The Centinela district is a 40-km-long segment of the late Eocene to early Oligocene porphyry copper belt of northern Chile. The main mineralization styles in the district include porphyry copper and associated skarns with gold and molybdenum credits, oxide copper in the form of either exotic deposits or in situ oxidation zones, and supergene copper sulfide enrichment blankets. Structurally controlled, district-wide porphyry copper mineralization formed between 44 and 41 Ma, contemporaneously with transpressional tectonism along the regional-scale Centinela-Limón Verde fault zone, a splay of the major Domeyko fault system. The Domeyko fault system accommodated tectonic uplift of the Cordillera de Domeyko during early stages of the middle Eocene Incaic orogeny. Several productive porphyry copper systems in the district were emplaced syntectonically along reverse- and oblique-slip faults that controlled the shape and attitude of both the dominantly dikelike intrusions and associated alteration mineralization. All the porphyry copper deposits in the district evolved from early potassic alteration with copper mineralization present as chalcopyrite and bornite, through sericite-chlorite alteration with chalcopyrite and pyrite, to late, overprinting pyritic sericitic alteration. Some systems developed advanced argillic lithocaps in their upper parts. Much of the copper was introduced with the potassic alteration, and all the gold-rich deposits display abundant hydrothermal magne ........

Centinela mines sulphide and oxide deposits and is one of Chile’s most important mining areas.

Centinela consists of Centinela Concentrates (Esperanza + Esperanza Sur and Encuentro Sulphide mostly sulphide porphyry deposits) and Centinela Cathodes (Tesoro Central and Tesoro Sur oxide deposits, including the oxide portion of the Mirador, Encuentro and Llano deposits).

Minning operations is carried out via conventional truck and shovel drill and blast method. Of all Centinela consumes the most diesel, operating some 120 mine haulage trucks and mining from six open pits.

Esperanza Sur pit
The Esperanza Sur pit is 4 km south of the Esperanza pit, close to Centinela’s concentrator plant. The deposit contains 1.4 billion tonnes of reserves with a grade of 0.4% copper, 0.13g/t of gold and 0.012% of molybdenum.

Pre-stripping by a contractor was completed in July and Centinela has taken over the operation of the pit using a fleet of 11 autonomous trucks, the first to be used by the Group. Ore from the pit is now being processed at the Centinela concentrator.

The opening of the Esperanza Sur pit improves Centinela’s flexibility in supplying its concentrator and, over the initial years, the higher-grade material from the pit will increase production by some 10–15,000 tonnes of copper per year, compared with production levels if the material was supplied solely from the Esperanza pit. This greater flexibility will allow Cent ........

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