Rare Earths

Updated February 2023

Rare Earth properties and uses

Rare earths elements (REE) were named by Johann Gadolin in 1794 for a group of chemically similar, metallic elements with atomic numbers 57 through to 71. In order from lightest to heaviest atomic mass, these are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).

These elements are commonly known as the lanthanide series and are divided into light rare earths (lanthanum–europium) and heavy rare earths (gadolinium–lutetium). Yttrium (Y) and scandium (Sc) are also generally included in the rare earth group because of their similar chemical properties.

Rare earth elements are vitally important in modern technologies due to their unique electrical, magnetic, catalytic, metallurgical, nuclear and luminescent properties. REE have a diverse range of applications, some of which include:

high-powered magnets (Nd and Pr), high-temperature magnets (Dy, Sm, Te) and very-high-power magnets (Ho)
light-emitting-diode (LED) lights – used in screens for televisions, computers and smart phones
catalytic converters (La and Ce)
batteries (lanthanum-based anodes in nickel-hydride used in electric vehicles)
MRI imaging (Gd)
currency security (Eu)
colouring agents in glass and ceramics.

Rare Earths in South Australia

South Australia currently has no rare earths production. However, there are a number of known REE deposits in South Australia and a significant amount of rare earths exploration is currently being undertaken across the state. Rare earths in South Australia are associated with multiple deposit styles. These include heavy mineral sands, ionic clays and iron oxide-copper-gold (IOCG) deposits.

Heavy Mineral Sands

Heavy mineral sand deposits often contain rare earth ore minerals such as zircon, xenotime and monazite. South Australia has two heavy mineral provinces, in the Eucla Basin (western South Australia) where the Jacinth-Ambrosia mine is located, and the Murray Basin (eastern South Australia), which hosts the Mindarie deposit. Rare earths are not currently produced at these deposits.

Ionic adsorption clay

Ionic adsorption clay (IAC) mineralisation is where positively charged rare earth elements are attached to negatively charged clay particles by ionic bonding (bonding between positively and negatively charged particles). This style of mineralisation is not typically associated with high REE grades, but there are a number of other factors that make these deposits highly advantageous compared to other styles of REE mineralisation. These include:

Clays are soft and easy to mine and they typically occur near surface, minimising initial mining costs.
Ionically adsorbed REEs are much easier to extract than REE from traditional minerals such as bastnaesite, monazite and xenotime, which significantly reduces processing costs.

Ionic adsorption clay rare earths have recently become a highly prospective target for exploration in South Australia, following the discovery of the Koppamurra deposit in the state’s southeast. A large amount of exploration for this style of mineralisation is currently occurring across the state with promising results. These areas include the southern Flinders Ranges, Eyre Peninsula, northern Gawler Craton and in the southeast of the state, adjacent to the Koppamurra deposit.

Iron oxide-Copper-Gold

South Australia's iron oxide-copper-gold (IOCG) deposits that formed during the early Mesoproterozoic in the eastern Gawler Craton are often associated with elevated concentrations of rare earths.

The hematite breccias at the Olympic Dam deposit are highly enriched in REEs. Five hydrothermal REE phases have been identified: bastnaesite, florencite, monazite, xenotime and britholite. BHP currently do not produce rare earths from the Olympic Dam deposit.

Elevated REE values have been recorded at the Carrapateena deposit, with a noteworthy interval of 178.2 m averaging 0.21% Ce and 0.13% La between 476 to 654.2 m. Anomalous rare earth concentrations have also been intersected at the Vulcan prospect, approximately 40 km north of Olympic Dam, with a five metre zone averaging 0.29% Ce and 0.18% La between 947 m to 952 m.

The Victory U-REE Prospect, approximately 150 km northeast of Coober Pedy, has also demonstrated REE potential. Surface sampling identified anomalous values of 412 ppm uranium and 0.39% REE.

Major mines

South Australia currently has one operational heavy minerals mine and another in care and maintenance. Although these mines are not currently producing rare earths, heavy minerals such as zircon are known to contain economic concentrations of rare earths.

Jacinth-Ambrosia (Iluka Resources) – Largest zircon mine in the world, with a total resource of 208.5 Mt material at 2.7% heavy minerals (5.7 Mt contained heavy minerals). Heavy mineral sands are 48.8% zircon, 27% ilmenite and 5.7% rutile.
Mindarie (Murray Zircon) – Total resource of 243.9 Mt material at 3.1% heavy minerals (7.5 Mt contained heavy minerals). Heavy mineral sands are 17.4% zircon, 44.4% ilmenite, 5.0% rutile and 7.4% leucoxene. Currently in Care and Maintenance.

Developing projects

Koppamurra (Australian Rare Earths) – Ionic clay-hosted deposit with a total resource of 81 Mt at 785 ppm total rare earth oxide (TREO)
Atacama (Iluka Resources) – Total resource of 93 Mt material at 7.63% heavy minerals (7.6 Mt contained heavy minerals). Heavy mineral sands are 13% zircon, 69% ilmenite and 2.0% rutile. Currently undergoing feasibility studies.
Sonoran (Iluka Resources) – Total resource of 27.9 Mt material at 7.4% heavy minerals (2.0 Mt contained heavy minerals). Heavy mineral sands are 17% zircon, 67% ilmenite and 2.0% rutile.
Tripitaka (Iluka Resources) – Total resource of 53.7 Mt material at 1.9% heavy minerals (1.0 Mt contained heavy minerals). Heavy mineral sands are 64% zircon, 11% ilmenite and 5.0% rutile.
Typhoon (Iluka Resources) – Total resource of 26.3 Mt material at 6.3% heavy minerals (1.5 Mt contained heavy minerals). Heavy mineral sands are 13.2% zircon, 62.7% ilmenite and 0.9% rutile.

Additional reading

Blissett AH 1976. Rare Earths - South Australia. In: Knight, C.L. (Ed.), Economic geology of Australia and Papua New Guinea, 4, Industrial minerals and rocks. Australasian Institute of Mining and Metallurgy. Monograph Series 8:329–330.

Drexel JF and Major RB 1990. Mount Painter uranium-rare earth deposits. In: FE Hughes (Ed.), Geology of the mineral deposits of Australia and Papua New Guinea. Australasian Institute of Mining and Metallurgy. Monograph Series 14:993–998.

Harben PW and Kuzvart M 1997. Industrial minerals - a global perspective. Industrial Minerals Information Ltd, Surrey, UK, pp.330–340.

Reeve JS, Cross KC, Smith RN and Oreskes N 1990. Olympic Dam copper-uranium-gold-silver deposit. In: Hughes, F.E. (Ed.), Geology of the mineral deposits of Australia and Papua New Guinea. Australasian Institute of Mining and Metallurgy. Monograph Series 14:1009–1035.

Robertson RS, Preiss WV, Crooks AF, Hill PW and Sheard MJ 1998. Review of the Proterozoic geology and mineral potential of the Curnamona Province in South Australia. AGSO Journal of Australian Geology and Geophysics 17(3):169–182.