Good Example of Bad Results from Exposed Sulfur Containing Rock

Vermilion Community College (VCC) in Ely, MN offers an excellent example of the bad results from water runoff of exposed rocks containing sulfur. A very thin band of exposed sulfur containing rock in the Greenstone outcropping in the VCC courtyard has produced a dead zone “downstream.” As you approach the massive Greenstone outcropping from the front of the courtyard you see what we would expect in Northern Minnesota, bright green vegetation, flowers, a healthy Birch Tree and a huge rock outcropping. Hidden from view, on the backside of this larger outcropping, is a smaller outcropping that contains a small thin band of exposed crumbly sulfurous rock that has, with rain running off and “downstream” from this rock, a dead zone where nothing lives, except the rocks. Although this is not the same kind of rock that will be mined for copper, sulfur in what ever form when exposed to air and water will produce acid mine drainage and release of arsenic and mercury and other heavy metals into the watershed and that DOES include the type of rock that contains sulfur in the form of sulfides that may be mined for copper in our region.