Base seal for a dump, in particular a residual salt dump

Abstract

The invention relates to a base seal of a dump, in particular a residual salt dump, said seal comprising two layers disposed on top of one another. The upper layer has a mixture of gravel, sand and bentonite or powered clay with a permeability coefficient of k≦10 −9 m/s and the lower layer has a mixture of sand and bentonite or powered clay with a permeability coefficient of k≦5*10 −10 m/s.

Claims: 
     
         1 . A base seal of a dump, more specifically of a residual salt dump comprising two layers disposed on top of one another, the upper layer having a mixture of gravel, sand and bentonite or powdered clay with a permeability coefficient of k≦10 −9  m/s, and the lower layer having a mixture of sand and bentonite or powdered clay with a permeability coefficient of k≦5*10 −10 . 
     
     
         2 . The base seal of a dump according to  claim 1 ,
 characterized in that   the friction angle of the upper layer amounts to φ≧35°.   
     
     
         3 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the friction angle of the lower layer amounts to φ≧30.   
     
     
         4 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the mixture of the lower layer comprises a polymer for improving the sealing properties.   
     
     
         5 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the sand has a grain range of 0-2 mm.   
     
     
         6 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the gravel has a grain range of 8-16 mm.   
     
     
         7 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the proportion of bentonite or powdered clay in the mixture for the upper layer amounts to ca. 2-10 weight percent, preferably 3-5 weight percent.   
     
     
         8 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the proportion of bentonite or powdered clay in the mixture for the lower layer amounts to ≧11 weight percent.   
     
     
         9 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the upper layer has a thickness of ≧0.2 m.   
     
     
         10 . The base seal of a dump according to one of the afore-mentioned claims,
 characterized in that   the lower layer has a thickness of ≧0.1 m.