Sunstone Metals has uncovered a substantial new zone of gold-copper mineralisation at its Bramaderos Project in Ecuador, with all 24 recent drill holes outside the existing 3.6Moz resource delivering long intersections. The Porotillo prospect alone now spans a 520m by 230m area, setting the stage for a resource update in December 2026.
- All 24 recent drill holes return extensive gold-copper mineralisation
- Porotillo mineralisation covers 520m by 230m beyond current resource
- Strongest hole PTDD017 hits 196m at 0.62 g/t AuEq from surface
- Additional assays pending before December resource update
- Deep drilling planned at Limon porphyry target starting August
Porotillo Discovery Broadens Bramaderos Resource Horizon
Sunstone Metals Ltd (ASX:STM) has announced a significant expansion of gold-copper mineralisation at its Bramaderos Project in southern Ecuador, with the Porotillo prospect emerging as a standout new zone outside the existing 3.6 million ounce gold equivalent resource. The latest batch of four drill holes at Porotillo delivered long, consistent mineralised intersections, extending mineralisation over an area measuring approximately 520 metres by 230 metres. This discovery will be incorporated into the company’s resource update scheduled for the December quarter of 2026.
The standout hole PTDD017 returned 196 metres grading 0.62 g/t AuEq from surface, including a higher-grade 143 metre interval at 0.72 g/t AuEq and a 4.8 metre section with 2.29 g/t AuEq featuring a high-sulphidation epithermal structure. These results underscore the continuity and tenor of the mineralisation at Porotillo, which lies beyond the current resource boundary.
Consistent Mineralisation Across Multiple Prospects
All 24 holes assayed so far in the 2026 drilling campaign across Porotillo, Copete, and Melonal prospects have returned long intervals of mineralisation, maintaining a perfect strike rate. The mineralised footprint at Porotillo is now defined over a northwest-southeast strike of 530 metres and northeast-southwest width of up to 230 metres, with trenching results further confirming extensive near-surface mineralisation. Contiguous trenches PO-5 and PO-6 combine for a surface intersection of 608 metres grading 0.52 g/t AuEq, highlighting the scale of the system.
Grade shells indicate the strongest mineralisation is near-surface and associated with an oxide-sulphide transition zone, which enhances copper tenor and copper-to-gold ratios. The mineralised domains appear to plunge steeply southeast towards a deep magnetic target below current drilling depths, representing a compelling target for future exploration.
Pending Assays and Upcoming Deep Drilling at Limon
Sunstone is awaiting assay results from several holes and trenches across Porotillo, Copete, and Melonal before finalising the resource update. This includes two drill holes at Porotillo and Copete, four holes and nine channel samples at Melonal, and four long trenches at Porotillo. These results, expected during August, could further enhance the resource base.
Meanwhile, the company is mobilising its drill rig to commence a 1,200-metre deep hole at the Limon porphyry target, located beneath and southwest of the shallow Limon gold-silver deposit. Limon has previously yielded impressive drill intersections, including 185 metres at 2.85 g/t AuEq and 269 metres at 1.05 g/t AuEq, indicating strong epithermal potential. This deep drilling aims to test the porphyry system at depth, representing a key exploration frontier for Sunstone.
Strategic Positioning and Project Outlook
Bramaderos remains a large-scale porphyry gold-copper system with a November 2025 resource estimate of 220 million tonnes at 0.50 g/t AuEq for 3.6 million ounces. The project also hosts substantial exploration targets that could significantly increase the resource size. Sunstone’s Managing Director Patrick Duffy emphasised the importance of the Porotillo discovery in adding to the cluster of outcropping gold-copper porphyry systems at Bramaderos, noting the consistent wide zones of mineralisation encountered in drilling.
The company continues to advance its strategic funding initiatives and exploration programs, aiming to unlock the full potential of its two world-class projects in Ecuador; Bramaderos and El Palmar. The upcoming resource update and deep drilling results at Limon will be pivotal in shaping the project's development trajectory.
Bottom Line?
Sunstone’s Porotillo discovery extends Bramaderos’ mineralisation footprint significantly, but pending assays and deep Limon drilling will be critical to defining the next phase of resource growth.
Questions in the middle?
- Will the pending assays from Porotillo, Copete, and Melonal confirm further resource expansion?
- How will the deep drilling results at Limon influence the overall project valuation and development plans?
- What funding strategies will Sunstone pursue to support ongoing exploration and potential development?