Geochemical processes in mill tailings deposits: Modelling of groundwater composition

1-17
Salmon S.U., Malmström, M.
Applied Geochemistry
Applied Geochemistry
19
http://dx.doi.org/10.1016/S0883-2927(03)00129-X
2004
http://www.sciencedirect.com/science/journal/08832927 


Abstract:

A general model is presented for geochemical processes occurring in the unsaturated zone of a carbonate-depleted, pyritic tailings deposit. Quantification of slow geochemical reactions, using published, empirical rate laws from small-scale experiments on monomineralic samples, and geochemical equilibrium reactions successfully reproduced the relative rates of field processes in the case study, Impoundment 1 in Kristineberg. Reproduction of absolute rates was achieved by scaling down all laboratory-derived mineral weathering rates by two orders of magnitude. The sensitivity of the modelled groundwater composition and pH to rates of pH-buffering processes and redox reactions indicated that inclusion and accurate quantification of all dominant geochemical processes on the field scale is necessary for reliable prediction of groundwater composition and pH.