What was the SS Fitzgerald’s Freight?

The SS Edmund Fitzgerald was carrying about 26,000 tons of taconite pellets.

Just what exactly is taconite?

Taconite is the result of a method that was developed by the University of Minnesota that crushes low grade iron ore and processes it. The end product is a round ball, about the size of a marble, that its high grade material. This process saved the mining industry in Northern Minnesota as most of the high grade ore had already been extracted. Without the taconite process, mining in Northern Minnesota would have shut down because the abundant low grade ore was not useable in its raw form.