The Radomiro Tomic porphyry copper deposit is located ~5 km NNE of the giant Chuquicamata deposit in northern Chile.

The deposit is concealed beneath 40 to 150 m of Neogene gravels. The orebody is hosted by the Chuqui Porphyry which is elongated north-south, and 1 km wide, that intruded the Early Cretaceous Elena Granodiorite.

Supergene leaching and oxidation affected the K-silicate zone to depths of about 400 m beneath the gravel-bedrock contact, generally varying between 180 and 200 m. This formed a horizontal blanket of oxide copper minerals that extend for 4.3 km north-south and up to 800 m east-west. Oxide mineralisation begins immediately below the gravel contact with a typical vertical distribution of leached-oxide zone, mixed zone and secondary sulphide zone. Underlying this oxidation zone, there is continuous but irregular immature supergene enrichment zone over a thickness varies from 20 to 150 m, characterised by weakly developed chalcocite and covellite. Enrichment has locally reached depths of up to 800 m along quartz-sericite faulted veins.The underlying hypogene zone extends for >200 m below the top of the sulphides.

The upper part of the enrichment zone, immediately below the top of sulphides, is characterised by the highest grades and is defined by the presence of >80% hypogene sulphides coated by chalcocite. In contrast, in the lower part of the zone, the main supergene sulphide is covellite, with only minor chalcocite.

Hypogene mineralisation is marked by concentric bornite-chalcopyrite, chalcopyrite pyrite and pyrite-chalcopyrite zones which average 0.5% total Cu. Some weak molybdenite mineralisation is present, either alone or associated with chalcopyrite and pyrite in quartz veins and veinlets striking north and dipping subvertically.

Pervasive K-silicate alteration is developed throughout the entire Radomiro Tomic deposit, typically represented by A veins composed of quartz and K feldspar, biotite alteration of hornblende phenocrysts and K feldspar introduction to the porphyry groundmass. The bulk of the hypogene copper mineralisation accompanied with the K-silicate alteration. Phyllic (quartz-sericite) alteration is less abundant and is controlled by NE- and north-south- striking subvertical structures, marked by quartz pyrite-chalcopyrite D veins with sericitic haloes. In the upper oxidation zone, supergene argillic alteration occurs as montmorillonite-kaolinite coatings on fracture planes and replacement of plagioclase phenocrysts. Oxidation and leaching of quartz-pyrite veins produced a low copper jarositic leached capping.

The main copper oxide minerals in the Radomiro Tomic deposit are atacamite, copper clays, chrysocolla, and copper wad. Their relative abundance provides the basis for dividing the oxide zone into two major geologic units: the Upper Oxide unit and the Lower Oxide unit. Furthermore, the study of mineral abundances in the oxide zones allowed the definition of an oxide mineral zonation that consists of five mineral assemblages, based on the relative proportion of the three main copper oxide components: atacamite, copper clays, and chrysocolla. These classifications allow both an understanding of the distribution of copper minerals throughout the zone and an interpretation of the supergene processes that formed it.

The Upper Oxide unit is mineralogically heterogeneous. The copper content is furnished, on average, by 40 vol percent atacamite, 31 vol percent copper clays with minor chysocolla and copper wad. The Lower Oxide unit is more homogeneous. Atacamite accounts for 70 vol percent of the copper ore minerals with minor amounts of copper clays and chrysocolla. Copper and chlorine concentrations and porosity are greater in the Upper Oxide unit, whereas hematite, chalcocite, and molybdenite concentrations and specific gravity are greater in the Lower Oxide unit.

The vertical distribution of the Cl/Cu ratio shows a chlorine-deficient zone located between elevations of 2,780 and 2,870 m. Between these elevations, the proportion of atacamite is lower and the proportion of copper clays, chrysocolla, and copper wad is higher than in other portions of either the Upper Oxide or Lower Oxide units.

Heap bioleaching of sulphides at room temperature is currently in industrial application at Radomiro Tomic Division.