The Tucumã Operation (formerly known as Boa Esperança) is an open pit copper mine located in the Pará State, Brazil. The project is owned by Brazilian copper mining company Mineração Caraíba (MCSA), which is 99.6% owned by Ero Copper.
In September 2021, Ero Copper announced the results of its optimised feasibility study on the Boa Esperança project.
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It estimated a mine life of 12 years, with an average annual copper production of more than 27,000 tonnes. In the first five years, Tucumã Operation is expected to produce approximately 35,000 tonnes per annum.
Total capital costs were estimated to be $507m, including an initial capital cost of $294m.
The company approved the construction of the copper project in February 2022. Tucumã secured the operational licence, the last permitting milestone for commercial operation, in June 2024.
In July 2025, Tucumã Operation achieved commercial production.
Tucumã Operation Location
The Tucumã Operation is located within the Carajás Mineral Province of southeastern Pará State. The site is within the municipality of Tucumã, approximately 40km to the southwest of the town.
Tucumã can be accessed by state highway PA-279.
Geology and Mineralisation
Tucumã’s copper deposit is situated within the Carajás Mineral Province, located on the eastern side of the Amazon Craton. This province is regarded as one of Brazil’s most significant mineral regions.
The Carajás Mineral Province features two distinct tectonic domains, both of Archean age. The older domain, known as the Rio Maria Block, is where the Boa Esperança deposit is found. It is characterised by a typical granite-greenstone belt terrain.
The younger domain, known as the Carajás Block, comprises volcano-sedimentary rocks and granitoids.
The Boa Esperança copper deposit is located on an isolated hill, situated 38km southwest in a straight line from the town of Tucumã.
This topographic high primarily consists of breccias made of quartz and magnetite, which intersect the Neoarchean biotite granite, the host rock for the copper mineralisation.
The Neoarchean biotite granite intrudes into the older Mesoarchean Rio Maria granodiorite. Mineralisation is hosted in a series of brecciated zones.
Tucumã Operation Reserves
Tucumã’s proven reserves consist of 30.674 million tonnes with a copper grade of 0.89%, containing 273,200 tonnes of copper. The probable reserves include 12.378 million tonnes with a copper grade of 0.67%, containing 83,400 tonnes of copper.
Overall, the total mineral reserves amount to 43.052 million tonnes with an average copper grade of 0.83%, resulting in 356,600 tonnes of contained copper.
Mining and Recovery
According to the Feasibility Study, the open-pit mining plan is focused on a single area through consecutive phases or pushbacks. The plan assumes a mill throughput of 4.0 million tonnes per year of sulphide ore.
Pre-stripping is required for a total of 13.2 million tonnes, with activities planned over 24 months.
The mining schedule will enable a maximum extraction of 20 million tonnes annually, with mining activity decreasing from Year 10 until completion in Year 12.
Mining will use selective processes to minimise ore dilution and loss, supported by ancillary activities, dewatering, grade control, and equipment maintenance.
The process plant is designed to process four million tonnes per year of Run-of-Mine (RoM) ore from the open pit to produce copper concentrate.
A sequential flotation process involves three-stage crushing and ball milling, followed by copper and pyrite flotation circuits.
The ROM ore will be crushed to a P80 of 12mm and then ground in a ball mill with classifying cyclones, achieving a P80 of 110 µm before entering the copper flotation circuit.
This circuit includes rougher flotation, regrind, and cleaner flotation stages. The final copper concentrate will be thickened and filtered.
Tailings from copper flotation will feed the pyrite flotation circuit, with the pyrite concentrate stored separately.
Final tailings will be thickened, filtered, and stored in a dry stacking facility.
Contractors Involved
The Feasibility Study Update, published in August 2021, was prepared by Ausenco Engineering Canada. Ero Copper and NCL Ingeniería y Construcción (NCL) also contributed.
