Caserones Copper-Molybdenum Mine is an active open pit operation located 125km southeast of Copiapó, Chile.
Environmental approval for developing the Project was granted by the Environmental Committee of the Atacama Region of Chile in February 2010.
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Minera Lumina Copper Chile (MLCC) owns and operates the project.
Lundin Mining (LMC) through its wholly owned subsidiary, holds a 51% majority interest in MLCC. JX Nippon Mining & Metals Corporation and certain of its affiliates hold the remaining 49% interest in the project.
The total investment was estimated at $2bn.
Construction of the production facilities began in March 2010. Production of refined copper from a dump leach by solvent extraction and electrowinning (SX-EW) plant began in 2013, and copper and molybdenum concentrate production started in 2014.
Based on the 2022 Technical report, at the end of 2020, the estimated mine life of the project is 17 years.
Caserones Location Details
The Caserones Mine is located approximately 6km east of the Chile-Argentina border, in the Atacama Region of the northern Chilean Andean Cordillera, at an approximate elevation of 4,300 meters above sea level (masl).
MLCC acquired the mine from Pan Pacific Copper in 2006. JX Nippon changed the name of the mine from Regalito to Caserones Mine in March 2007.
Geology and Mineralisation
The Caserones deposit is an Andean copper–molybdenum porphyry deposit. The Caserones deposit is hosted in a monzogranite within the Caserones Granite.
Copper mineralisation at the project consists of chalcanthite with subordinate chrysocolla, brochantite and minor amounts of malachite, azurite and antlerite in the oxide zone.
Reserves
The project is estimated to contain 1.070 billion tonnes grading 0.34% copper and 126 parts per million (ppm) molybdenum.
As of December 2022, the Caserones project’s total Measured and indicated resources include 1,023 million tonnes (Mt) of 3,150 kt (thousands of tonnes) of CuT 0.31 (%) and 105 kt of 0.012 (%) Mo.
A total estimated 69,704 t of copper and 2,393 t of molybdenum was produced from the Caserones mine in the first half of 2023 on a 100% basis. The copper production was comprised of 61,333t of copper in concentrate and 8,371t of copper cathodes.
Mining at Caserones Project
Mining at the Caserones project is conducted via open pit methods, using a conventional truck and shovel fleet.
The mining fleet includes 33 Komatsu 930 (300 t) haul trucks loaded by a combination of two electric rope shovels, one electric-hydraulic shovel, and two large front-end loaders. The project also utilises a second smaller diesel shovel operated by a contractor to supplement loading capacity.
The project Life of Mine (LOM) plan includes five phases, 5-10. The highest value material has been already mined out of Phases 1-4. A maximum movement of 60 Mt tons per year is considered as a restriction for each phase.
The concentrator is designed to process 27.9 Mt in 2023 and increase capacity to 33.4 Mt by 2027.
Ore processing
Caserones production includes copper concentrates, copper cathodes and molybdenum concentrates.
The Caserones mineral processing facility uses a conventional process flowsheet and conventional equipment. Run-of-mine (ROM) oxide ore is treated via a conventional dump heap leach.
Initially, the ore is crushed using a 60” x 113” primary gyratory crusher and stored in a covered coarse ore stockpile with a live capacity of 105 kt.
The crushed ore is reclaimed using apron feeders and conveyed to a semi-autogenous grinding (SAG) mill followed by a flotation circuit to produce separate copper and molybdenum concentrates.
Pregnant leach solution (PLS) from the dump leach is treated at a solvent extraction-electrowinning (SX-EW) plant to produce copper cathodes.
The concentrator plant has a nameplate capacity to process 105,000 tonnes/day (t/d) to produce an annual average of up to 150,000 tonnes/year (t/y) of fine copper in concentrates and up to 3,000 t/y of fine molybdenum in concentrates, together with a dump leach project combined with a SX-EW plant to produce up to 30,000 t/y of copper in cathodes.
Based on the July 2023 Technical report, the copper concentrate production is sold under a long-term offtake agreement to companies in Asia and the molybdenum concentrates are sold locally through an evergreen contract.
Infrastructure
Power required for the Caserones project operations is supplied from Chile’s national grid under a long-term contract until 2037 via a 190km double circuit 220 kV line.
The freshwater for the project is supplied from a wellfield connected to the Copiapó river basin.
Contractors Involved
In 2009, Lumina engaged Golder and Associates to complete a Mineral Resource estimate for the Caserones Project.
In December 2009, Lumina Copper Chile was engaged to prepare an internal feasibility study on the Caserones Project.
Fluor was awarded a contract to perform engineering, procurement, and construction management services for facilities, utilities and offsites, and mine-related infrastructure for the project.
FLSmidth was awarded a 5-year contract from SCM Minera Lumina Copper for the supply of maintenance services to the Caserones copper and molybdenum plant.
