The San Jose Project is centred at 36º49’S and 71º36’W in Region VIII of central-southern Chile, located 50km southeast of the regional city of Chillan and 390km south of the capital Santiago.
The San Jose Project is located in the foothills of the Andean pre-cordillera, equivalent to the older Coastal Cordillera of northern and central Chile. Although not represented within the project itself, the known basement within the district comprises gneisses of the upper Cretaceous Los Azules Metamorphics. These are disconformably overlain by andesites of similar age comprising the El Sauce Formation. The basement stratigraphy has been intruded by a series of co-magmatic batholiths of the Santa Gertrudis Suite.
The principal economic target within the San Jose Project is porphyry copper-molybdenum mineralisation. Chalcopyrite and molybdenite is associated with extensive potassic alteration within a dominantly granodioritic intrusive lying along a faulted contact with younger volcano-sedimentary rocks. The mineralised assemblage and alteration is entirely consistent with a porphyry system, with zones of higher tenor mineralisation associated with stockwork veining and fracturing proximal to the fault contact.
Porphyry copper-molybdenum mineralisation has been identified in semi-continuous exposures of granodiorite and monzogranite along the deeply incised valleys of the San Jose, San Juanita and Pierna Blanca creeks. Mineralisation is best developed by over a width of 400m immediately adjacent to the faulted contact between the intrusives and younger Pierna Blanca Formation to the west.
While the basement geology is obscured by the Cola de Zorro Formation between these valleys, it is reasonable to assume that alteration and mineralisation persist between and beyond these exposures over a distance of at least 3km.