In La Voluntad porphyry copper deposit the mineralization is related to a tonalité from the Chachil Plutonic Complex (Permian) intruded in the metamorphites of Piedra Santa Formation (Lower Paleozoic). Rhyolitic volcanic rocks from the Choiyoi Group (Triassic) cover unconformably the tonalité. The low mineralized vein densities indicate an hydrothermal system of low permeability with a weak fracturation atributed to a low hydrothermal fluid volume. The mineralization-alteration proceeded in two main stages. During the first stage, a low intensity pervasive potassic hydrothermal alteration with disseminated pyrite and chalcopyrite and scarce molybdenite was developed. During the second, a high intensity fracture related phyllic alteration was overprinted to the early potassic alteration. The mineralization consists of pyrite, chalcopyrite, bornite, molibdenite, sphalerite, arsenopyrite and scarce wolframite. Fluid inclusions indicate absence of hypersaline and presence of moderate to low salinity fluids, with temperatures between 240-420°C and sporadic boiling during main mineralization. This deposit belongs to a permo-carboniferous metallogenic cycle of unknown potential, related to a magmatic arc which trend SE south of Cerro Chachil, obliquely to the Andean Range.