Key Highlights

•  Rock-chip sampling at Eleys-Coondina, about 80 kilometres south-west of Marble Bar, identified lithium-bearing pegmatites and a silver-rich gossan.

•  The company links the area's granites to the lithium-caesium-tantalum deposits at Wodgina, Pilgangoora and Tabba Tabba.

•  Follow-up field sampling will refine drill targets, and rock-chip sampling will extend across the Coondina gossan to test for platinum group metals.

Tambourah Metals (ASX:TMB) has reported rock-chip sampling results from its Eleys-Coondina project in Western Australia's Pilbara, identifying lithium-bearing pegmatites and a silver-rich gossan. The results were reported on 27 October 2026.

The project lies about 80 kilometres south-west of Marble Bar. The area was historically worked for alluvial tin derived from pegmatites associated with the Split Rocks Supersuite, a group of granites the company links to the lithium-caesium-tantalum (LCT) spodumene deposits at Wodgina, Pilgangoora and Tabba Tabba.

Sampling results

A total of 79 rock-chip samples were collected across the project's Coondina and Eleys areas. The announcement did not give a sample breakdown by area.

At Coondina, the best lithium result was 1.14% lithium oxide (Li2O) from fractionated pegmatites bearing lepidolite, a lithium mica, associated with a mapped greenstone inlier. The pegmatite dykes are laterally extensive, between one and two metres wide, and dip shallowly to the south. Scree cover prevented the company from assessing their thickness and continuity elsewhere.

A limited number of fluorite-bearing pegmatites were also identified, which Tambourah said may indicate a hybrid between LCT pegmatites and the niobium-yttrium-fluorite family.

Separately, a malachite-bearing gossan next to an east-west trending ultramafic-mafic dyke returned 151.2 grams per tonne silver, 2,119 parts per million bismuth and 0.395% copper. Samples along strike returned mildly elevated silver and bismuth, which the company said suggests potential for a mineralising event linked to the intrusion.

At Eleys, the best tantalum result was 572ppm from a pegmatite along a north-west trending structure that was historically worked for tantalum, with elevated caesium, niobium and tin also recorded. The company said fractionated pegmatites extend north-east of the historic Five Mile alluvial tin operation, an area it described as not previously explored for LCT pegmatites.

Why it matters

The Pilbara hosts some of the world's major hard-rock lithium operations, and the presence of fractionated pegmatites in the same granite suite gives Tambourah a geological basis for further work. Lepidolite is a lithium-bearing mineral, although spodumene is generally the preferred mineral for lithium concentrate production in Western Australia, so the mineralogy of any future discovery will be important.

Caesium, tantalum, niobium and tin are commonly associated with highly fractionated pegmatites, and their presence at Eleys supports the company's view that the area warrants systematic exploration. Tantalum is used in electronic capacitors and is regarded as a critical mineral in several jurisdictions, although the reported result represents the best single sample rather than an average.

The silver-bismuth-copper gossan adds a second line of enquiry. Gossans form where sulphide minerals have weathered at surface, and they can indicate mineralisation below, although many do not lead to economic deposits.

Limitations and risks

The company noted that rock-chip samples do not represent the potential thickness, continuity or extent of mineralisation. Rock chips are selective by nature and can overstate the grade of a broader zone. No drilling has been reported at these targets, and no mineral resource exists for the project.

Scree cover restricts geological mapping, and the dykes observed so far are relatively narrow. Lithium prices have also been weak, which can affect funding for early-stage lithium exploration and the economics of any future project.

Next steps

Tambourah said it will carry out follow-up field sampling to refine LCT pegmatite drill targets, and extend rock-chip sampling across the Coondina gossan to test for platinum group metals.

The company has also undertaken a 167 square kilometre hyperspectral survey at Coondina and is working with CSIRO under a Kick-Start research collaboration to refine machine-learning methods for defining LCT targets. Those datasets are intended to help prioritise areas for future drilling. Tambourah describes itself as an explorer advancing gold and critical minerals projects across Western Australia.