Rare Earth Elements
The largest Rare Earth Elements (REE) deposit in the world is the Bayan Obo deposit in China, which has resources totalling at least 48 million tonnes of rare earth oxides (REO) out of a world total of 95.27 million tonnes. Australia’s share of the world’s economic resources of REO is modest at 1.65 million tonnes. Until 1995, Australia was a major producer of REO from monazite, a by-product of heavy mineral sand mining for ilmenite, rutile and zircon. There is no current production of rare earths in Australia, but with one REO project under construction in Western Australia and feasibility studies underway in the Northern Territory and New South Wales, Australia could become a producer once again.
Rare Earth Properties and Uses
Rare earths are a group of 15 elements with atomic numbers ranging from 57 to 71. In order of their respective atomic numbers the elements are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Two other elements, scandium and yttrium, are commonly classed as rare earths because of their natural association with rare earths.
The rare earths are a relatively abundant group of elements which range in crustal abundance from cerium at 60 parts per million (ppm) to lutetium at 0.5 ppm.
The most significant increases in demand for REO is attributed to a predicted expansion in hybrid cars, followed by petroleum catalyst, glass manufacturing and polishing and multi-level electronic components. The smallest sector by volume, but largest by value, is europium and terbium, which are used in the production of phosphors for televisions and energy efficient light globes.
Rare Earth Production and Exports
Although there is no current production of rare earths in Australia, mining begun in 2007 at the Mount Weld deposit in Western Australia, which led to around 98,000 cubic metres of ore being stockpiled awaiting the completion of a concentration plant at the mine site. The concentrates will be exported to an advanced materials plant being built in Malaysia.
In other projects, the Nolans Bore rare earth-phosphate-uranium-thorium deposit in the Northern Territory and the Dubbo Zirconia Project Toongi zirconium-hafnium-niobium-tantalum-REO deposit in New South Wales are each undergoing a feasibility study.
Globally, the production and resources of rare earths is dominated by China, which accounts for about 97 per cent of the production followed by India with about two per cent. These figures are only approximate because the production for the Commonwealth of Independent States, which is made up of former members of the Soviet Union, is not available.
REO Resources and World Ranking
China holds 36 million tonne or 37.8 per cent of the world’s economic resourses for REO, followed by the Commonwealth of Independent States with 19 million tonne or almost 20 per cent and the USA with 13 million tonnes or 13.7 per cent. Australia accounts for 1.73 per cent of world Economic Demonstrated Resources (EDR) at 1.65 million tonne.
The only production of REO from a carbonatite has been from the Mountain Pass deposit in California, which has total resources of 1.8 million tonne REO at an average grade of about 9 per cent REO.
Exploration and Discovery
Small-scale production of rare earths began in Australia at Byron Bay in New South Wales in the 1950s with a small quantity of monazite being processed to produce cerium oxide for glass polishing. In 1969, cerium, lanthanum, yttrium and thorium compounds were produced at Port Pirie in South Australia from locally produced monazite. However, the plant ceased operations in 1972.
Historically, Australia has exported large quantities of monazite from heavy mineral sands mined for the extraction of both rare earths and thorium in Western Australia, New South Wales and Queensland resulting in the export of 265 kilotonne between 1952 and 1995.
During the past decade there has been strong growth in demand for rare earths as a result of emerging technology applications in catalysts, glass, polishing, metal alloys and magnets, which accounts for about 80 per cent of the current total annual demand of around 124,000 tonne of REO.
Geoscience Australia Programs
The rare earth deposits associated with thorium are described in A Review of the Geochemical Processes Controlling the Distribution of Thorium in the Earth's Crust and Australia's Thorium Resources. Geoscience Australia Record 2008/5.
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