Reduction of nitrogen discharges in mining processes and mitigating its environmental impact.
Description of the problem
As a result of the use of ammonium nitrate based explosives in mining or cyanide in gold extraction processes, high nitrogen (N) levels are discharged into aquatic environments. Nitrogen causes eutrophication of the aquatic environment and has toxic effects on biota. Such effects are in conflict with current water legislation according to the European Water Framework Directive (WFD), which states that waterbodies must show at least good ecological status. Violation of the demands set by the WFD and national legislation has already resulted in, and will result in costly disputes with local authorities, lawsuits and enforced interruptions in mining operations.
The identification of treatment techniques that remove nitrogen from mine site drainage, so recipient concentrations are at levels that are in agreement with legislation.
Approach to solve the problem
In miNing, we develop and identify treatment techniques that successfully remove N from mine site drainage, so recipient concentrations are maintained at levels that agree with national and international legislation. To achieve this goal, three treatment techniques are developed, tested and evaluated:
a) Bioreactor systems for N removal from waste rock leachate and mine drainage
b) Techniques for optimizing microbial denitrification in tailings ponds
c) Wetland systems for N removal by denitrification and anammox as well as phytoremediation by macrophytes and algae.
The techniques and methods will be tested at laboratory, pilot and full scale. miNing will be mainly implemented at the LKAB mining site in Kiruna, but the results are expected to be relevant and applicable to other mining sites operating in cold climate.
Funding, Partners & Duration
miNing was funded by VINNOVA, LKAB and Boliden AB and was conducted in collaboration between SLU, Uppsala University and Luleå University of Technology.