Berkeley Pit in Butte, Montana. This is significantly smaller than the tailings pond proposed at Pebble, which would sit at the headwaters of Bristol Bay.
News that the U.S. Army Corps of Engineers has released its Draft Environmental Impact Statement relating to the proposed Pebble Mine raises the important question “Why are we so opposed to the plan?” In a great article from Save Bristol Bay spells it out in careful detail. Environmental scientist Molly Welker walks us through the problem of dealing with Pyritic tailings, acid-generating waste, and up to 10.6 billion gallons of waste water per year.
The sulfides in the tailings will react with oxygen and water to create sulfuric acid, which leaches other harmful metals from the surrounding rock, creating a toxic “soup” called acid mine drainage. Mines with acid drainage generally require on-site treatment in perpetuity.
That term in perpetuity is terrifying, or course, as it means that such water will require treatment for hundreds or thousands of years. Think about that. Then consider that “In a 2012 review of fourteen currently operating U.S. copper mines that account for 89% of U.S. copper production, 92% failed to capture and treat mine seepage, resulting in significant water quality impacts “
All we need to do is look at the two tailings dams that collapsed in Brazil. These were in an area with very little seismic movement. Pebble mine in in the Pacific rim, which has the greatest seismic movement on earth!