Can tiny microbes help clean up tailings left over from decades of mining and smelting? Nadia Mykytczuk thinks so, and there is potential to recover billions of dollars’ worth of metals in the process.
Mykytczuk, an environmental microbiologist at the Living with Lakes Centre in Sudbury, is studying how microbial communities already present in mine tailings can help neutralize the damaging effects toxic minerals have on the environment.
Because they accelerate the leaching of reactive minerals through the oxidation process, producing acid mine drainage, microbes aren’t traditionally considered allies of the remediation process. But Mykytczuk believes there is the potential to manipulate them for positive uses.
“If we take those microbial communities and make them work for us instead of against us, we can actually exploit their metabolic abilities to reduce the generation of acid mine drainage, and effectively recover metals from those remaining wastes that would otherwise be sitting in our landscape and polluting the landscape,” she said.
Recently awarded an NSERC Discovery Grant to further her research, Mykytczuk will look at specific local microbes that have adapted to the North’s cold climate. Most research to date has been published around microbes that operate at warmer temperatures, but they work differently than the ones that function at colder temperatures, she said.
If researchers could promote oxidation at a faster rate than what happens naturally, Mykytczuk believes the process of removing reactive minerals from waste could be accelerated, and metals could be recovered from leachate before they enter the environment through acid mine drainage. Bioleaching, used in facilities around the world, is a good example of this.
“We have yet to see it working in Sudbury and yet we have a lot of available tailings here that are still very rich,” Mykytczuk said. “In fact, there are potentially billions of dollars of metals sitting in our mining waste that we could recover.”
She is currently partnering with Vale and Cambrian College on a pilot project that is putting her theory to work. A bioleaching heap is being used to see if bioleaching could work in Sudbury. If it does, the metals recovery system could pay for itself.
Mykytczuk is one of several scientists looking at remediation techniques to rehabilitate mined lands to their original state.
John Gunn, the research chair for stressed aquatic systems at the centre, said in the past, mining companies have cleaned up pollution and returned the land to government regulation levels. But advanced rehabilitation is needed to be able to restore the functions of the original ecosystems, so they can once again produce clean water, maintain and produce clean air, sequester carbon, and produce food and wildlife.
“Those are the functions that natural ecosystems provide to us, whether we use the system or not,” Gunn said. “The intent is to try to put our heads around the concept of what do we need to do after we’ve extracted minerals to put systems back to their functional state again so they’re part of a global service system.”
Working up around the Attawapiskat River Watershed, Daniel Campbell, a scientist at the Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO), said while mining companies have traditionally been great at exploration and extraction, reclamation wasn’t always top of mind.
“Usually in the past, we’ve been very good at the first few parts of (the mining) sequence, but we haven’t always been as good at the last part,” Campbell said. “It’s one reason why mining has been given a bad name.”
Focusing on reclamation efforts at DeBeers’ Victor diamond mine, Campbell is trying to develop protocols for disturbed peat lands and the reclamation of uplands that are useful at the Victor Mine site, but are also applicable to other areas, such as the Ring of Fire.
He’s currently looking at different soil mixes to determine the best combination to conduct greenhouse trials.
Calling Sudbury “one of the most fascinating research environments on the planet,” thanks to years of mining and smelting, Graeme Spiers, director at MIRARCO, can actually trace mining trends through the decades based on anomalies in samples taken from the land.
“We can see those anomalies and can understand what was happening in the industry, both from an emissions perspective as well as from a process perspective,” he said.
Those samples show layers of particles emitted from the smelter that settled based on temperature. There are 200 to 400 times the enrichment of copper and nickel compared to pre-mining days, as well as concentrations of thallium, cobalt and other minerals, Spiers said.
But samples from more recent times show a drop in concentration of minerals, demonstrating emissions reduction programs have been effective at reducing the pollution emitted from mining operations, Spiers said.
Now researchers are looking at how long Sudbury’s world-renowned reclamation efforts will last, he added.
Thanks to a $1.65-million grant from the Natural Sciences and Engineering Research Council of Canada (NSERC), Laurentian University can step up its reclamation research efforts.
Through the grant, Laurentian will train 96 new highly qualified people over the next six years, specifically targeting the mining sector in areas of mineralogy, geochemistry, geomicrobiology, molecular geochemistry, toxicology, and aquatic ecology.
Their ultimate goal is to promote environmental management and sustainability in the mining sector, so companies can complete the mining loop through active recovery, waste reduction, remediation and green mining.
