Location and Geology
The Guanaco District is located 220 Km SSE of Antofagasta city and is situated in the middle of the Palaeocene-early Eocene volcano-sedimentary basin, where a thick pile of volcanic, pyroclastic and subvolcanic rocks are grouped in the three members of the Chile – Alemania Formation that represents the main filling of the basin.
The structural framework is characterised by first order of NNE structures that controls uplift/preservation. The ENE orientation of the mineralised structures suggests the presence of a transgressive component in the deformation style.
01. Guanaco Mine
The Guanaco Mine (100% Austral Gold) includes several open pits and underground infrastructures mined in various periods since 2011: Dumbo, Perseverancia, Cachinalito, Defensa, and Quillota. These areas are characterized by fine epiclastic and Ignimbrite strata with variable degrees of deformation that host a phreatomagmatic breccia unit. The Guanaco Mine project covers +44,000 hectares of mining concessions.
The Dumbo area concentrates most of the ledge-type structures controlled by phreatomagmatic dikes, being the center of the HS system, while all the other open pits are developed in secondary or satellite ledges.
02. Sierra Inesperada Project
The Sierra Inesperada Project (100% Austral Gold) comprises several maar-diatreme systems, which partially cover a volcanic sequence made up of lavas with andesitic-basaltic, andesitic, and dacitic compositions. Most of the maars show a low degree of erosion. The hydrothermal alteration affected the host rock and the phreatomagmatic rocks differently. The latter were better preserved due to the silicification and quartz-alunite type alteration that affects them in large part of the area.
Multiple targets were drilled during 2021, confirming an HS hydrothermal activity controlled by phreatomagmatic complexes with silver mineralization vectoring to potential blind gold mineralization.