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In the past, the eastern part of Germany (the former GDR) had been the world’s third larg-est producer of uranium. Although, uranium excavation is no more allowed in Germany since 1990 the uranium ore, pits, open-pit sites and tailings remain as old-polluted sites. The “Pond 4” is a tailings pond in Freital built in 1957 as a settling basin for residues of the uranium ore treatment of the Wismut compa-ny. In 2006 the authority of water management declared the Pond 4 as contaminated site to be remediated. The remediation concept consisted of an impermeable capping with the dual purpose of long-term reduc-tion of contaminant release and of providing the basis for subsequent landscaping. The construction of a cover system can be challenging due to the very soft subgrade. The use of geosynthetics provides the most economic and feasible solution and can be easily combined with other methods as for example in this pro-ject with vertical drains. In this paper the case study of Pond 4 in Freital is presented. Particular attention is given to the use of geosynthetics in the system. The stability analysis, the selection of the materials and the installation phases are fully described and can be used as reference for alternative solutions in similar projects.