Las Bambas pit overview, drill core and wrap-up presentation. Late in the afternoon the group returned to the Las Bambas Geology Office, skirting the upper benches of the Ferrobamba pit to view the context of the area we had traversed earlier in the day. Then to two core displays from drill holes through the Ferrobamba, Chalcobamba and Sulphobamba deposits. This was followed by a quick overview presentation that tied the visit together. By now it was evening and were returned to our hotel in Challhuahuacho after a long, very interesting and fulfilling day. Images by Mike Porter.
The Las Bambas cluster of deposits is located within the Bolivian Orocline section of the central Andes, just to the south of the Abancay Deflection in a structural setting interpreted to have rotated basement blocks during the Cenozoic. It lies near the northern extremity of the Eocene porphyry belt that is interpreted to extend southward into northern Chile where it includes such deposits as Collahuasi, Chuquicamata and Escondida. In this part of Peru, and in this structural setting, the corridor of porphyry deposits is unusually broad likely reflecting the underlying structural complexity. However, it also has many of the characteristics of the deposits of the Peruvian Andes, where the country rocks are typically Mesozoic shelf and shallow basinal carbonates, and skarn mineralisation is well developed. As such it represents a transition from the typical Central Andean setting to that of the Peruvian Andes.
The bulk of the economic mineralisation at the Las Bambas deposits is hosted within the skarns, with porphyry mineralisation generally being of lower grade.