Sunstone Metals (ASX: STM) Finds High-Grade Gold Between Bramaderos Porphyries

Sunstone Metals has completed a 30-hole resource-growth drilling program at its Bramaderos project in southern Ecuador, reporting one narrow high-grade gold interval and a second hole mineralised across almost its entire 368-metre length.

The company said all 30 holes intersected significant mineralisation outside the existing Bramaderos resource. Results will be incorporated into a Mineral Resource update due in the coming quarter.

High Grade Between Alba and Melonal

Hole MEDD005 returned 9.35 metres at 17.23 grams per tonne gold equivalent from 290 metres, including 5.95 metres at 26.61 grams per tonne.

Within that interval, the highest gold assay was 55.9 grams per tonne over two metres.

Sunstone said native gold was observed along a fracture within the high-grade zone, which sits beneath the valley floor roughly midway between the Alba and Melonal porphyry systems.

The hole also returned a broader 171.65-metre interval grading 0.43 grams per tonne gold equivalent near the top of the hole.

Sunstone calculated the high-grade interval at about 161 gram-metres, broadly comparable with the 166 gram-metres generated by the much wider MEDD007 intersection.

Broad Mineralisation at Melonal

MEDD007 intersected 367.99 metres at 0.45 grams per tonne gold equivalent from surface, including 272.9 metres at 0.49 grams per tonne.

The hole followed a mineralised diorite intrusion at a shallow angle toward the southeast, where Sunstone’s modelling suggests the body plunges in the same direction as the broader Brama-Alba system.

The drilling tested the upper portion of that interpreted intrusion and extended through the southeastern base of the company’s 2025 planned pit shell.

Sunstone cautioned that the reported intervals are downhole lengths and that true widths have not yet been established.

Resource Update Becomes the Key Test

Bramaderos currently contains 220 million tonnes grading 0.50 grams per tonne gold equivalent, equivalent to 3.6 million ounces based on the November 2025 estimate.

The latest campaign targeted mineralisation at Melonal, Porotillo and Copete outside the existing resource envelope, meaning the next update will incorporate drilling across several porphyry systems rather than a single extension zone.

Managing Director Patrick Duffy said every hole in the program had intersected mineralisation outside the existing resource.

Sunstone will now follow MEDD005 with hole BMDD051, which will be drilled from Alba’s southern margin beneath the valley toward Melonal.

Trenching at Porotillo is also nearing completion, with assays from another eight trenches expected shortly.

The coming resource update will provide the first clear measure of how much the latest drilling has added to Bramaderos’ scale and how the newly defined mineralisation changes the project’s overall geometry. Sunstone holds an 87.5% interest in the project, with Jiangxi Copper holding the remaining 12.5%.