How Northern Ontario researchers are using bacteria-powered technology to extract vital minerals from mine waste

Researchers in Sudbury, Ontario are working on scaling up a bacteria-powered technology in an effort to recover valuable metals from old mine waste.

A pilot facility run by Mirarco Mining Innovation is testing how microorganisms can break down mine tailings – rock and sediment left over from mining – and release important minerals such as nickel, cobalt and copper in a process called bioleaching.

Although bioleaching technology is a staple in international mining, it is used at about 30 mine sites globally and Canada has not yet achieved full-scale commercial deployment, according to Nadia. Mykytzuk, CEO of Mirarco, the research arm of Laurentian University.

Mickyczuk was among those who spoke to CBC during a recent tour of the 10,000-square-foot pilot facility in Sudbury, which included getting first-hand information about how bioleaching works.

Although researchers moved into the facility last May, it took several years to complete their work.

“Stitching is a very common thing that you see here in Sudbury or any mining community,” said Mykytczuk. In Sudbury alone, he said, there is $8 billion to $10 billion worth of nickel in the tailings.

Potential Environmental Risks

Regardless of the estimated value of the waste material, companies money still to be invested Reprocessing the tailings due to the significant cost of shipping the material back to the smelter.

Instead, the remains are typically mixed with water. stored in large ponds – Increasing concerns about long-term environmental risks.

Jaime Kane, co-lead of MiningWatch Canada’s national program, said there are two main risks: how the material behaves chemically and whether it remains physically stable over time.

One concern is that the residues could generate acids and release metals that could slowly leak into the surrounding environment.

To limit those reactions, the tailings are often stored underwater. But according to Keane, this creates another risk.

“Now you have millions of tons of material that is wet and not stable and that has to be held back by a dam, which has to remain intact for millennia, if not centuries, to keep that material from falling onto the rest of the landscape or being washed away in floods,” he said.

Kane highlighted the potential consequences if these structures failed, citing the 2014 collapse of the Mount Polley Mine tailings dam in British Columbia, which led to the release of toxic mine waste into nearby lakes and rivers.

If those structures failed, the consequences could be dire, Keene said. He pointed to the failure of 2014 Mount Polley Mine Tailings Dam In British Columbia, which caused toxic mine waste to enter surrounding lakes and rivers.

Call for more significant mineral development

Both federal and provincial governments have significantly intensified calls for critical mineral development to secure supply chains for clean energy technologies – such as EV batteries – and national defense due to rising global demands and the need to reduce reliance on unfavorable suppliers.

Mykytczuk said bioleaching is a way to deal with both the demand for critical minerals and mining cleanup.

“If we want to find a source of critical minerals in the near future, mine waste is a fantastic opportunity. There is potential for the extraction of billions of dollars worth of these critical minerals in a very short time frame.

“We want to make sure these technologies get into the hands of industry. So to scale that up we need to build larger spaces like this (Sudbury facility).”

Similar work is underway elsewhere in Canada, although much of it is still in the early stages.

In Nunavut, Canadian North Resources has tested bioleaching at its Ferguson Lake Project; In northern Alberta, an exploration company is studying whether microbes can help extract rare earth elements from black shale.

The Sudbury Project is one of several projects receiving support through federal Critical Mineral Research, Development and Demonstration ProgramThe aim of which is to take such technologies closer to commercial use.

How does bioleaching work?

The bioleaching process begins by grinding the remains and mixing them with a liquid solution that nourishes the bacteria. That’s also when microbes are added to the mix.

As the bacteria feed on the minerals, chemical reactions allow the metals to separate and pass into the liquid.

The resulting slurry is then taken through a series of reactors, where the process continues. The metal, now in liquid form, is extracted.

Researchers inside the lab are working to replicate how this process would work in a large mining operation.

This means designing a system in which materials move continuously through a series of tanks rather than being processed in separate batches, as explained Emmanuel Ngoma, a senior scientist at Miraco.

Ngoma said the setup allows the slurry to flow from one stage to the next – often using gravity – while fresh material is continuously added at the beginning.

“IIn the mining industry, you don’t work on a batch system. You’re always supplying new material.”

Once the process is complete, most of the metal inside the residue can be extracted.

“I can recover about 98, 99 percent of the nickel put in at the end of this process. And in terms of research that’s good… it’s really worth increasing the capacity and investing in a much larger system,” Ngoma said.

There is still waste left over after the process is complete, but Ngoma said it is “free of toxic materials and can be used for other things.”

He said the remaining material could potentially be reused in construction or buried underground as backfill in mining operations.

bacterial growth

In another lab at the Sudbury facility, Zach DiLoreto, a senior research associate, explained how the team grows the bacteria used in bioleaching.

“In these cultures, we grow bacteria that do the job,” DiLoreto said, adding that different types of microbes have been designed to target specific minerals found in mine waste.

Some of those microbes are acid-loving, meaning they thrive in highly acidic conditions. They are used to break down sulfide tailings, a common type of mine waste.

Others are designed to go after a variety of materials, including iron oxide and silicate minerals, which may contain valuable elements used in modern technology.

These include rare earth elements and metals such as lithium, dysprosium and neodymium, which are key components in, for example, electric vehicle batteries and clean energy systems.

“We use high-precision analysis, geochemistry, biogeochemistry, and we look at different strategies to effectively and economically extract things like rare earths from different mineral host rocks,” DiLoreto explained.

To study how well the process works, researchers analyze how the bacteria interact with different types of rocks. An example is spodumene, a mineral commonly found in the Sudbury area that naturally contains lithium.

DiLoreto said most lithium extraction today relies on processes that can be energy intensive.

“In today’s day and age, most (lithium extraction) is done at high temperatures, high pressures. But we can look at things like special organic acids and biomolecules produced by specific bacteria to target these minerals.”

next steps

The team is also exploring ways to transform the extracted metals into products with industrial applications.

DiLoreto said part of their job is to prove to industrial partners that the materials they process are commercially viable and more valuable than standard materials like iron.

For example, he could turn a basic iron resource into ferrofluid, which could be used for things like water purification.

The research team said the next step is to move from pilot testing in Canada to full-scale operations, hopefully within the next two to three years.

“There are already commercial examples globally. Canada hasn’t built a full-scale commercial bioleaching operation yet, but we’re really getting close to it,” Micyczuk said.