Design and construction of clay liners for establishment of MSW-landfills in abandoned mines and quarries

Mines and quarries are usually operated over a long period of time. After exploitation or abandonment they often form a deep excavated hole or a similar discontinuity in the landscape with mostly large horizontal extent. Reclamation and reinstatement is necessary and backfilling requires a huge volume of material. On the other hand in many regions there is a large demand by the public sector for appropriate locations for MSW-landfills. The paper describes the design and construction of the lining-system for establishment of MSW-landfills in mines and quarries. The mineral liner, as a very essential part of the lining system, has to withstand considerable vertical and lateral forces (say a filling height of the waste of up to 80 m), be compatible to settlement and provide long stability concerning low permeability and resistance to chemical attack. Recent field trials and a few implemented projects in Central Europe proofed the whole concept of establishing MSW-landfills in mines and quarries as feasible. Special considerations on the geotechnical set-up of the mineral liner, the migration of pollutants through the barrier and placement techniques on sleep slopes are necessary for a lasting function of the system. Latest state-of-art equipment has to be used for preparing/mixing the lining material. For many sites in-situ soils or locally available materials can be used; together with bentonite enrichments to satisfy the design criteria. The construction cost of this type of MSW-landfills is similar to a standard construction due to the high filling capacity and the very advantageous filling/lining-ration (m(3)/m(2)). The growing need for MSW-landfills with high public acceptance may support this technical approach.