Allup Silica (ASX:APS) has identified a potentially massive kaolin clay deposit after a broadly-spaced exploration scout drilling campaign for silica and rare earths at its Pink Bark project near Esperance in Western Australia.
The company believes it may be now sitting on a resource of between 700,000 and 1.2 million tonnes of kaolin within 69 square kilometres, prompting it to use XRF analysis to take a closer look at eight selected samples. Management says the kaolin was noted in thicknesses ranging between 5m and 20m in its reconnaissance air-core (AC) drilling of 41 holes averaging 20m depth across two exploration licences, for a total of 823m drilled and logged at 1m intervals.
Initial analysis of the early samples yielded results in the range of 17 per cent to 20 per cent aluminium oxide (alumina).
Kaolin – also referred to as kaolinite – is well-known as a non-swelling, soft clay with a plastic nature and white colour. It is composed of hydrated aluminium silicate, which forms through chemical weathering of aluminium-rich feldspar minerals contained in granites and pegmatites.
In the ceramics industry, the same formula for kaolin is expressed in terms of oxides, alumina and silica, or as aluminium oxide and silicon dioxide, respectively.
The recent wide-spaced drilling program – aimed at near surface silica and underlying rare earths potential, has confirmed the presence of a thick kaolin zone under shallow cover, presenting an interesting opportunity given the presence of silica sand above and rare earths and uranium potential below. While our initial focus was silica sand, the recent discoveries of clay-hosted rare earths deposits in the region prompted us to investigate this exciting rare earths potential at Pink Bark.
Allup Silica managing director Andrew Haythorpe
Prompted by the known industrial importance of kaolin and the proximity of the company’s project to the port of Esperance, management has sent a further 56 samples for analysis to assist in its understanding of the potential of the resource. Results are expected before the end of next month.
Haythorpe says the company will have a closer look at the kaolin, including characterisation studies to determine its quality and potential value. If the findings are encouraging, it will consider further AC drilling to refine the exploration target and develop an even better understanding of the resource.
Kaolin is mined in many countries and is an important raw material in many industries and applications. Commercial grades of kaolin are supplied and transported as powder, lumps, semi-dried noodle or slurry.
Global production of kaolin in 2021 was estimated to be 45 million tonnes, with a total market value of $6.4 billion.
About 70 per cent of kaolin production is used to make paper. In white ceramics, it can comprise up to 50 per cent of the product.
It is also used in insulation, a paint additive to extend the whitening mineral titanium dioxide used in pigments, an additive to rubber to modify its properties, as an additive to adhesives, an absorbent in water treatment, to modify various cements and their properties, in geopolymers and in cosmetics, in addition to many more minor applications.
Allup’s Pink Bark project is located in the emerging Biranup zone in the Albany-Frazer geological province north of Esperance. The zone has been shown to be rich in valuable rare earths by the Geological Survey of Western Australia and by other recent geological exploration.
Several ASX-listed companies have reported extensive areas of clays hosting rare earths mineralisation overlying the late-stage granite intrusive rocks in the region. They are rapidly emerging as a focus for exploration due to their clay and carbonatite-hosted rare earths content.
While Allup initially acquired the ground to explore and develop silica sand deposits, recent discoveries of clay-hosted rare earths prompted it to consider the possibilities of such deposits within its tenement area.
The discovery of kaolin potential alone is significant. But if additional silica and rare earths – and maybe even uranium – can be identified during the company’s follow-up infill and further resource drilling, it may live up to its name with a new grab-bag of mutually-supportive mineral resources, all within the same mining area.
And that could prove to be a first for WA.
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