Northern Minerals Ltd (ASX:NTU) has welcomed a material increase in the mineral resource estimate at the Wolverine rare earth element (REE) deposit of the Browns Range Project in Western Australia, generated in an independent review by CSA Global.
The Wolverine deposit’s REE bounty increased 47% to 6.44 million tonnes at 0.96% total rare earth oxides (TREO) for 61,492 tonnes of TREO.
The total Browns Range system’s mineral resource estimate now stands at 10.81 million tonnes at 0.76% TREO for 81,450 tonnes.
CSA Global’s independent review and assessment of Wolverine’s geological database included a full rebuild of the wireframe model, generating a new understanding of the deposit’s position.
Mineral resource classification and exploration target at the Wolverine deposit.
High-value magnet REEs present
A key feature of the Wolverine resource is the dominance of high-value dysprosium and terbium with average grades of 0.83 kg/tonne and 0.12 kg/tonnes respectively contained within xenotime mineralisation.
Dysprosium and terbium are essential ingredients in the production of neodymium-iron-boron (NdFeB) magnets used in clean energy, military and high technology solutions because their unique properties enable the magnets to better resist demagnetisation.
Northern Minerals executive chair Nick Curtis said the upgrade in Wolverine’s resource was highly encouraging for the project and reinforced the project as one of the world’s most exciting new sources of dysprosium and terbium, which were critical metals in a low carbon future increasingly reliant on rare earth permanent magnet electric motors.
“The increased mineral resource at Wolverine is an important step in our plan to establish ourselves as a significant producer of dysprosium and terbium, offering a reliable alternative to production sourced from China,” Curtis said.
Dysprosium plays an important in creating permanent magnets in electric vehicles, specifically in improving their resistance to demagnetisation and by extension their high-temperature performance.
Terbium is used to dope calcium fluoride, calcium tungstate and strontium molybdate in solid-state devices, and as a crystal stabiliser of fuel cells that operate at elevated temperatures.
As a component of Terfenol-D (an alloy that expands and contracts when exposed to magnetic fields more than any other alloy), terbium is of use in actuators, in naval sonar systems and in sensors.
The Wolverine resource increased compared to the 2015 estimate for the following reasons:
- Additional drilling – small increase on flanks.
- Detailed analysis of results based on grade control and exploration drilling.
- Gaining confidence in the classification of inferred mineral resources after analysis of continuity based on an exploration grid of 50 x 50 metres.
- Detailed structural analysis.
- Updating wireframes to include the structural controls.
- Updating the grade interpolation methodology to better reflect the grade variability/distribution by adopting the following methods - the application of Multiple Indicator Kriging (MIK); the use of flattening; and using a narrow search ellipsoid to better reflect the grade variability.
Read more on Proactive Investors AU
