See this? It’s not lava, or blood. Water laden with metal particles turns a bright, rusty color — not unlike an old faucet. It kills living organisms that live in streams, and endangers the drinking water of nearby residents. This phenomenon is happening all over the world, and it’s called acid mine drainage.
With current mining practices, where there is a mine that disrupts sulfide materials, there is also a high potential for Acid Mine Drainage. Acid Mine Drainage is one consequence of mining that has become a major concern for Wisconsin residents during recent debates over mining legislation.
But how does it happen; how does a clear Northwoods stream become a Day-Glo nightmare?
The mining process begins when large amounts of waste rock are removed from above iron ore deposits, then dumped into a nearby basin. Once iron ore is removed, it is mixed with huge volumes of water and separated by magnets. The slushy mixture of water and waste rock (known as tailings) is then also dumped into basins near the mine site.
Unfortunately, this isn’t the end of it. Often, waste rock and tailings contain sulfides disturbed during mining that react with oxygen and water — creating acid. That orange ooze blocks sunlight like a thick, wool blanket, and anything in the ecosystem that can’t handle the higher acidity levels will die. We’re talking plants, fish and other animals — plus acid isn’t the best for humans, either, as you might imagine.
When it comes to sulfides draining into water, here’s the rundown according to the EPA. Cadmium can cause damage to kidneys, which we rely on to filter our blood. Long-term exposure to copper can lead to liver and kidney damage, and upset stomachs with short-term exposure. Lead causes developmental disabilities. Iron in water does not directly cause health problems, the Wisconsin DNR says, but can cause discoloration in drinking water.
Any of these sulfides could turn up in a mine. And whether the acid forms right away or years later, things don’t look good for the environment. This uncertainty of the timeframe is exactly why water quality of the surrounding area must be monitored and treated for decades after a mine has closed.
The high risk of acid mine drainage at open-pit mine sites is one of many important reasons Clean Wisconsin fights hard to make sure Wisconsin’s mining laws remain strong and continue to protect our environment and the health of our families. Especially when you consider the beauty of the area just below the proposed mine site.
-Digging Up Dirt is a series of blog posts that highlight the environmental dangers of mining. This post was contributed by Sarah Witman and includes research by Laura Green.