Los Bronces Secures Desalinated Water Supply After 2022 Output Hit

On 28 September 2026, Anglo American opened the valve connecting the first supply of desalinated water to Los Bronces, a copper mine perched at roughly 3,900 metres in the Chilean Andes. Minister for Economy and Mining Daniel Mas performed the activation at a ceremony in Quilapilún, marking the inaugural phase of the operation’s Integrated Water Security Project.

The moment carries weight because Los Bronces has already paid a price for water scarcity. In Q1 2022, the mine reported a 17% year-on-year production decline partly tied to a lack of water, and at one point during the drought roughly 44% of its throughput was curtailed. Today’s inauguration is the direct operational answer to that documented vulnerability.

For an industry that depends on continuity from one of the world’s most water-stressed mining regions, this is a case study in how copper mine desalination is being deployed to protect supply. Here is what the infrastructure means for production resilience, and what investors and operators should understand about the model it establishes.

From drought casualty to water-secure operation: what just changed at Los Bronces

The mine has lived with water risk for years, and the numbers make that concrete. The 17% output drop in early 2022 was not a modelling exercise or a sustainability slide. It was a reported earnings event, tied directly to scarcity, and the 44% throughput limitation during the drought period showed how quickly a dry season can throttle a high-altitude operation.

That is the exposure this project is built to reverse.

The Integrated Water Security Project (IWSP) is a system, not merely a pipeline. Desalinated water from the Aguas Pacífico plant at Puchuncaví feeds into the mine’s existing recirculated water system, known as the SAR, which already re-uses approximately 90% of process water. Desalination becomes the outside top-up to an operation that was already recycling intensively.

The SAR system’s approximately 90% recirculation rate reflects broader advances in water efficiency in mining that have reshaped how operators calculate their external water dependency, turning process recycling from a cost-cutting measure into a core operational resilience strategy.

Phase 1 is the ramp toward a firm 2030 endpoint. The inaugural stage builds toward a full supply of up to 500 litres per second (l/s), covering more than 45% of the mine’s total water needs, with the stated goal of zero freshwater withdrawal for mining processes by 2030.

The key Phase 1 parameters:

• Desalinated supply of up to 500 l/s flowing to the mine
• More than 45% of total mine water needs covered at full supply
• Existing SAR recirculation rate of approximately 90%
• Target of zero freshwater intake for processes by 2030

For investors weighing Anglo American’s copper assets, the interpretation is straightforward. Water scarcity here was a documented financial exposure, not a hypothetical, and the IWSP is the structural response to it. This reads as operational de-risking with a production-stabilisation rationale, not a voluntary gesture.

100 kilometres of pipe, 3,900 metres of altitude: how the infrastructure works

The physical logic of the system is its own argument for why this approach was necessary. Water begins at the Aguas Pacífico desalination plant at Puchuncaví, on the coast in the Valparaíso Region. From there it travels roughly 100 km (some sources cite up to 105 km) inland to the Las Tórtolas sector in Colina, where it enters the mine’s SAR recirculated water system at an elevation of approximately 3,900 metres.

Moving water from sea level up into the Andes is not cheap or simple. That the engineering is worth doing tells you how unreliable continental water had become.

The project was built and is operated through a partnership between Anglo American and Aguas Pacífico, which constructed the multipurpose facility at Puchuncaví. This developer-operator structure, coastal desalination feeding an inland mine, is the reference architecture other water-stressed Andean operations may study.

The community water supply woven into the pipeline

The same pipeline that secures the mine also serves the people along its route. Around 25 l/s of clean water is allocated to rural communities in Colina and Tiltil, delivered through six rural sanitation service networks. The inauguration itself took place at the Santa Matilde Rural Sanitation Service facilities in Quilapilún, the point where community delivery begins.

The community benefits along the corridor:

• 25 l/s of potable water for surrounding communities
• Approximately 10,000 people benefiting directly in Colina and Tiltil
• Around 40,000 people benefiting along the full pipeline corridor
• Six rural sanitation service networks carrying the supply

This is where the design does more than move water. Sharing infrastructure between the mine and its neighbours is a deliberate social-licence mechanism, not an incidental benefit. For operators, it demonstrates that securing mine water and delivering community access can be engineered into the same asset.

Where Los Bronces sits in Chile’s sector-wide water shift

Today’s inauguration is the most visible milestone in a transition already under way across Chilean copper mining. It is not one company acting alone.

Chile’s shift toward seawater copper production accelerated well before Los Bronces came online, driven by tightening freshwater regulation and the physical depletion of Andean aquifer systems that historically supplied the country’s highest-altitude mines.

The sector-level numbers make the systemic point. According to a Chilean government communication in 2025, 11 seawater supply projects are already operating across Chilean mining, with a further 15 desalination plants planned by 2028. Los Bronces is a leading example within that broader wave, not an outlier.

The shift predates the current build-out. Cochilco-derived data published in the Journal of the Southern African Institute of Mining and Metallurgy, drawing on 2020 figures, put the Chilean copper industry at 1.84 m³/s of direct seawater use and 2.22 m³/s of desalinated water, for roughly 4.06 m³/s of total seawater-related inputs. Notably, desalinated volumes already exceeded direct seawater use even before the new plants arrive.

The government expects the volume of seawater used by the copper industry to approach near-parity with freshwater within roughly a decade. Officials at the ceremony framed the change plainly.

The Mining Undersecretary, Álvaro González, characterised the adoption of desalinated water as having moved from a future aspiration to a concrete operational reality, describing non-continental water sources as delivering certainty, competitiveness, and sustainability to mining.

For investors, the read-through is significant. The 15 planned plants signal a capital commitment wave, not a policy wish list. That means desalination infrastructure should be treated as a material operational factor across Chilean copper, a sector-wide capex theme rather than an Anglo American-specific one.

The limits of the model: what desalination alone cannot solve

The achievement is real. The professional investor’s checklist is longer than one pipeline.

McKinsey & Company frames the point directly in its paper “Desalination is not the only answer to Chile’s water problems.” Desalination is necessary, the firm argues, but insufficient on its own, and miners who lean on any single water source remain exposed to both physical scarcity and regulatory curtailment.

McKinsey warns that miners relying primarily on continental water remain at “constant risk” as droughts intensify and competition for shared water sources increases.

The firm sets out a four-part water-security portfolio:

1. Desalination to add a drought-immune supply source
2. Greater process efficiency and reduced water demand
3. Expanded reuse and recycling
4. Stronger governance of shared water basins

Measured against that framework, Los Bronces already ticks more boxes than most. Its SAR system delivering approximately 90% recirculation is the reuse-and-recycling component operating at scale, and now desalination adds the drought-immune source alongside it.

The tensions are not fully resolved, though. Reuters reported in 2022 that mines securing dedicated water, including desalination, while urban and agricultural users faced rationing created real allocation friction. Community-benefit design can soften that pressure. It does not eliminate it.

Water competition in mining is intensifying across every water-stressed copper jurisdiction, as agricultural users, municipalities, and expanding mine operations draw from the same shrinking continental sources, a dynamic that gives dedicated desalination infrastructure its clearest economic justification.

For anyone assessing water risk across copper assets, the lesson is a checklist, not a single test. The question is not simply whether a mine has a desalination pipeline, but whether it addresses all four portfolio components. Los Bronces sits further along that list than most, which is precisely why it functions as a benchmark.

What the Los Bronces model signals for copper supply and water-risk investment

The inauguration gives investors and analysts a fixed date to measure progress against. The commitment to zero freshwater withdrawal for mining processes by 2030 is not a soft aspiration. It was registered in the UN Sustainable Development Goals partnership registry on 31 December 2022, an externally trackable standard rather than a promise to accept on trust.

The UN SDG partnership registry serves as the formal global ledger of voluntary commitments made by corporations and multi-stakeholder groups in support of the Sustainable Development Goals, giving the 2030 zero-freshwater target at Los Bronces an externally verifiable status that internal sustainability reports alone cannot confer.

Phase 1’s up to 500 l/s, covering more than 45% of mine water needs, is the baseline against which that 2030 target will be reported.

The stakes reach beyond Chile. Copper demand tied to the energy transition makes continuity of Chilean production a global supply concern, which turns water security at assets like Los Bronces into a factor that matters well outside the region.

For investors assessing water risk across copper assets beyond Chile, the 2026 global picture shows that the hydrological pressures driving Los Bronces’s IWSP are present across every major copper-producing jurisdiction tied to the energy transition.

The three watch points from here:

• The 2030 zero-freshwater target, with the 500 l/s baseline as the marker of progress
• The 15 sector-wide plants coming online by 2028 as a Chilean copper capex theme
• The multi-purpose model, serving both mine and community, as a social-licence template

That last point may prove the most replicable. Infrastructure that secures mine supply and delivers potable water to around 10,000 direct beneficiaries, plus roughly 40,000 along the corridor, offers a template for earning and keeping social licence in water-scarce jurisdictions. For investors evaluating exposure to Chilean copper, Los Bronces now sets a reference for what genuine water-security infrastructure looks like and what it takes to build.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.

Forward-looking statements, including the 2030 target and sector projections, are speculative and subject to change based on market developments, hydrological conditions, and company performance.