For a project that already screams serious scale, the latest round of assays from St George Mining’s Araxá rare earths and niobium project in Brazil may have just taken the play up another notch.
The company has rattled off another batch of diamond drill results that read more like a wish list than routine step-out holes. Thick mineralised zones from right at the surface and running to depth are now appearing to be the norm rather than the exception.
Of the six holes reported, a standout hit included a 135.2-metre strike grading 3.37 per cent total rare earth oxides (TREO) and 0.58 per cent niobium pentoxide from surface and featured a 38.8m chunk running at an even richer 4.40 per cent TREO and 0.82 per cent niobium.
Not to be outdone, the next hole returned 99.2m at 4.63 per cent TREO and 0.61 per cent niobium from surface, with multiple higher-grade internal zones.
That was then backed up by a third drillhole that delivered 85.8m at a scorching 5.16 per cent TREO and 0.72 per cent niobium from surface. The run included a red-hot 22m slice grading 7.48 per cent TREO and 1.05 per cent niobium pentoxide.
The remaining assays all followed in a similar theme of high grades and big runs, including another impressive run of 100.6m at 3.9 per cent TREO.
Additionally, the best individual 1m intercept was 15.12 per cent TREO, supported by numerous assays in the range between 6 and 12 per cent TREO.
Together, these broad, coherent runs point to a large, continuous mineral system.
The latest drilling program has been designed to tighten the drill spacing in areas considered lightly tested. Crucially, it appears to confirm that the high-grade mineralisation remains remarkably consistent across the system — a characteristic that is pure gold for resource modelling, boosting confidence that tonnes and grades can be reliably projected between holes.
St George Mining’s executive chairman John Prineas said: “Its non-stop drilling at Araxá with exceptional results continuing to roll in. Significantly, with mineralisation open in all directions, we still have not found the limits of the system. The ongoing drill campaign will, we believe, deliver more tremendous intercepts that have potential to have a very positive impact on the volume of the resource.”
St George’s current 41 million tonne combined niobium and rare earths mineral resource estimate only extends to about 100 metres depth from surface. However, several of the new holes are already probing well below that depth and are still finishing in mineralisation.
Additionally, little drilling has been carried through to the interpreted base of oxidation, with most holes terminating about 20m above that significant boundary. The few holes that have been pushed closer to the base of oxidation are still carrying grades to about 5 per cent TREO.
That suggests there are plenty more tonnes to be captured when the existing resource model is updated and the extensive ground still open at depth points to a significant deeper resource expansion opportunity to be followed up on in due course.
Another tick for Araxá is its rare earths mix. The deposit continues to show a healthy proportion of the high-value magnet rare earths, neodymium and praseodymium, with ratios in line with, or better than, those of the existing resource.
These are the critical elements that end up in electric vehicle motors and wind turbines, tending to attract the most persistent demand and the best prices over the long term.
With three diamond rigs and a reverse circulation (RC) drill rig chewing through the metres around the clock, St George isn’t slowing down. Dozens of samples are already in the lab awaiting assays and a strong news flow can be expected soon.
If the latest results are any indication, Araxá is evolving from a large, high-grade resource into something potentially much more substantial - and in a world scrambling for secure supplies of critical minerals, St George is a story the market is likely to keep a very close eye on.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
