Potash seams are a valuable resource containing several economically interesting, but also highly soluble minerals. One of the major safety risks for subsurface mining operations is the formation of leaching zones which is controlled by the mineralogical composition and the dissolution rate of the salt rock. In the present study, a reactive transport model including mineral-specific, saturation-dependent dissolution rates is used to examine the influence of insoluble inclusions and intersecting layers. For that purpose, a scenario-analysis is carried out considering different rock distributions within a carnallite-bearing potash seam. The results show that the validity of the dimensionless Damköhler number (Da) decreases if insoluble areas become broader and more inclined. However, with regard to the growth rate of the leaching zone, the exact distribution of insoluble inclusions is of minor importance. While reaction-dominated systems (Da < 1) are not affected by these at all, the dissolution front of transport-dominated systems (Da > 1) advances more slowly compared to homogeneous potash seams. However, the ratio of permeated rock in vertical direction becomes higher. Accordingly, heterogeneous potash seams are beneficial with regard to risk assessment as long as the mechanical stability of the leaching zone is given. For determining dissolution rates, saturation-dependency should always be considered as it increases the hazard potential in the long-term. Literature data confirm the simulation results and indicate that most systems in nature are transport-dominated. To investigate the effects of mineral heterogeneity in further detail, more experimental data on the dissolution kinetics of potash salt are required.