UPPER PENINSULA, Mich. (WJMN) — Continuing our coverage of mining in the Upper Peninsula, we spoke with Nathan Manser, a professor of geological and mining sciences at Michigan Technological University about the mining process and management of its byproducts in the past and present, as well as what could lie ahead for the industry.
Problems left by legacy mines
A recent public hearing about a potential mineral rights lease for the purpose of mineral exploration was met with opposition last week. From a historical perspective, residents may have cause to be skeptical of the mining industry at large. Todd Malan, an executive with Talon Metals acknowledges as much, addressing concerns that opening more mining operations could harm the outdoor recreation industry, “we totally understand that some people are skeptical about that, and that that’s okay. It’s our job to engage with people and convince people that it doesn’t have to be a choice.”
In our conversation with Professor Manser, he noted people in the Upper Peninsula have had to deal with repercussions of what several legacy mines have left behind. Hazardous remnants can be as inert as the migrating stamp sands in the Keweenaw Bay threatening fish breeding grounds, to waste and pollution sites around old mines in most counties in the central U.P. Abandoned mineshafts are not uncommon, and pose their own unique danger. At least one abandoned shaft has been involved in the death of a young girl near Calumet in 1966, and sinkholes are still appearing as recently as this past April.
Manser says current regulations are a big factor making the difference between legacy and modern mines. “Thinking about how things have been managed here in the U.P., right? Poorly, I think in every case,” Manser said. “The mining systems here are old enough where the permitting wasn’t in place to hold them accountable. The mining systems here are old enough where the responsibility and ownership of the site after it’s closed was not necessarily maintained in any form or fashion. And so there was no remediation, there were no post-closure activities.”
The consequence of that, according to Manser, is hundreds of millions of taxpayer dollars spent through government agencies to evaluate, manage, and remediate those sites. A state environmental cleanup report from EGLE shows nearly $2 billion dollars were spent toward all remediation efforts in the state as of September 2020, though it is unclear how much of that related to the mining industry. Eagle Mine also reports spending millions toward remediation of historical mine pollution before starting their operation.
While regulations work to prevent the causes of polluted and abandoned mines, Manser says even modern mines are still grappling with what to do with the waste byproduct. He says in many operations, the groundwater risk of sulfur tailings is designed to be contained—but not eliminated—forever.
Lurking threat of sulfur tailings
Tailings are what is left when the commodity has been extracted from the ore. Mill tailings can look like sand, or be made up of particles as small as silt. The chemicals left among the tailings vary depending on what miners are trying to dig up. For nickel sulfide mines in the U.P., the leftover sulfur poses the largest threat. Manser says the sulfur starts becoming dangerous after it reacts with oxygen.
“When that happens, you basically have the potential to start an acid mine generation cycle,” said Manser. “The very first step in the acid mine generation cycle is the oxidation of sulfur. And so the number one significant risk that’s associated with [nickel sulfide mines and mills] is the type of ore body they’re mining.”
The professor says once the acid generation cycle starts it is very difficult to stop. From there on out, that acidic body of water is at risk of leaking into the groundwater if its container fails. That could happen by either a flaw in its design or a seismic event.
Manser says the problem and search for solutions to mine tailings is front-and-center for experts in the industry. “There has never been a bigger focus on just that particular topic than the tailings storage systems have been, especially in the last five years. It’s really accelerated.”
Planning to close
In an effort to eliminate future cost to taxpayers, one EPA requirement demands prospective mine operators to demonstrate it can pay the expected amount needed to close and remediate the mine.
“You have to have your mine closure plan done before you get a permit,” said Malan, of Talon Metals, “and have financial assurance in place to make sure that you’ve got enough resources to be able to do the closure if that company isn’t around… that there’s enough for the state to be able to take over.” As for how much, Manser says about 30% of the total cost of a mine is wrapped up in its closure and remediation.
Having the resources to do that, according to Manser, benefits large companies over small operations. “I think what we’ll see in the future is a consolidation in the corporations that are operating mines,” said Manser.
For some mines, closing still includes leaving potential hazards behind. “If you look at surface maps of the Cliffs operation, you can see a very large pit, two huge tailings settling and storage facilities, and a large rock waste facility that’s visible for 30 miles in every direction,” said Manser. “Those impacts will be lasting forever, and because of its scale and age, that surface mining system is not set up in a way to be easily reclaimable in a lot of senses. Just the physical method of how [iron was mined] here will leave a lasting impact on the landscape and how it’s managed.”
Professor Manser says though any judgments about a future Talon Metals mine in Michigan are hard to make without seeing a plan, it would make sense for them to utilize the Humboldt Mill. He says the move would save the effort and impact of creating another processing facility, and that sulfur tailings at Humboldt Mill are managed more safely than what is at Cliffs’ Tilden Mine site.
“I would think that for Talon to be successful, that Humboldt property would still be in play,” Manser said. “They’re not going to build a whole other mineral processing system, tailings storage facility… There is a highly functioning mineral processing site there in Humboldt close by, that has a really good tailings disposal strategy.”
Future of mining
Carbon-neutrality is a large theme for the industry looking forward. Talon Metals promises to use electric vehicles for all operations, and secure renewable power for its electrical needs. Nathan Manser’s own research works to reduce the mining industry’s carbon footprint. One particular study concerns the process of isolating minerals that happens at facilities like the Humboldt Mill.
“Things that I’d like to focus on are looking at ways to decarbonize the mineral lifecycle,” Manser said. “What I like to do is take microorganisms and see if they can help us recover minerals in a less carbon-intensive way.
He says microorganisms have a unique capability to reduce surface tension, which allows heavier materials to sink out of a slurry, while others float or remain suspended. Currently, mills use man-made chemicals. “The ecological footprint of an anthropogenic reagent is tremendous, compared to that of one produced by a microorganism,” says Manser.
“One of the projects that we’re working on right now is looking at separating silica sand from iron bearing minerals. And there’s a certain yeast that produces bio-surfactant that attaches to the surface of sand particles, but not to iron-bearing minerals.” Manser says that particular solution could cut the carbon emissions of that process by 60%.
As a teacher, Manser says his students are concerned about the environmental impact of mining now more than ever. “I think the students that are coming into my mining engineering program, they’re 50% environmentally driven… what really piques their curiosity is figuring out how to prevent the damage.”
He says even his entrepreneurially-minded students are interested in environmental solutions. “They see a lot of professional and financial benefit from understanding how to stop pollution from mine systems happening… being that problem solver is satisfying to them.”
As for tailings, the academics and industry professionals are still working toward a better solution. “It’s the biggest thing in the industry really. Oh yeah. Without a doubt.”
Manser said within the Society of Mining, Metallurgy and Exploration, an entire working group has been established in the last four years that is dedicated to tailings, and all the challenges that come with them.
“There has never been a bigger focus on just that particular topic than then the tailings storage systems have been, especially in the last five years. It’s really accelerated.”