Caserones is located in Chile’s Atacama Region approximately 125 km southeast of Copiapó, and approximately 100 km from Lundin Mining’s Candelaria Copper Mining Complex in Chile and 20 km from the Company’s Josemaria project in Argentina. The mine and mine infrastructure are situated at an elevation ranging between 3,200 m and 5,500 m above sea level. The mining industry is well-established in the Atacama Region. Mining services, supplies and fuel can be obtained in Copiapó. The closest large settlement is at Los Loros, approximately 60 km northeast of the mine site.
Caserones mine is a large open pit copper–molybdenum mine with a low ore to waste strip ratio. Mining is performed using a conventional truck and shovel fleet.
There are five mining phases remaining in the life-of-mine plan, phases 5–10. The phase designs are based on the optimized pit shells with the highest value material mined in the earlier phases and lower-grade higher strip ratio material mined in later phases.
The processing facilities have been in commercial operation since 2014 and have historically produced approximately 100,000–120,000 tonnes of copper in concentrate, 1,700 to 2,500 tonnes of molybdenum in concentrate and approximately 25,000 tonnes of copper cathodes per year. The grinding-flotation plant has a stated design capacity of 4,700 tonnes per hour operated (105,000 tonnes per day based on 93% availability) though has historically treated 3,800-4,000 tonnes per hour of operation. The SX-EW plant has a nominal capacity of 34,500 tonnes per year.
Currently, the majority of copper concentrate production and all cathode production is sold under a long-term offtake agreement, with the majority of molybdenum concentrates sold locally through an evergreen contract.
Geologic and Exploration Overview
The Caserones deposit is considered to be a classic example of an Andean copper–molybdenum porphyry deposit.
The basement assemblage is a Carboniferous assemblage of metavolcanic and metasedimentary rocks. This assemblage has been intruded by the Caserones Granite in the Upper Carboniferous and the El Colorado Granite in the Permo–Triassic.
The regional structure is characterized by a series of rigid blocks of granitic basement that occupy anticlinal cores that formed as a result of regional scale folding of the Mesozoic supracrustal sequences.
The deposit is hosted in a monzogranite within the Caserones Granite and is approximately 2 km long with a width of approximately 1.5 km. The oxide and secondary copper zones form a surface-parallel blanket over 1.2 km in diameter with a central “core” of at least one kilometre in diameter where thicknesses average 300 m and exceed 400 m in the central part. The oxide zone forms a cap that sits on top of the secondary copper zone in the northwest margin of the deposit area. Flanking the oxide zone and overlying the supergene zone, is a zone of “leached” material. Primary copper mineralization remains open in all directions.
Lumina Copper Canada (Lumina Canada) conducted an exploration drilling and surface mapping campaign at the Caserones Project (previously Regalito) between February 2004 and October 2004. The objective was to establish the shape and grade of the secondary sulphide enrichment zone.
In 2006, as part of a due diligence evaluation, Pan Pacific Copper S.A. completed two twin drill holes to validate the 2004 drill campaign information. Lumina Copper Chile completed exploration programs to capture information to support the pre-feasibility and feasibility engineering studies.
In 2009, Lumina Copper engaged Golder and Associates to complete a Mineral Resource estimate for Caserones Project which was completed in August 2009.
In December 2009, Lumina Copper Chile prepared an internal feasibility study on the Caserones Project.