Sunstone Metals Ltd (ASX:STM) continues to grow the mineralised footprint at its El Palmar gold and copper discovery thanks to drilling in northern Ecuador.
The results are in for another three holes, all of which have reported mineralisation close to the surface. Some of the best hits include:
- 277.6 metres at 0.32 g/t gold and 0.12% copper from 5.5 metres, including 100 metres at 0.50 g/t gold and 0.17% copper from 39 metres;
- 116.8 metres at 0.33 g/t gold and 0.11% copper from 12.2 metres; and
- 57.6 metres at 0.30 g/t gold and 0.12% copper from 22.9 metres.
Drilling at El Palmar continues to define clustered zones of mineralisation from the surface and to depths exceeding 600 metres within the original target area, pointing to the project’s scale potential.
What’s more, Sunstone is honing in on a compelling new porphyry gold-copper-molybdenum target east of the El Palmar mineralised envelope.
The target is slated for drilling in October, while Sunstone’s high-grade epithermal gold targets are being sampled before the rig arrives.
Moving into this next exploration phase, Sunstone has roughly A$19 million in cash and equities to keep the drill bit spinning.
Growing El Palmar’s broader potential
Sunstone managing director Malcolm Norris said the company was looking forward to “a very exciting and active” fourth quarter.
“Exploration at El Palmar is ramping up again after our drilling rigs have been focused on the Brama-Alba resource definition drilling program in recent months – and the latest program is testing some very strong targets,” he explained.
“Drilling within the main El Palmar circular magnetic target continues to define a large mineralised system extending from surface.
“We are now able to build a 3-D geological model of the El Palmar mineralised system and use that to guide our exploration.
“With a number of new targets now defined at El Palmar, the broader potential of this area is also continuing to grow.
“Several of these targets, such as T2 and the Tituana epithermal target, are scheduled for drilling while we continue to drill the main mineralised area laterally and to depth.”
New porphyry targets
Target T2, east of the El Palmar porphyry system, has emerged as a very compelling porphyry gold-copper target based on several independent datasets.
So far, surface sampling has defined an area of at least 70 metres by 50 metres, with rock chip sampling averaging 0.4 g/t gold and 0.1% copper.
The rock chip samples were consistently mineralised and included six samples which returned assays of greater than 1 g/t gold, which is encouragingly very high for porphyry systems.
Geophysical surveying has also defined a conductive body that coincides with the surface metal anomalism at El Palmar.
Sunstone is working on access permissions and aims to kick off priority drilling next month, with two holes planned.
Hunting for epithermal gold
Several epithermal gold targets have also been defined within the El Palmar concession but Sunstone’s eyes are fixed on the Tituana target.
The fieldwork team is progressing a trenching and infill soil sampling campaign, focused on areas where rock chip sampling has yielded a more than 85-metre-long (and open) zone.
Within this zone, 101 surface samples averaged 1.2 g/t gold, 25 g/t silver and 0.16% copper, with peak values recorded at 6.47 g/t gold, 225 g/t silver and 0.78% copper.
There’s enough potential in the ground to ready the Tituana anomaly for a drilling campaign.
The bigger picture
Tituana is on a north-northeast trending structure, which may link to the south to the main El Palmar porphyry system – a common scenario in porphyry and epithermal systems.
The interpreted geometry of the Tituana epithermal system is consistent with known epithermal mineralisation in the district, such as at the nearby operating El Corazon gold mine and the historically defined Verde Chico gold system.
El Palmar is in the same regional structural belt that hosts the 2.66-billion-tonne Alpala copper-gold deposit, grading 0.25 g/t gold and 0.37% copper.
It’s also near the Cascabel project’s 530-million-tonne Tandayama-America deposit, grading 0.19 g/t gold and 0.24% copper, and in the vicinity of the 1-billion-tonne Llurimagua copper-molybdenum porphyry deposit, grading 0.89% copper and 0.04% molybdenum.
As a result, several targets have been defined within the El Palmar concession and these will be systematically explored.
Sunstone says epithermal target testing is going well and these could hold the potential to deliver higher-grade discoveries down the track.