Sunstone Metals Ltd (ASX:STM) has, once again, struck strong gold-copper porphyry mineralisation during drilling of a second hole at the T3 porphyry target within its El Palmar project in northern Ecuador.
This comes on the heels of the discovery of another strongly mineralised porphyry gold-copper system during drilling of the first hole, EPDD026, in June.
The exploration company believes the latest results from drill hole EPDD028, combined with those from June, show T3 as a “very large gold-copper porphyry system”, at least 120 metres wide and remains open in all directions.
Importantly, T3 sits within the broad Toachi fault zone, which is a key control on mineralisation at SolGold’s 3-billion-tonne Alpala copper-gold porphyry deposit just 65 kilometres away and 15 kilometres away from Codelco’s 1-billion-tonne Llurimagua copper-molybdenum deposit.
High-grade potential
EPDD028 was drilled steeply into the same magnetic anomaly intersected by hole EPDD026, extending mineralisation to the northeast and below that encountered by the first hole and remains open in all directions.
Assays from EPDD028 show:
- 294.7 metres at 0.51 g/t gold equivalent (0.34 g/t gold and 0.11% copper) from 918 metres downhole, to the end of hole and open, including a higher grade zone of 26 metres at 0.96 g/t gold equivalent (0.68 g/t gold and 0.18% copper from 1,014 metres; and
- Discrete higher-grade intervals, including 3.2 metres at 0.38% copper and 1.65 g/t gold from 1,077 metres within the higher-grade zone of 26 metres, demonstrating the ability of the system to deliver higher grades.
This scenario of clustered deposits is very similar to the large Cobre Panama copper porphyry system in Panama, where seven porphyry centres contribute to its overall mineral resources of 4.4 billion tonnes at 0.35% copper and 0.06 g/t gold using a 0.15% copper cut-off grade.
Location of the T3 anomaly relative to other targets T1, T2 and T5.
Big system
“This latest result shows clearly that T3 is a significant copper-gold porphyry discovery,” Sunstone managing director Malcolm Norris said.
“This area is wide open. We will be targeting a mineralised body that is 500-700 metres in diameter with a vertical extent exceeding 500 metres in the area of holes EPDD026 and 28.
“We also have several other targets within T3 that require drill testing.
“Together, these have the potential to deliver a very large gold-copper porphyry mineralised domain in an environment with many similarities to the 3-billion-tonne Alpala deposit nearby, which is located within the SolGold Cascabel concession.
Raising optimism
“It is early days on the El Palmar concession but the potential here is huge.
“We see multiple porphyry systems, mineralisation extending from surface at T1 to depths exceeding 1,100 metres and grades locally exceeding 1 g/t gold equivalent or greater than 0.6 g/t gold and greater than 0.2% copper.
“We believe we are onto a significant discovery at El Palmar that could deliver significant value uplift to Sunstone shareholders.”
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