Located in Chile’s Atacama Region, Region III, at an elevation of approximately 650 m above sea level and 20 km south of the city of Copiapó, the Candelaria Copper Mining Complex is easily accessed using the public road system. Copiapó is a modern city with all regular services and a population of approximately 160,000. Employees come primarily from the Copiapó region.
Candelaria is an open pit and underground mine providing copper ore to an on-site processing plant with a capacity of approximately 75,000 tonnes per day (tpd). Ojos del Salado comprises two underground mines, Santos and Alcaparrosa. The approximate 3,800 tpd capacity PAC processing facility receives ore from the Santos mine, while ore from the Alcaparrosa mine is treated at the Candelaria processing plant.
The Candelaria open pit mine operates with an overall mining rate of approximately 270,000 tpd including approximately 64,800 tpd of ore sent to the Candelaria processing plant. Five phases of development remain in the life of mine plan as of June 2017. The overall strip ratio of the life of mine plan is 2.7:1 including ore delivered to stockpiles.
The Candelaria underground North Sector mine produced approximately 7,000 tpd of ore in 2017 and is ramping up to 10,000 tpd by 2019. Development of the Candelaria underground South Sector is underway with ore production due to commence in 2019 and ramp up to 4,000 tpd expected by 2021.
The Alcaparrosa underground mine produces approximately 4,300 tpd of ore and the Santos underground mine produces approximately 5,000 tpd of ore. The four underground mines of the complex utilize a sublevel stoping mining method for ore extraction.
Copper concentrates containing precious metals are sold on contract to local smelters or trucked to the Punta Padrones port, near Caldera, for export to overseas smelters.
Geologic and Exploration Overview
The copper-gold sulphide mineralization found at the Candelaria Copper Mining Complex is generally referred to as iron oxide copper gold (IOCG) mineralization. Depending on lithology and the structural setting, the polymetallic sulphide mineralization can occur as veins, hydrothermal breccias, replacement mantos, and calcic skarns within andesite and tuff units. Candelaria has become an exploration model for Andean-type IOCG deposits that display close relationships to the plutonic complexes and broadly coeval fault systems.
The complex has been a significant producer of copper since the mid-1990s and ongoing exploration is conducted with the primary purpose of supporting mining and increasing estimated Mineral Resources and Mineral Reserves. More than $210 million was invested between 2010 and 2017 in exploration primarily below the Candelaria open pit, to the north and south, and at the three underground mines. Exploration is currently focused on the known mantos, veins, and breccia masses in proximity to existing underground infrastructure. This strategy has proven very effective and has resulted in significant expansion of the Mineral Resource and Mineral Reserve estimates of the underground mines under the ownership of Lundin Mining and has contributed to the extension of their mine lives. Regional exploration is also undertaken on the large properties surrounding the mines to identify targets and define new areas with Mineral Resource estimates.