St George strikes standout rare earths-niobium combo in Brazil

St George Mining has nailed its thickest hit yet at the company’s Araxá rare earths and niobium project in Brazil, serving up a hefty slab of high-grade rare earths and niobium mineralisation beginning right from surface.

Fresh assays from 15 diamond drill holes include a new record intercept, reaming out a massive 178.7 metres assaying 4.34 per cent total rare earth oxides (TREO) and 0.75 per cent niobium pentoxide from surface.

Within that interval, the company also reported higher-grade zones, including 55.7m at 6.16 per cent total rare earth oxides and 0.95 per cent niobium pentoxide from 14m downhole depth. 

Significantly, a thinner intercept, included in the same hole, delivered 3.13m at a respectable 12.27 per cent TREO and 1.61 per cent niobium pentoxide from just 8.05m depth below surface.  

The stunning 178-metre intersection was closely supported by a second diamond hole, which returned 165.3m going 4.28 per cent TREO and 0.61 per cent niobium pentoxide from surface. That hole also included a high-grade intercept of 4m going 14.14 per cent TREO and 0.77 per cent niobium pentoxide.    

A third hole delivered 150.2m running 4.64 per cent TREO and 0.59 per cent niobium pentoxide from surface and also delivered 92m at 5.37 per cent TREO and 0.64 per cent niobium pentoxide from 46m. Notably, the results were also sweetened up with a handy 17m going 12.16 per cent TREO and one per cent niobium pentoxide from 59m depth. 

The recurring theme here seems simple: big widths, strong grades supporting high-grade core zones and plenty of it, beginning at or near the top of the hole.

St George Mining executive chairman John Prineas said: “The drilling results continue to show huge true widths from surface paired with very high grades. This unique combination is unrivalled among emerging rare earths and niobium developers. The commercial advantage of high-grade mineralisation starting from surface – as opposed to 50m or even more than 100m below surface – cannot be underestimated.” 

With the drill holes being vertical, St George says its true widths to date are up to 178 metres from surface, pointing to a substantial, near-surface orebody. The company believes that kind of geometry could deliver far simpler, cheaper mining than deposits that only hit paydirt after stripping away tens of metres of waste.

The current drilling momentum and ongoing substantial hits also align with St George’s recent move towards downstream planning. Last week, the company signed a memorandum of understanding with Boston Metal to trial its molten oxide electrolytic processing technology on Araxá’s potential feedstock. 

The initiative is aimed at more efficient production of ferroniobium, potentially lower costs and lower carbon emissions than are often achieved with conventional flowsheets.

Boston Metal’s technology was developed at the Massachusetts Institute of Technology and the company has attracted more than US$500 million in backing, including from heavyweight investors such as BHP, BMW, Microsoft, Vale and Aramco. 

St George says the test work will run alongside traditional metallurgical studies already underway at Araxá, keeping multiple processing pathways open.

In early March, St George announced a major resource upgrade for Araxá, totalling 70.1 million tonnes at 4.06 per cent TREO and 0.62 per cent niobium pentoxide at a 2.0 per cent niobium cut-off grade.

When coupled with an additional niobium resource of 24.56 million tonnes at 1.2 per cent TREO and 0.52 per cent niobium pentoxide, using a 09.2 per cent niobium cut-off grade, the combined resources have lifted St George’s total resource to 95.47 million tonnes.

The mineralisation in the latest diamond drill holes exhibits a high proportion of magnet rare earth elements, consistent with the ratios observed across the estimated mineral resources. The neodymium-praseodymium (NdPr) to TREO ratio consistently runs around 20 per cent and reached 26 per cent in two of the recent suite of diamond drill holes.

With the rods still turning full-time and the mineralised system remaining open in all directions, St George looks set to keep feeding the market a steady stream of giant intercepts for a while yet. These persistent runs of grade to depth could prove transformative, given the evolving cross-sectional picture of mineralisation extending to bedrock in some locations.  

If St George can keep hitting these sorts of numbers and converting them into a growing, cohesive resource with a sharp processing and offtakes story, the company’s Araxá project is likely to shape up as a serious contender in the global race for the next meaningful niobium and rare earths supply, well ahead of many others currently in the running.

Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au