Cobre Locks in Two Ore Deals Adding 300t Copper Cathode Monthly From Q4 2026

Cobre Limited's Sierra Atacama has signed two Cobre Sierra Atacama third-party ore purchase agreements in Chile's Antofagasta region, targeting ~300 additional tonnes of copper cathode per month from Q4 2026 and projecting a step-change in operating cash flow toward US$8–10M per month by 2027.
By William Hadrian -
  • Sierra Atacama SpA has executed ore purchase agreements with two third-party copper oxide miners, targeting 50–75 kt per month of 1.0–1.5% CuT feed and approximately 300 additional tonnes of monthly copper cathode production from Q4 2026.
  • The agreements are incremental to Cobre's existing production targets announced on 6 July 2026, which remain unchanged.
  • Sierra Atacama's SX-EW plant has 20,000 tpa of installed capacity currently running below nameplate; third-party ore is expected to accelerate utilisation toward that ceiling, spreading fixed costs and improving unit economics on own-ore processing simultaneously.
  • Indicative operating cash flow is projected to step from ~US$0.5M per month currently to ~US$8–10M per month in 2027, when underground, third-party ore, and open-pit mining are all contributing.
  • Further ore supply agreements with additional regional miners are described as well advanced, with additional deals expected in the near term.
Summarise with AI:

Two ore deals set to add ~300t of copper cathode per month from Q4 2026

Cobre Limited (ASX: CBE, CBEO) has announced that its wholly owned subsidiary, Sierra Atacama SpA, has executed ore purchase agreements with two third-party copper oxide miners in Chile’s Antofagasta region. As deliveries ramp up from Q4 2026, the agreements are expected to deliver 50–75 kt per month of 1.0–1.5% CuT oxide ore, adding approximately 300t of monthly copper cathode production.

This production is incremental to the company’s previously announced production targets from 6 July 2026, which remain unchanged. Further agreements are under negotiation and expected in the near term.

Cobre’s broader asset base extends beyond the Antofagasta region, with high-grade copper continuity in Botswana adding a second exploration front to the company’s portfolio as Sierra Atacama advances toward full plant utilisation.

What the agreements mean for production and cash flow

A step change in margin economics

Purchased ore bypasses the mining and development costs that sit behind every tonne of underground production. The incremental cost of the additional cathode is limited to the ore purchase price and variable processing costs, principally acid, power, and reagents.

Higher throughput also spreads fixed plant costs across a materially larger tonnage base, lowering the unit cost of Cobre’s own underground ore. That double margin benefit is the core economic logic here. Sierra Atacama’s installed SX-EW capacity is 20,000 tpa (approximately 1,600t per month), and the plant is currently operating below nameplate. These agreements are expected to accelerate utilisation toward that ceiling from Q4 2026.

Indicative cash flow by production phase

The announcement includes a production ramp-up and indicative operating cash flow chart. The figures below reflect what can be read from the chart as reproduced in the announcement.

Based on the chart as presented in the announcement:

Production Phase Cathode Volume (t/month) Key Driver Indicative Operating Cash Flow
Current (existing underground) 300–400 Underground ore only ~US$0.5M / month
Q4 2026 Optimised UG + Third-Party Ore Third-party ore ramps alongside underground ~US$1–2M / month
Dec 2026 run rate Full third-party ore delivery SX-EW at materially higher utilisation ~US$2–3M / month
2027 ramp-up UG + Third-Party Ore + Open Pit Open-pit commencement bridges in ~US$8–10M / month

Sierra Atacama — the regional processing hub explained

The SX-EW (solvent extraction–electrowinning) process works in three steps: oxide ore is crushed and leached with acid to dissolve copper into solution; the copper-rich solution passes through solvent extraction to concentrate and purify it; and finally, the copper is electroplated onto cathode sheets, producing high-purity copper cathode ready for direct sale. No smelting is required.

The commercial logic for regional miners is straightforward. Small-to-mid-scale copper oxide operators in the Antofagasta region hold high-grade ore but have no processing capacity of their own. Sierra Atacama offers shorter haul distances, faster payment terms, and a long-term commercial partnership, with no capital outlay required for processing.

That creates a hub-and-spoke structure: Sierra Atacama provides the processing node, and regional miners supply high-grade feed. Both parties benefit from the arrangement, which reinforces itself commercially as more suppliers join. For investors, the key implication is that each additional third-party agreement adds cathode volume with no new mining or development capital expenditure, making incremental production highly capital-efficient.

Sierra Atacama Processing Hub Model

Bridging to 2027 — how third-party ore de-risks the open-pit transition

The announcement outlines three ways the third-party ore agreements consolidate the transition to open-pit production in 2027:

  1. Full plant utilisation — the SX-EW plant continues to operate at materially higher throughput through the underground-to-open-pit transition, spreading fixed costs across a higher tonnage base and improving unit economics for own-ore processing as the open-pit ramps up.
  2. Commercial infrastructure — the regional supply contracts establish the commercial, logistical, and quality-assurance frameworks that are expected to scale as the company’s own production grows, providing proven systems in place when the open-pit reaches nameplate capacity.
  3. Metallurgical experience — processing a range of regional oxide ore sources through the SX-EW plant builds operational knowledge that strengthens plant performance and is expected to de-risk the open-pit ramp.

FY2027 guidance, incorporating the underground operation, the third-party ore contribution, and the planned commencement of open-pit mining, is expected to be provided in Q1 2027. Negotiations with additional regional ore suppliers are well advanced, and further agreements are expected in the near term.

Adam Wooldridge, Chief Executive Officer

“We are approaching a defining period for Sierra Atacama. The current underground operation will progressively transition through 2027 into a substantially larger open-pit operation, and third-party ore fills that gap — keeping the SX-EW plant at materially higher utilisation throughout the transition rather than allowing throughput to drop between the two production sources. These agreements are the direct product of the operational credibility we have built with regional counterparties, and they demonstrate the strategic advantage of Sierra Atacama’s location and processing capacity in the heart of Chile’s premier copper region. Sierra Atacama is being positioned as the regional processing hub, and the market is now recognising that.”

Kaveen Bachoo, Chief Financial Officer

“Financially, these arrangements deliver on three fronts. They generate incremental cash flow through 2027 that would not otherwise be available during the transition period. They spread the plant’s fixed cost base across a materially higher tonnage throughput, which improves unit economics for our own ore. And they establish the commercial framework — pricing, logistics, quality assurance – that scales seamlessly as our own production grows. These are not a substitute for our organic strategy; they accelerate it and provide meaningful optionality as Cobre moves into the 2027 growth phase.”

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Frequently Asked Questions

What is the Sierra Atacama third-party ore agreement announced by Cobre Limited?

Cobre Limited's Chilean subsidiary Sierra Atacama SpA has signed ore purchase agreements with two regional copper oxide miners in the Antofagasta region, securing 50–75 kt per month of 1.0–1.5% CuT oxide ore to add approximately 300 tonnes of monthly copper cathode production from Q4 2026.

How does the SX-EW processing hub model work at Sierra Atacama?

Sierra Atacama operates a solvent extraction–electrowinning (SX-EW) plant with 20,000 tpa of installed capacity; regional copper oxide miners truck their ore to the facility, where it is leached, purified, and electroplated into high-purity copper cathode ready for direct sale — with no smelting required and no capital outlay needed from the supplying miners.

What is the projected cash flow impact of the third-party ore agreements for Cobre?

Based on the company's indicative ramp-up chart, operating cash flow is expected to increase from approximately US$0.5M per month currently to US$1–2M per month in Q4 2026, US$2–3M per month by December 2026, and US$8–10M per month in 2027 when open-pit mining is also contributing.

When will Cobre provide FY2027 production guidance for Sierra Atacama?

Cobre has indicated that formal FY2027 guidance — incorporating the underground operation, third-party ore contribution, and planned open-pit commencement — is expected to be provided in Q1 2027.

Why does third-party ore improve unit economics for Cobre's own underground production?

Higher total throughput through the SX-EW plant spreads fixed processing costs across a larger tonnage base, which lowers the per-tonne cost of processing Cobre's own underground ore — meaning the third-party agreements improve margins on both the purchased ore and the company's own production simultaneously.

William Hadrian
By William Hadrian
Partnerships Director
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