Sunstone Metals Ltd (ASX:STM) has hit the ground running with a new drilling campaign at the T2 porphyry target, part of the El Palmar gold-copper discovery in northern Ecuador.
The explorer is buoyed by precious and base metal finds at the neighbouring T1 and T5 targets, as well as an epithermal gold and silver system at the Tituana prospect.
Considering the nearby prospectivity, Sunstone plans to drill two holes at T2 in March and chase assays in late April. The first hole is already underway and has reached 300 metres in down-hole depth.
As the target names suggest, T2 is one of at least five porphyry systems at El Palmar, but Sunstone is also interested in the mineralisation taking shape at the Tituana target.
This region is also home to some famous neighbours: El Palmar is on the same regional structural belt that hosts the 2.66-billion-tonne Alpala copper-gold deposit and the 530-million-tonne Tandayama-America deposit.
It’s also in the vicinity of the 1-billion-tonne Llurimagua copper-molybdenum porphyry deposit, which weighs in at 0.89% copper and 0.04% molybdenum.
Drill bit spinning
Sunstone managing director Malcolm Norris said two drill rigs were in play at the El Palmar project.
“One is testing the Tituana epithermal target, where we have intersected very encouraging mineralisation across multiple vein systems, and the other has commenced drilling at the large T2 porphyry copper-gold target, where we are seeing some trace levels of mineralisation and encouraging alteration.
“We expect to be in the main T2 target zone within a fortnight,” he explained.
“At Tituana, assays have been received from the first three holes of an 11-hole program. The results confirm the presence of an epithermal gold-silver-base metal system in multiple veins.
Visual results from recently completed holes suggest that mineralisation extends over 200 metres of strike but is open to the north and south.”
Testing T2
Sunstone begins exploration at T2 not long after it recorded gold and copper hits at the nearby T1 and T5 prospects.
One of the best results from the latter target was a 60-metre intersection, weighing in at 0.25 g/t gold and 0.13% copper from 100 metres, while the highlights from T1 include 867 metres at 0.26 g/t gold and 0.1% copper from surface.
Sunstone believes that’s enough to warrant further exploration, particularly because of the targets’ proximity to T2 and the growing potential for a material porphyry discovery.
They also underscore the theory that there could be a cluster of porphyry systems near the regionally significant Toachi fault — a control on the mineralisation at the giant Cascabel copper-gold deposit.
Targeting Tituana
Beyond T2, Sunstone has boots on the ground at El Palmar’s Tituana prospect — an epithermal target that’s never seen a drill rig.
The explorer has charted 11 drill holes, and assays for the first three confirm the epithermal system in multiple veins.
What’s important to note is that these veins remain open and include high gold and silver grades (such as 1.7 g/t and 12 g/t, respectively).
In addition, visual assessment of holes 6 and 7 suggests that mineralisation improves to the north based on the presence of galena and sphalerite, which are often associated with gold and silver in these epithermal systems.