Summary:
The Havieron deposit is hosted within two primary basement sedimentary units of the Puntapunta Formation; a thin planar biotite rich metasiltstone to meta-arenite, and a thickly bedded white to pale green calc silicate actinolite marble, both of which have been subject to low-grade regional metamorphism.
The deposit comprises an ovoid shaped zone with a series of nested vertically extensive breccia columns (the Breccia Pipe) that coalesce into a large volume of variable brecciation, alteration and sulphide mineralisation which trends northwest to southeast. Approximate dimensions of this pipe measure 650m in length by 350m in width and 1,400m in depth along a northwest orientation. The Breccia Pipe includes unmineralised to low-grade crackle breccia and a series of mineralised cemented breccias.
The breccia hosting the highest grade gold and copper mineralisation occurs on the southeast margins of the Breccia Pipe and is referred to as the South East Crescent (Crescent Zone). The Breccia Pipe also includes relatively small dioritic intrusions with brecciated contacts or wall rock clasts within the breccias. The Breccia Pipe is intruded by a 20–30m wide, north-northeast trending, steeply dipping post mineralisation dolerite dyke.
The Crescent Zone lies along the southeast margin of broader zone of hydrothermal carbonate-quartzsulphide-actinolite-biotite-cemented breccias, veins and replacements, defining an ovoid zone (800m x 500m) of calc-silicate alteration that is the footprint of Havieron.
The highest average grades of mineralisation is concentrated along the south-eastern edge of a complex of nested diorite intrusions emplaced into sedimentary host rocks. Higher grade zones are associated with increased sulphide concentrations, with sulphides including pyrrhotite, chalcopyrite and pyrite, commonly with quartz. Mineralisation has been observed to over 1,000m in vertical extent below the 420m of post mineralisation cover sequence.
Multiphase hydrothermal breccias at Havieron are classified on the dominant mineralogy of the breccia cement, based on variable proportions of actinolite, calcite and sulphide. A quartz-rich variant of the actinolite-cemented breccias also occurs. The hydrothermal breccias have a strong spatial association with the nested diorite intrusions.
Superior grades of gold (+2 g/t Au) and copper (+0.2% Cu) are typically associated with more rich sulphidebearing calcite-actinolite cemented breccia that in parts of the system transitions into the more massive sulphide mineralisation (i.e., the Crescent Zone). Still, higher gold grades (+5 g/t Au) can be found associated with the quartz-rich variant of the actinolite cemented breccia.
The Crescent Zone is a 5 - 40m wide zone of sulphide and quartz rich hydrothermal breccias and massive sulphide extending 700m in unfolded section from the basement contact and defined over 1,000m vertically, tapering to ~200m and open at that depth.
The Crescent Zone has been the focus of drilling and has been infilled to a nominal drill spacing of 50m for the Indicated Mineral Resources, and ~75m spacing for the Inferred Mineral Resources. The Crescent Zone appears to wrap around the south-eastern margin of the nested diorite zones. This relationship suggests the intrusions may have acted as a hard kernel around which deformation was focused, forming a structural zone for later mineralised fluids to be focused within and creating the acuate shape.
In 2023 drilling defined a new high-grade mineralised domain, referred to as the Link Zone, which is a moderately dipping 30m wide by 200 m long zone of mineralisation that extends northwards from the Cresent Zone from the 4,000 mRL down to the 3,750 mRL. This zone is interpreted to encompass the high-grade core of what was previously referred to as the Eastern Breccia Zone. The Link Zone remains open at depth and to the north at depth (bounded by the Breccia Pipe).