Aruma drills high-grade lithium-rubidium pegmatite

Mineral exploration company Aruma Resources has identified a high-value lithium-rubidium pegmatite at its Mount Deans project near Norseman WA.

Drilling intersected lithium grades up to 1.14 per cent lithium oxide in a 25 metres thick vertical pegmatite with a strike interpreted at more than 1500m.

Best results included 10m at 0.62 per cent lithium oxide with 0.57 per cent rubidium oxide and 7m grading 0.76 per cent lithium oxide with 0.69 per cent rubidium oxide.

The high value of rubidium is providing the project with a multiple metal program going forward.

RC drilling by Aruma has hit pegmatite in every hole to date at Mount Deans, with 13 of those returning intersections of more than 0.5 per cent lithium oxide. The lithium and rubidium intersections were present in the 25m thick vertical pegmatite commencing from 17m below surface.

Aruma has concluded the Mount Deans pegmatite is showing zonation with high-grade lithium oxide and rubidium oxide being present. The main pegmatite has a strike length across 1500m and is open at both ends along strike.

Rubidium oxide grades reached a peak of 1.05 per cent and the company believes it could become a key focus of future exploration.

Rubidium is typically found in pegmatite rock associated with the mineral lepidolite that is also a lithium ore mineral, or pollucite, which is a cesium rich mineral.

Conversion of lepidolite to lithium hydroxide takes place at approximately one quarter of the cost per tonne when compared to lithium hydroxide production from spodumene.

Aruma has not reported the mineral associations at this stage but they may become an important cost advantage if lithium is present in lepidolite.

Rubidium is not stable at room temperature when exposed to water or oxygen, so it is generally sold as rubidium carbonate, Rb₂CO₃. Recent 99 per cent pure rubidium carbonate prices are US$1060/kg but can increase five-fold for higher-purity products. A mind-blowing figure of more than $1 million per tonne.

Rubidium’s industrial uses include fibreoptic cables, GPS systems, sodium ion batteries and solar panels.

Aruma Resources Managing Director, Peter Schwann says: “The first phase of drilling at Mt Deans has delivered highly encouraging and positive results, returning strong lithium and rubidium grades in numerous intersections, some with significant widths. and our future work will target Mt Deans as a multi metal asset.”

The company is pushing ahead with completing the remaining 12 RC drillholes over 1800m as a priority.  The exploration concludes the successful maiden drilling program at Mount Deans that is located in the lithium corridor of south-eastern Western Australia, running south from Kalgoorlie to Norseman and beyond.

According to the company the lithium corridor in south-east WA hosts multiple significant hard-rock lithium projects including Mt Marion, Bald Hill and Buldania. Aruma interprets Mount Deans as being located within the same host rocks and structures as the other lithium deposits.

The multiple metal potential of Mt Deans is giving Aruma a significant point of difference compared with many other lithium plays.

Although it is early days, the addition of rubidium could prove to be a project maker although it brings into sharp focus the need for early metallurgical testing to see how much value the mineral brings to the equation.

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