Establishing tailings associated sulfur biogeochemical cycling across the resource extractive industries

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Mine tailings environments are one of the fastest growing and least studied biogeochemical landscapes on the planet. Every year the Canadian mining industry withdraws approximately one billion cubic meters of freshwater, approximately equivalent to ½ of our annual, renewable water supplies, which is predominantly returned to receiving environments.The alteration of this water through operational extraction activities can pose significant environmental threats. In those extractive processes, Canadian mining activities generate approximately 2 million tons of waste rock (overburden) and tailings (post-processed, toxic, aqueous slurries of highly altered, rock particles and chemical additives) daily. Because of the environmental and human health risks tailings can pose, they are typically stored on site in tailings ponds, resulting in large amounts of wastewater requiring treatment. The wastewater generated from these tailings impoundments has the potential to cause significant impacts to the downstream receiving environments if not properly treated. These tailings impoundments remain a microbial black box from which unpredictable impacts can emerge. In particular both metal mining (sulfide rich ores) and oil sands tailings, are known to be sulfur rich; and contain highly altered, varying concentrations of carbon, nitrogen and iron compounds that would enable a broad array of possible interconnections between sulfur and other biogeochemical cycles. At the global scale many existing tailings environments remain at risk of developing deleterious sulfur related impacts such as acid mine drainage, and high levels of hydrogen sulfide gas, highlighting that novel research efforts are necessary to elucidate the biogeochemical transformations governing S cycling in these contexts to better prevent such impacts. Further, as these contexts continue to increase worldwide, they will be an increasingly important contribution to the global sulfur biogeochemical cycle. The goal of the proposed innovative research program is to establish a comprehensive understanding of sulfur biogeochemical cycling occurring within tailings from across the extractive resources mining sector, from which vitally need new solutions for more sustainable management and a more comprehensive global sulfur biogeochemical model can be developed. This long-term research program goal will be met through experimental research activities that will systematically build a new knowledge platform based on the generation of mechanistic understanding of the different microbes involved, the catalyzed pathways and associated controls as well as the implications of varying electron donors and acceptors for sulfur redox cycling from a comprehensive suite of mine tailings samples. Ten HQP will receive training in cutting edge environmental biogeochemical research of critical Canadian importance.