Name of the Mine
Guanaco-Amancaya Operation.

Location  
About 220 km south-east of Antofagasta, in northern Chile, at an elevation of 2 700 m above sea level.

Mine Owner/s  
Austral Gold, through its wholly-owned subsidiary Guanaco Mining Company.

Brief Description  
The operation comprises the Guanaco mine (Guanaco) and Inesperada satellite deposit, the Amancaya mine, and the Guanaco heap-leach pads (heap reprocessing project).

Brief History  
The Guanaco-Amancaya Operation started production in 2010.

Mining at Guanaco was discontinued in February 2020.

Amancaya is currently in production, while Guanaco heap reprocessing and Inesperada are new projects that will start operations in 2023.

Amancaya's mineral reserves will be depleted in 2023, when Inesperada starts production. It is expected that the Inesperada openpit mineral reserves will be depleted by the end of 2025.

Reprocessing of the heaps is scheduled to start in 2023 and continue until the end of the mine’slife in 2033, taking advantage of underused processing capacity to drive production to more than 1.1-million tonnes a year.

Primary Metals/Minerals  
Gold.

Secondary Metals/Minerals  
Silver.

Geology/Mineralisation  
The Guanaco-Amancaya Operation is located in the Central Depression of northern Chile, which is a north-north-east-striking Paleocene to early Eocene morphostructure formed as part of a volcanic arc under extensional and/or transtensional conditions.

Guanaco is embedded in the Paleocene/Eocene belt, a geological feature that runs north to south through the centre of the Antofagasta region.

Amancaya is located about 60 km south-west of the Guanaco mine. Amancaya is a low sulphidation epithermal gold/silver deposit comprising eight mining exploration concessions covering 1 755 ha (and a further 1 390 ha of second-layer mining claims).

The Inesperada deposit is a high-sulphidation breccia controlled epithermal gold deposit, hosted in phreatomagmatic tuffs and breccias. Gold mineralisation is directly controlled by the morphology of the conduit of the phreatomagmatic unit. Mineralisation depth is estimated to be greater than 100 m, the large part of which is oxide, changing below 2 400 m above sea level to a sulphide association of silica-quartz-alunite-pyrite alteration, with enargite and traces of chalcopyrite, chalcocite, and covellite.

Reserves  
Total proven and probable reserves at Guanaco-Amancaya Operation, as at December 31, 2022, were estimated at 11.95-million tonnes grading 0.79 g/t gold and 4.84 g/t silver.

Resources  
Total measured an indicated resources for the Guanaco-Amancaya Operation as at December 31, 2022, were estimated at 14.65-million tonnes grading 0.97 g/t gold and 5.82 g/t silver. Inferred resources were estimated at 2.38-million tonnes grading 1.18 g/t gold and 3.93 g/t silver.

Mining Method  
Amancaya's mining method uses sublevel open stoping with a sublevel interval of 15 m. The mined-out stopes are not backfilled and remain permanently open in most cases.

Inesperada will be developed as an openpit operation. Mining will be undertaken by a contractor using conventional truck-and-shovel mining methods.

Austral Gold plans to reprocess the material contained in three spent heap-leach pads at the Guanaco site. The material in each of the heap-leach pads will be loaded onto trucks, hauled to the crushing facility, crushed to 3.3 mm P80, redeposited at a different heap-leach pad, and releached to recover part of the remnant gold and silver. The heap leach pads will be reprocessed in reverse order of their numbering: first Heap III, then Heap II, and lastly Heap I.

Major Infrastructure/Equipment  
On-site infrastructure at Guanaco includes a crushing plant, heap-leach infrastructure with a Merrill Crowe gold recovery plant, a new milling/agitated leach circuit, administration building, laboratory, warehouse, maintenance facilities, diesel power generating units, water pipeline and tanks, fuel tanks, and an accommodation complex. There is also a fleet of mobile equipment.

The Guanaco-Amancaya Operation also hosts a tailings storage facility with an estimated area of 235 000 m2, and capacity to store about 4.1-million tonnes.

Water for the operation is supplied by a 30 km pipeline from upstream catchments and water wells and stored in 600 000 ℓ water tanks. Existing infrastructure was reconditioned between September 2009 and March 2010.

Prospects  
Austral Gold continues to review exploration opportunities to increase mineral reserves in the Guanaco and Amancaya district. At Guanaco, the company has identified Natalia and Los Nanos as the best target areas.

Contact Details
Austral Gold (South America)
Tel +54 11 4323-7523
Email info@australgold.com

Sources
Austral Gold. Website: https://www.australgold.com/
Austral Gold. Technical report on the Guanaco-Amancaya Operation, Antofagasta region, Chile report for NI 43-101 (December 31, 2021).
Austral Gold. Austral Gold files 2022 Annual report (March 30, 2023).
Austral Gold. Quarterly report – December 2022.