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Si6 Metals sampling eeks out shallow Brazilian rare earths find

Updated: Apr 18

Si6 Metals has unearthed a clay hosted rare earths find in Brazil Credit: File

Si6 Metals (ASX: SI6) has unveiled clay-hosted rare earths hits from surface sampling at its joint-venture (JV) Caldera project in the State of Minas Gerais in Brazil, in addition to discovering further nickel-copper-cobalt at the company’s Maibele North deposit, part of its base and precious metals play in Botswana.

The company will now kick-off an auger drill campaign at its 50 per cent owned JV Caldera project to test for higher-grade rare earths mineralisation at depth. The program will consist of 26 holes and begin in early April.

The JV is with Foxfire Metals and covers its highly prospective suite of Brazilian rare earths, lithium and gold projects.

Si6 says it has confirmed saprolite clay-hosted rare earths mineralisation along the edge of the Poços de Caldas Alkaline Complex at its Caldera project in the State of Minas Gerais in Brazil.

Management says sampling returned results up to 933 parts per million total rare earth oxides (TREO) and notably, some 24 per cent of the total was the higher value “magnet” rare earth oxides (MREO) that are typically used in electric vehicle engines.

Importantly the high-value magnet rare earths comprised on average 94 per cent of the lucrative elements neodymium and praseodymium.

The highly sought-after neodymium and praseodymium rare earths are a primary component of industrial magnets, widely used in electric and hybrid motors and generators, clean energy technologies and wind turbines.

The encouraging assays came from 16 soil and channel samples, in addition to three rock-chip results providing a strong level of encouragement that the Caldera Project can follow the exploration success of neighbouring companies such as Meteoric Resources (ASX: MEI) and Viridis Mining (ASX: VMM).

We are now preparing an immediate auger drilling program to test the upper portion of the clay profile for the extent of the REE mineralisation.
Si6 Metals managing director Jim Malone

Viridis has produced several stunning ionic-clay hits as high as 24,894ppm and 25,075 ppm. It has also discovered higher grades at depth.

Si6 says ionic-adsorption clay deposits generally have lower grades near surface and improve with depth, with the magnet based rare earths average grades typically increasing with deeper drilling.

Promisingly, further high-grade results were uncovered in the eastern portion of the project area, with four results averaging 843ppm TREO.

Meanwhile in Botswana, Si6 has revealed final assays received from its multi-metals play, adding to its nickel-copper resources in the southern African country. It says 27 holes were completed recently for 5690m, consisting of 3663m of reverse-circulation (RC) and 2027m of diamond drilling across its three prospective areas of Dibete, Airstrip and Maibele North.

The Maibele North program aimed to test for extensions to the current resource by targeting geophysical anomalies believed to reflect sulphide mineralisation below and along strike from the current Maibele North mineral resource estimate (MRE).

The peak assays received from the latest drilling program at Maibele North are 3m at 0.83 per cent nickel, 0.18 per cent copper, 0.05 per cent cobalt and 0.36g/t platinum group elements (PGE) from 176m, including 1m going 1.59 per cent nickel, 0.37 per cent copper, 0.10 per cent cobalt and 0.64g/t PGE from 177m.

Previous assays delivered solid hits at Dibete, such as 6.15m at 7.2 per cent copper and 182 grams per tonne silver from 24.85m, including 0.5m at 10.8 per cent copper and 281g/t silver. Another 1m hit came in at a serious 13 per cent copper and 168g/t silver. A further hit of 9m going 1.54 per cent copper and 82g/t silver from 45m included 2m at 4.20 per cent copper and 269g/t silver.

The 2.38m tonne inferred resource for Maibele North boasts a mixed bag of multiple high-value minerals including 0.72 per cent nickel, 0.21 per cent copper, 0.08g/t platinum, 0.36g/t palladium, 0.04g/t of high-value rhodium, 0.05g/t ruthenium and 0.10g/t gold.

The company says it intends to review its Maibele North resource to include results from the recent drill program and the US$5 million (AU$7.63 million) spent on historical drilling by previous operators that has not yet been incorporated into the numbers. It will also undertake a review of potential open-pit mining options at Maibele North and nickel-copper-PGE sulphide production.

Si6’s Botswana project sits within a prolific nickel district and covers more than 2000 square kilometres within the highly prospective Limpopo Belt in eastern Botswana.

The Maibele North deposit is centrally located 50km from Premium Nickel Resources’ world-class Selebi-Phikwe nickel-copper-cobalt-PGE mine and 80km from Norilsk Nickel’s Tati nickel-copper mine.

Si6 says the project contains nickel sulphide mineralisation related to ultramafic intrusions and is broadly similar in style to other ultramafic intrusion-related nickel discoveries such as IGO’s renowned Nova-Bollinger operation, Chalice Mining’s Julimar play and the Thompson nickel belt in Canada.

According to the International Nickel Study Group (INSG), an intergovernmental organization designed to collect and publish nickel statistics, nickel use in electric vehicle batteries is forecast to grow this year, while stainless steel production – where most of the nickel is currently used – is expected to recover soon.

INSG says world primary nickel production is forecast to reach 3.71 million tonnes this year, with primary nickel usage expected to increase to 3.47 million tonnes.

While it is still early days for Si6 with its developing nickel-copper-rare earths plays, its compelling mix of in-demand metals that are all expected to play a big role in the future clean-energy transition could prove to be a potent mix.

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