Sunstone Metals Ltd (ASX:STM) has generated a maiden mineral resource estimate (MRE) for the Brama-Alba porphyry deposit of the Bramaderos Gold-Copper Project in Ecuador, totalling 156 million tonnes at a 0.53 g/t cut-off for 2.7 million ounces of gold equivalent, mostly in the inferred category.
The MRE does not include any of the other prospects and targets on the projects or at the El Palmer Project to the north.
“These results show that Bramaderos is heading towards being a very significant project with huge potential for growth,” Sunstone Metals managing director Malcolm Norris said.
“The size of the metal inventory, the fact it runs from surface and the extent of the known mineralisation which sits outside the boundaries underpin a strong future for Bramaderos and Sunstone."
Initial exploration target
The company has also produced a large exploration target of between 3.3 million ounces and 8.6 million ounces gold equivalent at a grade between 0.44 g/t and 0.74 g/t gold equivalent (gold + copper) in addition to the estimated resource.
This conceptual exploration target is still limited in scope, covering only three targets (Brama-Alba extensions, Melonal and Limon) of several possible, and focused specifically on near-surface mineralisation.
“It is important to note that these estimates are just the start. We are highly confident that ongoing drilling will continue to grow the size of the opportunity,” Norris continued.
“We can see a clear line to a 5–10-million-ounce gold equivalent resource for the project and our exploration program is focused on delivering that.
“Our goal is to grow the metal resource inventory significantly by drilling more holes at all targets including Brama-Alba extensions, Melonal, Limon, Sandia, Porotillo, Playas and Yeso.
“We have taken a somewhat conservative approach to the exploration target estimate and not considered porphyry gold-copper targets at several areas where Sunstone has not yet drilled, but we will drill those areas in 2023.
“We aim to deliver a globally significant gold-copper inventory across multiple nearby targets. This has been very efficient exploration with a discovery cost of A$9/ounce on a gold equivalent basis.”
Ideal location, potential beneficiation
Norris said the results of preliminary metallurgical studies to produce a clean gold-copper-silver concentrate were positive and recent preliminary leach tests suggested that an even larger opportunity may present itself with leaching of low-grade material.
“Bramaderos is ideally located for a large mining development project,” he said.
“It is at about 1,000 metres above sea level, in proximity to the Pan-American highway, has adequate power supplies nearby from Ecuador’s hydropower grid, the project is also supported by nearby commercial airports and significant cities (Loja, population 200,000) and has a supportive community keen to benefit from all that a responsible mining development brings.”
Norris will provide an investor update today at 12:00 pm AEDT, accessible here.