Waste Rock Pile Remediation at Schlema-Alberoda

Rehabilitation of the waste rock piles at the Schlema-Alberoda site is one of the main tasks in mineland reclamation in Saxony. Located within and around the Schlema community and bearing witness to former uranium mining, waste rock piles were removed only in the recent past. They were the most visible signs of the devastation of a densely populated area. The Schlema site exemplifies the profound change the entire region has undergone. Formerly devastated by uranium mining, the landscape and community have developed into a spa centre, attracting visitors from all over Germany and from abroad.

In 1990 – following decades of uranium mining – the situation was quite different. Not less than 18 waste rock piles were a disgrace to the community. In the very heart of Schlema, at the site of today's spa gardens, the surface had subsided by approximately six metres. Numerous public buildings and residential quarters had to make room to allow mining to proceed. Waste rock used to be dumped onto mountain slopes in very close proximity to where locals lived. Waste pile slopes were steep and mostly barren of vegetation. In addition to lack of stability, exposed waste rock surfaces were a source of increased radiological exposure, in particular by dusting and radon exhalation.

Based on an analysis of their radiological, chemical, and geotechnical parameters as well as on their respective distance to habitation centres, Wismut GmbH established in 1992 a priority list for the remediation of the waste rock piles. As one of the first on the priority list, waste pile 250 was completely removed from a residential area in the Schlema community and used to refill a large subsidence area in Oberschlema (spa gardens).

The largest waste rock piles across the Schlema-Alberoda mining area will be left in place to be rehabilitated in situ. This involves regrading of the slopes. Finally, to reduce dust emanation, radiological exposure, and infiltration of precipitation, they are capped with a one metre thick cover consisting of a sealing/storage layer and humus-rich topsoil to foster vegetation growth. Comprehensive work is to be done with regard to the construction of trails and in terms of hydraulic engineering work on waste rock piles which then will have to be vegetated.

With a view to preserving and maintaining the remedial performance, maintenance and environmental monitoring will have to be run for several years. In 2009, work was initiated on waste rock pile 309 and in 2010 operations were started on waste rock pile 310. While work on seven waste rock piles is already accomplished, remedial work is under way at all other mine dumps.