Mining residues (tailings) undergo major transformations when they are subjected to changing environmental conditions. This weathering of the residues causes serious environmental problems which affect all mining companies around the world. In the present work the microbiological evolution of pyritic railings was studied under both laboratory and real environmental conditions. A column model peas designed for this purpose. The microbiological selection and succession were determined for the real system and then these conditions were reproduced by means of the column model selected The microbiological implications of transformation of the mining residues were demonstrated.