Initial situation

As part of the technological developments which took place during the 1960s in the Spreetal opencast mine, industrial waste of all kinds began to be temporarily stored in what had been a depression in a central area conveniently close to the mine. After mining operations ceased, it became necessary to develop a rehabilitation concept for the tip and then to implement it.

Approach

Extensive exploratory work allowed the extent of the area where the industrial waste had been stored and its composition to be identified.
Because of the high proportion of foreign matter, and the need for separating materials, the amount of waste was estimated to be 200,000 m³.
Further rehabilitation-related tests showed that local conditions were such that final disposal in the immediate vicinity would be the most efficient form of rehabilitation.

Result

A landfill base-sealing layer was added to a nearby tip plateau and prepared for the storage of the separated materials. In the course of separation, a total of 160,000 m³ of contaminated material (soil and rubble) was transferred and deposited in alternate layers.
As the basic rehabilitation of the mining area progressed, the dumping area was expanded in stages until it finally covered a total of 9 hectares. This involved including a further 640,000 m³ of mine waste from mining sites in the tip; the end result being the storage of a total of 800,000 m³ of contaminated material. Finally, the tip was permanently sealed with a two-meter landfill surface seal layer.
This method of implementing rehabilitation allowed substantial savings to be made.