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Marimaca reports positive results from the Phase 5 metallurgical programme

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Global Mining Review,

Marimaca Copper Corp. has announced the results of the Phase 5 metallurgical testing programme recently undertaken at its flagship Marimaca Oxide Copper Project (MOD), located in northern Chile.

The Phase 5 programme represents the most comprehensive metallurgical study completed to date for the MOD and is the final phase expected prior to the planned commencement of the definitive feasibility study (DFS).

The Phase 5 programme is an important de-risking event for Marimaca, and confirms the results from the previous four phases of metallurgical testing, which indicate good leach kinetics and moderate acid consumption. Results from Phases 1 – 5 metallurgy and the 2021 variability programme will form the basis for the updated process design criteria and metallurgical assumptions for the DFS.


  • The rigorous fifth phase metallurgical test-work programme represents a milestone de-risking event for Marimaca, further improving confidence in the expected metallurgical performance at the MOD.
    • Complements and extends previous four phases of metallurgical testing.
    • Programme consisted of full-scale column testing, mini-column testing, container-leach testing, sulfation tests, acid sensitivity testing, Iso-pH testing, and head characterisation for heap leach (HL) and run-of-mine (ROM) samples.
    • Robust sample set with several composites across all mineral subdomains through all phases of testing.
  • Confirms the understanding of the MOD’s metallurgical performance with results from Phase 5 consistent with Phases 1 – 4 metallurgy.
    • Results significantly improve the resolution of Marimaca’s geo-metallurgical dataset.
  • Confirms metallurgical performance in scaled-up, industrial height operating design conditions (4 m columns).
  • Provides further confidence in expected acid consumption with clear potential for optimisations to reduce acid consumption demonstrated in both HL and ROM test results.
    • Testing also confirms very low levels of carbonates (<1%) and nitrates (<0.03%) in general within the MOD.
  • Results continue to demonstrate potential upside to recoveries when in industrial-scale operation.
    • Recoveries in the column and bottle roll tests generally exceeded the solubility ratio and leaching potential of the samples, indicating a potentially larger proportion of total copper will be recovered in industrial-scale operations.
  • Completing final confirmatory work programs on particle size distribution and impurities balance to inform update process design for the planned DFS.
  • Recovery and acid consumption models will be updated on the back of the 2022 geological and resource model update planned for 3Q22, immediately following the completion of the 2022 infill drilling programme.

Hayden Locke, President and CEO of Marimaca Copper, commented:

“The Phase 5 metallurgical programme completes the acquisition of an incredibly comprehensive metallurgical dataset for Marimaca. This is a critical de-risking milestone and we are very pleased with results.

“The results from Phase 5 further improve our confidence in the strong metallurgical performance at the MOD. In addition, several opportunities for optimising acid consumption, while maintaining or improving copper recoveries, have been identified and will be integrated into our process design going forward.

“Similar to the trends identified in previous phases, copper recoveries continue to demonstrate upside beyond those projected by acid solubility and leaching potential given the longer leaching cycle of the black oxide component of copper oxide mineralisation at Marimaca. This provides opportunities with respect to recoveries in industrial-scale operations beyond the positive results demonstrated in this phase of testing.

“Marimaca continues to distinguish itself as an exceptionally high-quality copper development project. This year’s infill and extensional drilling campaigns are progressing well, and we look forward to delivering our planned updated resource estimate in 3Q22.”

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Copper mining news South American mining news