ABx Group has expanded the rare earths zone at its Deep Leads-Rubble Mound project in northern Tasmania, with new drill hits showing mineralisation enriched in the valuable heavy rare earths, dysprosium and terbium.
The company says its latest drilling proves that the site west of Launceston retains the highest proportion of the two elements of any clay-hosted rare earths resource In Australia. It now has its focus on an exploration target area exceeding 100 square kilometres.
ABx’s latest suite of results show several strongly-mineralised intersections within the eight holes that were drilled, with 66 assays now received from the 97 holes being targeted in the campaign. About 230 assays are still outstanding.
Management says the dysprosium-terbium levels average about 4.5 per cent of the total rare earth oxides (TREO). It says ratios above 5 per cent are rare anywhere in the world, making the resource a valuable source of heavy rare earths.
And an added benefit to the resource is the low levels of thorium and uranium.
Interestingly, ABx says it was the first time it had aimed drilling specifically at rare earths within the high-grade Rubble Mound zone that was previously only targeted for bauxite in shallow zones. It is also continuing its research into a low-impact method for extracting the mineralisation.
The company has found there is typically a low-grade, rare earths-depleted surface layer of 2m to 5m that overlays an enriched layer of about 4m to 17m in thickness.
ABx Group managing director and chief executive officer Mark Cooksey said: “It is exciting to see that our exploration program continues to produce outstanding results. A focus of the recent drilling campaign was to expand the Rubble Mound high-grade zone within the existing resource, and this has been achieved. A distinctive feature of the ABx deposits is the high proportion of dysprosium and terbium, and the recent results confirm this pattern.”
Management also says that once the outstanding assays have been received, a resource update will be undertaken that will include its Wind Break deposit for the first time. A recent 30-hole drilling campaign at Wind Break produced many 1m intersections grading higher than 2000 parts per million TREO and elevated levels of dysprosium-terbium in line with the levels encountered across the full resource.
The company revealed a mineral resource estimate for its Deep Leads-Rubble mound project in November last year, using a statistical “block-modelling” method that is widely employed within the industry. It provides the benefit of mapping the distribution of high-grade sections within the deposit.
The resource contained 52 million tonnes at 817ppm TREO and 26 per cent magnet rare earth oxides (MREO). Dysprosium-terbium made up 4.4 per cent of the TREO.
With the attractive levels of both magnet and heavy rare earths contained within the resource, ABx’s strategy is to produce a mixed rare earths carbonate that it can sell to existing refineries to increase their production. The fact that the carbonate is expected to be high in the valuable heavy rare earths and low in radioactive elements, is almost certain to be attractive to many prospective customers.
If ABx’s super-shallow resource that contains the outstanding levels of heavy rare earths and valuable magnet oxides can be bolstered further with even more exploration, it may just prove to be rare, indeed.
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By Craig Nolan
