As the world’s largest copper producer, Chile is in the race to rationalize mining’s water use.
Central-north Chile, home to more than 10 million inhabitants, has experienced an uninterrupted sequence of dry years since 2010 with mean rainfall decrease of around 20–40%. The so-called Mega Drought (MD) is the longest event on record and with few analogs in the last millennia. It surrounds a broad area, with adverse effects on water availability, vegetation and forest fires that have proportion to social and economic impacts.
Droughts vs mining water demand
Chile is well-known for its strength on the mining scene, producing nearly 28% of all copper globally. Seeing such potential one cannot imagine the challenges behind the production of all this material. The north of the country, where mining is concentrated, is one of the driest areas on the planet, and surface water resources are scarce. To make matters worse, what is seen is a growing demand for water by industrial and local users, communities and the environment.
The recent record-breaking droughts in Chile set an alarm for both private and public sectors on how water shortage could impact Chilean mining operations, forcing these agents to expand their search for alternative sources, whether new continental freshwater, pricey desalination plants, water recovery treatment. Even workers and the general population is being encouraged to rationalize water usage.
Projections reveal that water consumption in Chilean mining operations will increase to nearly 56% by 2030 (Cochilco, 2019).
Mineral processing vs water recovery – It is time for a greater balance?
The concentration steps of copper ores represent the largest consumption of water in terms of volume. It includes comminution of the mineral, followed by flotation, classification and thickening. An important part of the water used in the flotation process is contained in the tailings which are thickened in order to recover part of this water (overflow focus).
At the end of 2022, the concentration process is expected to account for 58% of the total water used in copper mining at an expected water rate of 13,9 m3/sec. Although 73% of the water used by Chilean copper mines came from reuse (70% from continental water and 30% from sea or desalinated water) – 2021 base, this value still needs to increase to guarantee goals linked to regional and global sustainable development.
The case of fresh water is even more critical since it is also used for population development. The reduction in continental water usage is unlikely to be fast enough to meet the goals of the 2050 national mining policy which was drafted by the government in 2021. This set a goal of reducing continental water usage by mining to less than 10% by 2030 and 5% by 2040.
Based on that and looking more closely at the drought challenge facing Chile, the use of thickeners turns into a much more important topic for recovering water.
In the case of mining, there are concrete commitments that will have to be put in place.
Leveraging Thickeners into the next level with AI
In light of this, the implementation of in-line instrumentation, automatic control systems and artificial intelligence present an opportunity to improve separation processes, such as thickening, to significantly increase water recovery.
Here at Intellisense.io, a great job is being done to take the use of thickeners into the next level. To address process challenges, a predictive decision-making approach that is based on given limits coupled with material modeling provides recommendations to maintain operational stability and desired performance of thickeners tanks.
Through a partnership with BASF, we have combined respective expertise in ore beneficiation by embedding high-level knowledge and chemical interaction directly into our models. Aside from drawing on a unique synergy between hands-on chemistry and a fit-for-purpose AI, the Thickener Optimization Application makes it possible for Chilean mining sites to truly optimize their thickener operations, improving water recovery and minimizing the need for new freshwater intake.