The present study elucidates the remediation of mine waters by means of geo
chemical barriers ("active barriers"). Active barrier systems (ABS) are dev
eloped which can prevent heavy metal dispersion by introducing the barrier
into the mine. Therefore, low-cost materials are investigated which can rem
ove contaminants by chemical, and/or physical mechanisms from water. The ma
terials investigated are industrial byproducts (e.g. fly ash, red mud scale
arrears), natural wastes (e.g. tree bark), and relatively cheap natural pr
oducts (bentonite, zeolites). Red mud and fly ash show the best results for
the removal of Zn, Cd, Ni, and Mn from model water. Cd seems to have the s
trongest binding of the investigated metals on the sorption sites. The main
mechanisms of metal removal from solution in this case are sorption and pr
ecipitation. Both materials have very good sorption and acid neutralization
capacities (ANC), but ANC seems to be the determining factor.