Andean Silver accelerates strategy to upgrade resources at Cerro Bay silver-gold project

Andean Silver (ASX: ASL) has reported a strong end to a March quarter that saw it grow and upgrade the mineral resource at its flagship Cerro Bayo silver-gold project to incorporate the Pegaso 7 and Cristal discoveries.

The new resource has improved on last year’s maiden result by 22% and now sits at 111 million ounces of silver equivalent (AgEq) grading 353 grams per tonne.

The increase of 1.5 million tonnes at 408g/t for 20 million ounces AgEq (239,000oz gold equivalent at 4.9g/t) includes initial resources for Pegaso 7 and Cristal, which sit within the Laguna Verde Mine Complex (LVMC) and account for over 65% of the latest additions.

Growth trend

The upgrade continues a growth trend that Andean has enjoyed on the back of an aggressive drilling and exploration strategy and demonstrates the considerable potential remaining within the Cerro Bayo tenure.

Andean has grown the Cerro Bayo mineral resource by approximately 439% since  acquiring the project in February 2024.

Chief executive officer Tim Laneyrie said the company would continue its aggressive approach to uncover further potential.

“The scale of this project continues to grow rapidly and supports our belief that Cerro Bayo has the potential to be a globally significant silver-gold asset which will be highly rewarding for our shareholders,” he said.

Expansion and infill work

Drilling during the quarter at the LVMC comprised three rigs aimed at expanding and infilling existing resources at the Coyita North deposit and defining deeper mineralised shoots within Pegaso 7.

Andean’s campaign intercepted the main Coyita North structure at the sill to a depth of 100m below historic drilling, with a best intercept of 1.5 metres at 513g/t AgEq (360g/t silver and 1.8g/t gold at 6.2g/t).

The company’s drilling continues to expand the Pegaso 7 deposit, where it has tested less than 50% of the known strike, with significant vein and stockwork intercepts in cross-cutting and parallel zones within 300m of the central corridor still to be explored.

Cristal corridor

Initial work at Cristal showed that the central corridor represents an intersection of multiple structural zones trending north-to-south and north-west-to-south-east.

Drilling and surface mapping demonstrated a broad mineralised area underpinning the main zone that contains multiple adjacent subsidiary zones.

The company believes the road stock work veining that envelopes the principal veining occurs at Cristal’s structural intersections and will focus on it in future open pit optimisations.

Geophysical survey

Andean commenced a large geophysical survey during the quarter to support the potential presence of a mineralised system extending north from the Sinter Hill prospect, situated at the southern limits of the Cerro Bayo district.

The area contains greenfield exploration targets that correspond to known surface veins not previously identified due to the existence of shallow cover, with new north-to-south trending structures identified in February and March demonstrating mineralisation potential over 2km of strike length.

Andean has completed approximately 50% of the Sinter Hill geophysics program and is still to survey key targets of the Cascada trend and southern section.

Mr Laneyrie said Sinter Hill remained a high-priority target for Andean and hoped the geophysics survey could identify potential intact epithermal mineralised zones below extensive vein networks.