design: Sub-samples from the tailings samples were collected using sterilized sampling utensils, placed into sterile plastic containers, capped and stored at 4C for approximately 48 hours until DNA extraction occurred. DNA was extracted using the Qiagen DNeasy PowerSoil kit (Qiagen, Mississauga, ON) and DNA quantified using the Qubit dsDNA HS Assay (Life Technologies, Burlington, ON). For metagenome sequencing,100 ng to 1 g of gDNA was sheared using the Covaris S2 focused sonicator (Covaris Inc., Woburn, MA) to achieve a fragment size ranging from 300 to 400 bp. Libraries were prepared according to the NextSeq 500/550 High Output Kit v2.5 (300 Cycles) Kit and indexed using the NEXTflexTM DNA Barcodes (Bio-O Scientific). The libraries were sequenced through the paired-end sequencing workflow at 2 X150 cycles on the NextSeq500 at Molecular Biology Service Unit (MBSU) at the University of Alberta.