Content maintained by Yanis Miezitis and Dean Hoatson
Content maintained by Yanis Miezitis and Dean Hoatson
The rare earth elements (REEs) are a group of 17 metals which comprise the lanthanide series of elements: 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), in addition to scandium (Sc) and yttrium (Y), which show similar physical and chemical properties to the lanthanides. The REEs have unique catalytic, metallurgical, nuclear, electrical, magnetic and luminescent properties. Their strategic importance is indicated by their use in emerging and diverse technologies that are becoming increasingly more significant in today’s society. Applications range from routine (e.g., lighter flints, glass polishing mediums, car alternators) to high-technology (lasers, magnets, batteries, fibre-optic telecommunication cables) and those with futuristic purposes (high-temperature superconductivity, safe storage and transport of hydrogen for a post-hydrocarbon economy, environmental global warming and energy efficiency issues). Over the past two decades, the global demand for REEs has increased significantly in line with their expansion into high-end technological, environmental and economical environments (Hoatson et al 20111).
During the past couple of years Sc bearing lateritic nickel-cobalt (Ni-Co) deposits have attracted increasing attention in response to anticipated rise in demand for Sc. Zirconia stabilised with Sc rather than Y as an electrolyte for Solid Oxide Fuel Cells (SOFCs) reduces the operating temperature of the fuel cell significantly, thereby providing a much longer life. SOFCs are expected to play a major role in the developing battery powered electric transportation industry (cars, trucks, trains, etc) as well as in stationary applications such as electricity generation in the home or as a substitute for coal fired power plants2.
The group of REEs is variously, and inconsistently, reported by companies as light REEs consisting of La, Ce, Pr, Nd and, sometimes, Sm. Heavy REEs may start with Sm, followed by Eu through to Lu. However, the heavy REEs are sometime subdivided further into middle REEs comprising Sm, Eu, Gd, Tb and Dy with the remainder of the group, Ho to Lu, referred to as the heavy REEs. Because of inconsistent reporting, the component elements of light, medium and heavy REEs are best noted in each case. The resources of REEs are usually reported as rare earth oxides (REO). Kingsnorth3 grouped La to Nd as light REEs, or Ceric, Sm to Gd as medium REEs and Tb to Lu plus Y as heavy REEs, or Yttric.
|Rare Earth Oxide||Application||Nolans Bore %||Mount Weld %||Mountain Pass USA %||Baiyunebo China %|
|Lanthanum||Petroleum cracking catalysts, batteries (NiMH)||19.74||25.6||33.2||27.1|
|Cerium||Autocatalyst, glass, polishing||47.53||45.74||49.1||49.86|
|Europium||Phosphors, nuclear control applications||0.4||0.55||0.12||0.19|
|Gadolinium||Intravenous contrast agents, phosphors||1.0||0.97||0.17||0.4|
|Dysprosium||Magnets (NdFeB), lasers||0.33||0.16||0.3|
|Other Rare Earths (Ho, Er, Tm, Yb, Lu)||0.21||0.04||0.16||0.03|
|Yttrium||Phosphors, metal alloys||1.32||0.37||0.1||0.2|
The REEs are a relatively abundant group of elements which range in crustal abundance from Ce, which is the twenth-fifth most abundant element at 60 parts per million (ppm), to Lu, the sixty-first most abundant at 0.5ppm.
|Application||Examples||Rare Earth Elements|
|Light Weight Magnets||Cars
Light weight magnets in motors for windows, windscreen wipers, starter motors, alternators, etc
Magnets in disc drives for computers, data storage, portable music players (e.g. iPods), video recorders, consoles, video cameras
|Nd, Pr, Sm, Dy, Tb|
La, Ce, Nd, Pr, Sc
|Hybrid vehicles|| Electric motors and generators
|Nd, Pr, Dy, TbLa, Nd, Ce|
|Compact fluorescent lights, energy saving lamps||Eu, Tb, Y, Sc|
|Polishing powders||TV and computer screens
LCD, Plasma, CRT
Precision optical and electronic components
|Ce, La, Pr, Sc|
|Glass additives||CRT screens to stabilise glass from cathode ray
Small optical lenses
TV and computer screens
|Ce, Er, Gd, Tb, La, Nd, Yb, Pm, Sc|
|Ceramics||Dy, Er, Pr, Gd, Ho, Ce, La|
Geoscience Australia’s estimate of Australia’s rare earths reported as REO on 31 December 2011, amounted to 2.03 million tonnes (Mt) of Economic Demonstrated Resources (EDR), 0.41Mt Paramarginal and 34.48Mt in the Submarginal Resource categories.
There is a further 25Mt REO in the Inferred Resources category. About 53Mt REO (predominantly La and Ce) of the Submarginal and Inferred Resources are in the Olympic Dam iron oxide-copper-gold deposit in South Australia (SA). The REO at Olympic Dam are not recovered in current mining operations and finish up in the tailings storage facility at the mine site. About 6190 tonnes of Sc, mostly in the Subeconomic and Inferred categories were reported in 2011. In addition, about 56 140 tonnes of Paramarginal and Inferred Resources were reported as REEs.
Significant resources of REEs are contained in the monazite component of heavy mineral sand deposits, which are mined for their ilmenite, rutile, leucoxene and zircon content. Monazite is a rare earth-thorium-phosphate mineral found within heavy mineral sand deposits in Australia. Using available information, Geoscience Australia estimates Australia’s monazite resources to be in the order of 7.4Mt. Assuming the REO content of monazite to be about 60 per cent, the heavy mineral deposits could hold a resource of around 4.44Mt contained REO. Currently, extraction of REEs from monazite is not viable because of the cost involved in the disposal of thorium and uranium present in the monazite.
Historically, Australia has exported large quantities of monazite from heavy mineral sands mined in Western Australia (WA), New South Wales (NSW) and Queensland (Qld), for the extraction of both REEs and thorium. Between 1952 and 1995, Australia exported 265 kilotonnes (kt) of monazite with a real export value (2008 dollars) of $284 million (Australian Bureau of Statistics 2009)5.
Small-scale production of REEs has taken place in Australia but records on these activities are incomplete. The following information on historical attempts to establish a rare earth production industry in Australia is drawn from Cooper 19906. In the 1950s, Zircon Rutile Ltd at Byron Bay, NSW, processed a small quantity of monazite to produce cerium oxide for use in glass polishing. In 1969, Rare Earth Corporation of Australia Ltd, operating at Port Pirie, SA, began producing cerium, lanthanum, yttrium and thorium compounds from locally produced monazite. However, the plant ceased operations in mid 1972 because of a lack of working capital and the difficulty of breaking into world markets for processed rare earths.
In January 1987, it was announced that the French chemical company Rhone-Poulenc proposed to build a two-stage monazite processing plant at Pinjarra in WA to produce rare earths from monazite, but the project was suspended. Deckhand Pty Ltd, a wholly owned subsidiary of Currumbin Minerals, was blocked in 1988 on environmental grounds from establishing a rare earths processing plant at Lismore, NSW. SX Holdings Ltd of SA was planning to establish a plant at Port Pirie to process monazite with a 2000 tonnes per annum (tpa) cracking and separation plant but the project did not proceed.
Barrie (1965)7 reported that a pegmatite deposit six kilometres east of the Cooglegong crossing, WA, was worked in 1913 and 1930 and yielded about two tonnes of gadolinite (yttrium iron beryllium silicate (Ce,La,Nd,Y)2FeBe2Si2O10). An analysis of Cooglegong gadolinite yielded 45.78% of yttrium trioxide (Y2O3) and 4.81% of other REO. Note that gadolinite does not contain more than trace amounts of gadolinium.
In 2007, mining operations commenced at the Mount Weld deposit in WA and around 98 000 cubic metres of ore has been stockpiled pending the completion of a concentration plant at the mine site. There has been no recorded production of REO in Australia during the period 2007 to 2011.
Globally, the production and resources of rare earths are dominated by China followed by India. China accounts for about 94 per cent of the production but this is expected to fall to 70 per cent by 2015 (Roskill, 20128) while India accounts for about two per cent. These figures are only approximate because production for the Commonwealth of Independent States, which is made up of former members of the Soviet Union, is not available.
The main consumers of rare earths are China, the USA, Japan, Korea and Thailand with China reportedly accounting for about 70 per cent of the world’s consumption in 2011 (Roskill op. cit.).
According to Roskill (op. cit.), all the growth in demand between 2005 and 2010 of 11 per cent per year was from China while growth in the rest of the world fell by almost four per cent per year. The reduction was largely the result of the global economic downturn in 2009 and a tightening of the Chinese export quota in 2010, which restricted availability. In the years to 2015, the main demand driver will be the use of rare earths in neodymium-iron-boron (NdFeB) magnets, which are forecast to grow between 11 and 13 per cent per year as potential markets expand to include applications in permanent magnet motors for electric vehicles and wind turbines. Magnets could account for nearly one third of demand by 2015. Strong growth in demand is forecast also for rare earths in nickel-metal hydride (NiMH) batteries, phosphors, optical glass and ceramics.
Lynas Corporation Limited reported in May 20119, that demand for rare earths of 127 000 tonnes in 2010 is set to increase to about 177 200 tonnes in 2014.
China has continued a nationwide crackdown on the illegal mining of rare earths. In addition, it has been reported that on 6 August 2012 China’s Ministry for Industry and Information Technology introduced new restrictions which are expected to reduce the existing 23 rare earth mines in China by one third and the 99 smelting and extracting operations by up to a half10.
China holds 55Mt (48.2%) of the world’s economic reserves for REO, followed by the Commonwealth of Independent States with 19Mt (16.7%) REO and the USA with 13Mt (11.4%)11. Australia’s EDR accounts for 1.82% of world’s economic reserves with 2.07Mt REO.
The main types of REE deposits worldwide include the Bayan Obo deposit in China, which is predominantly REE-iron ores with bastnasite and monazite as the main REE bearing minerals. The only production of REOs from a carbonatite has been the Mountain Pass deposit in California, which has 35.35Mt of Measured, Indicated and Inferred Resources at 6.35% REO (2.24Mt REO). Deposits associated with carbonatite laterites, include Araxa in Brazil which has 28.29Mt of Measured, Indicated and Inferred Resources at 3.754% REO (1.06Mt REO) and Mount Weld in WA which has 23.94Mt at 7.867% REO (1.88Mt REO). Other deposit categories with significant REO resources include a vein type at Nolans Bore in the Northern Territory (NT) and an alkaline trachyte deposit at Toongi in NSW, along with a peralkaline syenite deposit at Lovozero in Russia.
Lynas Corporation Ltd: The Mount Weld deposit in WA occurs within a lateritic profile developed over an alkaline carbonatite complex. On 12 January 2012, Lynas reported Measured, Indicated and Inferred REO resources for the Central Lanthanide deposit at a cut-off of 2.5% REO of 14.949Mt at 9.8% REO including Y2O3. An updated resource for the Duncan Deposit in the weathered carbonatite complex stands at 8.992Mt of Measured, Indicated and Inferred Resources at 4.8% REO including Y2O3. In another part of the carbonatite complex there are 37.7Mt of mostly Inferred Resources grading 1.07% Nb2O5, total lanthanides at 1.16% and 0.09% Y2O3, 0.3% ZrO2, 0.024% Ta2O5, 7.99% P2O5. The company completed the first stage of mining activities in 2008 and commenced construction of a concentration plant at Mount Weld and an advanced materials plant in Malaysia.
The concentration plant was commissioned in May 2011 and by the end of October, Lynas reported that the plant achieved a concentrate grade of 36.8% REO and a recovery of 64 per cent. At the end of the June quarter 2012, more than 13 000 dry tonnes of concentrate containing more than 4800 tonnes of REO was bagged ready for export. Lynas also reported in its June 2012 quarterly report that the construction of phase 1 of the Lamp Advanced Materials Plant (LAMP) in Malaysia was completed and the commissioning progress was 64 per cent complete. A decision by the Malaysian Atomic Energy Licensing Board to approve a Temporary Operating Licence for the LAMP is subject to appeals from parties opposing the project.
Arafura Resources Ltd: Nolans Bore rare earth-phosphate-uranium-thorium deposit is located 135 kilometres northwest of Alice Springs in the NT. In June 2012, Arafura published a revised total Measured, Indicated and Inferred Resource figure of 47Mt grading 2.6% REO, 11% P2O5 and 0.02% U3O8 down to a depth of 215 metres. According to Arafura, the distribution of the light REEs currently being considered for extraction, (La, Ce, Pr, and Nd) amount to 95 per cent while the heavy REEs (Sm, Eu, Gd, Tb, Dy) amount to 4.23 per cent. The company is planning to process the rare earth-phosphate-uranium-thorium ore concentrate from the Nolans Bore deposit at Whyalla in SA. Environmental studies are being conducted at Nolans Bore and the proposed rare earth processing plant at Whyalla.
On 7 August 2012, Arafura announced a definitive base case study which indicated that the Nolans Bore project could generate a net present value (NPV) of $4.3 billion with a 10 per cent discount rate and an internal rate of return of 30 per cent, both calculated on an after tax basis over 20 years. On this basis, full capital payback will be achieved during the fourth year of operation12.
Alkane Resources Ltd: The company’s Dubbo Zirconia Project, based on the Toongi deposit 30 kilometres south of Dubbo in NSW has a reported Measured Resource of 35.7Mt and 37.5Mt of Inferred Resources grading 1.96% ZrO2, 0.04% HfO2, 0.46% Nb2O5, 0.03% Ta2O5, 0.14% Y2O3, 0.745% total REO, 0.014% U3O8, and 0.0478% Th. On 16 November 2011, Alkane announced a Proved and Probable Reserve for the deposit of 35.93Mt grading 1.93% ZrO2, 0.04% HfO2, 0.46% Nb2O5, 0.03% Ta2O5, 0.14% Y2O3, and 0.74% total REO. On 19 September 2011, the company released results of a definitive feasibility study which indicated a NPV for the project of $181 million at a processing rate of 400 kilotonnes per annum (ktpa) and $1.207 billion at a processing rate of 1000ktpa. In July 2012, Australian Zirconia Limited (AZL), a wholly owned subsidiary of Alkane Resources Ltd, signed a Memorandum of Understanding with Japan’s Shin-Etsu Chemical Co Ltd to produce a suite of separated heavy and light REEs using the rare earth concentrates from the Dubbo Zirconia Project.
Kimberley Rare Earths Ltd: The company’s Cummins Range carbonatite deposit occurs in the southeast part of the Kimberley region in WA. On 13 February 2012, Kimberley Rare Earths Ltd announced a revised Inferred Resource for the Cummins Range deposit of 4.9Mt at 1.74% REO, 11.2% P2O5 145ppm U3O8 and 48ppm Th. The resource was calculated at a cut-off grade of 1% REO. The total REO was subdivided into 95.6% light REO (La, Ce, Pr, Nd), 4.1% middle REO (Sm, Eu, Gd, Tb, Dy) and 0.3% heavy REO (Ho, Er, Tm, Yb, Lu). A mineralogical investigation of the Cummins Range deposit by the CSIRO Minerals Down Under Flagship was completed during the March 2010 quarter with the principal rare earth bearing minerals being primary apatite and monazite and only subordinate amounts of secondary rare earth bearing minerals are present.
The company carried out a pit optimisation study to produce a potential mining inventory for ore and waste for the project. Metallurgical testwork and associated mineralogical studies have been successfully completed both in Australia and China. Based on the study results, a mineral concentration flow sheet was established which confirmed the beneficiation process is able to achieve a concentrate grade of more than 15 per cent total REO (TREO) and a recovery of more than 59 per cent TREO. Three options for downstream processing and rare earth separation flow sheets were identified resulting in different rare earth product regimes. The results of study have been incorporated into a conceptual mine schedule for a preliminary evaluation study financial model.
Capital Mining Limited: Peralkaline granitic intrusions of the Narraburra Complex 177 kilometres northwest of Canberra contain anomalous amounts of zirconium, REO and low concentrations of Th (73.2Mt at 1250 grams per tonne (g/t) ZrO2, 146g/t Y2O3, 327g/t REO, 45g/t HfO2, 126g/t NbO2, 54g/t Ga2O3, 118g/t Li2O and 61g/t ThO2, Capital Mining Limited13). In the March quarterly report in 2010, the owners of the project, Capital Mining Limited, reported that it was conducting metallurgical test to recover hafnium (Hf), Th, tantalum (Ta), Nb, Nd and Ce.
Hastings Rare Metals Limited: Historic exploration records reported that the Yangibana ferrocarbonatite-magnetite-rare earth bearing dykes (ironstones) form part of the Gifford Creek Complex in WA. The dykes occur as lenses and pods and are typically the last stage of carbonatite fractionation and are enriched in REEs fluorite and U-Th mineralisation. The Yangibana prospect has a recorded historic resource of 3.5Mt at 1.7% REO. The rare earths are in coarse grained monazite containing up to 20% Nd2O5 and 1600ppm Eu2O3. On 11 November 2011, Hastings published results of 38 surface samples collected from six prospects located in the western portion of the Yangibana group. The samples indicated a distribution profile of REO as shown in the table 4 below:
|Light rare earths||Heavy rare earths|
|% of TREO||18.6||42.9||5.9||25.5||4.0||0.8||1.4||0.3||0.6|
The REO distribution of the Yangibana ironstones is biased towards the light REO (LREO) but proportion of Nd in the rare earth mix is relatively high at 25%. Neodymium is a key metal in industrial high strength magnets used in hybrid motor vehicles and wind turbines.
Hastings is considering a reverse circulation drilling program to further define the previously drilled ironstone targets and establish JORC compliant resources in 2012.
Crossland Uranium Mines Limited: On 15 May the company reported resources for a new type of placer deposit, the Charley Creek deposit, containing zircon, monazite and xenotime. The company reported that the Charley Creek deposit is an alluvial outwash which comprises an Indicated Resource of 387Mt containing 27 000 tonnes of xenotime, 161 000 tonnes of monazite and 196 000 tonnes of zircon. The xenotime and monazite were stated to contain about 114 000 tonnes of total REO (TREO). In addition, another 418Mt of Inferred Resources was reported to hold about 121 000 tonnes of REO in about 31 000 tonnes of xenotime and 167 000 tonnes of monazite as well as 220 000 tonnes of zircon14. An earlier report by Crossland dated 5 April 2012 stated that the average equivalent monazite in the heavy mineral concentrate (HMC) (calculated from chemical analyses) is 87 372 grams per tonne (g/t) and equivalent xenotime is 8310g/t while the HMC in the alluvium was 2.54%15.
GBM Resources Ltd: On 9 August 2012 GBM announced an Inferred Resource of 187Mt at 558ppm TREO and 52ppm Y2O3 for the Milo deposit located about 76km east of Mount Isa and 22km east of the Mary Kathleen uranium REO deposit. The Milo deposit is reported to be a poly-metallic deposit with a range of metals including REEs, Y, Cu, Mo, Au. GBM is currently conducting a scoping study including metallurgical testing to evaluate the deposit.
Marathon Resources Limited: In August 2005, the company reported that an Inferred Resource of 51 800 tonnes La-Ce is associated with its uranium deposit at Mount Gee, about 520 kilometres north-northeast of Adelaide in SA. In July 2011, the South Australian Government established the Arkaroola Protection Area that will be reserved from operation under the South Australian Mining Act. In due course it is proposed to enact legislation protecting the Area and an application for World Heritage Listing will follow. As a consequence, future exploration and mining titles will not be granted in the Area.
BHP Billiton Limited: About 53Mt of the Submarginal and Inferred Resources are in the Olympic Dam iron oxide-copper-gold deposit in SA (predominantly 0.2% La and 0.3% Ce) and are not currently economic.
Chinalco Yunnan Copper Resources Ltd: REEs have been intersected in drill holes at the Elaine 1 deposit, about 80 kilometres south of the Mary Kathleen deposit in northwest Qld. Chinalco has published resources for copper and gold for Elaine 1 deposit but resources of REO have not been released for the deposit. The historic uranium mine of Mary Kathleen is essentially a uranium-rare earths skarn deposit which has a remnant resource in tailings of about 5.5Mt at 6.4% REO +Y. Commonly occurring REEs minerals in the original deposit were stillwellite and allanite while other REEs-bearing minerals included apatite, titanite and garnet.
Metallica Minerals Limited: Metallica’s scandium resources are located within its lateritic Ni-Co deposits near Greenvale about 190 kilometres west-northwest of Townsville in Qld. The company’s Kokomo deposit is 50 kilometres north-northeast of Greenvale and the Lucknow deposit is two kilometres south of Greenvale. On 19 January 201116, Metallica reported Indicated and Inferred Resources for the Lucknow deposit totalling 6.24Mt grading at 169g/t Sc, 0.2% Ni and 0.04% Co delineated at a cut-off-grade of 70g/t Sc. The company’s Measured, Indicated and Inferred Resource for the Kokomo deposit totals 9Mt grading 109g/t Sc, 0.24% Ni and 0.03% Co associated with a lateritic Ni-Co deposit of 16.3Mt at 0.67% Ni, 0.12% Co and 36g/t Sc. The total Sc resource for the two deposits amounts to 15.1Mt at 133g/t Sc, 0.22% Ni, 0.04% Co. The contained scandium metal in the two deposits amounts to approximately 2000 tonnes Sc17.
The Lucknow deposit includes a high grade zone at a cut-off-grade of 120g/t Sc measuring 4.12Mt of Indicated and Inferred Resources at 206g/t Sc, 0.21% Ni and 0.05% Co.
Metallica also announced on 4 July 2012 that a scoping study confirmed technical and financial viability for the proposed development of the Nornico project and its associated Greenvale, Lucknow and Kokomo deposits, demonstrating that existing nickel-cobalt and scandium resources can support a 75 000 tpa operation over a 20 year mine life with an estimated capital expenditure of $597 million. The average annual operating costs was estimated at $138 million with a NPV of $402 million (pre-tax, 10% real discount rate, 100% equity, 20% capital expenditure contingency) and an internal rate of return of 16.4% average annual operating margin of $179 million. Metallica is progressing the scoping study to a pre-feasibility study stage. On 27 July 2012, Metallica changed the name of its Nornico project to Sconi.
Jervois Mining Ltd: In June 2005, the company reported that its Nyngan lateritic nickel-cobalt-scandium-platinum deposit in NSW had a resource of 16Mt at 0.87% Ni and 0.06% Co. A Sc-rich portion of this deposit was updated in June 2009 as Measured Resources of 2.718Mt at 274ppm Sc and Indicated Resources of 9.294Mt at 258ppm Sc. Jervois formed a joint venture agreement with EMC Metals Corporation of Canada which is conducting a three phased test-work to study the recovery of scandium from lateritic ores at Nyngan. By the end of 2011 EMC reported results of a semi-continuous pilot plant included the following:
EMC reported in their annual report for 201118 that key elements of environmental site work on the Nyngan Scandium Project have been completed and a Conceptual Project Development Plan (CPDP) has been submitted to the NSW regulators. The CPDP submission forms the basis for an Environmental Impact Study.Krucible Metals Ltd: Inferred phosphate and REE resources have been recently published for the Korella phosphate-yttrium deposit as 13.72Mt at 0.70k/t Y2O3 and Nd and Dy are also reported to be present, but their resources have not been estimated (Krucible Metals Ltd, 201119). The Korella deposit also has an Inferred Resource of 8.3Mt at 27.36% P2O5 at a cut-off grade of 20% P2O5 (Krucible Metals Ltd, 2010). The anomalous zone of yttrium enrichment at Korella appears to remain open towards the Duchess deposit to the north. There is little published data in regard to REE resources in phosphorite in Australia. Total phosphate resources in the Georgina Basin are considered to be of the order of four billion tonnes (Lottermoser, 199120), but total REE contents in the phosphorites are generally much less than 1000ppm.