Sunstone Metals Ltd (ASX: STM) has announced that drilling at the Brama prospect within its Bramaderos project in Ecuador has reported strong assay results, intersecting 505m of mineralised gold-copper porphyry. Assays included 84m at 0.8g/t gold and 0.11% copper; 216m at 0.61g/t gold and 0.11% copper.
Assays included 84m at 0.8g/t gold and 0.11% copper; 216m at 0.61g/t gold and 0.11% copper
The company said that it has received final assays from holes BMDD008 and BMDD008W1 (wedge hole off BMDD008 from 347.1m) at the Brama prospect. STM reported that BMDD008W1 has extended the previously reported 450m BMDD008 intersection to deliver a gold-copper mineralised porphyry from surface to a depth of ~500m and remains open at depth.
Sunstone reported that drill hole BMDD009 has been completed and BMDD010 has commenced. The company noted that the visual inspection of drill core from BMDD009 revealed it intersected a strongly and continuously veined porphyry system hosted by diorite in its upper 515m, with assays expected by mid-July.
The company announced that the drilling at the El Palmar project in northern Ecuador is expected to commence in early July.
Drilling at Brama prospect
The company had recently commenced drilling at the Brama prospect within the Bramaderos gold-copper project. The drilling was aimed to further demonstrate continuity of the higher-grade zones within the extensive outer envelope of lower-grade gold-copper mineralisation at Brama.
The drill hole BMDD008 had intersected a strongly mineralised high-level intrusive breccia body located above the north-west edge of the main Brama system in April 2021.
The DD hole BMDD008 had returned 450m at 0.47g/t gold, 0.10% copper, and 27ppm molybdenum from surface, including 216.9m at 0.61g/t gold, 0.11% copper, (0.77g/t AuEq) and 32ppm molybdenum, from 135.1m, including 84.3m at 0.80g/t gold, 0.11% copper, (0.96g/t AuEq) and 42ppm molybdenum, from 179.7m.
The company has now reported encouraging final assays from holes BMDD008 and BMDD008W1 (drilled as a wedge off hole BMDD008 commencing at 347.1m downhole) at the Brama prospect.
505m of mineralised porphyry
The company announced that the drill hole BMDD008W1 extended the previously reported 450m BMDD008 intersection to deliver a gold-copper mineralised porphyry from surface to a depth of ~500m and remains open at depth.
Assays included 505.1m at 0.43g/t gold, 0.1% copper, (0.57g/t AuEq1) and 25.8ppm molybdenum from surface, including 113.4m at 0.37g/t gold, 0.15% copper, (0.58g/t AuEq) and 23.9ppm molybdenum, from 347.1m.
Summary of intervals in drill hole BMDD008W1, and previously reported BMDD008 are as shown below.
The company said that both drill holes BMDD008 and BMDD008W1 extended towards a deeper magnetic anomaly but failed to intersect that target.
BMDD009 completed
The company announced that drilling was completed for hole BMDD009, which was drilled in the east and central parts of the main Brama porphyry system. BMDD009was drilled from the east and towards a modelled deep magnetic anomaly that lies central to the 0.1% Cu contour.
Visual inspection results
STM reported that the visual inspection of drill core from BMDD009 revealed that it intersected a strongly and continuously veined porphyry system hosted by diorite in its upper 515m, with visual chalcopyrite associated with intense stockwork veining. The company said that assays are expected by mid-July.
The drill hole BMDD009 continued to test the deeper magnetic domain, that corresponds to the deeper target in BMDD008 and BMDD008W1, and encountered peripheral stockwork magnetite veinlets that likely explain the magnetic anomaly in the wall rocks south of the main mineralised intrusive body.
The company noted that the long and well-mineralised sections of holes BMDD001, BMDD0002, and BMDD009 indicate that the main porphyry target on the eastern sector of Brama is defined by strongly veined diorite with moderate magnetic character.
BMDD010 drilling commenced
Sunstone reported that the DD hole BMDD010 has just commenced and is testing several targets that include a magnetic anomaly around the eastern rim of the system, with a magnetic character similar to the mineralised intrusive breccia to the west; the potential southwest extension of the high-grade pod intersected in holes BMDD001, BMDD02, and CURI-03, in the strongly veined diorite; and the potential continuity of high-grade mineralisation between BMDD001 and BMDD005/BMDD008/CURI13, i.e. the relationship between the stockwork mineralisation and the intrusive breccia mineralisation.
The company said that the aim of the ongoing drilling is to further demonstrate continuity of the higher-grade zones within the extensive outer envelope of lower-grade gold-copper mineralisation at Brama.
El Palmar project update
The company reported that logistical preparation is well advanced for the commencement of drilling at El Palmar project. STM said that three drill pads have been prepared and some equipment is on site.
Sunstone said that the drill targets have been defined on the basis of a classic porphyry signature in 3-D magnetic modelling and supported by strong surface sampling of up to 2.2g/t gold in rock chip samples, and re-logging and interpretation of 3 historic diamond drill holes. STM said that soil sampling is continuing and is 70% complete across the main El Palmar target area.
Funding in place
Sunstone reported that it remains well capitalised with ~A$12m cash and 61m Copperstone shares valued at ~A$12m.
“These latest assays and visuals provide more strong evidence that Brama has the potential to be a large gold-copper mineralised porphyry”
Management comments
Sunstone Managing Director Malcolm Norris said: “These latest assays and visuals provide more strong evidence that Brama has the potential to be a large gold-copper mineralised porphyry.
We are now confident that we have a 500m vertical extent of good gold and copper grade. The porphyry plus intrusive breccia zones, at this stage, cover a surface footprint of 350m x 150m, which we expect can be expanded with more drilling.”
Images: Sunstone Metals Ltd