Predicting reserves of lithium

What is the link between TERN, Australia’s national ecosystem research infrastructure, and lithium, a chemical element Australia and many countries see as critical to their transition towards a lower carbon economy? 

The answer lies in a new paper, Digital soil mapping of lithium in Australia, written by authors from Sydney University (including TERN Science Advisory Committee member, Professor Alex McBratney) and Geoscience Australia. The paper was published in “Earth System Data” in June. 

The authors of the paper developed a new digital soil map specifically to identify potential locations of elevated lithium concentrations in Australia. With this critical element being used in the increasing number of batteries, phones, laptops and electric vehicles, not surprisingly, the study has already featured in Australian Manufacturing, which reported to its industry readers that the map agrees with locations of existing lithium mines and highlights areas that can be potential future lithium sources

Critical elements

Critical elements such as lithium are among the chemical elements you learned about in school lessons on the Periodic Table. They are classed as critical because they are the ones in demand – but which will be available in limited supply in the near future. While Australia is currently the world’s leading supplier of lithium, an ability to predict additional locations of extractable and sustainably mineable lithium in Australia will extend the element’s availability to industry and therefore, help Australia maintain its momentum towards a net zero carbon economy. 

NCRIS-enabled AuScope in The Minerals Challenge described the need to keep exploring for critical minerals as follows:

“Australia has benefited enormously from diverse and rich mineral endowment for almost two centuries, but it now faces an urgent challenge: finding enough of the right minerals in more complex environments to supply emerging low carbon economies globally.”

The focus for lithium exploration in Australia has been salt lakes and mineral deposits. Lithium-rich salt lakes are not an economic source of the element for Australia and to date, Australia has concentrated on mining ore deposits where rocks such as spodumene contain the sought-after lithium. Significantly, lithium is also found in trace amounts in all soil types across our continent – this is the lead followed by the researchers in their paper.

Australian soils

In developing the digital soil map for lithium, the researchers drew upon datasets from the National Geochemical Survey of Australia (NGSA) and TERN’s Soil and Landscape Grid of Australia, along with a cubist model. The TERN data product includes data about soil attributes such as texture, structure, and density and the known distributions of environmental covariates like rainfall, parent material, vegetation, and landforms, all of which affect soil formation. The TERN Soil and Landscape Grid product uses the best available data from existing databases, TERN sensor measurements and novel spatial modelling to present fine spatial resolution (3 arc-seconds or approximately 90 x 90 m pixels) digital soil and landscape attribute maps.

The paper concluded that despite most mineral exploration for lithium being conducted in Western Australia, the digital soil mapping of lithium predicts other regions (such as Queensland, New South Wales, and Victoria) have elevated lithium concentrations and could become potential areas of interest.

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