Predictive Modelling of Multicomponent Reactive Transport in Mining-affected Acidic Groundwater Environments

Groundwater contamination from acidic mine tailings effluents is a serious problem in many countries that have an active mining industry. In Canada, of particular concern are large tailings impoundments at active or abandoned metal mine sites. At such sites, sulfide oxidation releases acidic effluents which can dissolve toxic heavy metals from the tailings. This can result in groundwater as well as surface water contamination. Remedial measures can be uncertain and costly; as estimated by Feasby et al. (1991), the cost of remediating existing mine sites in Canada may exceed 3 billion dollars. It is therefore important to quantify the natural buffering capacity of aquifer minerals, which tends to neutralize acids and immobilize certain dissolved metals. These reactions can be utilized in remediation programs to prevent harmful environmental effects.