There is enough arsenic buried underground at Giant Mine in the Northwest Territories to kill every human on earth. The stores are a ticking time bomb, and Dr. Ahmad Ghahreman might have the tools to diffuse it.
Part of the challenge is the astronomical cost of dealing with the toxic substance: in order to render all the arsenic at Giant Mine inert using conventional methods, the cost would reach upwards of $1 billion. Dr. Ghahreman, the Associate Head of the Robert M. Buchan Department of Mining, has invented a technique that could cut that expense in half.
Rather than employing the exotic oxidants normally needed to treat arsenic prior to immobilization, Dr. Ghahreman has discovered a new oxidation technique that is equally efficient, and uses only air and activated carbon—a benign substance commonly found inside household items like Brita filters. His is the cheapest method of immobilising arsenic ever formulated. “There are many mines around the world with arsenic problems, especially in the U.S., Canada, South America, and Australia,” he said. “This technology is going to be critical in many of those developments.”
Dr. Ghahreman is currently in talks with Giant Mine about running a pilot project in which the process would be tested on their vast underground arsenic stores. On top of using the technique to neutralize dangerous stockpiles, it could also breathe new life into projects around the world that were previously deemed unviable due to the astronomical costs of arsenic disposal.
Coming up with a viable solution to an intractable issue like arsenic waste would serve as a defining career achievement for most researchers, but for Dr. Ghahreman it’s just one among his several innovations that could serve to revolutionize the mining industry.
One of his current projects, for example, is aimed at detoxifying gold mining operations, which require one of the most dangerous chemicals on earth: cyanide.
Historically, cyanide has been used during gold leaching at extremely low concentrations, and treated with the utmost care by the industry. Its extreme toxicity means that its use and transport continue to pose a threat to human health. Dr. Ghahreman’s patented solution is to stop producing cyanide in factories and shipping it all over the world, and to instead manufacture the chemical on-site, using bacteria.
His lab found that with the addition of sugar, organisms that are no more harmful than those found in yogurt can be induced to release cyanide on gold-containing ore within a reactor. They’ve also demonstrated that the process is as efficient as using industrially produced cyanide.
The project is part of a broader effort on the part of Dr. Ghahreman and his team, in collaboration with large mining conglomerates like Glencore, Barrick and Newmont, to make gold mining from low-grade ores—which are abundant in Canada—safer, cheaper, greener, and more efficient.
The effort comes after decades of experience in the world of hydrometallurgy, a process that has fascinated Dr. Ghahreman from a young age.
As a junior-high school student in Iran, he was taken on a field trip to a copper plant, where the metal was taken in as a blue-tinted aqueous solution and transformed, seemingly by magic, into its shiny-red solid form. He was in awe of the process, and endeavored to learn all he could about the concept of electrochemistry.
In one of his earliest experiments, Dr. Ghahreman figured out that he could generate electricity by putting two metal spoons in a salt-water solution and connect them to a lightbulb. What he didn’t realize is that he would ruin the spoons in the process. “My mom was not happy,” he said.
That enthusiasm carried him through his undergraduate and master’s degrees in materials science and engineering at the Sharif University of Technology in Tehran, where he continued to build his knowledge of extractive techniques. He went on to complete his PhD at the University of British Columbia, where he would leave a major mark on the industry that first piqued his interest in the field: copper mining.
A mineral called chalcopyrite is the world’s most abundant source of copper, but most mines discard it as a waste product, because extracting the metal is simply too expensive. What’s more, the historical method for processing chalcopyrite, a process called pyrometallurgy, has been in steep decline across the world due to its negative environmental consequences.
Working with professors Ed Asselin and Dave Dixon, Dr. Ghahreman came up with a novel hydrometallurgical method of extracting copper from low-grade sources like chalcopyrite. “For the same capital cost, you are extracting double the copper,” he said.
The patented technique involves a catalytic process aimed at severing the bonds between copper and sulfur, and can be easily integrated into a mine’s normal operations. The technology attracted the attention of American venture capitalists Mike Outwin and Andrew Perlman, who through their company Jetti Resources, have implemented the technique at two mining operations thus far, including the Pinto Valley mine in Arizona, run by the Toronto-based Capstone Mining Corp. The company is using the technique to extract copper from their massive stores of unused chalcopyrite, apparently with great success. The value of Capstone’s shares has increased by 500 percent in the last year.
These innovations, while significant, are just the tip of the iceberg in terms of Dr. Ghahreman’s contributions to the field. His incredible productivity was officially recognized in 2020, when he received the Faculty of Engineering and Applied Science Excellence in Research award—the first time the distinction has gone to a member of the Robert M. Buchan Department of Mining.
“Ahmad is the most productive researcher in the department and is making a significant impact in the mining industry with the innovations generated and also with the training of highly qualified graduate students,” said Dr. Julián Ortiz, Associate Professor and Department Head. “He has shown a tremendous drive to engage with industrial partners, which is an example on how to bridge the gap that exists between academia and industry. His contributions are improving the sustainability of the mining industry.”
Dr. Ghahreman launched his lab at Queens in 2014, and since that time it has grown to become one of the busiest hydrometallurgy laboratories in North America. Along with his talented group of mostly PhD students, he’s working on several projects that could dramatically lessen the environmental impact of resource extraction.
Recently, Dr. Ghahreman’s lab filed a patent for a process in which lithium is leached from spent LFP batteries. LFPs are currently being used with increasing frequency, especially within the electric vehicle industry, but to this point no one has figured out a profitable method of recapturing lithium from the spent batteries. Industrial adoption of Dr. Ghahreman’s process could have massive implications for the circular economy.
Without a robust recycling strategy, he says, “we will generate mountains of spent LFP batteries that we don’t know what to do with.”
One of his most exciting endeavors is looking at using waste materials to directly offset the mining industries carbon footprint. Dr. Ghahreman’s lab has shown that certain tailing materials, when treated with oxygen, can convert carbon dioxide into a solid mineral state. Results from a pilot study using tailings from a nickel mine owned by Canada Nickel Corp. have been extremely encouraging. They showed that the technique could potentially capture more carbon than the entire operation emits.
One of the challenges of mining innovation, according to Dr. Ghahreman, is the tendency of the industry to be risk averse. “Everybody wants to be second, no one wants to be first,” he said, but he does not let that discourage him. “That’s part of the challenge, inventing new technologies that make industry feel like it would be a missed opportunity if they didn’t try them,” he said.
Another thing that keeps Dr. Ghahreman optimistic is the skill and dedication he sees in the younger generation of engineers. “They realize the value of being innovative with methods of processing materials,” he said. Industry itself is also waking up to the fact that they need to find solutions to some of their most pressing issues, a trend he says will create “amazing opportunities,” for young engineers entering the field.
This all bodes well for the realization of Dr. Ghahreman’s ultimate goal: “My mission is to develop the technologies that will make the future of mining carbon neutral,” he said.