Key Highlights

  • Four of ten grab samples exceeded the laboratory’s upper detection limit of 10,000 parts per million tungsten.
  • That is equivalent to about 1.26% tungsten trioxide.
  • The samples were collected within a Mining application held by a third party, next to Gold Mountain’s Logradouro tenements.
  • Stream-sediment sampling suggests a possible additional mineralised zone.

Gold Mountain (ASX:GMN) has reported rock-chip results from the historical Malhada do Angico tungsten mine in north-eastern Brazil's Seridó tungsten province. Four of ten grab samples exceeded the laboratory's upper detection limit of 10,000 parts per million tungsten, equivalent to about 1.26% tungsten trioxide, the form in which tungsten grades are usually quoted.

The ten samples ranged from 0.12% to more than 1.26% WO3. Gold Mountain calculates an average of about 0.82%, but that is a minimum because the four over-limit results were capped at the detection limit for the calculation. Further assays are under way to measure their actual concentrations. Two of the four over-limit samples came from historical mine waste rather than outcrop.

Why grab samples need caution

Grab samples are deliberately selected pieces of rock. They indicate that tungsten is present at meaningful grades, but they are not representative of the tonnage or average grade of a deposit. Gold Mountain itself states that the samples were taken to indicate the tenor of mineralisation and will not be used in any resource estimate. No drilling has yet been reported.

Sample MARK0001, taken from the south-east of the tenement, returned 1.07% WO3 outside the main historical workings. The company regards that as encouraging evidence that mineralisation extends into an eastern skarn belt.

Mapping and stream sediments

A skarn forms where hot fluids react with carbonate-rich rock, and the main target here is skarn-hosted scheelite, a tungsten mineral. Geological mapping has identified about two kilometres of skarn associated with the main historical workings and a further two kilometres, with minor old workings, in the eastern part of the tenement.

Stream-sediment sampling is consistent with the rock chips. Tungsten and bismuth anomalies largely coincide, and the data suggest a possible additional mineralised zone in the central part of the tenement, away from known workings. Gold Mountain notes that the highest values may be partly affected by contamination from historical mining, though strong anomalies also occur where no mining is known.

Executive director David Evans described the roughly four kilometres of prospective strike, supported by rock chips and stream sediments, as a significant step forward in defining the project's tungsten potential.

The company also notes that mineralisation may not be limited to the mapped skarns. Other prospective settings include shear zones near the contacts of Ediacaran-age granites and structures within older basement gneisses. Those ideas broaden the search area but remain entirely untested.

Not yet owned

An important qualification is ownership. The samples were collected within mining application 848.365/2011, covering about 857.53 hectares and held by Emprogeo Mining Business EPP Ltda. It sits next to Gold Mountain's Logradouro tenements. Under a heads of agreement announced on 5 October 2026, Gold Mountain has an exclusive 12-month right to acquire the application while it completes technical, legal and regulatory due diligence. Any Acquisition remains subject to that process.

Why tungsten is attracting interest

Tungsten is used in hard metals, defence and industrial applications, and Supply has been heavily concentrated in China. That backdrop has prompted many junior explorers to revisit historical tungsten districts. Interest alone, however, does not establish an economic deposit; grade, scale, metallurgy and permitting still need to be proven.

Next steps

High-resolution magnetic and LiDAR surveys are scheduled for November, with the contractor mobilising. Auger sampling of historical tailings is partly complete for metallurgical testing aimed at producing a high-quality tungsten concentrate with low penalty elements. Diamond drilling is planned once permits are granted, and detailed mapping and soil sampling will follow up eastern and central anomalies.

The company lists permits, metallurgical outcomes and access to funding as factors that could cause results to differ materially from expectations. The over-limit assays and first drilling will be the next meaningful data points.