Terrain Minerals has uncovered a 66 square-kilometre shallow regolith clay basin prospective for rare earths using airborne electromagnetic (AEM) survey data at its Lort River project in the Albany Fraser belt of Western Australia.
The AEM survey completed at Lort River, near the town of Esperance, mapped the extent, thickness and depth of conductive regolith horizons, interpreting the scale of the basin to be 12km in length and 5.5km wide.
Previous drilling identified rare earth-bearing regolith horizons, producing impressive results and correlating with the interpreted basin.
An 8m stretch hit 4037 parts per million total rare earth oxides (TREO) from a shallow 23m, along the edge of a second mafic-intrusive unit located within the Albany Fraser belt. Two separate one-metre intervals returned solid hits of 1m going 9842ppm TREO from 25m and 1m at 9022ppm TREO from a depth of 27m .
Notably, significant magnet rare earths were discovered, with 1m at 2362ppm neodymium, 647ppm praseodymium and 291ppm of the more valuable heavy rare earths mineral, dysprosium.
A further 1m interval clocked-up 1645ppm neodymium, 437ppm praseodymium and 215ppm dysprosium.
Terrain now plans to push the Lort River project ahead as a rare earths clay-hosted discovery.
The company is now looking to undertake a follow-up air-core drilling program and metallurgical sampling over the summer period.
Terrain Minerals executive director Justin Virgin said: “The completion of the regolith mapping via airborne electromagnetics marks a key milestone in advancing the rare earths potential of our Lort River project. Early data interpretation has confirmed a broad conductive regolith clay basin that correlates with potential rare earths enrichment.”
Virgin said the results, in combination with previous geochemical work, reinforce the company’s belief in the Lort River project as a potentially unique critical minerals discovery within the Esperance region.
The company says the drilling program at Lort River that uncovered the rare earths first nailed thick zones of mineralisation at a shallow 23m depth in a contact zone between the weathered bedrock and the fresh rock, ideal for cost-effective, clay-hosted extraction.
The Lort River project covers 320 square kilometres across the Esperance region, which has established itself as something of a rare earths province.
Its next-door neighbour, ASX-listed OD6 Metals, has revealed a massive mineral resource of 682 million tonnes at 1338ppm TREO for 910,000 tonnes of contained TREO at its flagship Splinter Rock project.
A little further east, Mt Ridley Mines today revealed an enormous gallium resource of 838.7 million tonnes at 29.3ppm for 24,584 tonnes of contained gallium. Mount Ridley also has a rare earth resource of 168mt grading 1201ppm at its eponymous project.
Terrain has also been kicking some big goals with drilling at its Lightning gold project.
A 22-hole reverse circulation drill program returned several head-turning results, such as 22m assaying 2.87g/t gold from 105m, including 21m at 15.79g/t silver from 105m, 1m at 70.59g/t silver from 108m and 1m at 60g/t silver from 124m, alongside another 5m hit running 10.83g/t silver from 129m.
The gold-silver connection is confirmed by a second hole which delivered 17m at 3.43g/t gold and 17.88g/t silver from 147m, including 2m at 17.7g/t gold and a 4m hit at 48.80g/t silver from 151m.
A third hole also delivered the goods, returning a 13m stretch at 8.13g/t gold from 122m, including a 2m slice going at 48.22g/t gold and 2m at 12.79g/t silver from 128m, with an additional 1m running at 5.16g/t silver from 159m.
A fourth hole produced a solid 11m at 6.03g/t gold and 43.5g/t silver from 75 metres.
The broader Albany Fraser belt that takes in Terrain’s Lort River project is no stranger to big discoveries. It is famous for the stunning Nova nickel-copper discovery by Sirius Resources back in 2012 and is now becoming better known for critical minerals such as rare earths and gallium. Terrain may be looking in just the right place at the right time.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Craig Nolan
