The exploitation of mineral deposits generates large amounts of wastes such as fine size particles,
known as tailings. Mine wastes are characterized by the presence of pyrite, pyrrotite, galene,
sphalerite, chalcopyrite and arsenopyrite. One of the most important environmental problems
derived from the treatment and disposition of mining tailings is acid mine drainage (AMD) which
results from the oxidation of the sulfurous minerals contained in these tailings. The acid generated
is produced by a series of complex chemical reactions; the production rate is controlled by leaching
microorganisms, which are present mining processes. In this work the bioleaching kinetics of heavy
metals such as Cu, Fe, Zn, Cd, Pb, Ni and As, from a Tizapa tailing sample in presence of
mesophilic and moderately thermophilic bacteria were studied and compared. The microorganisms
used in this work were previously adapted to the tailing sample by the conventional method of
successive steps. The percentage of dissolution of heavy metals at 45°C was smaller than at 35°C
and the value of parameters such as redox potential and bacterial growth increased with
temperature. Bioleaching studies were compared with the corresponding control systems.