ASX-listed Aldoro Resources is concentrating efforts on exploring the Loop Pegmatite structure at its Wyemandoo pegmatite project in Western Australia. The exploration focus is following up a series of high-grade lithium and rubidium assays and completed satellite imagery which indicate a similar structure immediately to the south in the pegmatite swarm.
The Loop Pegmatite area is in the central Fairway Pegmatite corridor of the company’s Wyemandoo pegmatite project in WA and contains highly anomalous lithium and rubidium values. Aldoro says the rubidium values are comparable with the world’s richest JORC compliant rubidium deposit located in Namibia. The area is only 25 kilometres north-northwest from the Youanmi Pegmatite Field owned by Lithium Australia.
A total of 22 pegmatite rock chip samples taken around the Loop Pegmatite structure had an average of 1.06 per cent lithium oxide and 0.94 per cent rubidium, with samples reporting up to 2.6 per cent lithium oxide and 1.7 per cent rubidium. Amazingly, over half the 20 samples analysed assayed up at greater than 1 per cent lithium oxide with a maximum grade coming in at a stunning 2.12 per cent lithium oxide.
Rubidium assays are generally consistently above those typically found in lithium-caesium-tantalum -or “LCT” pegmatites, with an average of 0.94 per cent of values up to 1.7per cent. Caesium values averaged 262 parts per million with values up to 542 parts per million.
The anomalous assay data stretches over an area greater than 9 kilometres over four contiguous exploration permits which Aldoro has termed the Wyemandoo Project. Interestingly, these grades are comparable to the grades recorded at Lepidico’s Namibian Karibib deposit where, according to Aldoro, the only rubidium JORC compliant deposit in the world has a published 6.7 million tonnes of ore grading at 0.23 per cent rubidium, 0.46 per cent lithium oxide and 320 parts per million caesium.
The rubidium and lithium appear to be hosted in the purple mica lepidolite found in the pegmatites. Curiously, pegmatites like the Loop Pegmatite sit further away from the parental granitic magma and are therefore more fractionated with greater potential for enriched lithium, rubidium and caesium.
The Wyemandoo Project, 80km southeast of Mount Magnet in WA, covers nearly 260 square kilometres over a contiguous belt along the margin of the Windimurra Igneous Complex. Aldoro has agreements over two further licence applications which both lie within the pegmatite corridor. The Windimurra Igneous Complex is an Archean layered mafic intrusion cut by numerous pegmatite dykes. There is also an extensive zone of high-grade hydrothermal tungsten veins.
The company recently expanded its Windimurra lithium pegmatite footprint after settling a deal with Meridian 120 Mining earlier this year to acquire the Wyemandoo and Niobe tantalum-lithium projects adjacent to its Windimurra project.
Aldoro says the pegmatite corridor appears to be at least 10km long and up to 4km wide with lepidolite micas found in several locations in the central zone. The company says it will be targeting this zone in the next phase of rock chip sampling across the Fairway Pegmatite Corridor.
The pegmatites at Wyemandoo generally follow a northeast orientation and have a strike length of around 1km. They tend to vary in thickness from 1 to 20 metres with shallow to moderate dips, typically 30 to 60 degrees. While generally linear and sub-parallel to the strike of host gabbro, the pegmatites do show a range of morphologies.
Importantly, the pegmatite swarm appears across a huge northeast trending corridor which is over a 10km long and up to 4km wide, however the full extent is masked by young alluvium cover.
Whilst more than 20 pegmatite dykes have been mapped to date, of which 10 have been sampled, Aldoro says dozens more are yet to be mapped and sampled. Significantly, they are located only 25km north-northwest of the Youanmi lithium pegmatite field owned by Lithium Australia.
A larger, systematic sampling program is currently being finalised and is expected to kick off in about a week. It will focus on sampling at 40-meter intervals along the extent of the outcropping pegmatite. Portable XRF will be utilised to indicate the occurrence of rubidium mineralisation for immediate forward planning of drill hole positions.
Aldoro says the Wyemandoo pegmatites represent a new lithium-rubidium bearing pegmatite field and will be a high-priority focus of investigation in the coming months.
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