Key elements of sustainable water stewardship in mining

Securing water resources and quality

The increasing pressure from climate change, population growth and quality of life means that more of the water that is available is needed by the communities. This makes it more challenging for mining operations to secure the water resources they need for their operations. The mining industry has adapted to this added pressure by improving the efficiency of water use and by utilizing alternative water resources, like municipal effluent and seawater, which are less attractive to communities.

Tailings disposal is the activity where most of the water is lost. Therefore, technologies that maximize the recovery of water from tailings help drive the efficient use of water. The same applies to technologies that change the way the ore is processed in order to reduce the amount of fine tailings. Technologies that improve operational efficiency by reducing water consumption can also improve energy efficiency.

Water quality is important at the interfaces of mining when returning surplus water to the environment. Water quality can also define the recovery and grade of the metal concentrate produced. Selecting lower quality water resources can create challenges for mineral processing; in fact, technologies are needed to adapt the water treatment process to ensure that commercially viable mineral processing targets are achieved.

Increasing legislation and other environmental and water security demands put into place by communities steer miners to safer practices and to the transformation of their processes to reduce the environmental impacts of mining. This social pressure also extends to the stock market, where investors see sustainable operations as a prerequisite for a license to operate; there, good water stewardship is rewarded.

Water efficiency is an increasingly important topic for our customers

Water availability and minimizing water-related risks have become an increasing concern and cost factor for mining operations. De-risking tailings storages by using less water is one area where technology can transform existing operations and put them on a path to sustainability through good water stewardship. 

Evolution requires change, and innovation is critical to circuit optimization. Metso Outotec’s solutions to mitigate water-related environmental, health and safety, and societal risks in mining operations include sustainable tailings solutions, water treatment, and new processes that can help transform tailings ponds of waste into valuable resources, like cobalt, and thus help drive society to a more sustainable future.

Our approach to water stewardship is multifaceted

For us, water stewardship is about respecting the precious role of water by reducing water consumption and waste throughout the value chain.

Water consumption can be reduced not only by improving the efficiency of use but also by reducing the amount of waste that is in contact with water. We already have technologies for this:

• Dry processing alternatives in a broader portion of plant flowsheets
• Sorting and separation processes that reduce the amount of fine tailings
• Dewatering technologies, like paste thickening and filtration, that reduce water intake by improving water recovery from tailings

With the increasing complexity of ores, declining ore grades and the lower quality water resources, water management is of increasing importance in minerals processing. We can help our customers with efficient water-quality management:

• In minerals processing, sometimes the right quality is a better solution than high quality, which is not always necessary. We have solutions for treating process waters to improve metal recovery in flotation.
• We’re meeting the ever-tightening legislative limits regarding, for example, low nitrate levels in excess water in mines in fragile Arctic environments, smelters in Indonesia with zero liquid discharge and dry stack operations with high water recycle rates. We have solutions to treat effluents that are discharged into the environment.
• Seawater and high salinity groundwater can be effective resources; making minor changes to the processing plant can substantially reduce the pressure on high-quality freshwater resources.
• We also have other solutions, like raw water treatment, that enable cleaned municipal wastewater to be used as the raw water source for mines – without compromising recovery.

Our Planet Positive offering helps customers with their water challenges

Central to our sustainability efforts is our Planet Positive offering – products that are demonstrably more energy or water efficient than the market standard or help our customers achieve other priorities, such as circularity and safety, as well as services that help our customers improve their productivity. Our Planet Positive portfolio already includes more than 100 products, and we aim to continue expanding and improving this offering by constantly innovating. Our target is to have a Planet Positive product for every part of the value chain. To achieve this, all our R&D projects have sustainability targets.