Up to now various methods including bioleaching with thermophilic archea have been studied to enhance the leaching of chalcopyrite. However, the combined effect of pH and ORP at thermophilic temperatures (65-80°C) has attracted little attention. Therefore, in this work, various chalcopyrites including two concentrates and two ore minerals were leached. It was found that a temperature of 65°C and an initial pH of 1.0 can lead to copper extractions comparable to those obtained in bioleaching with A. brierleyi and S. metallicus. Furthermore, with the addition of Fe3+ (200mg/L) at an initial pH of 1.0 where jarosite precipitation could be avoided and low ORP values could be induced, higher leaching rates than in bioleaching were obtained. In addition to the low ORP values derived from the presence of low amounts of Fe3+ (200mg/L), the notable enhancement is attributed to the generation of sufficient amounts of Fe3+ that resulted from the oxidation of the released Fe2+ by oxygen at 65-80°C and initial pH of 1.0 without the aid of thermophiles.