462m Trench at Porotillo Averages 0.55 g/t AuEq, Expanding Bramaderos Resource

• 462m trench at Porotillo averages 0.55 g/t gold equivalent
• Porotillo lies within a cluster of five porphyry systems at Bramaderos
• Exploration Target at Copete-Porotillo estimated at 135–180Mt for 1.7–3.5Moz AuEq
• Drilling underway with two holes completed at Copete and second rig arriving at Porotillo
• Scoping study advancing to assess project economics

Expanding the Bramaderos Footprint

Sunstone Metals Limited (ASX:STM) has announced a major step forward in its exploration campaign at the Bramaderos Project in southern Ecuador. The company revealed assay results from a 462-metre-long trench (PO-5) at the Porotillo porphyry system, which returned an average grade of 0.55 grams per tonne gold equivalent (AuEq). This substantial surface intersection not only extends the known mineralisation footprint but also bolsters confidence in the project's potential to grow beyond its current 3.6 million ounce AuEq resource.

Porotillo is part of a cluster of five porphyry systems within Bramaderos, including the nearby Copete, Brama-Alba, and Melonal deposits. The trench results highlight extensive mineralisation open in all directions, with higher-grade intervals reaching up to 195 metres at 0.67 g/t AuEq. These findings complement previous trench assays and historical drilling, underscoring Porotillo's significance as a key growth area within the project.

Drilling Momentum and Exploration Targets

Drilling at Bramaderos is progressing well. Two diamond drill holes have been completed at Copete, with a third about to start. A second drill rig is mobilising to commence drilling at Porotillo imminently. Sunstone aims to convert a substantial portion of the Copete-Porotillo Exploration Target, estimated between 135 and 180 million tonnes grading 0.25 to 0.40 g/t AuEq, equating to 1.7 to 3.5 million ounces, into a defined mineral resource.

While the Exploration Target remains conceptual, the scale and grades reported so far provide a compelling case for further resource expansion. The company’s Managing Director, Patrick Duffy, expressed optimism that ongoing drilling and forthcoming assay results will underpin rapid resource growth and validate the project's economic potential.

Advancing Towards Development

Alongside exploration, Sunstone is advancing a scoping study focused on the Bramaderos cluster, which includes Brama-Alba, Melonal, Copete, and Porotillo. Mine design and planning are largely complete, and metallurgical testwork is underway in Canada to refine processing methods. Early indications suggest a flotation circuit with strong recoveries for copper and gold, supplemented by cyanide leaching for gold extraction.

This integrated approach aims to demonstrate robust project economics, leveraging the cluster’s outcropping gold-copper porphyry systems. The Bramaderos Project benefits from established infrastructure and community engagement, factors that enhance its development prospects.

Strategic Outlook

Sunstone’s broader strategy includes advancing its El Palmar Project in northern Ecuador, which also hosts significant porphyry targets. The company is actively exploring funding options to unlock value from its world-class assets and is open to new opportunities within Ecuador’s mining sector.

With drilling ramping up and a scoping study in progress, Sunstone is positioning Bramaderos as a potential multi-million ounce gold-copper mining centre. Investors and analysts will be watching closely as assay results and study outcomes unfold over the coming months.

Bottom Line?

Sunstone’s expanding Porotillo discovery and advancing drilling programs set the stage for a pivotal growth phase at Bramaderos.

Questions in the middle?

• Will upcoming drilling convert the large Exploration Target into a formal Mineral Resource?
• How will the scoping study results influence Sunstone’s development timeline and funding strategy?
• What are the potential impacts of Ecuador’s regulatory and community environment on project advancement?