Rubbing salt into the wounds: The obstacles facing desal plants for Chilean miners

The lack of specific regulations for seawater desalination in Chile, among other challenges such as those related to maritime ecology, put pressure on mining companies seeking to install or optimize their plants.

Of the 24 plants operating in the country, 85% belong to the mining sector, and there are seven projects in the feasibility stage and 12 in other development phases.

However, more water is still needed for mining. State copper commission Cochilco expects water consumption to grow at an annual rate of 2.3% from 2022 to 2034 as copper mining continues to shift toward sulfide minerals and more water-intensive processes such as flotation due to the depletion of oxide reserves.

By 2034, almost 70% of the water supply will come from the ocean, Cochilco anticipates. Companies such as BHP at Escondida, Lundin Mining at Candelaria, Mantos Copper at Mantoverde, Antofagasta Minerals at Centinela and Antucoya, and Minera Las Cenizas are already operating with seawater and there are plans for expansion.

Other players want to join the trend to reduce the use of continental water, but there are challenges.

UNREGULATED INDUSTRY

In Chile there is no special regulation for desalination and maritime concessions are not an enabling title to extract water from the ocean, but only allow for the carrying out of works.

These reasons underpin the debate in the senate on a bill to regulate seawater for desalination, create a national strategy, define consumption priorities and determine the areas where new projects can be implemented.

Other key aspects are:

• Create a unique type of entry into the environmental review service for industrial seawater extraction and desalination projects.
• Incorporate desalination plants into the urban planning and construction law for building permits and identification of networks, layouts and pipelines.
• Ensure water availability to surrounding communities with a capacity reserve of up to 5% of industrial projects.

More details on the bill can be seen in the presentation of the Chilean desalination association in the Documents box in the top-right corner of the screen.

The bill is currently under review by the senate's water resources committee and is likely to get the green light given that more than 60% of Chile's land and over 70% of its population are under water stress, according to a report from the chamber.

ADDITIONAL CHALLENGES

Along with incorporating technologies to address changes in the marine environment, such as rising temperatures, changing salinity, discharge of nutrients, fertilizers or wastewater, and seasonal growth of algae and jellyfish, there are the potential impacts of other regulations.

Law 20,249, known as the Lafkenche Law, seeks to protect a coastal marine space for legitimate use by indigenous peoples, although this could be abused by other groups to hinder projects, the mining sector has warned.

Nicolás Calderón, partner for climate change and sustainability at consultancy firm EY, told BNamericas that it is essential to move forward in establishing clear criteria that define indigenous peoples and ensure the appropriate use of coastal areas.

"While the law is a good step forward in the rights of indigenous peoples, it is important to move towards a management of coastal space that is flexible and sustainable, so that there is a balance between the protection of indigenous traditions and the possibility of developing investment projects," he said.

Calderón advocates that education on coastal conservation needs to be provided “with the participation of indigenous communities and the community in general and that a clear framework for investment be provided, with instances of conflict resolution and environmental and cultural monitoring systems.”

DESAL PROJECT

State copper giant Codelco is building a desalination plant in northern region Antofagasta involving investment of over US$1bn that will use reverse osmosis technology and have initial capacity of 840lt/s.

The plant will supply Codelco’s Chuquicamata, Ministro Hales and Radomiro Tomic operations from 2026, and a future expansion to 1,956lt/s is planned.

The water intake and pumping system is being built by the Aguas Horizonte consortium under a contract modality that involves operation and a subsequent transfer to Codelco, while engineering, procurement and construction (EPC) is being carried out by Techint Engineering and Construction.

Techint has described the project as “one of the most technically complex works” in its more than 70 years in Chile.