A new dawn for desalination in Chile

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Water scarcity and industrial development are pushing desalination up the agenda in Chile. The mining sector is spearheading a wave of new projects in the north.

On 18 November, Cochilco, the Chilean copper commission, presented findings from a report entitled: “Consumption of water in the Chilean mining industry: actual situation and projections”. Water scarcity is a serious constraint to the Chilean mining sector and the economy as a whole, given that mining accounts for around a fifth of Chile’s GDP.

The report concludes that, after peaking in 2017, copper production will reach 7.3 million tonnes in 2020, and in order to meet this demand, water usage will need to increase by 45%. Currently, the mining industry in Chile consumes 1.03 million m3/d, with copper production accounting for 976,300m3/d of that in 2008. The needs of the sector will reach 1.47 million m3/d in 2020, and without expected efficiency savings from improved water use practices, this figure would reach 1.75 million m3/d.

Resourcing is clearly an issue, and the overexploitation of limited groundwater resources throws into question not only the sustainability of existing mines, but the future of new ones.

At the Cochilco press conference, Santiago González Larrain, Chile’s minister for mining, raised concerns that without additional sources of water, prospective mining developments are unlikely to be brought online. He encouraged miners to seek alternatives, stating: “We must motivate the construction of desalination plants as an alternative.”

Securing a water source is vital in order to gain environmental approval for waterthirsty industrial operations such as mines. Increasingly, alternative sources such as desalination will be necessary to support any consumption-intensive development.

While desalination is not new to Chile, the combination of scarcity and a renewed push for industrial development is driving a new wave of desalination projects in the north of the country, which will lead to a significant increase in the nation’s installed capacity. These projects are to be found in Chile’s northern desert regions: XV (Arica and Parinacota), I (Tarapacá), II (Antofagasta), and III (Atacama).

Region III marks one of the major desal frontlines. There, the copper industry currently consumes 105,150m3/d of water, which is in excess of the water rights allocated. The consumption volume in this region alone is forecast to grow by 102% in the period to 2020.

“Some [mines] already have water rights, but the problem is that the water isn’t there to support the right,” explains Agbar Chile’s general manager Salvador Villarino. “The problem is that the aquifer [around Tierra Amarilla] will be exhausted in probably two to three years.”

Agbar is promoting one of a number of desalination projects mooted in the inland region around Copiapó. It has completed the basic engineering for a $285 million, 86,400m3/d SWRO plant with pipeline (see table), and plans to present tariff proposals to prospective mining customers shortly.

Meanwhile, Cleanairtech, a project company representing Chilean mining concern CAP SA, submitted an environmental application at the end of November for a $248 million desal plant to be located on the coast at Punta Totoralillo. Another mining entity, AguasMin, also has plans for a desalination plant, although these are thought to be less advanced. MPX Energia’s Castilla power plant, meanwhile, which is currently undergoing environmental approval, has outlined its vision for a 71,000m3/d SWRO facility.

Villarino thinks there may be scope to combine several of the proposed projects into one larger facility. “In my opinion, I think it would be ridiculous to have more than one project. The need for the water in that region [the Tierra Amarilla mining area near Copiapó] should be around 86,400m3/d. Maybe in the future we will need more desalinated water. With two projects of d each you are not going to get the economies of scale, especially when you have to pump the water. Because 30-40% of the cost is desalinated water and the rest is pumping, I think at the end of the day we are going to have one project, and we trust this will be our project because we are independent of the mining industry and our business is water.”

Villarino indicated that there have already been talks to collaborate, and confirmed that Agbar is open to taking an equity stake in a project, although its main interest is as an operator.

Further south, the El Morro mine is proposing a $900 million 63,936m3/d SWRO plant and pipeline in order to secure environmental approval for the mining operation, while in Region II, the Escondida and Esperanza mines are both looking to the sea for supplies of water. Escondida received environmental approval for a 276,480m3/d desalination plant in June 2009.

According to mine owner BHP Billiton, however, the plant is still at the prefeasibility stage, and Minera Escondida has not yet decided when this project will move forward, or how and when it will be executed. Elsewhere, Minera Esperanza has plans to use untreated seawater directly for process water.

With the copper price having recovered throughout 2009, projects thrown into doubt by the steep decline in the second half of 2008 are now looking more attractive. As the commodity price improves, so do the prospects for desal.