Biocover solutions of mining sites in Kainuu

The goal of the project is 1) to reduce the environmental effects of mining waste, such as the runoff of acidic and metal-rich leachate from side rock and tailings areas, 2) to minimize the amount of moraine needed for cover, 3) to develop cover materials, 4) to make use of local recycled nutrients, such as composted or digested sewage sludge, biochar made from demolition wood and power plant ash and 5) to increase cooperation between mines, the municipality and by-stream producers.

As part of the project's measures, covering materials for mines will be tested using analyzed recycled materials. As preliminary experiments, grass growth is piloted with different growth media mixtures in a greenhouse. Based on the results, promising growth media mixtures are selected, from which test plots will be established on top of the mine's waste rock area. Grass is sown on the test plots and cultivated like silage grass. It is fertilized by mowing the vegetation as green manure. If possible, the grass pulp can also be used as a feed stock in biogas plant and the residue can be used as a fertilizer for test plots.The quantity and quality of the water percolating through the vegetation is monitored based on the water collected with pipes (GTK). The thickness of the finished cover layer and its variations are determined either by ground radar or by some other electronic sounding method (GTK). Luke will analyze the microbiome of the cover layer and monitor the development of the vegetation until autumn 2025.

The production of biochar from demolition wood and by-products of wood processing is being tested on a pilot scale. The properties of the waste/by-stream-based biochar raw materials are surveyed and the technology and safety issues related to the processing are clarified. In addition, availability of feed stock materials and limitations of regulation (KAMK) are investigated. In the project, the profitability of the operation, the effects on the environment and a LCA (life cycle assessment) will be carried out, as well as the official regulations for different bio-covering materials will be clarified.

As a result of the project, the waste rock area has been landscaped to a higher standard than the mandatory post-treatment. In addition the management of mine leachate and the state of nearby waterways will improve. The cycle of nutrients and carbon is enhanced as recycled materials (e.g. demolition wood, sewage sludge) are used instead of virgin materials (peat, artificial fertilizers).The mines will receive a plan for established bio-covers for the 3 years after the project. The official approval of covering solutions will be clarified.

New business activities and a cooperation concept is emerged along with the mining industry. The target groups are the mining industry, municipal waste plants producing compost and biochar producers, ash producers, contractors and entrepreneurs (e.g. former peat entrepreneurs), land and green construction entrepreneurs. Indirect target groups are various authorities, residents of the area and tourism.