- Mines
- Sustainability
Water treatment at Boliden Zinkgruvan – an investment with real impact
When our water treatment plant at Boliden Zinkgruvan became fully operational in March 2025, it marked an important milestone in our long-term environmental work. With a capacity of more than 500 cubic metres of water per hour and extensive process-control capabilities, the plant provides us with more stable water management, both today and over the longer term.
– For us, this means taking responsibility for the water we manage. The solution needs to work today, but it must also stand the test of time, says Lena Vikmång, Health, Safety and Environment Manager at Boliden Zinkgruvan.
Boliden Zinkgruvan, just outside Askersund, is one of Sweden's oldest operating mines. We have mined ore here since 1857, and today our underground mine extends approximately 1,450 metres below ground. In addition to zinc concentrate, we produce lead and copper concentrates at the site. We return approximately 30 % of the tailings generated in the process underground as backfill, while depositing the remainder in the Enemossen tailings storage facility.
Only treated water is discharged
As part of our measures to improve dam safety, we had to lower the water level in the tailings storage facility slightly. This increased the risk of leaching, which means that more metals may be carried with the water into the receiving waters. Lena Vikmång explains:
– Since the plant was built, the water we discharge is much cleaner, and the removal rate for zinc, for example, is as high as 99 % in the treatment plant. This was a necessary investment for us, and it also prepares us for future requirements. Under our current environmental permit, we may deposit a maximum of 9.2 million cubic metres of tailings. After that, we will need to apply for a new permit, and we will have to be able to guarantee that our excess water is sufficiently clean.
Removal rates at the right levels
We invested approximately SEK 150 million in the new water treatment plant at Boliden Zinkgruvan, and analyses show that the treatment process is achieving the levels for which the plant was designed. Our overall vision is to be the most climate-friendly metal provider in the world, and Lena Vikmång believes this is reflected throughout our sustainability work.
– You can really see it. I believe there is a high level of ambition and a strong desire to act as a responsible member of society. This means that our operations are held to high standards, and there is an extraordinary depth of expertise within Boliden. That applies not only to mining, but also to areas such as sustainability, water management and the reclamation of closed mines, she says.
Strong trust in the local community
With approximately 500 employees, we are the largest private-sector employer in Askersund Municipality. Lena Vikmång says that our operation enjoys a high level of trust in the local community:
– Society's demands and expectations regarding sustainability are increasing, but I believe we are firmly rooted here and maintain a constructive dialogue with both residents and the municipality. The strong trust we enjoy in the local community is evident, among other things, in our community surveys, where our SLO Index (Social Licence to Operate Index) is 4.2 on a five-point scale. As an industry, we can of course improve further, but surveys show that people who live near a mine often have a positive view of it.
