Evaluation and appraisal of the Wismut GmbH remediation project

Country / Region: Germany / Saxony & Thuringia

Begin of project: January 1, 2012

End of project: December 31, 2026

Status of project: August 14, 2024

Background
From 1946, a total of 231,000 tonnes of uranium were mined in eastern Germany, first by the Soviet Stock Company (SAG) Wismut and from 1954 by the Soviet-German Joint Stock Company (SDAG) Wismut until the end of 1990. This corresponded to the fourth largest national uranium production at the time.

Fig. 1: Culmitzsch tailings management facility (2023 and 2024) Source: BGR

In 1990, the post-mining landscapes left behind by Wismut comprised a total of 32 km² of operating areas, five uranium mines with a total of approximately 1,500 km of open mine workings, a residual open pit with a void volume of 84 Mm³, 48 waste rock piles with low-level radioactive material of approximately 311 Mm³ and four tailings management facilities containing a total of 160 Mm³ of radioactive sludge (Figure 1).

With German reunification, the Federal Republic of Germany assumed sole social and financial responsibility for the remediation of the uranium mines and the post-mining landscapes. Since 1991, the federal government has commissioned the federal company Wismut GmbH to carry out the remediation work. The federal government has made a total of around 7 billion Euros available for this purpose until the end of 2022. The Federal Ministry for Economic Affairs and Climate Action (BMWK) is the sole shareholder of the Wismut GmbH.

Fig. 2: Crossen waste rock heap and the adjacent uranium ore processing plant (1998 and 2021) Source: Wismut GmbH

More than 30 years have passed since remediation work began in 1991, during which time Wismut GmbH can look back on successful remediation activities in Saxony and Thuringia. The quality of life of the people in the regions formerly affected by uranium mining and the general environmental conditions have improved enormously. The traces of mining that were clearly visible in the landscape at the end of the 1980s have almost completely disappeared (Figure 2).

Nevertheless, there is still some work to be done on the ground, particularly with regard to covering heaps and tailings management facilities and the safe closure of mine sites. As things currently stand, the core remediation work will not be completed until 2028. On almost all completed remediation objects, long-term tasks will follow. These include, in particular, the inspection, maintenance and repair of covers, the treatment of flood and seepage water, mining safety and inspection work, the elimination of mine related damage, long-term environmental monitoring and preservation, as well as the continuous updating of the remediation documentation.

Mandate
At the beginning of 2012, the BGR was commissioned by the BMWK to advise it in the fulfilment of its tasks and to assess and evaluate the remediation activities of Wismut GmbH during the project. To this end, the BGR provides the relevant expertise for technical advice to the BMWK.

Activities at the Ronneburg remediation branch office
In the remaining years of core remediation, Wismut GmbH's work is focused in the Ronneburg remediation branch office. Here, the BGR is primarily involved in the following work:

• At the Ronneburg remediation site, the remediation of contaminated areas of shaft complex 375 and the construction of the new Lichtenberg office building, as well as the continuation of the remediation of the footprint of the heap “Absetzerhalde” and the demolition of old infrastructure.
• At the Seelingstädt remediation site, the contouring and final covering of the Culmitzsch tailing pond and the connection of the runoff collecting channel to a nearby tributary (Figure 1). The focus is also on the extraction of material from heaps surrounding the tailing pond and their subsequent remediation.
• The completion of the construction of the southeastern connection to the receiving water and the finalisation of the contouring and covering, which will complete the remediation of the Trünzig tailing pond in the near future.
• At the Helmsdorf remediation site, the old Helmsdorf water treatment plant will be dismantled now that the new water treatment plant has been commissioned.

In November 2021, the remediated area of the waste rock dump at the Crossen site was released from mining supervision. The area is reused as a floodplain and retention area in accordance with existing regional spatial planning and land use plans. For Wismut GmbH, this is another site that is no longer under mining supervision (Figure 2).

Fig. 3: Remediation of site 371 North Source: BGR

Activities at the Aue remediation branch office
At the Schlema-Alberoda site, the BGR is supporting surface measures to control the radon situation on the remediated waste rock dumps. In addition, the removal/application of material and the rerouting of the seepage water drainage as part of the “371 Nord” foreland site remediation (Figure 3). Important investment projects above ground include the general overhaul of the Schlema-Alberoda wastewater treatment plant and the replacement of the water extraction facility in the Zwickauer Mulde.

Fig. 4: Excavation of a gallery “Feldstrecke 27a” Source: BGR

Underground, BGR's current supervision is focussed on activities to excavate a new gallery (Figure 4) as well as mining excavation and reconstruction work on the Markus-Semmler sole with the aim of ensuring a safe and secure water and radon drainage. The construction of a new machine house (shaft 382) is planned as an investment.

Activities at the Königstein remediation branch office
In Königstein, the controlled flooding of the Königstein mine with a hydraulic test including accompanying measures up to a flood level of 150 metres above sea level is the current focus of the project-accompanying examination by the BGR. Parallel to raising the flood level, reactive substances are injected into the mine with the aim of improving the quality of the mine water. The sludge removal in a dewatering gallery flowing into the Elbe River also being monitored by the BGR.

The aboveground work at the site that is being assessed includes the dismantling of the northern part of the former process stage for uranium removal, the former heating plant, industrial pools and heap leaching areas, as well as the corresponding rare species protection measures in preparation for dismantling.

Outlook
So-called long-term tasks are required at all sites, the execution of which is continuously monitored by the BGR with regard to the use of costs and resources.

Over the next few years, Wismut GmbH will face the major challenge of restructuring the company in such a way that it meets the requirements for fulfilling these long-term tasks.

Instead of the optimisation of remediation work, which has been at the forefront in recent decades with the aim of fulfilling tasks as quickly and cost-effectively as possible, the focus in future will be on cost optimisation in dealing with the so-called perpetual obligations and the economic utilisation of the company's own real estate and properties. In addition, the aim is to achieve climate neutrality in the company's activities.