Seawater use in Chile's mines grows by a third

Seawater consumption across Chile's copper mining industry has seen steady growth over the years, and in 2015 it grew 33% to 2.3m3/s, state copper commission Cochilco said in a presentation in capital Santiago.

Since 2012, the use of seawater, both desalinated and non-desalinated, has surged 130% from 1.0m3/s, the agency said.

According to Cochilco's most recent water consumption forecast – published at the end of each year – seawater consumption is set to account for 50% of all water consumption in the mining industry by 2026.

While freshwater consumption in the industry last year was 13.07m3/s, growing only slightly compared to 12.95m3/s, the bulk of water consumed in the industry was reutilized water, reaching 40.4m3/s last year, Cochilco said.

Jorge Cantallopts, head of studies and public policy at Cochilco, said the small increase in freshwater consumption, paired with the increase in the reutilizing of water, shows the industry's commitment to lowering its impact on the limited water resources where mining operations are located.

Cantallopts said that reutilized water now accounts for 72.5% of water consumed in mining operations, while in the case of concentration, the most water-intensive process in the industry, reutilized water accounts for 73.2% of all water consumption.

In the coming years there are a number of new desalination plants that will help quench the industry's thirst. These include BHP Billiton's Escondida Water Supply project, expected to be the country's largest desalination plant. At a cost of US$3.43bn, it will treat 2,500l/s when it starts operating, due to happen next year.

Over the long term, other desalination plants set to come online include one for Codelco's RT Sulfuros project; a new plant for Teck Resource's QB2 expansion of Quebrada Blanca; one for project NuevaUnión, the JV between Teck and Goldcorp; and a facility for the next expansion phase of Antofagasta Minerals' Los Pelambres mine.