Indiana’s initial technical review of its Central Gawler Craton has validated the interest in ionic adsorption clay-hosted rare earth elements following a recent third-party discovery.

The review of historical drill intercepts at the project for three common REEs, yielded anomalous results that highlighted its potential to host shallow ionic-clay hosted mineralisation.

This is hugely intriguing for Indiana Resources (ASX:IDA) as not only are REEs irreplaceable for the global transition towards sustainable energy and defence applications, ionic-clay mineralisation is considered to be one of the lowest cost sources of heavy and critical REEs due to being close to surface and being easy to dig up without need for drill or blast.

Interest in such mineralisation in the Gawler Craton, South Australia, was sparked by Petratherm’s (ASX:PTR) discovery of REEs within a prospective clay horizon at its Comet project, which abuts Indiana’s northern tenements.

Technical director Felicity Repacholi-Muir said the clearly anomalous results for the three common REEs, which are typically considered to be geochemical indicators for IOCG deposits, highlighted the clear potential for ionic REE mineralisation in the company’s extensive Central Gawler Project area.

“It is important for us to analyse for the other 12 rare earth elements, including the critical ‘magnet metals’ – neodymium, praseodymium, terbium and dysprosium – to determine the enrichment of these elements in the weathered clay profile,” she explained.

“Fortunately we are able to access our extensive sample-pulp inventory to assay for the full REE suite.

“Our Central Gawler Craton Project has already demonstrated its clear potential to host a significant gold mineralisation system and we are now eager to unlock further value from this asset through the review of potential REE mineralisation.”

Ionic adsorption clay-hosted rare earths

IAC REE mineralisation makes up the majority of Chinese REE production, which in turn accounts for about 85% of global REE supply.

These deposits form when REEs derived from the weathering of underlying basement rocks are subsequently enriched in the regolith profile, forming a shallow, continuous, sub-horizontal zone that is typically easy to mine.

While exploration for this style of REE mineralisation outside of China has been limited, recent discoveries have led to growing interest in various parts of Australia and the US.

Indiana is particularly interested in the concentration of REE accumulations in the northern portion of the project where previous aircore drilling had returned results such as 46m at 1,105 parts per million rare earth oxides (lanthanum oxide, cerium oxide and yttrium oxide) from 20m and 36m at 1,400ppm REO.



This article was developed in collaboration with Indiana Resources, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.