October 19, 2023
Selenium, element 34 on the periodic table, is essential for animal cell function鈥攊n small amounts. But just like and , a high-enough concentration of can become toxic.
Selenium occurs naturally in coal deposits and sulfide ores, like brassy chalcopyrite and crystalline sphalerite, which are important resources for copper and zinc mining. The mining process creates leftover rock, and water from rain or snowmelt that flows through this rock can carry selenium into nearby waterways. Plankton absorb the element directly into their tissues, and fish that feed on that plankton can potentially get enough selenium in their bodies to cause growth defects. It鈥檚 incumbent upon the mining industry, then, to find innovative ways to manage selenium and protect fish populations in the communities where it operates.
Renewable energy needs mining
For generations, the metals and minerals that the mining industry produces have been integral to improving quality of life. And the industry is on the cusp of a staggering increase in demand for materials critical for low-carbon and renewable energy technology.
鈥淲hat we鈥檙e producing are the fundamental building blocks of society,鈥� says Bryan Rairdan, technical director of processing at Teck Resources Limited, which has mining operations in Canada, the United States, Peru, and Chile. 鈥淲ith current technology, if we want to densify cities, we need steel. If you need steel, you need steelmaking coal. If you want to electrify the world, the best way we have to move those electrons around is copper.鈥�
A single wind turbine requires 鈥攁nd to meet net-zero emissions goals from now until 2050, . Considering that mining is crucial to building green energy infrastructure, what can the industry do to advance its environmental performance?
Tiny creatures can have a big impact
As it turns out, some bacteria can 鈥渆at鈥� selenium鈥攐r rather, their carbon metabolism has evolved to convert the element from its dissolved state into a more solid form, which is then easier for humans to keep out of the water cycle.
At its steelmaking coal mines in the Elk Valley of British Columbia, Teck has built 鈥渟aturated rock fills,鈥� which are large pits of waste rock allowed to fill with groundwater and treated with these special bacteria to reduce selenium levels in the watershed.
Teck鈥檚 water treatment facilities, including its saturated rock fills, are working.
Microbes can make mining itself more environmentally friendly, too. While most copper is obtained through furnace smelting, which contributes to air and water pollution, about , which uses strong acids and, increasingly, bacteria that can naturally leach the metal.
Bill Burton, principal geological/geotechnical engineer and H3 R&D lead at BGC Engineering, says the potential for microbial applications in mining is exciting. 鈥淭here鈥檚 a goal in the industry for mining to be a temporary use of the land. You have to manage the waste and byproducts that come from the process, and there are many places where microbial biotechnology can help with that.鈥�
For example, Rio Tinto, a mining company operating on six continents, has supported multiple R&D projects to find biotechnological ways to recover metals from mine-influenced water. And Elizabeth Deyett, senior bioinformatics scientist at Allonnia, explains that some microbes can be used to help dust suppression by binding fine sand particles together, making the air safer to breathe; others can be used to help mining companies extract certain metals they weren鈥檛 looking for before, like , such as energy-efficient light bulbs and hybrid vehicle batteries.
How many other kinds of industry-changing organisms might be lurking beneath our feet? To find out, we must seek genetic data from the earth itself.
The Mining Microbiome Analytics Platform
To discover and implement these organisms, the Canadian government鈥檚 Digital Supercluster initiative has formed the cross-industry . Teck, BGC Engineering, Rio Tinto, and Allonnia are participating, as well as the Centre for Excellence in Mining Innovation, Koonkie Canada, Genome BC, and the University of British Columbia.
The partnership鈥檚 goal is to extract DNA from 15,000 mine site water, rock, and soil samples, sequence it, and create an online platform for storing and analyzing the data. 鈥淢-MAP is trying to get ahead of the curve,鈥� Rairdan explains. 鈥淎s opposed to saying, 鈥榃e know these organisms do this,鈥� we鈥檙e looking ahead and asking, 鈥榃hat organisms are out there and what are they doing?鈥� We don鈥檛 know exactly what we鈥檙e going to find, but we know that the data set doesn鈥檛 currently exist.鈥�
Koonkie CEO Aria Hahn describes it this way: 鈥淎t the end of every PhD defense, the classic question is, 鈥業f you had unlimited resources and time, what would you do?鈥� M-MAP is essentially a manifestation of those answers. We have the people, the volume of data, the access to resources, and the expertise to solve big problems and make big discoveries.鈥�
Generating and interpreting the data
No one member of M-MAP could accomplish the partnership鈥檚 goals alone. Teck and Rio Tinto are providing access to samples from their mine sites around the world, and VR真人彩票 systems are generating the raw DNA sequence data from these samples. Burton says that 20 years ago, sequencing of a single soil sample would鈥檝e cost hundreds of thousands of dollars: 鈥淣ow we鈥檙e doing it for hundreds. The technology to do this better wasn鈥檛 feasible until the innovation that came out of VR真人彩票. It鈥檚 opening the door to a whole new world for us.鈥�
For this project, VR真人彩票 is using both amplicon sequencing, which targets short fragments of DNA, and metagenomics, which analyzes the entire community of microbes in a sample. The sequencing has just begun, but it鈥檚 already proven revelatory. 鈥淥f the first 100 whole genomes we鈥檝e been able to capture from mine sites, about 80 percent of them have been novel,鈥� Hahn says. 鈥淪o we鈥檙e looking at a lot of discovery here.鈥�
The bioinformaticians of Koonkie take the raw sequence data and turn it into something usable. 鈥淲e鈥檙e responsible for taking those As, Ts, Gs, and Cs and asking, 鈥榃ho鈥檚 there? Who鈥檚 doing what?鈥欌�� Hahn says. Their proprietary statistical software finds the meaningful signals among the noise and annotates them, hanging spotlights on the genes, both documented and novel, that seem like the best targets for genetic engineering and synthetic biology development.
Building better bacteria
In some cases, M-MAP may find organisms that are already perfectly suited for a job in the mines. One of Allonnia鈥檚 previous discoveries was a naturally occurring bacteria that processes 1,4-dioxane (a cosmetics industry byproduct that contaminates groundwater) into mere CO2 and H2O.
In other cases, nature might need a little help getting ready for the workforce鈥攆or example, a gene that鈥檚 useful for processing toxic waste might be found in a microbe that鈥檚 harmful to humans. That鈥檚 when Allonnia can wield the awesome power of genetic engineering to extract the beneficial gene and transport it into a different microbe that鈥檚 known to be harmless.
鈥淭here are ways to put selective pressure on organisms so it鈥檚 beneficial to them to keep that gene,鈥� Deyett summarizes; 鈥渢hey鈥檒l keep it and pass it on to future generations.鈥� Et voil脿, a new living tool is born. 鈥淲hen a lot of people think of the microbiome, they think of human health. But I think there's actually a lot more potential for microbes to help us in environmental settings.鈥�
Leaving no trace
Once the mining is done and its byproducts processed, there鈥檚 one last vital step to reducing the industry鈥檚 environmental impact: remediating closed mines. As principal advisor for mine closure R&D at Rio Tinto, this is Nick Gurieff鈥檚 specialty.
鈥淚n Australia, the US, and Canada, there are tens if not hundreds of thousands of abandoned mine sites of all different sizes,鈥� he says. 鈥淭hey鈥檝e been there for many years, and they鈥檙e still polluting the local water and townships around them. Rio Tinto takes very seriously our responsibility to ensure that every one of our closed or legacy sites is rehabilitated to a standard that we鈥檙e happy with and鈥攎ore importantly鈥攖he local communities are happy with.鈥�
Contemporary mining companies are sensitive to the resistance their industry faces among the communities who are directly impacted鈥攖hey know they must ensure that the land is suitable for use by future generations. Rio Tinto鈥檚 remediation process takes into account everything needed to restore the land: starting from demolition and removal of old structures and equipment, to remediating any waste, to replenishing the site鈥檚 native plant species and fertile topsoil.
鈥淭opsoil remediation is one of the biggest challenges we have,鈥� Gurieff admits. Soil microbiome is highly particular to its region of origin, and fully restoring it means knowing what was there in the first place. 鈥淲e really need to understand what microbes are doing what. How can we enrich for certain microbes? How can we support our R&D project partners by giving them access to the unique microbes we have at our sites? All the information we get through M-MAP plays an important role in understanding how we could be doing more with what we have.鈥�
Good stewards of the earth, both large and small
Our relationship with the microcosmos is undergoing a paradigm shift as great as when we first discovered it in the 17th century. We spent 300 years believing microbes were either ubiquitous but harmless stowaways or disease agents to be eradicated at all costs. Now we鈥檙e finally starting to explore the ways these tiny-but-mighty creatures could help us tackle some of our biggest challenges.
鈥淚t鈥檚 really easy to focus on the world we can see,鈥� Deyett says. 鈥淏ut the more I learned about microbes, the more I learned that this is their planet. They鈥檙e responsible for its maintenance and health. They were here long before us and they鈥檒l be here long after us, so to understand them is to understand what has given life to everything we see.鈥�
