The local circular bioeconomy offers solutions to cover mining waste areas

Growing demand for earth metals is likely to increase mining in Finland. Mining causes various environmental impact both during and after operations. With the Geological Survey of Finland, we have produced covering and landscaping solutions for mining waste areas suitable for northern conditions.

The separation of precious metals from ore also generates tailings and waste rock that are usually covered with moraine. The purpose of covering is to prevent the oxidation of any sulphides contained by mining waste, the acidification of runoff, and the spread of harmful substances into the environment.

Our research results show that adding biochar, ash and composted material produced from local dismantled wood and wastewater to the covering layer, or bio-cover, helped plants grow.  Lush vegetation bound soil in place, reduced the discharge of water towards mining waste layers and minimised erosion. The solution reduces the realisation of environmental risks and benefits local companies.

The pilot project also assessed the value chain’s financial and environmental lifecycle impact. Financially, a biochar-based cover solution had the highest price per cubic metre. Then again, it was an effective carbon sink and the best growing medium for plants and reduced the amount of seepage water in mining waste.