Key Highlights

  • Trench results include 126.3 metres at 0.41 g/t AuEq from PO-16a and 95.5 metres at 0.50 g/t AuEq from PO-15.
  • PO-10b recorded the highest average grade in the program, at 30.4 metres at 0.64 g/t AuEq.
  • Copper-in-soil anomalism extends south of the Porotillo Resource pit shell, and a new reconnaissance trench is being assessed.
  • The current resource is 6.2 million ounces AuEq, while the exploration target is 4.4 to 11.2 million ounces.

Sunstone Metals Limited (ASX:STM) has reported trenching and sampling results from the Porotillo deposit at its Bramaderos Gold-Copper Project in southern Ecuador, in an announcement dated 4 November 2026. The company says the results point to possible extensions of its existing 6.2 million ounce gold equivalent resource.

Trench and Sampling Results

Broad surface intervals include 126.3 metres at 0.41 g/t AuEq from trench PO-16a and 95.5 metres at 0.50 g/t AuEq from PO-15. Trench PO-10b returned the highest average grade, at 30.4 metres at 0.64 g/t AuEq.

Because these are surface intervals from trenching and sampling, they are not resource estimates. The company uses them to guide where further exploration should be focused.

The results are presented as a sequence of broad surface intervals, which the company uses to show continuity of gold-equivalent grades along the trench lines. Because they are measured at surface, the intervals show where mineralisation is exposed and how wide it appears in those trenches, but they do not replace drilling for depth or resource purposes.

Target Areas Beyond the Pit

Coherent copper-in-soil anomalism extends south of the Porotillo Resource pit shell. Sunstone is assessing short reconnaissance trenches to test this additional target, which the company regards as a possible extension of the system.

Additional trenching is also under way between the Copete and Melonal areas. That work tests mapped diorite outcrops associated with magnetic responses, anomalous gold, copper and molybdenum rock-chip results, and porphyry-style veining.

The mapped diorite outcrops and magnetic responses are central to the targeting. The company is using them to define where porphyry-style veining may be present, and the Copete and Melonal results will show whether those features align with the gold, copper and molybdenum readings already reported.

Exploration Target Context

The company refers to an exploration target of 300 to 474 million tonnes at grades of 0.46 to 0.74 g/t AuEq, equivalent to 4.4 to 11.2 million ounces. The release states that the potential quantity and grade of these targets are conceptual in nature.

The announcement notes that there has been insufficient exploration to estimate a resource for the reported exploration target areas, and that it is uncertain whether further work will result in a resource.

The company states that the potential quantity and grade of its exploration targets are conceptual. The target range should therefore be read as an area of interest for future work rather than a measured figure, and the release notes that the targets are in addition to the existing resource.

Understanding the Gold-Equivalent Measure

AuEq figures combine gold and other metals into a single gold-equivalent grade, and the company's resource and target figures are expressed in this way. The conversion depends on the metal prices and recovery assumptions used in the calculation. Readers comparing the Bramaderos figures with other projects should note that each company's AuEq calculation can use different inputs. The release does not present a revised metallurgical or economic study.

Final Word

The announcement describes surface results and early targeting work rather than a resource upgrade. The company's own disclosure states that further exploration may not lead to a resource estimate, so the results are best read as guidance on where drilling and mapping may be directed. The data also leaves the scale of the exploration target unresolved, as the targets are conceptual.