prediction accuracy, the authors of the paper believe they have demonstrated a step forward in the development of machine learning in generating predictive geochemical maps.