Mine closure - Impacts and possibilities

In this project, the potential of closure facing mine sites in Northern Ostrobothnia to function as a platform for new possibilities will be assessed. The project will also increase the understanding of the performance of cover structures, and hydrogeological and geochemical changes at a mine site under closure. The results will provide necessary information for the future closure projects of mines and other industrial sites. The environmental impacts related to the project are significant, as possible decisions concerning e.g. cover structures can already be affected during the project. The need for water treatment development will be assessed by water quality studies, and the harmful element mobility by hydrogeological studies.

Mine closure is an essential part of the development of sustainable mining industry. Many challenges are related to closing a mine site, and from an environmental perspective it is important to understand the impacts of different closure measures. In Finland, we are in a unique situation as in the near future several mine sites are being closed according to current legislative requirements. These mine sites include Hitura (Nivala), Pyhäsalmi Mine (Pyhäjärvi) and Särkiniemi (Leppävirta). The target site for this project is Hitura. This provides an excellent opportunity to develop and document the mine closure processes. The Hitura mine will be the first mine site closed as required by the current environmental legislation, the closure work implemented by a state authoritative. The Hitura closure project will be regarded as an example for the future closure work. Hitura also offers a study site to investigate the efficiency of the implemented closure activities. As a result, in addition to the site specific information, a valuable information package will be assembled for future closure activities. The mine closure should be developed in a way that, after the end of mining activities, it would be possible to utilize the area by other activities.

The main objective of the project is to promote the utilization of secondary raw materials in e.g. cover structures or water treatment applications. Another important topic is the usability of microbial communities as environmental indicators in mine area and as tools for biological remediation in an open pit lake. Microbial DNA sequencing methods and gene databases have been strongly developed in recent years, and the sequencing-based methods are being increasingly used in various environmental studies. Recent studies have shown that the composition of microbial communities indicates the state of the environment over a longer period of time, making the method a more stable status indicator compared with individual physical or chemical measurements.

The project will be operated between 1 Sept 2019 – 31 Mar 2021 together with University of Oulu Kerttu Saalasti Institute, Geological Research Centre (GTK) and Finnish Environment Institute (SYKE).