Sunstone Metals Ltd (ASX:STM) has unearthed a well-mineralised gold-copper porphyry system during drilling at Limon target within the Bramaderos Project in southern Ecuador.
Drill hole LMDD010 returned the best results, intersecting 0.90 g/t gold equivalent over 79 metres from 90 metres (0.52 g/t gold, 0.19% copper and 9.4 g/t silver), including 1.26 g/t gold equivalent over 34.7 metres from 94 metres (0.77 g/t gold, 0.24% copper and 14.1 g/t silver).
The discovery has reinforced the view that the concession hosts multiple gold-copper porphyry systems within its 50 square kilometre area.
Significantly, it highlights the potential to grow the Bramaderos mineral resource at higher grades.
Limon drill status plan showing the status of drilling on backdrop of gold-in-soil results.
"Very exciting results"
“The Limon discovery could have a potentially substantial impact on the total resource, the overall grade and the upfront development options at Bramaderos,” Sunstone’s managing director Malcolm Norris said.
“These results are very exciting because they deliver ore-grade porphyry mineralisation in drilling that extends from surface over substantial widths.
“The shallow and relatively higher grades allow us to contemplate development options that may include higher-grade starter pits.
“We are also now drilling some strong soil gold anomalies associated with high sulphidation style epithermal gold-copper targets at Limon.
“Today’s results significantly upgrade the prospectivity of the large Limon target to deliver additional porphyry mineralisation.
“We are delivering on our undertaking to build the gold-copper inventory towards our exploration target of between 3.3 million ounces and 8.6 million ounces of gold equivalent. The exploration target is in addition to the recently announced mineral resource of 2.7 million ounces of gold equivalent.”
Bramaderos concession showing the location of Limon and other gold-copper porphyry targets in yellow.
The Limon strategy
Based on Limon’s large 1.5 by 1-kilometre target area, Sunstone is approaching exploration on three fronts:
- Current drilling on high sulphidation targets in the northeast. This is following up previous drilling that returned 15.4 metres at 0.10 g/t gold, 0.42% copper, and 2.3 g/t silver from 57.8 metres in LMDD004 and 128 metres at 0.18 g/t gold from 3.5 metres in LMDD006;
- Planning for follow-up to hole LMDD010. Modelling of magnetics is suggesting a 300-metre plunge to a magnetic body that is likely related to the porphyry mineralisation. The magnetic body measures 100 by 100 by 300 metres and is connected to a larger magnetic feature at depth. Drill hole LMDD011 has been completed and intersected an intrusive breccia and marks the underside margin of the southwest plunging target zone; and
- Preparation for deeper drilling based on geological interpretations of a significant porphyry target and as follow-up to previous drilling that included results such as 14 metres at 0.10 g/t gold, 0.20% copper, 0.4 parts per million (ppm) molybdenum and 1.7 g/t silver in LMDD002 from 879.6 metres; 40 metres at 0.10 g/t gold, 0.12% copper and 19.4 ppm molybdenum from 863.5 metres in LMDD004; and 21.8 metres at 0.11 g/t gold, 0.12% copper and 3.8 g/t silver from 700 metres in LMDD007.
Limon is just 2.7 kilometres northeast of the Brama-Alba gold-copper deposit, which hosts a porphyry resource of 2.7 million ounces of gold equivalent.
The Bramaderos project, meanwhile, straddles the Pan-American highway and is close to available hydroelectric power, which supports further development opportunities.
The project is also supported by nearby commercial airports and significant cities such as Loja, with a population of 200,000 offering strong community support.
Ecuador sources 88% of its power from hydroelectricity and is ideally placed in the global demand for clean energy-sourced metals.
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