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Australia’s Clay-Hosted Rare Earth Element (REE) Deposits: Key Insights and Challenges

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Highlights

  • Comprehensive study of 91 Australian REE exploration projects reveals distinct mineralogical and geological differences from South China’s ion-adsorption clay deposits.
  • Most Australian clay-hosted REE deposits contain less than 10% ionically adsorbed REEs, with only select regions showing higher proportions.
  • Research underscores the need for advanced exploration, technological innovations, and further study to unlock Australia’s potential in the global REE market.

A recent study led by Manuel Knorsch (opens in a new tab) of Curtin University (opens in a new tab) offers a comprehensive overview of Australia’s clay-hosted rare earth element (REE) deposits, exploring their mineralogy, economic potential, and key differences from similar deposits globally, particularly in South China. This study provides critical data on 91 Australian REE projects and analyzes their formation, mineral composition, and extractive challenges.

What’s the Premise?

The paper hypothesizes that Australia’s clay-hosted REE deposits differ significantly from the ion-adsorption clay deposits of South China in their geological formation and REE extraction potential. Researchers examined 91 exploration projects, collecting mineralogical and geochemical data to identify REE-bearing minerals and evaluate their economic viability. The study relied on advanced techniques like scanning electron microscopy (SEM) to characterize minerals from weathered granitic and mafic rocks.

REE deportment in Australian clay-hosted REE deposits and their respective mineral processing pathways. Modified after Voßenkaul et al. (2015) (opens in a new tab).

A diagram of different types of minerals Description automatically generated

Findings

The researchers discovered that Australia’s clay-hosted REE deposits are predominantly associated with granitic source rocks and contain a mix of primary minerals like monazite, allanite, and bastnäsite. During weathering, these minerals decompose into secondary forms such as rhabdophane and cerianite, though the proportion of ionically adsorbed REEs—important for economic extraction—is often less than 10%. Only a few deposits in South Australia, Queensland, and Tasmania showed ionic REE proportions above 40%, making them more comparable to South China’s deposits.

The study highlights significant regional differences: while South China’s deposits benefit from gentle slopes, humid climates, and abundant HREE-enriched granites, Australia’s flat landscapes, semi-arid conditions, and older source rocks pose challenges for similar mineralization and preservation.

Limitations and Biases

While the study provides a valuable dataset, it is limited by the infancy of Australian exploration projects—most lack feasibility studies, making economic assessments speculative. Additionally, variability in extraction test results suggests that uniform processing methods may not be suitable. There is also a potential geographic bias, with most projects clustered in Western Australia, leaving other regions underexplored.

Conclusion

The research offers a critical starting point for understanding Australia’s potential to become a global player in the REE market. However, the study underscores the need for further exploration, technological innovations in extraction methods, and more robust comparisons with established deposits worldwide. Despite challenges, this research highlights promising opportunities in Australia’s emerging REE sector.

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