Microorganimsm may greatly affect the flotation processes of metal processing plants. However, the microboal communities of metal processing and flotation plants are not well known. Here we characterized the microbial communities (bacteria, archaea, fungi) in three different sampling points ofver the time span of 2 months. This study is part of the H2020 ITERAMS project (Grant agreement# 730480)

Closing water loops in metal processing plants may strongly decrease the ecological footprint of mining, but presents also challenging due to build-up of flotation chemicals, metal ions and microorganisms in the recycled water affecting the flotation performance. The microbial communities if the flotation process circuit in the Boliden Kevitsa mine was characxterized over a 2-month period, by microbiome sequencing, enumeration of bacteria, archaea and fungi by qPCR, and cultivation. The microbial communities showed high diversity, but were dominated by Alpha- and Gammaproteobacteria and various fungal taxa, whereas the archaeal taxa were sparse. The number of bacterial 16S rRNA gene copies in in the studied samples varied between 50000 – 330000 16S rRNA gene copies/mL, whereas fungi were present at 300 – 81000 5.8S rRNA gene copies/mL, and the number of archaea fluctuated between 88 – 320000 16S rRNA gene copies/mL. This study is part of the H2020 ITERAMS project (Grant agreement# 730480), which strives to improve the recycling of water and minimise the environmental impact of mines.