The target for rare earth elements (REE) is ion adsorption clay deposits – and the preferred location is South Australia.
These clays contain the four key elements of magnets used in electric vehicles, wind turbines and many others: neodymium, praseodymium, dysprosium and terbium.
In electric vehicle (EV) motors, the typical neodymium-iron-boron magnet is composed of 29% to 32% neodymium and praseodymium, with an additional 4% to 9% of its mass terbium and dysprosium .
But this very small amount of these last two elements increases the maximum operating temperature of the magnet from about 60 degrees Celsius to 240 degrees Celsius.ohC, a crucial factor for EV traction motors. Iron makes up most of the rest of the mass, with 1% being boron.
This means that the economy of ionic clays is much more attractive than that of hard rock rare earth deposits.
Unlike hard rock deposits, these clay deposits are shallow, require negligible blasting, there is no crushing or grinding, and no radioactive residue of uranium or thorium to process.
You can mine the key magnetic rare-earth elements you want – and you don’t have to worry about others, meaning miners won’t see their ‘basket price’ lowered by lanthanum and low cerium. value.
That’s why London-based mining analyst Christopher Ecclestone of Hallgarten & Co recently dubbed ionic clay deposits the “holy grail” of the rare earth industry.
Five key players make up the rush to SA REE
Companies to watch are iTech Minerals (ASX:ITM) – which discovered the clay deposits while exploring for its kaolin project on the Eyre Peninsula – as well as Taruga Minerals (ASX:TAR), Resource Base (ASX:RBX), Australian Rare Earths (ASX:AR3) and that company’s neighbor, Lanthanein Resources (ASX:LNR) (formerly known as Frontier Resources).
The relative ease of mining these clays – and the resulting improved economics of rare earth production – is not the only key factor.
That other factor: China has run out of its clay-hosted heavy rare earths – which have allowed it to continue dominating the global rare earths space – and now depends for around half of its supplies on Myanmar.
This supply crisis was predicted in a 2013 paper from Peking University’s Department of Environmental Science and Engineering, which stated that China’s heavy rare earth resources would be depleted within 10 at 15 – and nine years have already passed.
Clays at ETR discovered 50 years ago
The clay deposits were discovered in 1970 in Ganzhou, Jiangxi province, followed by other discoveries in the other southern provinces of Guangdong, Fujian, Zhejiang, Hunan, Guangxi and Yunnan.
The main ore bodies are between 5 m and 30 m from the surface, so the rare earths can be extracted by surface mining followed by heap leaching.
While these clays represent only 2.9% of China’s total rare earth reserves, they are vital for this country; between 1988 and 2007, clays accounted for 26% of total REE production, rising to 35% in 2009.
However, there have been production cuts more recently, with China imposing stricter environmental controls and also cracking down on illegal mining.
The South Australian breakthrough comes amid tightening Chinese control of rare earths, now implemented by the merger of the three producers in China – China Minmetals Rare Earth, Chinalco Rare Earth & Metals and China Southern Rare Earth Group.
Explorers step up a gear
Earlier this month, Taruga Minerals announced that samples from its Morgan’s Creek project, located on the Adelaide Fold Belt, confirmed the presence of high-value rare earths in the clay, which will allow a metallurgical scheme simple.
In the clay zone, the company reported an average recovery of 85% of total rare earth oxides (TREOs) and 93% of higher value magnetic TREOs.
Taruga had so far focused on copper at Morgan’s Creek, but said the presence of ionic rare earths represented significant added value.
Also this month, Resource Base announced what it described as “very” good shallow air drilling results at its Miter Hill project, located in the Murray Basin, straddling the Victoria-Israel border. South Australia.
Drilling hit mineralization 3m from surface grading 1m at 1421 parts per million TREO and another hole intersected 1m at 1090ppm (5m from surface).
iTech Minerals also had success in mid-May on its Ethiopian kaolin prospect on the Eyre Peninsula.
Reporting on assays from the first 23 of 115 drill holes, the company said the results confirmed substantial intervals of REE in the clay, including 12m at 1,057ppm from 7m.
Australian Rare Earths recently launched a small-scale trial mining program at its Koppamurra project near Naracoorte in South Australia, with the work aimed at improving its understanding of clay (their style varies from deposit to deposit ) as well as collecting bulk samples for metallurgy. work.
Its neighbour, Lanthanein Resources, began work on its Murrayduim project files ahead of planned drilling.
And in April, Petratherm (ASX:PTR) – a veteran of the short-lived hot rock energetic phase – said drilling at its Comet Project in the northern Gawler Craton of South Australia had discovered rare earths “ majors” of great value.
Shallow rotary air blast drilling tested the top of the prospective clay horizon and intersected rare earths that remain open at depth and in surrounding areas.