Biomining: an Established and Dynamic Biotechnology

“Biomining” is generic term to describe the application of living organisms to extract and recover metals from mineral ores and waste materials. Since its inception as a crude technology (“dump leaching”) for treating “run of mine” rocks and boulders that contained too little copper to be processed by conventional processing, engineering options used in biomining have become increasingly refined and diverse. Currently, microbiological processing is used to extract both base metals (copper, and to lesser extents nickel and zinc) and precious metals (mostly gold) from ores and mineral concentrates in heaps and stirred-tank bioreactors, as well as in dumps. Recent developments include the demonstration, at pilot-scale, of indrect leaching of zinc sulfide concentrates, in which the biological step (regeneration of ferric iron) is carried out independently of abiotic mineral oxidation, and using microbiologically-mediated reductive dissolution of ferric iron minerals to liberate nickel from lateritic ores.