High-salinity mine water infiltration into carbonate aquifers may enhance contaminant migration due to the pre-dissolution of carbonate minerals. This short article presents the results of PHREEQC thermodynamic modeling of the Svystunova Gully mine water impoundment (Ukraine). The calculations demonstrate that aggressive mine waters, initially undersaturated with respect to carbonates, induce local dissolution, thereby potentially increasing permeability. This, in turn, further accelerates the spread of contamination. Pre-dissolution is therefore identified as a key mechanism explaining both the intensity and extent of groundwater contamination in carbonate environments.