Sunstone Metals has pushed the boundaries of its Bramaderos gold-copper project in Ecuador with a standout 176m mineralised intersection at Porotillo, expanding the footprint well beyond the current 3.6Moz resource and setting the stage for a resource update in December.
- 176m drill intersection at Porotillo grading 0.50 g/t AuEq from surface
- Porotillo mineralised footprint now 520m by 230m outside existing resource
- All 26 recent holes at Porotillo, Copete, Melonal show long mineralised intervals
- Additional assays pending ahead of December resource update
- Deep 1200m exploration hole underway at Limon porphyry target
Porotillo Discovery Expands Mineralised Envelope
Sunstone Metals Ltd (ASX:STM) has revealed a significant new chapter in its Bramaderos gold-copper project in southern Ecuador, with drill hole PTDD020 at the Porotillo prospect delivering a 175.8-metre intersection grading 0.50 g/t gold equivalent (AuEq) from surface. This result pushes the known mineralisation footprint at Porotillo to approximately 520 metres by 230 metres, extending well beyond the existing 3.6 million ounce resource.
The intersection includes a higher-grade 58.6-metre zone at 0.66 g/t AuEq, underscoring the prospect's potential. Porotillo is one of five deposits and prospects within Bramaderos but lies outside the current resource boundary, highlighting its role in the anticipated resource update planned for the December quarter.
Consistent Mineralisation Across Multiple Prospects
All 26 drill holes assayed in the recent campaign across Porotillo, Copete, and Melonal have returned long mineralised intersections, reinforcing the project's upside. Trenching efforts have also expanded surface mineralisation at Porotillo, with contiguous trenches PO-5, PO-6, and PO-7 combining to a 698-metre intersection grading 0.52 g/t AuEq.
Sunstone's Managing Director Patrick Duffy emphasised the continuity of these results, noting that "the Porotillo discovery now measures a large area of around 550m by 240m," and that the combined drilling and trenching campaign has been "highly successful" in outlining significant mineralised zones outside the existing resource.
Pending Assays and Deep Exploration at Limon
Additional assays remain outstanding for four holes and nine channel samples at Melonal, plus three trenches at Porotillo, with results expected through August and early September. These will feed into the forthcoming resource update, which aims to incorporate these new mineralised zones and refine the project's resource base.
Meanwhile, exploration continues at depth with a 1,200-metre diamond drill hole underway at the Limon porphyry target, situated beneath and southwest of the shallow Limon epithermal gold-silver deposit. At present, the hole has reached 387 metres and is progressing, targeting a deeper gold-copper porphyry system that could add further scale to Bramaderos.
Strategic Implications for Bramaderos and El Palmar
These results bolster Sunstone's strategy to grow Bramaderos beyond its current 3.6Moz AuEq resource, which already includes a 220Mt mineral resource at 0.50 g/t AuEq. The company also holds a substantial porphyry exploration target estimated between 4.1Moz and 11.2Moz AuEq within 315 to 505Mt. The ongoing drilling and surface sampling campaigns are critical steps toward converting this exploration potential into a formal resource.
Sunstone's El Palmar project, located 60km northwest of Quito, also holds promise with a 64Mt resource at 0.60 g/t AuEq and an exploration target ranging from 15Moz to 45Moz AuEq. Drilling at El Palmar is set to resume in September 2026, complementing the development pipeline alongside Bramaderos.
Infrastructure and Community Engagement
Both projects benefit from robust infrastructure, including proximity to power, road, and port facilities, which could facilitate future development. Sunstone emphasizes strong community relations and ESG standards, having published its inaugural Sustainability Report in 2023 detailing engagement with local stakeholders.
Bottom Line?
Sunstone’s latest drilling at Porotillo confirms significant mineralisation expansion, but the upcoming resource update hinges on pending assay results and the outcome of deep Limon exploration.
Questions in the middle?
- Will the pending assays at Melonal and Porotillo materially alter the scale of the December resource update?
- Can the deep Limon porphyry hole uncover a new high-grade system to complement Bramaderos’ surface deposits?
- What funding strategies will Sunstone pursue to advance Bramaderos and El Palmar beyond exploration?