Roughly ten thousand years ago, raging glacial meltwaters created the broad valley of the Upper Mississippi River that we know today. They also helped form one of the river’s most famous and significant landmarks: Barn Bluff.
After the discovery of taconite in the late nineteenth century, scientists struggled to find ways to extract iron ore from this sedimentary rock, which contains 25 to 30 percent iron. The process that was eventually developed involves crushing the hard rock into a powder-like consistency. The iron ore is then removed with magnets and turned into pellets.