Let’s transform mining water from a liability to an asset

Blog post
Päivi Kinnunen

Wastewater and mining waste have been considered to only have a negative value. However, it is possible to transform the current environmental challenges related to water and waste into a business opportunity with our collaborators, we succeeded in completely reinventing the role of water and waste in mining in the EU-funded ITERAMS project.

One of the main challenges of this century is to conserve and protect freshwater. Even though the mining industry is not a huge water consumer on a global scale, the local effects on freshwater withdrawals and water quality in the environment are clear. No matter whether in water-scarce or in water-excess areas, water is a critical issue for all mining companies and nearby societies. 

Closing the water loops

The mining industry is facing the need to recycle all used water in order to secure water for operations and also for environmental benefits. The closure of water loops accumulates different substances, such as chemicals, into the water and may harm the process performance. 

In households, very clean water is only needed for drinking, dirtier water could be used to flush the toilets. In a similar way, the purpose of the water used in mining processes should be cleverly reconsidered. Water should be cleaned only as much as is necessary for its purpose. Our pilot campaigns at three different mining sites in Finland, Portugal and South Africa have already shown that the water technologies developed in the project can manage water recycling. 

Creating added value from waste

When the water loops are closed, water is also recovered from the tailings. Tailings are the uneconomical part of the ore that are disposed of as waste in landfills. They typically represent over 90% of the material and belong to the largest waste volumes in Finland and Europe. Dry tailings can be transformed into a cement-like material in a process called geopolymerisation. Geopolymers made out of tailings can be used, for example, in water- and oxygen-tight covers for the deposited tailings and in mine back-fill use, where the removed material is returned to the underground part of the mine. These materials have shown excellent properties in the mining sites.

Creating a business case out of better environmental performance

We need to rethink how we understand the concept of wastewater and waste. Wastewater and tailings should not only be considered as liabilities for companies, they should also be considered valuable potential inputs to the process. Water and waste are valuable resources, which can and will be reused in the mining industry. Water recycling and waste valorisation lead to an improved environmental and economic result and to the increased social acceptance of mine operations. Water and waste can be a business opportunity for the companies and, at the same time, improve the overall performance of the mining sector. 

The next action is to get the mining industry to close the water loops in the coming years, as has already happened in many other sectors. The time to transform water from a liability to an asset is now.

Päivi Kinnunen
Päivi Kinnunen
Research Professor
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