Possibilities for the recovery of non-ferrous and precious metals from Kapan polymetallic mine tailings (Armenia) were studied. The aim of this paper was to study the possibilities of bioleaching of samples of concentrated tailings by the natural microbial consortium of drainage water. The extent of extraction of metals from the samples of concentrated tailings by natural microbial consortium reached 41-55% and 53-73% for copper and zinc, respectively. Metal leaching efficiencies of pure culture Leptospirillum ferrooxidans Teg were higher, namely 47-93% and 73-81% for copper and zinc, respectively. The content of gold in solid phase of tailings increased about 7-16% and 2-9% after bio-oxidation process by L. ferrooxidans Teg and natural microbial consortium, respectively. It was shown that bioleaching of the samples of tailings could be performed using the natural consortium of drainage water. However, to increase the intensity of the recovery of valuable metals, natural consortium of drainage water combined with iron-oxidizing L. ferrooxidans Teg has been proposed.

Concentrated tailings samples resulting from the benefication of polymetallic ores (Armenia) were exposed to bioleaching in order to recover non-ferrous and precious metals. Bioleaching of concentrated tailings samples was performed by the natural microbial consortium of drainage water. It was shown that the extent of extraction of metals from two samples of concentrated tailings by the natural microbial consortium reached 55, 56% and 63, 73% for copper and zinc, respectively. However, the application of the natural microbial consortium together with an iron- oxidizing Acidithiobacillus sp.13Zn resulted in an increase of extraction of metals from concentrated tailings to 70 - 93% for Cu and 75 - 90% for Zn. Thus, to increase the recovery of non-ferrous and precious metals, the use of a natural microbial consortium of drainage water combined with an iron- and sulfur- oxidizing Acidithiobacillus sp.13Znis proposed.