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The Science of Environment

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MWP writer Jenn Hyvonen talked to Iron Range-based women who have been engaged in the mining issue, to learn about environmental concerns from their perspective. One of them was Chisholm-based resident Elanne Palcich, a retired teacher who writes opinion articles about the topic.

Palcich laid out the scope of the plans: “PolyMet Mining Inc. has proposed to dig three open pits, in what is now the Hundred Mile Swamp in Superior National Forest. Teck Resources has a deposit adjoining PolyMet. Twin Metals/ Chile-based Antofagasta has plans for an underground mine under the nearby Birch Lake and a facility bordering the Boundary Waters Canoe Area Wilderness. The operations would become one giant sulfide mine district.”

She does not trust Polymet’s ability to safely remove toxic residue. “PolyMet plans to treat plant site water with Reverse Osmosis (RO) when the mine closes. However, if adjoining mine operations intend to use PolyMet’s plant, closure would be postponed indefinitely. RO is very costly and the track record appears to be that it is not effective on the scale of such mining. PolyMet has no specific plans for what to do with the toxic residue that would need to be cleaned from the RO filters.”

Palcich adds, “I am surprised that U.S. Senators Amy Klobuchar and Tina Smith are jumping in to assure that PolyMet gets permitted. When women lose their deep-seated connections to water and life, we lose our way as humanity. The struggle for power represented by the push for sulfide mining in northeast Minnesota represents all that is the worst within us.”

“After dumping 67,000 tons of taconite tailings into Lake Superior each day by the 1960s, the [Silver Bay Taconite] plant became the focus of a bruising, decade-long pollution lawsuit. Taconite’s seemingly miraculous technological and engineering feats were possible only because they shifted the costs onto the environment. When those costs could no longer be ignored — as when spreading taconite tailings began discoloring Lake Superior — people reassessed the overall costs and consequences of industrial development.” 

— from “Taconite Dreams: The Struggle to Sustain  Mining on Minnesota’s Iron Range, 1915–2000,” by Jeffrey T. Manuel

Historically Minnesota’s lands have been mined for its iron deposits, as taconite mining. Extraction of precious metals would be part of the state’s first sulfide mine. The impact of mining on environmental resources, locally and globally, has not been good — with destruction of usable land, toxic watershed spills, higher rates of mercury found in children, and long and expensive environmental clean ups.

Cloquet-based biologist and aquatic ecology scientist Nancy Schuldt is a Fond du Lac Water Projects coordinator who specializes in toxicity research and watershed hydrologic modeling. She offered this perspective on the science behind the environmental concerns. 

Q: How is the newly proposed copper-nickel (sulfide) mining different from Minnesota’s existing iron ore (taconite) mines? 

Sulfide mining extracts precious and strategic minerals, like copper, nickel, silver, and gold, from the Earth’s rock and sediment. Chemically these minerals are bound with sulfur within the rock, thus the term ‘sulfide ore.’ When the ore is blasted and crushed, sulfide is released and exposed to air and water. Upon exposure, the sulfide waste becomes sulfuric acid, a compound highly toxic to humans and aquatic life. The process also releases dissolved heavy metals, such as mercury, in toxic concentrations.

Taconite is a low-grade, iron-bearing ore that is similarly blasted and crushed, and then concentrated to make higher-grade iron pellets used for steelmaking. 

Both types of mining create footprints of permanently destroyed habitat and leave waste in the form of tailings [waste rock that has been blasted and separated from precious metals], contaminated water, air toxins, and dust. The wastewater of sulfide mining is more toxic than taconite mining, but taconite wastewater is also polluted. 

Q: Are there processes to clear pollutants and contaminants from wastewater and rock?

Wastewater is recycled in plant processing, then slurried into a basin, where it seeps out of purposefully “leaky” tailings dams to ensure structural stability. Tailings basins themselves are considered “treatment systems,” to avoid certain requirements, but the only treatment they provide is some settling of the fine tailings solids. 

“Adding sulfate to a wetland can not only produce toxic levels of sulfide, but also increase the surface water concentrations of nitrogen, phosphorus, mercury, and methyl mercury.”

— study reported in Journal of Geophysical Research, November 2017, written by Minnesota scientists 

Q: What protections prevent leaks?

Minntac has installed collection systems outside the dams, and is pumping seepage back into the tailings pond, but they only capture about 50 percent. PolyMet proposes to install seepage collection systems outside the tailings dam, but claims of nearly 100 percent capture are not supported by evidence.

“Preventable safety blunders by the pipeline operator Enbridge and lax regulation led to the disastrous 2010 rupture and oil spill in the Kalamazoo River in Michigan. The pipeline spewed 843,000 gallons of highly polluting oil sands crude into the river. The cleanup has cost more than $800 million so far.”

— The New York Times, July 2012

Persistence of Mercury 

Mercury pollution is common in Minnesota waters. A 2012 Minnesota Department of Health study found one in ten babies along the North Shore of Lake Superior are born with unhealthy levels of mercury in their bodies. Mercury can impact a child’s ability to learn and process information. The Minnesota Biomonitoring Program is studying the amount of mercury exposure in newborns in some Minnesota communities.


“Researchers examined dozens of core samples and found more mercury from past mining is sticking around in local waterways than they thought. The findings could have implications for industrial sites around the Great Lakes.”

— “The legacy of mercury in Lake Superior,” research by Michigan Technological University, published in Journal of Great Lakes Research, 2016