Minera Antucoya S.A. is a 70% subsidiary of Antofagasta, and holds the Antucoya operations. Marubeni Corporation, the Antofagasta’s 30% minority partner in Antucoya.
Summary:
The Antucoya porphyry copper deposit is situated 120 km northeast of Antofagasta in the Early Cretaceous metallogenic belt of the Coastal Cordillera.
The mineralized system is related to granodioritic porphyry (Antucoya porphyry) and dacite porphyry (Buey Muerto porphyry). Late dacitic dikes intrude the former ore-related intrusions and Jurassic andesitic host rocks in a tectonic environment dominated by splays of the Atacama Fault System.
The principal mineralization constitutes a column 350 m thick, composed of atacamite, brochantite, Fe-Cu sulfates, Cubearing limonite, chrysocolla and black oxides, with rare chalcocite and covellite in a thin supergene enrichment blanket.
In the underlying hypogene zone, the mineralization is dominated by chalcopyrite>pyrite>bornite hosted by A- and B veins in potassic alteration, and in C-veins on the periphery of the porphyry intrusions. The pyrite/chalcopyrite ratio is greater in D-veins within a shallow phyllic zone. The Mo distribution is erratic and poorly characterized.
Reserves at December 31, 2023
The ore reserve cut-off grade is 0.16% copper, while the cut-off grade for mineral resources is 0.15% copper.
Mineral Resources are reported inclusive of Mineral Reserves.
Summary:
Antucoya is a low-grade, low strip-ratio, oxide deposit.
Conventional open-pit mining method with preliminary drilling and blasting operations is utilized for extraction oxide ore.
There are electric shovels and front-end loaders used for extraction-and-loading.
Comminution
Crushers and Mills
Summary:
There are three stages of crushing at the Antucoya processing plant, primary jaw crushing, secondary and tertiary cone crushing.
Processing
- Sulfuric acid (reagent)
- Crush-and-stack plant
- Heap leach
- Solvent Extraction & Electrowinning
Summary:
Mined oxide ore is crushed, piled into heaps and then leached with sulphuric acid, producing a copper sulphate solution. This solution is then put through a solvent extraction and electrowinning (“SX-EW”) plant to produce copper cathodes, which are sold to fabricators around the world.
Solvent Extraction And Electrowinning
A process for extracting metal from an ore and producing pure metal. First the metal is leached into solution, the resulting solution is then purified in the solvent-extraction process before being treated in an electrochemical process (electrowinning) to recover cathode copper.
Recoveries & Grades:
Pipelines and Water Supply
Summary:
Antucoya has processes in place to manage and conserve freshwater.
Antucoya uses seawater in both mining and electrowinning plant. It also has reverse osmosis plant to produce drinking water for the camp. All the water used in camps and offices is collected for treatment in the wastewater treatment plant and is used to moisten our internal roads and the open pit loading area.
Antofagasta already only uses sea water for Antucoya operation. By 2025, Antofagasta expects 90% of mining operations’ water consumption will be recirculated or sea water.
The shared pipeline between Antucoya and Centinela is a major synergy.
Production
All production numbers are expressed as cathode.
^ Guidance / Forecast.
Production Costs
^ Guidance / Forecast.
Heavy Mobile Equipment
EV - Electric
