Abstract: The present invention relates to a process for bio-oxidating insoluble mineral compounds from ores comprising the steps of:a) conditioning the ore with an acidic solution;b) adding a microbial inoculum to the conditioned ore;c) drying the ore until soluble bio-oxidized products in solid state are obtained, the solid products containing microbial colonies;d) maintaining the ore into an adequate range of temperature for the employed microorganism, until the bio-oxidation is completed; ande) separating out the soluble bio-oxidized products in solid state by washing or by another suitable method.