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Could Sudbury's mine waste feed the steel industry?

Biomining company sees tonnes of iron waiting to be extracted from Sudbury tailings
Vale tailings site
Google Earth image of Vale's Copper Cliff tailings site in Sudbury (Image supplied by MIRARCO)

A biomining company that’s rooting around Sudbury’s mine tailings insists there are multiple metal and commodity products waiting to be extracted. 

Toronto’s BacTech Environmental is filing a patent application for its unique and innovative bioleaching process that recovers valuable metals from mine waste while also cleaning up toxic industrial environments.

BacTech’s process has demonstrated it’s already capable of recovering nickel, copper and cobalt from mine tailings, but now there’s the potential to pull the iron out of the pile while also making a fertilizer product.

Bioleaching is a globally well-known biotechnology that was developed 40 years ago. Companies like BacTech have been fine-tuning its process, using Sudbury as a testing ground in co-operation with MIRARCO, a Sudbury mining innovation centre, and local nickel mining giant Vale.

The bioleaching process involves using naturally occurring and harmless bacteria to target certain ores and contain other substances that are harmful to humans.

The company estimates there are 80 million to 100 million tonnes of pyrrhotite tailings from mining operations in the Sudbury basin

Pyrrhotite is an iron sulphide mineral containing low levels of nickel, cobalt, and copper. It’s discarded by the mining companies as an uneconomical waste byproduct, but it continues to perpetuate an environmental legacy problem that’s in need of remediation.

In filing an expanded provisional patent application, BacTech said it’s come up with new intellectual property and a novel method to convert soluable iron into iron metal that can be used in “green steelmaking.” In thinking ahead, BacTech tosses out the idea of doing iron metal production in Sudbury or manufacturing iron pellets to send to the steelmakers.

BacTech is confident that it can create another marketable product by taking the bioleach acid, used during the process, to produce ammonium sulphate that can be packaged and sold as a premium organic fertlizer. 

Other potential products in the mix could include a magnetite powder and geopolymer silica for construction material or mine backfill.

In his weekly newsletter, Ross Orr, BacTech’s president-CEO, sees multiple revenue resources that comes from reprocessing this material, adding “from one tonne of waste, we hope to sell five different products leaving behind zero waste.”

With the help of MIRARCO, a Sudbury mining innovation centre, BacTech is running a pilot plant of its bioleaching process that will involve breaking down pyrrhotite to free up small amounts of cobalt and nickel. The results are crucial toward securing patent protection and could lead to a larger demonstration-scale plant that could lead to prototype production facility in Sudbury.