2.11 Potential for Australian critical commodity production
Consideration of the geological occurrences of the critical commodities described in Part 2 of this report together with the assessments of criticality of commodities documented in Part 1, leads us to conclude that almost all of the critical commodities considered in this study can be grouped into three families of mineral systems. The potential for each of these groups of critical commodities are summarised below.
Mineral system family (1): Mafic-ultramafic-related nickel, platinum-group elements, chromium and cobalt—These commodities are among the most critical commodities for the world’s major economies, and are assessed in this study as high potential for Australia. Their geological occurrence is closely related to mafic-ultramafic igneous intrusions, particularly for Ni, PGE and Cr. Based on known resources in Australia, the continent appears to be under-represented in world-class intrusion-hosted Ni, PGE and Cr deposits. However, the country’s geology and in particular the presence of many previously unrecognised large igneous provinces leads us to conclude that Australia is highly prospective for major deposits of Ni, PGE and Cr. Nevertheless, there are significant challenges for mineral exploration companies targeting intrusion-hosted Ni and/or PGE and/or Cr deposits, including: (a) locating the host mafic-ultramafic igneous complexes in remote areas where the prospective rocks are concealed beneath regolith and sedimentary basins, and (b) targeting the most prospective parts of these complexes.
Mineral system family (2): Felsic igneous-related rare-earth elements, tungsten, niobium, tantalum, molybdenum, beryllium, tin and bismuth—These commodities are ranked as high or medium potential in this study, and are mostly of high criticality for major economies. All of these metals occur (albeit not exclusively) in association with felsic igneous intrusions, in particular with either highly-fractionated granitic rocks and/or with alkaline igneous rocks. Potential exists in the regions where deposits of these metals are already known in Australia (brownfields), and in the under-cover extensions of these mineral provinces (brownfields to greenfields). Understanding the distribution of alkaline-igneous rocks in Australia is rudimentary at present, but information available from diamond explorers in their search for kimberlites, carbonatites and other alkaline-igneous intrusive rocks may assist in identifying new greenfields targets for commodities such as REE, Nb and Cu.
Mineral system family (3): Heavy mineral sand-hosted zirconium, titanium, rare-earth elements and thorium—These commodities rank as high to moderate potential and criticality (except for a low criticality ranking for Th). They are either major commodities (Zr, Ti) or are potential by-products (REE, Th) of heavy mineral sand mining. New discoveries of heavy mineral sand provinces recently in Australia attest to the potential of the continent for further delineation of major resources of heavy mineral sands.
In addition to these mineral system families, a group of metals and semi-metals including antimony, indium, gallium, germanium, cadmium, tellurium and selenium are primarily the by-products of the refining of the major commodities Zn, Cu, Pb, Au, Al and Ni. Australia’s high global ranking in resources of all of these major commodities implies that there is significant potential for new or increased production of the minor-element by-products listed above. However, some of the impediments in exploiting this potential include: (a) lack of (public) knowledge of minor-element compositions of Zn, Pb, Cu, Au, Al and Ni ores and concentrates from many of Australia’s major mines and refineries, (b) metallurgical issues in extracting the by-products, and (c) economic viability of extracting the by-products.