Ecosystem recovery promoting biocovers for mining sites (Biopeitto3)

The environmental impacts of mining are related to the disposal of sulfide-rich waste rocks and resulting acidic and metal-containing run-off and leachate waters. Therefore, the waste rock sites and tailings are typically covered with till. This project develops cover technologies by adding circular economy based side stream products (e.g. biochar from forest residues or waste wood, composted sewage sludge, ash from heat production) to till-cover to decrease the leaching of metal rich water and to enhance plant growth on closed mining sites.

The project seek solution for the questions:

1) can thickness of cover structures be reduced by application of various side-stream materials and vegetation,

2) how do the side-stream materials, vegetation and thickness of cover structure affect the quantity and quality of leachate waters,

3) does side-stream materials improve the revegetation of waste rock sites, especially the growth of natural plants and plant-growth supporting microbes and in the long run the restoration of whole ecosystem, and

4) how to support the approval of biocovers by authorities?

The project provides information to support the decision-making of mining companies, circular economy companies and supervisory authorities. A better understanding on how organic matter applications affects the layer thickness, age and properties of biocovers, plant growth, and ecosystem restoration helps to find the best solutions for challenging conditions in Northern Finland.