Modelling of leachates from dolomitic mine tailings.

The REDEQL.EPAK computer model was used to study speciation of Pb, Cd, Zn, and Ca in leachates from dolomitic Pb mine tailings. By allowing or disallowing precipitation of solids and equilibration of the modelled leachate with atmospheric C02, comparison of fresh and aged leachates was made. The effects of treatment of the tailings with phosphate containing fertilizer were studied through addition of P043− to the modelled solution. Equilibrium constants pertaining to metal ion-humic acid complexation were added to the thermodynamic data base of the model in order to study the effects of decaying plant material on tailings leachate.