Content maintained by Yanis Miezitis and Dean Hoatson
Content maintained by Yanis Miezitis and Dean Hoatson
The rare-earth-element (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 technology, environment and economic areas (Hoatson et al 20111).
During the past few years, scandium bearing lateritic nickel-cobalt (Ni-Co) deposits have attracted increasing attention in response to anticipated rise in demand for scandium. Zirconia stabilised with scandium rather than Y as an electrolyte for Solid Oxide Fuel Cells (SOFCs) reduces the operating temperature of the fuel cell significantly, resulting in a much longer life. SOFCs are expected to play a significant 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 lanthanum, cerium, praseodymium, neodymium and, sometimes, samarium. heavy REEs may start with samarium, followed by europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. However, the heavy REEs are sometime subdivided further into middle REEs comprising samarium, europium, gadolinium, terbium, and dysprosium with the remainder of the group, holmium, erbium, thulium, ytterbium and lutetium, 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 lanthanum, cerium, praseodymium and neodymium as light REEs, or Ceric, samarium, europium and gadolinium as medium REEs and terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium plus yttrium as heavy REEs, or Yttric.
|Rare Earth Oxide||Application||Nolans Bore %||Mount Weld %||Mountain Pass USA %||Baiyanobo 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 cerium, which is the twenty-fifth most abundant element at 60 parts per million (ppm), to lutetium, the sixty-first most abundant at 0.5ppm.
|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 2012, amounted to 3.19 million tonnes (Mt) of Economic Demonstrated Resources (EDR), 0.42 Mt Paramarginal and 31.14 Mt in the Submarginal Resource categories.
About 67% of Australia’s Accessible EDR comprises Reserves as defined under the Joint Ore Reserve Committee (JORC) Code.
About 33% of the EDR comprises published JORC Code compliant Measured and Indicated Resources in operating mines, deposits being developed for mining and in deposits which have published scoping/feasibility studies with positive results.
There is a further 16.13 Mt REO in the Inferred Resources category. A major proportion of REO (predominantly lanthanum 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 10 250 tonnes of scandium, mostly in the Subeconomic and Inferred categories was reported in 2012. In addition, about 56 140 tonnes of Paramarginal and Inferred Resources was 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 that Australia’s monazite resources are around 7.8 Mt. Assuming that the REO content of monazite to be about 60%, the heavy mineral deposits could hold a resource of around 4.68 Mt contained REO. Currently, extraction of REEs from monazite is not viable because of the cost associated with 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) to be used for the extraction of both REEs and thorium. Between 1952 and 1995, Australia exported 265 kilotonnes (kt) of monazite with a real export value of $284 million in 2008 dollars (Australian Bureau of Statistics 2009)5.
Small-scale production of REEs has taken place in Australia, but records are incomplete. The following attempt to establish rare earth production in Australia is based on historical information 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. In 1988, Deckhand Pty Ltd, a wholly owned subsidiary of Currumbin Minerals, was blocked on environmental grounds from establishing a rare earths processing plant at Lismore, NSW. SX Holdings Ltd was planning to establish a plant at Port Pirie in SA 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 in 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.
Globally, the production and resources of rare earths are dominated by China followed by India. China accounts for about 94% of the production, but this is expected to fall to 70% by 2015 (Roskill, 20128) while India accounts for about 2%. 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% 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 year was from China, while growth in the rest of the world fell by almost 4% 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 by between 11% and 13% per year as potential markets expand to include applications in permanent magnet motors for electric vehicles and wind turbines. It’s anticipated that 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.
Alkane Resources Ltd reported in November 20139, that consumption of rare earths of 115 000 tonnes in 2012 is set to increase to about 162 000 tonnes in 2016.
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 half10.
China holds 55 Mt (47.7%) of the world’s economic resources for REO (including Y2O3), followed by the USA with 13 Mt (11.3%)11. Australia’s EDR accounts for 2.8% of world’s economic resources with 3.19 Mt REO.The main types of REE deposits worldwide are REE-iron ores with bastnasite and monazite as the main REE bearing minerals and include deposits such as the Bayan Obo in China. The only production of REOs from a carbonatite has been the Mountain Pass deposit in California, which has 35.35 Mt of Measured, Indicated and Inferred Resources at 6.35% REO (2.24 Mt REO). Deposits associated with carbonatite laterites, include Araxa in Brazil, which has 28.29 Mt of Measured, Indicated and Inferred Resources at 3.754% REO (1.06 Mt REO) and Mount Weld in WA which has 23.94 Mt at 7.867% REO (1.88 Mt 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 18 January 2012, Lynas reported Measured, Indicated and Inferred REO resources for the Central Lanthanide deposit at a cut-off of 2.5% REO of 14.949 Mt at 9.8% REO including Y2O3. An updated resource for the Duncan Deposit in the weathered carbonatite complex stands at 8.992 Mt of Measured, Indicated and Inferred Resources at 4.8% REO including Y2O3. In another part of the carbonatite complex there are 37.7 Mt 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 reported in its September 2013 quarterly report that ramp up of phase 2 concentration plant continued at the Mount Weld mine site and at the end of the quarter, 18 425 tonnes of concentrate containing 6724 tonnes of REO were ready for export to its rare earth treatment plant, the Lynas Advanced Materials Plant (LAMP) in Malaysia. Lynas reported that, by early June 2013, the plant had achieved nameplate production capacity (11 000 tpa REO capacity) in cracking and leaching units of phase 1 of the LAMP. Total tonnes produced during the latter half of 2013 amounted to 397 tonnes on an REO equivalent basis.
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 47 Mt 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%, while the heavy REEs (Sm, Eu, Gd, Tb, Dy) amount to 4.23%.
Because of much lower rare earth prices over the past year, Arafura has decided to reduce capital and operational costs by relocating its planned intermediate rare earth chemical processing plant from Whyalla in SA to a site near its Nolans Bore deposit12 in the NT.
Arafura announced on 9 September 2013 that it had signed a memorandum of understanding with Shenghe Resources Holding Co.Ltd to jointly fund development of the Nolans Bore Project and develop rare earth sales opportunities.
Alkane Resources Ltd: The company’s Dubbo Zirconia Project (DZP) based on the Toongi deposit 30 kilometres south of Dubbo in NSW has a reported Measured Resource of 35.7 Mt and 37.5 Mt 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 35.93 Mt grading 1.93% ZrO2, 0.04% HfO2, 0.46% Nb2O5, 0.03% Ta2O5, 0.14% Y2O3, and 0.74% total REO. 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 DZP.
In October 2012, Alkane announced in its annual report for 2012 that the company had engaged Credit Suisse (Australia) Limited, Sumitomo Mitsui Banking Corporation and Petra Capital Pty Limited to provide investment banking services, including the arrangement of project financing to fund the development of the DZP. Securing the finance package of around $1 billion is expected to take up to 12 months and coincide with final project approvals, allowing the construction program for the DZP to commence in 2014.
Crossland Strategic Metals Limited: On 15 May 2012 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 387 Mt 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 418 Mt 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 zircon13. 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 8310 g/t while the HMC in the alluvium was 2.54%14. A scoping study for the deposit was released by the company on 15 April 2013 which highlighted a low capital cost requirement of $156 million based on a mine life of 20 years and projected an annual revenue of $154 million. Crosslands reported in its September quarterly report for 201315 that a work program for the detailed feasibility drilling at the Charley Creek Project had been designed. Applications for all regulatory approvals required for this drilling have been submitted to the Northern Territory Department of Mines and Energy.
Hastings Rare Metals Limited: The Hastings rare earth deposit (previously known as Brockman) is located about 16 kilometres southeast of Halls Creek in WA. It is a large, low-grade zirconium-niobium-REE (Zr-Nb-REE) deposit hosted in altered trachytic tuff of Paleoproterozoic age. On 8 September 2011, Hastings reported 36.2 Mt of Indicated and Inferred Resources grading 8.86 ppm ZrO2, 3.55 ppm Nb2O5, 182 ppm Ta2O5, 110 ppm Ga2O5, 318 ppm HfO2, 186 ppm Dy2O5, 1120 ppm Y2O3, 2102 ppm TREO and 1802 ppm heavy REO.
In July 2013, the company announced the discovery of two new prospects, the Levon, about 1.3 kilometres south of the main deposit, and Haig, about 4.5 kilometres to the southwest16. Nineteen rock chip samples from the Levon prospect averaged 2025 ppm TREO and 13 rock chip samples from the Haig prospect averaged 2485 ppm TREO.
Hastings Rare Metals is investigating toll treatment partnerships in ore milling extraction and separation, and in final product refining. The company considers that the benefit of taking the above functions off-shore reduces risks for the Hastings project , by reducing overall processing operating expenses and by making a significant reduction in capital cost while being able to access lower cost funding.
The Yangibana prospect, about 900 kilometres north of Perth in WA, has a recorded historic resource of 3.5 Mt at 1.7% REO. The rare earths are in coarse grained monazite containing up to 20% Nd2O5 and 1600 ppm Eu2O3. 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 uranium-thorium mineralisation. On 11 November 2011, Hastings published results from 38 surface samples collected at 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.
|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 neodymium in the rare earth mix is relatively high at 25%.
Navigator Resources Ltd (Holding Deed of Company Agreement): 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 4.9 Mt at 1.74% REO, 11.2% P2O5 145 ppm U3O8 and 48 ppm 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. The investigation also showed that only subordinate amounts of secondary rare earth bearing minerals were present.
In its December 2013 quarterly report, Navigator reported that Anova Metals Limited (previously Kimberley Rare Earths Limited) has agreed to terminate the Cummins Range joint venture and transfer Anova’s 25% interest in Cummins Range back to Navigator. The appointed administrator to Navigator reported in May 201317;
Following a price peak in July 2011, light rare earth metals became oversupplied and prices fell by approximately 70%. As a result, Kimberley Rare Earths concluded that short-term commercial development of Cummins Range was not viable and that long-term development was dependent upon factors outside of their control.
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 thorium (73.2 Mt at 1250 g/t ZrO2, 146 g/t Y2O3, 327 g/t REO, 45g/t HfO2, 126g/t NbO2, 54 g/t Ga2O3, 118 g/t Li2O and 61 g/t ThO2, Capital Mining Limited18). In the March quarterly report in 2010 Capital Mining Limited reported that it was conducting metallurgical test to recover hafnium, Thorium, tantalum, niobium, neodymium and cerium.
GBM Resources Ltd: On 9 August 2012, GBM announced an Inferred Resource of 187 Mt at 558 ppm TREO and 52 ppm Y2O3 for the Milo deposit in northwest Qld about 76 kilometres east of Mount Isa and 22 kilometres 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, yttrium, copper, molybdenum and gold. On 22 November 2012 GBM reported that results of a scoping study suggested a long term base case for a project with a net cash flow of $701 million over a 11 year mine life19.
Northern Minerals Ltd: On 15 October 2013 Northern Minerals announced that its Browns Range Project about 655 kilometres northwest of Alice Springs in the NT has Indicated and Inferred Resources totaling 4.13 Mt at 0.68% TREO. These resources are shared between the Area 5, Gambit and Gambit West deposit while the Wolverine deposit has most of the Indicated and Inferred Resources totalling 2.14 Mt of ore grading at 0.86% total REO (which includes 4970 ppm Y2O3), 35ppm U3O8, and 28 ppm ThO2. The main ore mineral is xenotime which occurs within hydrothermal silicified and hematitic breccias. The resource has a well defined high grade (less than 1% total REO) central zone.
BHP Billiton Limited: A major proportion of REO (predominantly lanthanum and cerium) of the Submarginal and Inferred Resources are in the Olympic Dam iron oxide-copper-gold deposit in SA. A research paper published in 2012 stated that Olympic Dam ore contains20 about 0.17 weight (wt) % La and 0.25 wt % Ce. The REO at Olympic Dam are not recovered in mining operations and are contained in the tailings storage facility at the mine site.
Metallica Minerals Limited: Metallica’s scandium resources are located within its lateritic nickel-cobalt deposits near Greenvale about 190 kilometres west-northwest of Townsville in north Qld. The company’s Kokomo deposit is 50 kilometres north-northeast of Greenvale and the Lucknow deposit is two kilometres south of Greenvale. On 21 October 2013, Metallica reported Measured, Indicated and Inferred Resources for the Lucknow deposit totalling 7.3 Mt grading at 176 g/t Sc, 0.23% Ni and 0.06% Co delineated at a cut-off-grade of 100 g/t Sc. The company’s Measured, Indicated and Inferred Resource for the Kokomo deposit totals 4.7 Mt grading 140 g/t Sc, 0.40% Ni and 0.07% Co totalling 112.1 Mt at 0.30% Ni, 0.06% Co and 162 g/t Sc. The total Sc resource for the two deposits amounts to 15.1 Mt at 133 g/t Sc, 0.22% Ni, 0.04% Co. The contained scandium metal in the two deposits amounts to approximately 1950 tonnes.21
The Lucknow deposit includes a high grade zone at a cut-off-grade of 120 g/t Sc measuring 4.12 Mt of Indicated and Inferred Resources at 206 g/t Sc, 0.21% Ni and 0.05% Co.
Metallica announced on 16 October 2012 that a revised scoping study indicated that, under an updated mine plan, there are sufficient Measured, Indicated and Inferred Mineral Resources at the SCONI project to allow production of approximately 90 tpa of scandium oxide over not less than 20 years based on a processing rate of 750 000 tpa of ore.
EMC Metals Corp: In June 2005, Jervois Mining Ltd reported that its Nyngan lateritic nickel-cobalt-scandium-platinum deposit in NSW had a resource of 16 Mt at 0.87% Ni and 0.06% Co. A scandium-rich portion of this deposit was updated in June 2009 as Measured Resources of 2.718 Mt at 274 ppm Sc and Indicated Resources of 9.294 Mt at 258 ppm Sc. Jervois formed a joint venture agreement with EMC Metals Corporation of Canada which conducted a three phased test-work to study the recovery of scandium from lateritic ores at Nyngan.
In 2013, EMC acquired full ownership of the Nyngan scandium project from Jervois Mining Ltd with Jervois receiving royalties on sales of product from the project in lieu of a cash payment. EMC reported on its website (http://www.emcmetals.com/new/Nyngan.asp) that processing and refining plant details are still being finalised. Previous pilot plant scale metallurgical test work during 2011-12 revealed that recoveries of more than 70% were achievable with conventional processing techniques on laterites, specifically acid leaching and solvent extraction. Subsequent bench scale test work in 2013 explored several modified flow sheet approaches with the results indicating that improved recoveries, better product grades and lower acid consumption rates were possible, all of which would point to better economics and environmental outcomes.
Krucible Metals Ltd: Inferred REE resources for the Korella phosphate-yttrium deposit were reported to total 13.72 Mt 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, 201322). Anomalous values of other valuable heavy REEs have also been intersected in drilling at Korella including one metre at 831 ppm Nd and 336 ppm Sc from a hole depth of 13 metres and two metres at 294 ppm dysprosium from a hole depth of 19 metres. Mineralogical investigations have indicated that yttrium is contained in the phosphate mineral xenotime (YPO4), generally encapsulated within larger clay-silica-phosphate secondary minerals.
There is little published data associated with REEs in phosphorite in Australia. Total phosphate resources in the Georgina Basin in the NT and northwest Qld are considered to be of the order of four billion tonnes (Lottermoser, 199123), but total REE contents in the phosphorites are generally much less than 1000 ppm.
Chinalco Yunnan Copper Resources Ltd: REEs have been intersected in drill holes at the Elaine1 deposit, about 80 kilometres south of the Mary Kathleen deposit in northwest Qld. Chinalco has published resources for copper and gold for Elaine1, but resources of REO have not been released for the deposit. Inferred Resources have been published for a small deposit near Elaine1 consisting of 83 000 tonnes of ore grading 3236 ppm REO and 283 ppm U3O8. The historic uranium mine of Mary Kathleen is essentially a uranium-rare earths skarn deposit which has a remnant resource in tailings of about 5.5 Mt at 6.4% REO plus yttrium. Commonly occurring REE minerals in the original deposit were stillwellite and allanite while other REE-bearing minerals included apatite, titanite and garnet.
Marathon Resources Limited: In August 2005, the company reported that an Inferred Resource of 51 800 tonnes of lanthanum and cerium 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, reserving the area from operation under the South Australian Mining Act. It is proposed that, in due course, legislation will be enacted to protect 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 Arkaroola Protection Area.