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Re-mining as remediation method for critical metals (Be and W) in historical skarn tailings

Critical metals (CM) are important to develop a sustainable society in the EU. Today, more than 80% of most CM are imported and EU is striving for a higher internal production to reach the Green Deal. Historical tailings can be a source of CM due to high concentrations left in the waste. The possibility to re-mine Be and W from skarn tailings was studied in a research project between 2016-2021. The volume of the waste was low, the CM-concentrations were lower than in the primary ore, and the tailings has been physically stratified during deposition. Geochemical processes has partly relocated Be and W to secondary minerals, and altered the surface properties of their primary minerals. However, the project showed that if the environmental and social aspects are considered, re-mining can be beneficial for the tailings. Thus, the mine drainage contained high concentrations of Be, which caused adverse impact on ecosystems downstream the repository. Weathering of the tailings will continue for 100 of years, which stress the need for remediation. Traditional techniques such as cover and water-saturation are not suitable to use. Re-mining could instead be implemented to decrease the environmental impact. Future studies should develop extraction methods that targets both primary and secondary minerals enriched in CM to generate environmentally safe waste, and the extracted product could support the internal production of CM. Moreover, taking responsibility for contaminated tailings could increase the social license towards mining, which is an important factor to increase the metal production in the EU.


Lina Hällström
Luleå University Of Technology, Sweden
GeoKarlsruhe 2021