Sunstone Metals has lifted the Bramaderos Mineral Resource by 72% to 6.2Moz AuEq after drilling success, while restarting deep drilling at its much larger conceptual El Palmar target. The exploration gains come with a clear funding constraint: A$6.5 million of cash represented about 1.8 quarters of estimated funding at quarter-end.
- Bramaderos Resource rises 72% to 6.2Moz AuEq across 464Mt
- Indicated Resource reaches 3.3Moz AuEq across 229Mt
- Bramaderos Exploration Target adds a conceptual 4.4Moz to 11.2Moz AuEq
- Two rigs resume testing El Palmar’s 15Moz to 45Moz AuEq Exploration Target
- A$6.5 million cash balance provides an estimated 1.8 quarters of funding
Bramaderos Resource reaches 6.2Moz AuEq
Sunstone Metals Ltd (ASX:STM) has turned a drilling program into a substantial resource upgrade, increasing the Bramaderos Mineral Resource by 72% to 6.2 million ounces of gold equivalent. The October estimate covers 464 million tonnes at 0.42g/t AuEq, including 229 million tonnes of Indicated Resources containing 3.3Moz AuEq. The company says the result provides a foundation for future studies of a potential open-pit development, with early higher-grade ore and a low stripping ratio.
The uplift was driven by the new Copete-Porotillo resource, the expansion of Melonal and changes to the existing pit footprint, alongside higher gold and copper price assumptions. The resource update follows the Bramaderos resource upgrade, which reported the same 6.2Moz AuEq estimate and highlighted the remaining gap between exploration success and a mine-ready project.
Drilling continues to expose Bramaderos upside
The drilling numbers offer some texture behind the headline. At Melonal, hole MEDD005 returned 6.0 metres at 26.60g/t AuEq within 9.4 metres at 17.23g/t, including a peak gold assay of 55.9g/t over two metres. Hole MEDD007 produced a different sort of result: 369 metres at 0.45g/t AuEq. Those results follow the Melonal drilling extension, where long mineralised intersections had expanded the porphyry system ahead of the resource update.
Porotillo also delivered broad mineralised intervals, including 143 metres at 0.72g/t AuEq in PTDD017, 95 metres at 0.68g/t in PTDD018 and 175.8 metres at 0.50g/t from surface in PTDD020. Sunstone says drilling has now defined mineralisation across more than 500 metres northwest to southeast and up to 180 metres in the perpendicular direction. The company intends to keep testing areas around existing and emerging pit footprints.
Improved recoveries strengthen the study inputs
Metallurgical testwork has also moved in the company’s favour. Revised average recoveries are 80% for copper and 93% for gold, compared with 75% and 85% respectively in the Bramaderos Scoping Study. Sunstone says the higher figures are expected to affect potential production, unit costs and net present value, although updated project metrics have not yet been provided. The recovery improvement was previously reported in the higher Bramaderos recoveries, making it an important input to any revised economic assessment rather than a completed project outcome.
El Palmar drilling targets a much larger conceptual system
At El Palmar in northern Ecuador, two rigs restarted drilling in early October to test deeper targets around the Toachi Fault and beneath the identified T1 starter-pit area. Four holes totalling about 3,650 metres are planned, including two holes of roughly 1,400 metres aimed at the deep T3 porphyry target. Sunstone holds 82.6% of El Palmar after a US$540,000 payment in July and is pursuing a staged acquisition of the remaining interest.
El Palmar’s current Mineral Resource is 1.2Moz AuEq across 64 million tonnes, but the project also carries a conceptual Exploration Target of 15Moz to 45Moz AuEq across 1.0 billion to 1.2 billion tonnes. That range includes material at T1, T2 and T3 and extends to depths of up to 1,500 metres. The company’s earlier drilling had returned 190 metres at 0.58g/t AuEq and 251 metres at 0.56g/t in the deeper porphyry environment, but the Exploration Target remains conceptual and is not a Mineral Resource.
Cash runway remains the immediate constraint
Sunstone ended September with A$6.47 million in cash and no unused financing facilities. Quarterly operating and exploration outflows totalled A$3.65 million, leaving an estimated 1.8 quarters of funding under the Appendix 5B calculation. The company raised A$9.94 million before costs through a July placement, spent A$2.72 million on exploration during the quarter and paid A$777,000 to increase its El Palmar interest.
Sunstone says it expects to fund future activity through further equity issuance and project-level strategic partnerships. That gives the exploration program room to continue for now, but the next phase of drilling and any conversion of conceptual targets into resources will need to compete with the company’s limited cash balance. The next material test is whether El Palmar’s deep holes can produce results strong enough to justify that funding conversation.
Bottom Line?
Sunstone has added scale and stronger metallurgical inputs, but the value of the exploration story now depends on El Palmar results and a credible funding path beyond the reported 1.8-quarter runway.
Questions in the middle?
- Will the four planned El Palmar holes confirm continuity and grade within the deep T3 target?
- How much of Bramaderos’ 4.4Moz to 11.2Moz AuEq Exploration Target can be converted into a Mineral Resource?
- Will Sunstone secure equity or strategic funding before continued drilling materially reduces its A$6.5 million cash balance?