Sunstone Metals Ltd (ASX:STM)’s latest strong assay results have again confirmed that its Alba discovery within the Bramaderos Project in southern Ecuador is a high-grade gold-copper porphyry deposit.
This has been a highly successful drilling campaign from Sunstone so far, with grades in line with, or better than, other porphyry gold-copper deposits demonstrating Alba is a gold-copper porphyry discovery with scale.
Results contain significant, consistent gold-copper intervals greater than 300 metres, with high-grade sub-intervals.
Highlights include:
- 345.5 metres at 0.37 g/t gold and 0.13% copper from 82.5 metres in BMDD022 including 24 metres at 0.70 g/t gold and 0.18% copper from 306 metres;
- 397 metres at 0.30 g/t gold and 0.10% copper from 102 metres in BMDD025 including 22 metres at 0.61 g/t gold and 0.14% copper from 159 metres.
"Consistently well mineralised"
“With each set of assay results the Alba gold-copper porphyry grows in scale. We are now seeing a consistently well-mineralised system with local higher grades of a significant scale,” Sunstone managing director Malcolm Norris said.
“The mineralisation extends from surface to greater than 400 metres deep, where the system is wide open and untested. The grades are in line with or better than those seen in many gold-copper porphyries around the world.”
“Current drilling is testing both the lateral extent and the vertical extent based on the recent results from an electrical geophysical survey which suggest a 1,000-metre vertical extent.
“Drill hole BMDD024 also intersected a narrow but significant gold zone, that is located 350 metres away from the centre of the Alba porphyry. This could support the concept of high-grade roots of epithermal veins also overprinting the upper porphyry body.”
Looking at specific holes
In a nutshell, all holes have intersected copper as chalcopyrite, bornite and covellite in variably veined stockwork porphyry. Local visible gold was identified in BMDD025, while BMDD024 intersected a gold zone of 2.8 metres at 1.21 g/t 350 metres from the previously reported upper gold zone (7 metres at 27 g/t) – expanding this target area.
Drill hole BMDD024 was drilled well southwest of the main target area during a period when electrical geophysics was being completed over the main target zone, precluding drilling in the target area.
BMDD025 was drilled below hole BMDD023 (which intersected 84.2 metres at 0.51g/t gold and 0.16% copper from 183 metres within 222.4 metres at 0.37 g/t gold and 0.13% copper from 76.4 metres). BMDD025 has added nearly 200 metres of additional vertical extent to this well-mineralised system below BMDD023.
Drill hole BMDD027 has further tested this vertical extent a further 100-250 metres below BMDD025 on this section (assays pending).
Significant gold intersections from all holes drilled to date at Alba.
Sunstone has three rigs operating at Alba, drilling holes 28, 30 and 31.
The company is cashed up with $26 million in the bank, following a capital raising that introduced several well-respected institutional funds to the share register.
A Securities Placement Plan (SPP) is underway to raise an additional A$4 million. The SPP closes on May 6.
Watch: Sunstone Metals ends quarter with promising copper-gold targets at the Bramaderos Project in Ecuador