Vale Base Metals to deploy coarse particle flotation at Salobo copper mine
Vale Base Metals in the coming years is set to deploy CPF for its Salobo III copper operation in Brazil. The project was recently referenced during VBM Day on March 31, 2026 when Alfredo Santana, Chief Operating Officer, gave some examples of how VBM is driving excellence across its operations. He said that the use of coarse particle flotation (CPF) at the Salobo copper mine in Brazil will enable production to increase from 35 Mt of copper ore milled in 2025 to an expected 42 Mt in 2029.
The detail behind the project is detailed in the latest Technical Report for Salobo which was dated December 31, 2025. CPF is a flotation technology designed to enable the processing of significantly coarser particle size distributions compared to conventional mechanical flotation, with the potential to reduce specific grinding energy consumption and support increased plant throughput.
The report states that preliminary assessments indicate that operation at a coarser primary grind size could allow a substantial increase in processing capacity at Salobo, potentially of up to approximately 50%, while largely utilising the existing grinding circuit configuration. “By repowering the plant without the addition of new ball mills, the CPF project could deliver a material increase in capacity with comparatively lower capital intensity, while also reducing specific grinding energy consumption.”
The CPF configuration allows for the early removal of coarse material from the processing circuit, “generating a coarse tailings stream creating potential opportunities for future optimisation of coarse tailings management. Overall, the adoption of CPF represents a potential strategic advancement to improving process efficiency, energy performance, and the sustainability profile of the Salobo Operations.
The Salobo processing plant currently operates with a conventional comminution and flotation flowsheet designed for a primary grind size of approximately P80 106 µm. As part of the proposed process configuration to support increased throughput and coarse particle recovery, modifications to the grinding, classification, flotation, and selected utility systems have been assessed to enable the integration of CPF into the existing Salobo plant.
In the crushing area, the planned modifications are primarily focused on the removal of capacity constraints associated with increased plant throughput. Changes include upgrades to the secondary crushing and screening circuits, with the replacement and expansion of screening equipment and the repowering of conveyors, feeders, and drive systems. These modifications are intended to ensure stable and continuous operation under the revised operating conditions, preventing throughput limitations upstream of the concentration plant.
The concentrator stockpile associated material handling systems will be upgraded to accommodate the higher operating throughput. Modifications include mechanical upgrades to conveyors and feeders, as well as structural adjustments where required. These changes are designed to ensure reliable and consistent ore delivery to the grinding circuit and to minimise the risk of operational interruptions or instability.
To support implementation of the CPF Project, modifications to the existing ball milling and classification system are planned. These modifications include replacement of the existing hydrocyclone clusters, relocation of associated structural steel and piping, and upgrades to the electrical room to accommodate the revised equipment configuration and operating duty.
The current grinding circuit comprises two clusters of ten 26‑in hydrocyclones, which classify the milled product that feeds the conventional rougher flotation circuit. Under the CPF project basis, the hydrocyclone classification duty will be adjusted to coarsen the grinding product, increasing the average particle size reporting to the Eriez HydroFloat® CPF circuit (which will include three HydroFloat CPF cells), which is designed to recover value from coarser particle size fractions than those typically treated by conventional mechanical flotation. To accommodate this operating regime, the existing cyclone clusters will be replaced by two clusters of larger diameter hydrocyclones.
Under the CPF project basis, the primary grind P80 is planned to increase to approximately 250 µm, enabling increased mass throughput through the grinding circuit; however, this product size is considered coarse for conventional mechanical flotation. To enable integration of coarse flotation with the existing plant, a secondary classification stage will be introduced. A new hydrocyclone cluster will receive overflow from the primary grinding cyclone cluster and split the slurry into two size fractions – a fine fraction (predominantly <106 µm), directed to the existing conventional mechanical flotation circuit; and a coarse fraction, directed to the CPF circuit employing the HydroFloat® cells.
The CPF circuit is based on HydroFloat® technology, which combines flotation and fluidised‑bed separation principles to recover value from coarse particle size fractions. The HydroFloat® concentrate will be processed through an additional grinding stage to reduce particle size to a target P80 of approximately 106 µm, suitable for subsequent treatment in the conventional flotation circuit. This duty will be provided by two additional Metso vertical stirred mills (VTM1500), consistent with the existing Salobo configuration, operated in closed circuit with the new hydrocyclones.
The product from this additional grinding stage will then be combined with the overflow (fine fraction) from the first CPF cyclone cluster to form a combined feed to the conventional flotation circuit. This integrated configuration is intended to improve overall recovery, particularly for value contained in coarse fractions; improve energy utilisation by limiting regrinding of already liberated material; and provide an integrated grinding–classification–flotation arrangement with operational flexibility.
The conventional flotation circuit will be adapted to operate in an integrated configuration with the CPF circuit. The fine fraction generated by the revised classification system will continue to be processed through the existing mechanical flotation cells and columns. Additional streams originating from CPF concentrate regrinding will be incorporated into the circuit. These modifications are intended to maintain conventional flotation performance while accommodating the integrated flowsheet.
The CPF implementation and associated capacity increase will require upgrades to the electrical distribution system, including new electrical loads, electrical rooms, panels, and substations. In parallel, automation, control, and telecommunications systems will be expanded and integrated to ensure that all new equipment and process areas are fully incorporated into the existing plant control and monitoring infrastructure.
The project includes the construction and modification of civil and structural infrastructure required to support the new process equipment and utilities. This includes foundations, steel structures, pipe racks, and industrial buildings, as well as upgrades to selected support facilities. The scope has been developed to maximise the use of existing infrastructure, minimize additional footprint and ensure the safe and efficient integration of the CPF circuit into the operating plant.
The existing compressed air system includes six dedicated compressors, with five units operating and one standby, supplying air to the flotation columns. In addition, three compressors supply the main Service Air and Instrument Air distribution networks for the concentrator. The system includes associated pressure vessels and dryers to maintain air quality suitable for instrumentation and process equipment.
To meet the additional air demand associated with the CPF project, three new oil‑injected rotary screw compressors will be installed. These units will supply compressed air for the coarse flotation circuit and instrument air for the new systems and will be integrated into the existing pressure vessels to maintain reliability and provide redundancy.
To support the additional water demand associated with the CPF circuit, upgrades to the recovered water reservoir pumping system are planned. A total of eight new water pumps will be installed at the recovered water reservoir, comprising four operating units and four standby units, to supply process water to the new demand points within the coarse flotation circuit. The recovered water will be distributed to the CPF circuit for process dilution, utility water supply, and pump sealing services.
Considering the full scope of the Salobo III Project, including the CPF circuit and changes to flow rates of existing equipment, the total water demand for infrastructure sizing increases to 6,800 m³/h. To accommodate this increased demand, expansion of the water reclaim and pumping system at the TSF will be required. The scope of work includes modification of the existing pumps and procurement of additional pumping capacity.
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