Rare earths in plentiful supply

Materials World magazine
,
27 Sep 2019

Worldwide developments are affecting consumption and supply of rare earths.

Seventeen elements make up the category of rare earths, a term which has been overshadowed by their relative abundance. As an example, cerium (Ce) is recognised as the 25th most frequent element in the Earth’s crust at 68ppm, which is more common than copper at 50ppm. This frequency is reflected in prices quoted by the US Geological Survey (USGS) for 1kg of cerium oxide – US$5 in 2014 but US$2 in 2018.

One challenge to would-be rare earth miners is the dissipated nature of the elements as they are not often found to be concentrated. For example, rare earth elements are often found with thorium and, more rarely, uranium. Another host is monazite, a reddish brown phosphate mineral. Here, the most common rare earth contained is lanthanum (La), as confirmed by two companies, Appia Energy and Medallion Resources. Monazite sand is rich in rare earth elements neodymium and praseodymium – forming NdPr as an alloy – which are critical for lightweight, powerful rare earth magnets.

While China has the largest supply globally, there are several rare earth projects, which collectively could influence the balance of market share.

China’s dominance

As well as being the key producer of rare earths, China is also a key refiner – the country does not only control the market by sheer production but can also affect it by lowering output or threatening embargoes. This has led to a response by USA President Donald Trump advocating a boost of the country’s domestic production of rare earths. Another consideration is how the USA obtains enough rare earths for its defence commitments. Senator Marco Rubio mentioned this when he proposed the bill
S 2093: RE-Coop 21st Century Manufacturing Act on 11 July, which called for a rare earths refining cooperative run and funded by a private agency.

Whichever policy is decided, it is undisputed that the USA lacks rare earths resources. The USGS recorded mining of bastnaesite, a rare earth fluorocarbonate mineral, which was excavated as a primary product at Mountain Pass, California in 2018. This mine was placed under care-and-maintenance in 2015 but brought back online in an attempt to reduce the volume of rare earth imports. For all that, USA imports of rare earth compounds and metals totalled US$160mln in 2018, up from US$137mln in 2017.

Despite any success at Mountain Pass, the USA is not out of its rare earth dilemma. About 80% of the imports in question came from China, with 6% from Estonia and 3% each from France and Japan. Even then, imports of compounds and metals from Estonia, France and Japan were derived from mineral concentrates and chemical intermediates produced in China and elsewhere.

Numerous projects show how direct action has been taken to reduce China’s dominance and how new developments will change the balance, even if that is not the original reason for such developments.

Restoring market balance

There are ways of combating China’s dominance, although these do not seem to be applied very often. In 2010, Japan invested in a rare earths miner called Lynas. This company operates in Australia with processing carried out in Malaysia, which is beneficial to all countries combined – Japan, Australia, Malaysia and the USA – because in May this year Lynas signed a Memorandum of Understanding with the Texas Corporation Blue Line, with the intention of jointly growing American rare earths separation.

To put Lynas in context, it does not only host the Mount Weld Central Lanthanide Deposit (CLD), one of the world’s highest grade deposits, but it is also preparing to exploit two more rare earths deposits, Duncan and Crown. CLD is currently a 51m-deep open pit with rare earths hosted in secondary phosphates. Once mined, 240,000 tonnes (t) per year of ore go through onsite flotation before being exported for processing.

Medallion Resources said China has dominated the rare earth industry for 30 years and there is little to indicate this will change. As the demand for rare earth magnets increases in order to drive electric transportation and produce clean energy solutions, this is likely to continue. The company said the rest of the world must counter the dominance either through exploiting new rare earth deposits, developing alternative materials or reducing the quantities of their consumption.

The company has turned its attention to this challenge and said it, ‘has been developing an approach to achieve significant and low-cost production of these magnet metals by acquiring and processing monazite. Given the long timeframes and high-capital investment required to develop new mining operations, Medallion’s plan lowers risk and cost to deliver a viable alternative, delivering near-term magnet metals’.

Third party proposals

At present, Medallion Resources is looking to produce magnet metals and is welcoming third party proposals to help it develop a rare earth extraction plant within North America. So far, one proposal calls for Canada and the USA to host logistics and plant facilities. The company is preparing for near-term production of rare earth magnet materials in North America through the processing of byproduct monazite sand – rare earth magnets are essential to automotive and robotics, particularly in electric motors, defence, for missile guidance systems, and clean energy such as wind turbines.

‘Since May, rare earths have been front and centre due to the Chinese-USA trade friction and their growing importance in the electrification of transportation, particularly electric vehicles,’ Medallion Resources President and CEO, Don Lay, told Materials World. ‘As a result, prices of the key magnet metals such as NdPr have been buoyant. We feel it is the right time to initiate the evaluation of plant sites for a commercial monazite processing plant as a key part of re-building a North American rare earth value chain.’

Further aspects under consideration by the company include mineral processing and transportation. In more detail, these studies will assess suitable jurisdictions for the company’s proposed monazite crack and leach plant as well as the transporting of monazite sand feedstock, reagents, finished product and waste material. Further consideration must be given access to and costs of re-agents such as sodium hydroxide and hydrochloric acid, energy, human resources, permitting and social and environmental impacts.

Using own resources

Appia Energy is a publicly traded Canadian company in uranium and rare earths. It focuses on delineating high-grade critical rare earths and uranium on the Alces Lake property in northern Saskatchewan, as well as prospecting for high-grade uranium in the prolific Athabasca Basin, where the company holds the surface rights to exploration for 57,048ha in Saskatchewan.

Alces Lake is located within the Beaverlodge Domain, formerly host to more than 17 individual uranium mines. Rock types identified on Alces Lake include monazite accumulations, which constitute the rare earth elements mineralised system. In fact, the geochemical assay results from Alces Lake demonstrate the highest-grade rare earth occurrences in Canada.

To reinforce this claim, Appia Energy stated that Alces Lake’s rare earths are of a comparable quality to those of the historical Steenkampskraal mine in South Africa and Mountain Pass deposits, as well as the currently producing Gakara project in Burundi, East Africa and Mount Weld mine in Australia – the latter producing more than 12% of global rare earth supply in 2017.

A total of seven high-grade rare earth zones have been discovered to date at Alces Lake, six at surface and one within 15m of the surface. Three more rare earth zones, which imply grades consistent with the quality of the other seven, have been identified. Mineralisation is consistent in all zones and rock types, occurring as isolated grains through to 1-3cm lenses and massive clusters up to several metres thick of monazite grains.

Easy separation

Rainbow Rare Earths is a London-listed mining company focused on production from and expansion of the high-grade Gakara rare earth project in Burundi, which forms one of the world’s richest rare earth deposits. Initial production and sales to Rainbow’s off-take partner thyssenkrupp Materials Trading, commenced in the fourth quarter of 2017. This 10-year offtake agreement is for exclusive sales of at least 5,000t per year of concentrate and forms part of a strategy to target Gakara’s wider potential and to delineate a JORC estimate to further prove Gakara’s potential.

Veins at Gakara are discrete and narrow, although mineralised material separates easily from the less dense host rock, which in itself is amenable to manual digging. The veins range in thickness from a few to a few dozen centimetres, having been shown to extend laterally for up to 80m, and to depths greater than 25m. Outcropping occurs on steep slopes or river incisions but this is frequently under cover.

Exploration work undertaken by Rainbow Rare Earths at Gakara so far includes mapping of geological traverses, geophysical and geochemical orientation surveys and the collection of 150 grab samples from rare earth veins which were submitted for analysis by the ALS Chemex independent laboratory. Samples yielded consistently high grades at 58% average rare earths, ranging from 47-67% rare earths. Magnet rare earths, particularly neodymium, praseodymium and dysprosium, account for approximately 22% of rare earths contained within Gakara ore.

Recent work also includes detailed mapping of two localities, mineralogical and gravity separation test work, hydro-metallurgical studies, design of a processing plant and a conceptual mining study based on a trial bench mining exercise at Gasagwe and Gashirwe West – two localities within the mining licence.

Global considerations

The rare earths sector is undergoing a complicated situation as the USA experiences shortages of rare earths while China is the dominant producer and has the capacity to increase or decrease output at will. This will continue despite the start of mining at new resources, such as the Gakara project. While certain countries might have the capacity to extract such resources, much of their success will be affected by the economics to do so and in particular, the processing methods.