Alison Elzayed
Business & Finance Writer | StockScope
Sunstone Metals is building considerable momentum across its Ecuadorian gold-copper portfolio, with a 72% expansion of the Bramaderos Mineral Resource to 6.2 million ounces of gold equivalent (AuEq), alongside improved metallurgical recoveries and renewed exploration at its second major project, El Palmar. The latest developments strengthen the technical foundations of both projects and provide a clearer pathway towards more advanced development studies. With a substantial resource base emerging, the focus is now shifting towards demonstrating project economics and securing the partnerships and funding needed to unlock their longer-term potential.
Key numbers
The October resource upgrade marks an important milestone for Sunstone, demonstrating the growing scale of the Bramaderos mineral system and the contribution of several expanding deposits.
The updated estimate comprises 464 million tonnes grading 0.42g/t AuEq, containing approximately 6.2Moz of gold equivalent and 1.03 billion pounds of copper.
Particularly encouraging is the 229 million tonnes containing 3.3Moz AuEq classified as Indicated. This represents approximately 53% of the total resource and provides a stronger geological foundation for future mine planning and development studies.
The new Copete-Porotillo discovery contributed approximately 1.1Moz AuEq, while continued drilling has expanded the Melonal mineralised system.
Some results highlight the potential for further discoveries. At Melonal, drill hole MEDD005 returned 9.4 metres at 17.23g/t AuEq, including 6 metres at 26.60g/t AuEq. Another hole intersected 369 metres grading 0.45g/t AuEq, demonstrating the potential scale of the underlying porphyry system.
Sunstone owns 87.5% of Bramaderos, with Jiangxi Copper holding the remaining 12.5%.
The company has also outlined an additional Exploration Target of 4.4Moz to 11.2Moz AuEq. Although conceptual and requiring further drilling, this highlights the considerable exploration potential that may exist beyond the current resource.
The resource expansion is being complemented by encouraging metallurgical progress, potentially strengthening the project's future economics.
Updated testwork indicates gold recoveries of approximately 93%, compared with 85% assumed in the April 2026 Scoping Study. Copper recoveries have also improved to 80% from 75%.
These improvements are significant because higher recoveries could allow more saleable metal to be extracted from each tonne of processed ore, supporting production efficiency and potentially improving project margins.
The proposed processing approach involves conventional crushing and grinding, flotation to produce a copper-gold concentrate, followed by cyanidation of flotation tailings to recover additional gold.
The combination of a larger resource and better recoveries provides a stronger technical foundation for the next stage of evaluation.
Sunstone is now assessing a revised Scoping Study incorporating the expanded resource and updated metallurgical performance. This should provide greater clarity around potential production, capital expenditure, operating costs and development economics.
Beyond Bramaderos, Sunstone is advancing its second major opportunity at El Palmar in northern Ecuador.
The company increased its ownership to 82.6% following a US$540,000 acquisition payment in July 2026, with a further US$1.16 million required by July 2027 to acquire the remaining interest.
El Palmar already contains an established Mineral Resource of approximately 1.2Moz AuEq. Its broader Exploration Target ranges from 15Moz to 45Moz AuEq, although this remains conceptual and requires substantial additional drilling.
The September-quarter programme included mobilisation of two diamond drilling rigs, with four holes totalling approximately 3,650 metres planned.
Two deeper holes, each targeting approximately 1,400 metres, are designed to test the T3 porphyry system along the Toachi Fault.
Previous drilling returned intersections including 190 metres at 0.58g/t AuEq and 251 metres at 0.56g/t AuEq.
The programme provides an opportunity to investigate deeper mineralisation and establish whether El Palmar could support a significantly larger resource over time.
Having two projects at different stages of exploration and development also gives Sunstone multiple avenues for future value creation.
Sunstone finished September 2026 with A$6.47 million in cash, following a July capital raising that generated approximately A$9.94 million before costs.
During the September quarter, operating cash outflows totalled A$926,000, while investing activities consumed approximately A$3.51 million, including A$2.72 million in exploration and evaluation expenditure.
The Appendix 5B calculated approximately 1.8 quarters of funding based on relevant quarterly outgoings of A$3.65 million.
While further funding will be required as both projects advance, the July capital raising demonstrates the company's ability to secure external capital to support its exploration activities.
Management has also completed its arrangement with RBC and continues discussions around potential funding partners.
A strategic partnership or project-level funding arrangement could provide an important pathway to accelerate development while reducing reliance on repeated equity raisings.
What stands out to us is the combination of Bramaderos' 6.2Moz resource, improving metallurgical recoveries and the additional exploration potential at El Palmar. The 3.3Moz Indicated component is particularly encouraging, providing a stronger foundation for future development studies. We see an increasingly attractive technical proposition emerging across both projects, particularly if the revised Scoping Study confirms favourable economics. The next important milestones are demonstrating commercially viable project assumptions and securing a sustainable funding pathway.
Sunstone has made considerable progress in strengthening its Ecuadorian gold-copper portfolio, with Bramaderos emerging as a substantial development opportunity and El Palmar providing another avenue for exploration success.
The 72% resource expansion, higher-confidence Indicated inventory and improved metallurgical recoveries represent meaningful advances. Importantly, these developments are strengthening the technical foundations required to move towards more advanced project evaluation.
Funding remains an important consideration, but the company's growing resource base and two-project portfolio provide a credible platform for strategic partnerships and further development.
We believe the revised Bramaderos Scoping Study, El Palmar drilling results and progress towards project funding could mark an important next phase for Sunstone as it works to convert exploration success into commercially viable mining opportunities.
Alison Elzayed is an experienced business and financial writer with more than 10 years of experience in the publishing industry, having previously worked as an author with Bloomsbury Publishing, specialising in business and finance. Throughout her career, Alison has developed a strong understanding of financial markets, corporate developments, economic trends and investment-related topics. Her background in financial publishing has equipped her with the ability to research complex subjects and communicate them in a clear, accurate and engaging manner.
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