Hot Chili Limited announced another Resource increase for its Costa Fuego copper-gold project, located in the coastal range, 600 km north of Santiago, Chile. Costa Fuego comprises the Cortadera, Productora (including Alice) and San Antonio deposits, all of which have updated Mineral Resource Estimates and lie proximal to one another, at low altitude (800 m to 1,000 m), approximately 600 km north of Santiago. The MRE update follows 24 months of material investment, totalling 24.5 km of drilling across Costa Fuego; a mix of development, metallurgical, geotechnical, resource expansion and exploration drilling, designed to progress the Costa Fuego project towards its Pre-feasibility Study (PFS) expected in second half 2024.

At Cortadera, the Company completed 43 Reverse Circulation (RC) and Diamond Drillhole tails (DD) for 17,000 metres of additional exploration and Resource extension drilling at Cortadera, including six development drillholes. The Cortadera MRE (porphyry copper-gold deposit) has again delivered the majority of Resource growth for Costa Fuego. Cortadera is defined by over 108,000 metres of drilling and now contains an Indicated Resource of 531 Mt grading 0.44% CuEq (previously 471 Mt grading 0.46% CuEq) and an Inferred Resource of149 Mt grading 0.29% CuEq (previously 108 Mt grading 0.35% CuEq).

The Productora MRE (breccia hosted copper-gold deposit) has been re-estimated following an additional 16 RC and DD exploration drillholes for 5,000 metres (including four metallurgical drillholes), a large pulp resampling campaign for silver and soluble copper assays, and a new approach to estimating the oxide and transition weathering domains. The MRE was reported using RPEEE constraints, similar to those used at Cortadera. Immaterial positive changes were reported for the Productora Indicated MRE copper and gold contained metal, as well as an additional 2.8 Moz of silver metal at 0.35 g/t, which has now been incorporated into the CuEq contained metal, in line with the approach at Cortadera.

The porphyry deposit Alice (previously included in Productora MRE reporting) has also been re-estimated. The previous historical MRE was completed in 2015 and has now been brought into line with the approach taken at Cortadera, which comprises a similar style of mineralisation. An additional nine drillholes for 2,600 metres, including one DD metallurgical drillhole (800 m), completed in 2017 and 2022, respectively, were also included.

These changes did not result in a material change to the overall MRE tonnage or grade, but improved confidence in the local variability of the estimation, which has been reflected in the updated Resource Classifications. A San Antonio MRE update included an additional 16 drillholes (2,500 metres), including three DD metallurgical drillholes, designed to upgrade the Inferred Resource to Indicated Classification. Additional mapping and sampling were also completed to validate the higher-grade copper mineralisation exposed at surface.

This additional information resulted in 3 Mt grading 0.71% CuEq being converted to Indicated Classification, from the previously Inferred 4 Mt grading 1.15% CuEq.