ASX-listed Aldoro Resources has the drill rig at the ready having received encouraging assay results from its recent sampling program over the Niobe East, Niobe Southeast and Breakaway pegmatites in Western Australia. Almost 50 rock chips were collected with assay results confirming rubidium and lithium prospectivity beyond the Niobe main pit. Aldoro says it is now geared up and ready to unleash the drill rig once a heritage survey is completed.
Of the 46 rock chips collected, rubidium values ran up to an impressive 9,307 parts per million. Rubidium is considered a key pathfinder for lithium and intriguingly, the samples did contain evidence of lithium and caesium mineralisation.
At Niobe East, anomalously high rubidium and lithium values were found to extend over a massive 400 metres in strike length, providing Aldoro with solid justification for its proposed drilling programme into this multilayered pegmatite section. The company has a drill rig booked and ready to roll once the heritage survey is complete.
At the Breakaway pegmatites to the west, anomalous rubidium and lithium extends up to a strike length of 100m, while at Niobe Southeast the few samples collected so far have rubidium values up to 0.2 per cent.
These assay results confirm rubidium and lithium prospectivity beyond the current Niobe main pit.
Aldoro Resources Chairman, Joshua Letcher said: “The rock chip results show the potential for the area and give confidence for increasing the Exploration Target tonnage”.
Aldoro has mapped the outcrop spread of rubidium and lithium results and has confirmed they are generally consistent with those obtained historically in the mid 1980s. It says the results provide confidence in the historical drilling assays from the same period which were used to define an exploration target over the Niobe Main pegmatite.
The exploration target is approximately 33,000-150,000 tonnes at grades ranging 696-1457ppm rubidium oxide defined from an 80m by 65m area of detailed drilling.
Niobe sits approximately 70 kilometres north-west of Mount Magnet in WA and contains many pegmatites with significant lithium and tantalum enrichment. Aldoro recently initiated the re-evaluation of the Niobe prospect, part of the giant ultramafic-mafic Windimurra Igneous Complex, as values of rubidium oxide grading over one per cent were recorded from historical mid-1980s reverse circulation drill holes by Pancontinental Mining.
A total of 31 close-spaced, shallow, interval holes over an area of 80m by 65m were drilled by Pancontinental between 1984 and 1986 to depths between 13m and 48m. Down hole sampling was conducted at 1m intervals and sub-samples were analysed for the lithium pegmatite suite of elements including lithium, rubidium, caesium, niobium, tantalum and tin.
The pegmatites in the area are commonly zoned with an outer wall zone, intermediate zone and quartz rich core. The quartz core is itself zoned towards the base with most of the mineralisation occurring in the intermediate contact zone with the lithium-bearing mica zinnwaldite which is common in the lower zone. Rubidium also appears to be hosted in the zinnwaldite in this lower zone.
Rock samples taken by Aldoro in this rock chip sampling commonly have a greisen-like morphology with micaceous laths and microcline.
Aldoro now plans to expand the exploration target area to encompass the mapped pegmatite on the western side of Niobe - Pegmatite No.1, the high rubidium bearing sections of Niobe East - Pegmatite No.2, the Breakaway pegmatites and Niobe Southeast Pegmatites.
The company recently received approval for a programme of works and negotiations are underway with Wajarri Aboriginal corporation for a heritage survey over the area. A reverse circulation drill rig is booked and awaiting mobilisation once this survey is complete.
Rubidium is a very soft, silvery-white metal and rubidium compounds are sometimes used in fireworks to give them a purple colour. Rubidium is also used in a range of industrial applications including specialty glasses in fibre optic cables, GPS systems,night vision gear and importantly, has the potential to be applied in sodium-ion batteries. It has a variety of biomedical uses, particularly for imaging brain tumours and interestingly can also be used to treat depression.
The two most notable source of rubidium currently are deposits in Manitoba, Canada and on the Italian island of Elba. However, the recently discovered Tiantangshan tin-tungsten-rubidium deposit in the Guangdong province of China contains over 100,000 tonnes of rubidium oxide hosted in micas, at the average grade 0.109 per cent, which ranks it the biggest rubidium deposit in the world.
Aldoro is quietly building its multi-element portfolio in WA and could become Australia’s’ first rubidium producer if its continued exploration proves successful.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Matt Birney
