Wismut GmbH

Tiny microorganisms could play an important role in the future remediation of former uranium mines. For many years, environmental engineers have been investigating how natural processes can be harnessed to permanently bind uranium in mine water and thus prevent the spread of this contaminant.

It is well known that microorganisms are found in nearly all environmental settings. They adapt their metabolism to their surroundings and can thereby alter chemical substances. Environmental scientists are capitalizing on this effect: By selectively adding certain nutrients, they can influence the activity of the microorganisms. The goal is to convert dissolved uranium into a sparingly soluble form so that it remains in the rock and is no longer transported by the water.

Wismut GmbH, based in Chemnitz/Germany, has been investigating this method for about 20 years. The research focuses on two key questions: Can the formation of stable uranium minerals be specifically promoted? And do these minerals remain stable over the long term once the treatment is complete?

The method developed is already being applied in practice at the Königstein site. There, an injection system is used to introduce suitable substances into the flooded mine to stimulate the desired microbial processes. At the same time, researchers are investigating how durable the formed uranium minerals are. Previous experiments at other sites worldwide have shown that bound uranium can later dissolve again under certain conditions.

New findings are now provided by a joint study conducted by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Wismut, which was published in the renowned journal *Nature Communications*. In the laboratory, the researchers analyzed mine water from Schlema. By adding glycerol—a readily available carbon source for microorganisms—they were able to bind approximately 95 percent of the previously dissolved uranium into solid minerals.

It is particularly noteworthy that these uranium compounds remained largely stable even after a four-week treatment under oxygen-rich conditions. Using state-of-the-art X-ray analysis, the researchers were able to demonstrate that, in addition to the expected uranium minerals, previously unknown uranium compounds had also formed. These could play a decisive role in making the bound uranium more resistant to being released again.

Why these compounds are so stable has not yet been fully elucidated. Further investigations will now determine whether the results can be confirmed.

For Wismut, this research is part of a long-term commitment. The remediation of former uranium mining sites is not a completed task but an ongoing process that continually requires new scientific insights. That is why Wismut is working together with research institutions to gain an ever-better understanding of natural underground processes and to further develop innovative remediation methods. Through its research, Wismut aims to accelerate the natural purification processes occurring underground. The goal is to reduce, as much as possible for future generations, the long-term environmental impacts of former uranium mining sites that have persisted for many decades.

Further information:
Wismut GmbH
www.wismut.de

On 8th August 2023, the German Mining, Geology and Environment Association (VBGU), Berlin/Germany, an employers’ association that has been dedicated to constructive dialogue in mining and raw materials extraction in Germany for over 30 years, appointed its previous Vice President Jens-Peter Lux, Managing Director of DMT GmbH & Co. KG, Essen/Germany, as President and Michael Paul, Technical Managing Director of Wismut GmbH, Chemnitz/Germany, as Vice President.

The appointment of the new Executive Board had become necessary after Michael Seifert had to step down from his honorary position as President of the association on 1st August 2023 for health reasons. The VBGU would like to thank him for his special commitment and achievements during his presidency and wishes him much strength, health and energy.

The partially newly appointed Executive Board consisting of Jens-Peter Lux, Michael Paul and Nici Hoppe (Figure 1) will represent the association externally, initially until the next regular Board election at the General Assembly in September 2024, which means that the VBGU is ideally positioned for the future. (VBGU/Si.)

Under the motto “Rethinking rehabilitation mining – Innovative approaches on the road to sustainability”, the international mining symposium WISSYM 2023 came to a successful close. From 25th to 28th September 2023 in Dresden/Germany, 200 participants from 15 countries discussed issues of innovation, technology development and resource efficiency, as well as the highly topical subject of public perception and acceptance of mining within society.

The starting signal to “enter” the mining symposium by means of a shaft bell was given by Michael Paul, Managing Director Wismut GmbH, Chemnitz, in the presence of Olaf Alisch, Association of Mining, Geology and Environment (VBGU), Berlin, the Mayor of the City of Dresden, Eva Jähnigen, and Prof. Bernhard Cramer, Saxon Mining Authority, Freiberg (Figure 1). Video greetings reached the participants from Michael Kellner, Parliamentary State Secretary at the Federal Ministry of Economics and Climate Protection (BMWK), and from Bodo Ramelow, Prime Minister of Thuringia.

Once again, the symposium was introduced with an excursion day. The excursions took the participants to the Wismut sites in Crossen, Aue and Königstein/Dresden-Gittersee. In another excursion, the mining experts were able to see for themselves the successful redevelopment of a former lignite site into a recreational area in the Czech town of Most. The excursions formed the basis for the exchange of experience on the three subsequent days of the conference.

Wismut was able to attract numerous renowned experts to the event. In 35 presentations during the three-day lecture program, national and international experts from politics, industry, science and administration exchanged experiences and innovations in mining rehabilitation.

Another highlight of the symposium was the panel discussion in which the Prime Minister of Saxony, Michael Kretschmer, discussed the topic “Mining for the global “green” transformation – but not on my doorstep!” with five international experts from the mining sector.

The 5th International Mining Symposium WISSYM 2023 again provided a platform for national and international mining rehabilitators, mining operators, scientists, representatives of authorities and administration as well as engineering companies to exchange and discuss experiences in mining rehabilitation. (Wismut/Si.)