Dear John, 

If you’re receiving this email, you likely know that the Boundary Waters is threatened by proposed copper mining — but what exactly is copper mining, and why is it so dangerous? 

This is the second email in our series about the threats facing the Boundary Waters. Today, we’re breaking down the basics of copper mining and why it is so dangerous:

What is copper mining? 
You might know that Minnesota has a proud history of over a century of iron mining — but copper mining is a whole different story. Copper mining is a risky type of mining considered the most toxic industry in America, and it has never been done in Minnesota. Not once.

This type of mining involves blasting massive amounts of rock, crushing it into smaller pieces, and using chemical processes to separate the valuable metals. Because copper makes up less than 1% of the mined rock, the vast majority–millions of tons–become toxic waste that must be stored indefinitely. 

What is the copper mining project next to the Boundary Waters?

Twin Metals, owned by Chilean mining giant Antofagasta, wants to build a copper-nickel mine immediately upstream of the Boundary Waters. In its early years alone, the mine could generate over 4 million tons of waste rock along a 1,000-acre facility on the shores of Birch Lake (just a stones throw from the Boundary Waters).

When this waste rock is exposed to air and water, it creates a chemical reaction that produces acid mine drainage which is often compared to battery acid and includes sulfuric acid, heavy metals, and other toxins that could pollute for centuries.

Why is copper mining in the Boundary Waters dangerous? 

• 100% of copper mines pollute. There has never been a sulfide-ore copper mine that hasn’t resulted in pollution.
• The Environmental Protection Agency has deemed hardrock mining America’s most toxic industry.
• Pollution would spread beyond the mine site. Because the Boundary Waters is a vast network of interconnected lakes and rivers, toxic waste would not stay contained. It would travel downstream through the Rainy River-Headwaters Watershed, affecting Voyageurs National Park, Quetico Provincial Park, and eventually flowing into Hudson Bay.

Is mining next to the Boundary Waters needed for the clean energy transition?

Absolutely not! The Twin Metals project would be both insignificant and irrelevant to America’s security and clean energy transition — barely denting U.S. demand for copper. (Read next weeks email for more on this topic!)

Is there another way to get copper?
Yes! Copper is an important, and abundant resource globally, with growing resources. The United States, among the top five producers, holds plentiful reserves.

But, mining is not the only way to obtain it. Copper is one of the most recyclable (and recycled) of all metals.

We can’t allow America’s most toxic industry next to America’s most visited Wilderness. 

Once copper mining pollutes the Boundary Waters, it's forever—there are no second chances. The Boundary Waters is public land. This maze of lakes and rivers, carved by glaciers, lined with towering pines, and brimming with crystal-clean water, belongs to all of us.

Save the Boundary Waters leads the charge to defend and protect this national treasure. Over 80% of the gifts we receive come from individual donors giving $100 or less. People like you power the grassroots movement to protect the Wilderness—donate today. 

Stay tuned. Next week in this series, we’ll talk about mining conglomerate corruption.