Brown: Sulfate debate yields hard truths and hope for Iron Range jobs

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Picture an oily 12-year-old Boy Scout, one shirttail dangling on his rumpled khaki shirt, kicking rocks on some back road along Minnesota’s Iron Range. That was me. Once, during a badge workshop, I announced to our troop that I wanted to become a chemist.

“No, you don’t,” said our senior patrol leader, an Eagle Scout whose uniform was crusted with Patton-like decoration.

I protested, so he wrote out a complex chemistry equation on a piece of paper and asked, “Does this look interesting?”

It did not. Thus ended my career in chemistry, until now.

Today, the fate of 4,000 jobs on the Iron Range, billions of dollars and the health of Minnesota waters rest on a chemistry equation, not much different from the one that frightened me all those years ago. To best serve the place and people I’ve loved all my life, I would have to do the unthinkable. I would have to learn chemistry.

To many speakers, this was a matter of life or death for the mine, owned by U.S. Steel, but also the entire Iron Range economy. To others, it was about an existential threat to Minnesota’s environment.

In fact, it is both. Fixing this problem will be difficult, but I hope to prove that it is possible.

U.S. Steel’s position is indeed dire. Minnesota’s mines, which produce 85% of America’s iron ore, face a looming economic downturn and rapidly changing technology for which they’re not yet well prepared.

Nippon Steel of Japan recently bought the vertically integrated steel company, which employs about 14,000 North American workers, mostly in the Great Lakes states and Arkansas. This week, Nippon announced a $3.1 billion investment in the Gary Works steel mill in Indiana, but also idled its mill in Granite City, Ill. Both facilities use taconite pellets from U.S. Steel’s Minnesota Ore Operations.

Forcing Minnesota iron mines to comply with a water standard of 10 milligrams of sulfate per liter would inflate their cost of production by about $17.50 a ton, according to the company. That’s a big jump, about 15% of the ore’s current value, which is expected to drop over the next year.

“It’s the kind of cost that would mean the end of Keetac and other mines,” said Cliff Tobey, a former union president at the mine, when he addressed the hearing.

Before last Wednesday’s hearing, I visited laboratories around the state and spoke to mining and sulfate experts from around the world. What they told me provides a clear path forward for Minnesota. I land on three broad truths: Sulfates are bad, mines can and must mitigate sulfates, and the sulfate standard must be made more accurate by accounting for site-specific factors.

Sulfate is a sulfur ion. It has a negative electrical charge, which I would compare to a person who is hungry. A hungry person is not necessarily bad — I mean, I could eat — but they will consume food given the opportunity. Similarly, “hungry” sulfates like to react with things they find in nature, which is the problem.

One potential reaction is for sulfates to convert to hydrogen sulfide, a gas that can convert into a solid toxin that settles into the sediments of river and lake beds under certain conditions. It kills wild rice and inspired the state’s sulfate standard.

Another potential reaction is for sulfates to methylate into mercury that enters the food chain, making fish unsafe to eat. This involves a different set of conditions, but there is a proven relationship between sulfates in the water and mercury from air emissions.

High levels of sulfates can and should be mitigated to avoid toxic reactions. Nevertheless, sulfates are not unusual. They exist in certain places across the Range and are common anywhere water passes through certain kinds of rock. The limit for drinking water is 250 mg/L. Some bottled waters are almost 80 mg/L.

O’Niell Tedrow, a chemistry instructor at Minnesota North College in Ely, has conducted several extensive studies of wild rice and sulfates in Ontario and Minnesota. In fact, he’s conducting one right now. Last month, I visited his makeshift greenhouse on the college’s crumbling tennis courts.

When I visited, I saw rows of pots with watery sediment, each containing certain amounts of sulfates or chloride. These elements are found in mining-impacted waters. Green rice had sprouted in all the pots.

“Sulfur and sulfate and the way it changes form, or doesn’t, is influenced by myriad factors,” said Tedrow. “It’s almost nonpredictable. In some cases, some general statement could be made, but it won’t be the case everywhere.”

While the threat of hydrogen sulfide is important, Tedrow said other factors also contribute to Minnesota’s wild rice crop decline. These include water levels, higher temperatures, competition from other plants and wildlife eating the rice.

Tedrow believes that is the best way forward. I wasn’t sure if I agreed with him until last week, when I learned the wild rice plants in all his pots were still growing, even in the sulfate-rich water.

It will take years of research to arrive at an appropriate, effective system of site-specific sulfate standards. That research must start as soon as possible, but mines cannot wait to act. For everyone’s good, but especially their own, companies should agree to develop more affordable sulfate reduction plans now.

Mines often use reverse-osmosis filtration to reduce sulfates because of its proven effectiveness, but it’s among the more costly methods. The cost rises exponentially the closer you bring sulfate levels to zero. That’s why Minnesota’s limit of 10 milligrams is considered so challenging for mining companies, farms and wastewater treatment facilities.

“It’s hard to get sulfate down to that level, especially with the volumes involved in taconite mining,” said Rob Beranek, water services manager at the Eagle Mine in Michigan.

At Eagle, they mine for copper and nickel with much smaller water output. They process the sulfates using reverse osmosis, taking the hydrogen sulfide all the way down to a solid salt that must be discarded.

There is another way, though it will take work.

On my tour of makeshift research facilities this summer, I stopped at the Clearwater BioLogic mobile lab in Babbitt, Minn., actually a trailer parked in Jeff Hanson’s driveway on Birch Lake. Clearwater is using anaerobic bacteria to consume sulfates in large bioreactors that can be placed in mining-affected waters.

The microorganisms convert sulfates into sulfides in a controlled environment so they can be removed.

I’ve been following Hanson’s work for years. Early tests conducted with the Natural Resources Research Institute showed promise but excessive cost in processing the sulfide waste. Hanson says he’s solved that problem by using direct-reduced iron to process sulfates into iron sulfide, a solid that can not only be captured but sold as a commodity.

The Clearwater method has been met with skepticism in mining circles, in part because of the complications and costs of the first experiments.

It’s understandable that the mining industry would want proven technology for something so important and expensive. But next generation bioreactors are showing more promise. I found one example overseas.

In Sweden, the Kiruna iron mine has been in operation for 125 years, almost as long as those here on the Mesabi Range. Their operations are mostly underground, but they have the same problem with sulfates leeching from waste piles.

So, I contacted the project manager for SULFREM in Sweden. When I explained Minnesota’s wild rice sulfate standard, his reaction was surprising.

“The level 10 is too low,” said Roger Herbert, an associate professor of hydrology at Uppsala University in northern Sweden. “In Sweden they think about salmon fry, but it’s still 100 mg or so per liter that they’re working with.”

In fact, two years ago the Swedish government issued an order for LKAB, the corporation that runs the Kiruna mine, to address high sulfate levels in its pits. LKAB’s sulfate amounts, 1,000mg/L, were similar to those at U.S. Steel’s Minntac mine in Minnesota. The number Swedish courts required was 150 mg/L.

“I am optimistic that this will work,” said Herbert. “Other methods could work but this is a viable solution.”

Herbert warns that the method isn’t cheap, but he still predicts it will be more affordable than reverse osmosis.

Each of the speakers at last Wednesday’s MPCA hearing on the Iron Range, regardless of their views, spoke of culture. Who we are. What we do. Anytime we engage in mining, we accept a certain risk that must be justified by what we receive in return.

Leaving high sulfate levels in perpetuity across the Iron Range is not acceptable. Nor should we shut down our nationally significant mining industry prematurely. A pending economic slowdown is all the more reason to address the sulfate issue now, so that the pits aren’t abandoned later.

The economic fear I saw among the people in that hearing, a room that included many friends, was real. Fear, too, must be mitigated with creativity, cooperation and leadership.