Today's mining activities are facing deposits of decreasing metal content and an increase of complexity. Biohydrometallurgy is an industrial application that uses microorganisms to facilitate the release of metals from mineral ores, especially sulfide ores. A testing site for in situ bioleaching was established in an underground mine to recover indium and germanium from a zinc sulfide ore vein. The downstream processing of the pregnant leaching solution is also realized as in situ application by means of a membrane pilot plant, which was exclusively designed for this special application.