Water Scarcity and the Future of Mining
Water scarcity threatens copper production in Chile, a country that accounts for more than 25% of the global supply of this metal. According to World Meteorological Organization, the nation experienced below-normal rainfall in 2021, a trend that has now held for 13 years. There was a rainfall deficit of 20-60% over different regions of the country, and its main reservoirs are operating at a mere 30% of capacity.
Furthermore, the general trend of decreasing ore grades in the local mining industry is leading to an increased amount of water needed to process, for example, fine copper. Minerals need more intensive treatment to reach the same production and more contaminants need to be removed. This will certainly require a new business model with greater technology, efficiency, and a circular economy-focussed strategy.
Given the historic drought and challenges that have stricken the region for more than a decade, desalination has gained traction as a possible alternative to extend potential water usage
Are Desalination Plants Sustainable?
– Chilean Mining Experience
In light of these circumstances, a nation wide strategy is being developed to encourage the efficient use of water, which includes desalination plants as a supplement to improve supply, both for mine use and the local population. These factories have grown quickly in recent years, and their installed production capacity is about to reach 6,000 l/s this year. According to the Chilean desalination association Acades, that capacity should be doubled by 2032.
From a technical-economic point of view, there are elements that show the sustainability of making investments of this type. The most tangible proof is the fact that there are already desalination plants in operation in the mining sector – some with a total capacity of approximately 3,000 l/s, alleviating some of the pressure on natural water sources. While there are important companies such as Aguas Antofagasta and Aguas Nuevas that are offering desalinated water for human consumption, which is already adressing the ongoing challenges in the region.
There are currently 20 mining firms in Chile using seawater in their operations and for urban purposes, including the most expressive:
- Minera Escondida and Spence copper mine complex (BHP), Antofagasta region, have desalination plants with a total capacity of 4,025 l/s (including ongoing expansion projects);
- ADASA La Chimba, owned by Aguas Antofagasta, with a desalination plant capacity of 1,053 l/s (Urban use only);
- Aguas CAP (Compañía Minera del Pacífico) with a desalination plant capacity of 600 l/s;
- Candelaria copper mine (Lunding Mining) with a desalination plant capacity of 500 l/s.
Through 2025, 10 projects are expected to come into operation, including three replacement/expansion projects – Los Pelambres from Antofagasta Minerals (1,400 l/s), Codelco mines (>2000 l/s), Quebrada Branca from Teck Resources (865 l/s) and Collahuasi (1,900 l/s).
BHP Minera Escondida 2,500-l/s desalination plant, Antofagasta Region. Aiming to supply their copper mines’ needs, the whole system includes two 42” pipelines to transport the water to 3,200 metres above sea level, four high-pressure pumping stations, a reservoir at the mine and high-voltage electricity infrastructure to operate the circuit.
Although, future – and extremely needed – investments rely on many variables including location, availability, and production capacity. Additionally, the facility is only one component of the supply chain. The system that transports water to the needed areas/operations (pipeline pumping) is the other component; depending on the level of investment and running expenses, it may even become more crucial than the plant itself. It is estimated that between 15% and 30% of the total expense of the desalination system can be spent on the plant and pumping system to supply water from the ocean to mining operations.
We need to take ‘short-term’ measures because if you start a desalination project today, the execution will take seven or eight years. I believe that we cannot reach 2030 without concrete solutions in the regulations.
It is important to note that desalination plants and water transport networks are high energy consumers and the associated greenhouse gas emissions and the consequent environmental impact is cause for concern. Thus, looking for more efficient methodologies is crucial during this transition process.
Following this purpose, IntelliSense.io are committed to developing the best AI-based applications for the mining value chain. Our Pipeline Pumping Optimization App, for example, can assure continued transport of water withminimal energy consumption and increase pump life expectancy by reducing the number of pump switches ON/OFF. This allows the pumping to be in line with best practices. In addition, the Thickener Optimization App can help leverage water recovery from the downstream mineral processing circuit by stabilizing the process to maximize underflow density, preventing undesired stoppages and reducing the demand for fresh make-up water for the process.
Environmental and Political Factors
The use of desalination plants by themselves is already a great advance towards ensuring the supply of potable water and encourages the development of arid regions such as Antofagasta. This movement however also has political impacts. For example, the ‘Aguas Antofagasta’ project contributes to social development by favoring t local labor and services for installation works, strengthening the regional economic dynamism. From a political standpoint, these projects can be viewed, by local government, as a feather in the cap for their efforts to raise awareness around their concerns for regional development.
In addition to contributions from a social-economic point of view, desalination projects will guarantee the sustainability of water supply in the medium term, using an inexhaustible source such as the ocean. In this way, it will be possible to meet the demand of the current population, also ensuring supply for future generations.
All the above endorse the already critical concern, in terms of engineering, around the ability to develop desalination projects. However, today’s task is to be able to promote, through governmental and private entities, stronger policies and technology frameworks that allow for more sustainable and reliable development of desalination plants and water recovery initiatives.
Wrapping-up
The desalination plants are playing an increasingly important role in the Chilean regions as a response to the drought-induced challenges that the mining industry is facing. It is great to see the growing interest of companies in investing to make their processes more sustainable and efficient.
Modern AI-based applications can support these initiatives by driving a more efficient decision-making framework. It lends potential to create entirely new opportunities for continuous optimization of mining operations/plants throughout their life cycle.
