ADDING OF STM VERTICAL MILL TO CARAIBA CONCENTRATOR

The integration of the STM vertical mill into Ero Copper's Caraíba Concentrator Flowsheet has proven to be a significant advancement for the operation. Installed as part of the Phase 1 expansion of the Caraiba Mining Complex, the 2300 kW vertical stirred mill has had a positive impact on plant performance since its commissioning in August 2020.

The STM mill receives feed from the existing Derrick Stack Sizer screens oversize, with the STM mill product joining the Derrick screen undersize distributed to the flotation roughers. This integration has led to 5%-6% improvement in overall concentrator copper recovery.

There are opportunities to further enhance copper recovery, particularly considering the expanded tonnages required by the expansion plan. Utilizing HIG mill technology is identified as a potential avenue for improvement. Additional mills could be deployed to treat locked composite copper in the current Derrick Stack Sizer screen undersize, and regrinding of flotation intermediate concentrates could also be implemented to optimize liberation and recovery.

The ongoing work aims to capitalize on these opportunities and optimize the liberation and recovery processes further. By leveraging innovative technologies and strategic interventions, Ero Copper is poised to enhance the efficiency and effectiveness of its operations at the Caraíba Concentrator.

https://erocopper.com/site/assets/files/6398/investor_presentation_-_november_2023.pdf

https://www.stmminerals.com/wp-content/uploads/2023/10/S16P5_176_Pereira-Lawinscky-da-Silva-et-al-Adding-HIGmill-Technology-to-the-Ero-Copper-Caraib.pdf