Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.1999.157.160RahmanMujeeb ur GulShereen 1199921A bacterial leaching study was carried out in order to evaluate the potential of two stage bioleaching process, (1) Biological oxidation of Fe++ solution and (2) Leaching of copper by the acidic Fe+++ sulfate solution, from Saindak copper-gold ore. In first stage, the isolated strain of Thiobacillus ferrooxidan oxidized the Fe++ iron in 360 hrs up to a concentration of 2950 ppm Fe+++ iron, and decreased the pH of the medium from 2.0 to 1.5. The oxidation of Fe++ iron was higher in log phase of bacterial growth. In second stage, in columns dia. 2.5", length 48", 74.86 percent copper was leached in 144 hrs at 35±2°C. 1:1 ratio of ore: leaching solution was found the best for these columns. In large size columns (dia. 6", length 96") containing 60 kg ore, 88.39 percent copper leaching was achieved in 128 hrs at 35±5°C, however the efficiency of Fe+++ iron was decreased.]]>Ahonen, L. and O.H. Tuovinen,199157138145Ahonen, L. and O.H. Tuovinen,199258600606Ballester, A. and W.C. Cooper,19871987pp: 510511Chapman, J.T., P.B. Marchant, R.W. Lawrence and R. Knopp,199311243252Herrera, L., P. Ruiz, J.C. Aguillon and A. Fehrmann,198944171181Kelly, B.C. and O.H. Tuovinen,19881988pp: 33-53pp: 33-53Khinvasara, N.J. and A.D. Agate,19871987pp: 558560Krafft, C. and R.O. Hallberg,199311121127Lindstrom, E.B., E. Gunneriusson and O.H. Tuovinen,199212133155Munoz, J.A., F. Gonzalez, A. Ballester and M.L. Blazquez,199311109119Pakinkar, K.M. and A.D. Agate,19871987pp: 558560Rossi, G.,1990Said, M.F. and D.B. Jhonson,19871987pp: 561562Silverman, M.P. and D.G. Lundgren,1959Ferrobacillus ferrooxidans. I. An improved medium and a harvesting procedure for securing high cell yields.]]>77642647Toro, L., F. Veglio, M. Terreri, C. Ercole and A. Lepidi,199311103108Tuovinen, O.H., B.C. Kelley and S.N. Groudev,19911991pp: 373-427pp: 373-427