The paper presents the design philosophy and criteria applied for the geotechnical design of the permanent underground infra-structure works of the future Chuquicamata underground mine, located in the Atacama Desert, Chile. The design was carried out at an advanced basic engineering level, as part of the integral feasibility study of the mine, which will constitute one of the largest underground mining operations in the world. The design scope included the permanent traffic access, ore transport and ventilation tunnels with lengths varying from 4.3km to 7.45km, with steep gradients (-9% to -15%) and low to high overburden conditions (up to 1250m), in addition to various associated ancillary structures, such as shafts and connection drifts. Excavations will be carried out in intrusive and meta-plutonic rocks with different degree of alteration with the use of the conventional excavation method.