Key Highlights

  • Cobre has defined a staged pathway at Sierra Atacama targeting about 18,000 tpa, then about 25,000 tpa, with a larger case of up to about 50,000 tpa to be evaluated.
  • A Declaración de Impacto Ambiental (DIA) for the 25,000 tpa case is targeted for submission by the end of 2026, and Stage 1 tendering is expected to be awarded by the end of the quarter.
  • Stage 3 depends on a 40,000 metre drilling programme, updated resource modelling, further studies, economic evaluation and environmental approvals.

Cobre Limited (ASX:CBE) announced on 13 October 2026 a staged and modular expansion pathway for its Sierra Atacama copper project. The company says the plan builds on existing infrastructure and is fully funded, and it targets an initial increase in copper cathode capacity to approximately 18,000 tonnes per annum (tpa), followed by about 25,000 tpa and an evaluation of a longer-term case of up to about 50,000 tpa.

Stage 1: restoring existing capacity to about 18,000 tpa

A comprehensive engineering review of the existing SX-EW Facility was completed by ARSEM SpA. It sets out the works needed to refurbish and optimise the operating solvent extraction circuit and recommission the second electrowinning bay. The proposed scope also includes expanded run-of-mine and dynamic leach-pad capacity, additional crushing capacity, and associated pumping, electrical and solution-management infrastructure.

A formal tender process for the SX refurbishment and electrowinning recommissioning is starting, with an award expected by the end of the quarter. The release describes the infrastructure Capital requirements as relatively modest but does not give a cost figure for any stage.

Stage 2: processing capacity of about 25,000 tpa

In parallel, Cobre has begun conceptual engineering and environmental studies to evaluate recommissioning and upgrading the second solvent extraction line and building a new electrowinning bay. This is designed to support about 25,000 tpa and the requirements of the DIA, with detailed engineering to follow later.

Supporting infrastructure being engineered includes expanded ROM and leach pads, increased crushing capacity, a connection to the 110 kV grid power supply, increased water Supply and storage, additional open-pit Mining areas, expanded site accommodation, and solution-management and materials-handling systems. Engineering, metallurgical, architectural and environmental studies are underway to incorporate these elements into a new DIA targeted for submission by the end of 2026.

Stage 3: evaluating up to about 50,000 tpa

Cobre's ongoing 40,000 metre drilling programme is intended to provide the geological information needed to update the Sierra Atacama Mineral Resource and support expanded open-pit mine design and scheduling. After the drilling and resource modelling are complete, the company intends to evaluate a substantially larger open-pit case targeting up to about 50,000 tpa of copper cathode.

The release states that this larger case would need additional mining and processing infrastructure and would be subject to further technical studies, economic evaluation and environmental approvals. It is therefore an evaluation target rather than a committed project.

Resource basis and reporting status

The announcement references the company's 2025 NI 43-101 Mineral Resource, reported on 12 February 2026, and says the company is advancing toward a JORC-compliant Mineral Resource Estimate. It confirms it is not aware of new information that materially affects the earlier estimate. The existing configuration described in the release includes two solvent extraction lines and two electrowinning bays, with one bay operating and the second available but idle. The expansion plans are covered by the company's forward-looking statements cautionary note, which refers to commercial, operational, market and counterparty risks.

Existing plant description and references

The release describes the current configuration as including SX Line 1, SX Line 2 operating at part capacity, an operating EW Bay 1 and an idle EW Bay 2, alongside crushing, leach pads and solution management. The Stage 2 text refers to the second solvent extraction line as currently unused, so the descriptions of the solvent extraction lines are not worded identically in different parts of the announcement.

For background, the company points to its ASX announcements of 7 July 2026, covering an increased ownership interest in Sierra Atacama, and 31 August 2026, covering majority ownership of the project. The expansion plans are also tied to the 14 July 2026 company presentation.