The Minerals Research Institute’s study is aimed at identifying reagents and methods suited to recovering critical minerals such as gallium from their regolith-hosted and/or related substrates, with a strong emphasis on non-toxic and environmentally-acceptable methods.
Such methods might include the use of near-neutral but typically slightly acidic leaching agents that are often common with natural organic humic acids in the weathered and usually near-surface soil-regolith profile.
The term “regolith” refers to the three-dimensional zone of relatively loose, unconsolidated rock and fine rock particles through every size range to the finest clays that lie above natural bedrock and soil.
The trick in recovering desired elements from the regolith lies in finding the right leaching agent specific to each element for its particular regolith host conditions.
Results from the research project will be provided to Terrain and will be significant to future mineral resource modelling and any onward exploitation of the company’s Larin’s Lane gallium project, about 350km northeast of Perth.
Terrain Minerals’ executive director Justin Virgin said: “The Phase-1 drilling has shown us a glimpse of what Larin’s Lane holds, and our planned drilling campaigns aim to substantially increase our understanding of the mineralisation. With 95% of the prospective area still to be properly drilled, this represents an enormous opportunity for the company and its shareholders.”
Virgin said the company is pleased with the progress of its on-going discussions with potential international partners about gallium mineralisation at Larin’s Lane and the release of future updated exploration target estimates will play a vital role in advancing the discussions.
Terrain’s geological team is also currently preparing a new reverse circulation (RC) drilling program to follow up its successful November AC gold drilling program at its Wildflower target.
While the RC rig is on the job, the company also proposes using it to drill a hole to twin a previous gallium-rich hole to obtain metallurgical sample material for its imminent gallium recovery test-work.
The previous RC hole selected for twinning intercepted 48m at a grade of 39.41ppm gallium oxide.
Three other better near-surface gallium oxide grades reported by the company at the end of May include 16m at 53.74g/t gallium oxide from 64m, 20m going 48.33g/t gallium oxide from 4m and 30m running 40.32g/t gallium oxide from 24m.
The hole to be twinned sits in Terrain’s JORC-compliant exploration target envelope for rare earth elements and gallium that was compiled by SRK and released in early November.
SRK’s exploration target report defines an initial Phase-1 exploration target for Larin’s Lane and is based solely on Terrain’s 2023 AC program that covers less than 5 per cent of the inferred prospective geology at the project.
Based on the then-existing information, the conceptual exploration target ranges between 25 million tonnes and 33mt grading between 10g/t and 21g/t gallium.
As part of its report, SRK also proposed and designed a follow-up AC drilling program to explore an expanded footprint of potential mineralisation at Larin’s Lane.
The proposal added a further 53 holes for about 3500m of drilling that Terrain figures could potentially triple the amount of prospective geology subjected to Phase-1 level reconnaissance.
Such a program could give Terrain a decent handle on the greater gallium potential further afield within the overall project area and would also go some way towards testing SRK’s estimated exploration target potential.
Terrain says the government-assisted Minerals Research Institute’s gallium recovery studies will cost it about $15,000 and it sees results from the recovery test-work as potentially a key inflection point in its fortunes with the commodity and the project.
The company says the proposed drill-out will cover the entire 27 square kilometre Larin’s Lane target area and it has budgeted about $600,000 for its next two AC drilling phases.
The gallium – and rare earths – mineralisation sits in the regolith meaning that it is all shallow and accessible to the cheaper AC drilling method which permits good protected sample recovery.
If a new gallium mine gets off the ground at the project, the shallow, weathered resource zone will constitute an extensive, low-cost, free-digging program.
Terrain will deliver its metallurgical samples late this month, with recovery testwork to begin immediately. Results are expected to be available in mid-2025, although interim results are expected as work progresses.
Terrain says it expects its Phase-2 drilling results and a revised exploration target to be available by mid-2025, focused on defining higher-grade gallium zones.
It is also designing a Phase-3 drilling program to cover the remaining 80 per cent of the prospective part of the Larin’s Lane geology.
Critical minerals came into sharp focus this year as global geopolitical uncertainty and wars saw various government’s start focussing on them. The AI boom has also coincided with the focus on critical minerals, many of which are needed to create artificial intelligence semi-conductor chips.
As a result, a lot of ASX-listed public companies are now on the hunt for critical minerals such as gallium and antimony. Terrain’s advantage is that it was an early adopter and has a significant head start on the market.
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