Exploited coal seams are used to deposit industrial residues from thermal energy and waste incineration plants in North Rhine Westfalia, Germany. Use of such an underground repository requires proof that dissolved contaminants cannot reach the biosphere. Numerical models may be used as tool to predict the local and temporal migration of pollutants. In order to investigate the migration of heavy metals in a porous sandstone block containing a single fracture, two tracer experiments were performed under precisely defined hydraulic flow conditions. In the experiments, pyranine, cadmium and lead were applied, and the hydrochemical conditions corresponded to a depth of 1000 m below ground surface. The fracture was considered as a two dimensional parallel plate conduit and the rock matrix was treated as a three dimensional porous medium. Together with rock properties determined in the laboratory, the modelling yielded a good agreement between measured and simulated breakthrough curves by calibrating the fracture aperture and longitudinal dispersion.Exploited coal seams are used to deposit industrial residues from thermal energy and waste incineration plants in North Rhine Westfalia, Germany. Use of such an underground repository requires proof that dissolved contaminants cannot reach the biosphere. Numerical models may be used as tool to predict the local and temporal migration of pollutants. In order to investigate the migration of heavy metals in a porous sandstone block containing a single fracture, two tracer experiments were performed under precisely defined hydraulic flow conditions. In the experiments, pyranine, cadmium and lead were applied, and the hydrochemical conditions corresponded to a depth of 1000 m below ground surface. The fracture was considered as a two dimensional parallel plate conduit and the rock matrix was treated as a three dimensional porous medium. Together with rock properties determined in the laboratory, the modelling yielded a good agreement between measured and simulated breakthrough curves by calibrating the fracture aperture and longitudinal dispersion. 262325331Berkowitz, B., Bear, J., Groundwater flow and pollution in fractured rock aquifers (1987) Developments in Hydraulic Engineering, pp. 175-238. , ed. by P. Novak, Elsevier Appl. Science Publ 4Frick, U., Beurteilung der Diffusion im Grundwasser von Kristallingesteinen. Ein Beitrag zur Kristallinstudie 1993 (1993) Int. Ber., NAGRA, 92-92, , NAGRA, SwitzerlandGrisak, G.E., Pickens, J.F., Solute transport through fractured media 1. The effect of matrix diffusion (1992) Wat Resour. Res., 16 (4), pp. 719-730Himmelsbach, T., König, Ch., Risk assessment of subsurface waste disposal in the near field of coal mines (1997) Groundwater in the Urban Environment, Problems, Processes and Management, 1, pp. 421-426. , ed. by J Chilton et a/., Balkema, The NetherlandsHimmelsbach, T., Wendland, E., Schwermetalltransport in Sandsteinen unter Bedingungen einer hochsalinaren Porenwasserlosung: Laborversuch und Modellierung (1999) Grundwasser, 3 (4), pp. 103-112Jager, B., Obermann, P., Wilke, F.L., Studie zue Eignung von Steinkohlenbergewerken im rechtsrheischen Ruhrkohlenbezirk zur Untertageverbringung von Abfall- Und Restoffen (1990) Machbarkeitstudie in Auftrag des Landesamt für Wasser und Abfall NRW, , unpublishedNeuzil, C.E., Tracy, J.V., Flow through fractures (1981) Wat. Resour. Res., 17 (1), pp. 191-199Rasmuson, A., Neretnieks, I., Radionuclide transport in fast channels in crystalline rock (1986) Wat. Resour. Res., 22 (8), pp. 1247-1256Tang, D.H., Frind, E.O., Sudicky, E.A., Contaminant transport in fractured porous media. Analytical solution for a single fracture (1981) Wat Resour. Res., 17 (3), pp. 555-564Tsang, Y.W., Tsang, C.F., Channel model of flow through fractured media (1987) Wat. Resour Res, 23 (3), pp. 467-479Wendland, E., Schmid, G., Symmetrical streamline stabilization (S3) for high advective transport processes (1996) Proc XI International Conference on Computational Methods in Water Resources, pp. 569-576. , Cancun, Mexico, Computational Mechanic Publ. no. 1, Southhampton, UKWitherspoon, P.A., Wang, J.S.Y., Iwai, K., Gale, J.E., Validity of the cubic law for fluid flow in a deformable rock fracture (1980) Wat Resour. Res, 16 (6), pp. 1016-1024