Sunstone Finds High-Grade Gold Zone Between Bramaderos Porphyries

High-Grade Gold Emerges Between Alba and Melonal

Sunstone Metals Limited (ASX:STM) has ended its latest Bramaderos drilling campaign with its most eye-catching result yet: a 5.95-metre interval grading 26.61 g/t AuEq in a zone between the Alba and Melonal porphyry systems in southern Ecuador.

The interval sits within a broader 9.35m intersection grading 17.23 g/t AuEq in hole MEDD005. The result included a peak assay of 55.9 g/t gold over 2m, with native gold observed in the relevant core. Sunstone said the zone has a skarn-like mineral assemblage, strong anhydrite and unusually elevated molybdenum in the lower part of the hole.

MEDD007 Adds Nearly 368 Metres of Mineralisation

The same campaign also delivered scale. Hole MEDD007, drilled from the southeastern edge of Melonal, returned 367.99m at 0.45 g/t AuEq from surface, including 272.9m at 0.49 g/t AuEq.

Sunstone said the hole tracked a southeast-plunging, mineralised diorite intrusion dominated by stockwork veining. The reported intersection extends through the southeastern base of the company’s 2025 planned pit shell, although the announcement cautions that true widths of the mineralised lodes are not yet known.

Thirty-Hole Program Now Feeds Resource Estimate

Both holes sit outside Bramaderos’ existing 3.6Moz AuEq Mineral Resource. Sunstone said all 30 holes from the recently completed growth program across Melonal, Porotillo and Copete intersected significant mineralisation beyond the current resource and will be incorporated into the 2026 Mineral Resource update, scheduled for release in the coming quarter.

That gives the pending estimate a larger dataset across several porphyry systems rather than a single standout intercept. The key question is how much of the new drilling can be converted into resource tonnes and contained metal once continuity, geometry and economic assumptions are applied.

Follow-Up Drilling Targets High-Grade Zone

Sunstone plans to test the high-grade MEDD005 zone with hole BMDD051, to be collared on the southern margin of Alba and drilled beneath the valley towards Melonal. The company has also completed Melonal channel sampling, reporting six significant intersections from the latest surface program.

A 20m section near the bottom of MEDD005 has been re-sampled for repeat assay. That introduces a modest but material qualification to the headline high-grade result: the reported numbers remain laboratory assays, but confirmation of the repeat sample is still pending.

Resource Update Becomes the Next Test

Sunstone Managing Director Patrick Duffy described the two holes as a substantial contribution to the impending update, while the company said trenching at the Porotillo porphyry is nearing completion and assays from eight additional trenches are expected shortly.

The drilling results strengthen the exploration case at Bramaderos, but they do not yet establish mineable widths or alter the published resource. The next meaningful test will be whether the 2026 estimate captures the broad Melonal mineralisation and the higher-grade Alba-Melonal zone without relying on the conceptual Exploration Targets that remain outside the Mineral Resource.