Elements of bio-mining: Engineering collaboration aims to turn mine waste into valuable metals – by Tyler Irving (U of T Engineering News – September 13, 2017)

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They are invisible to the naked eye, able to withstand extreme conditions and capable of breathing rocks. They are the microbes that thrive in tailings ponds at mining sites around the world, and a team of Canadian researchers believes they are the key to transforming waste material into something much more valuable.

“There are bugs that thrive on metabolizing sulfur, others on metabolizing iron,” says Professor Vladimiros Papangelakis (ChemE). “If we can control such biochemical reactions, we could both remediate the waste and recover valuable metals that could pay for the cost of processing.”

Papangelakis, along with Professor Elizabeth Edwards (ChemE) is leading the Elements of Bio-mining project, a multidisciplinary collaboration between U of T Engineering, Laurentian University, and the University of British Columbia (UBC), as well as a number of technology, engineering and mining companies, including Glencore, Vale, Teck, Barrick and Hatch.

Together, the team is developing ways to process a number of different types of material left over from mining activities across Canada, from nickel mines in Sudbury, Ont. to coal mines in British Columbia. They aim to understand how native microorganisms at these sites convert chemicals one form to another, and how they might encourage certain beneficial reactions while discouraging others.

For example, nickel refining produces tailings, which are rich iron sulfide. When exposed to the oxygen in the atmosphere, chemical reactions begin to convert the sulfides into sulphuric acid. This process — known as Acid Mine Drainage (AMD) — is catalyzed by microorganisms that live in the rainwater or melting snow that washes over the tailings.

For the rest of this article: http://news.engineering.utoronto.ca/elements-bio-mining-engineering-collaboration-aims-turn-mine-waste-valuable-metals/