Over 100 freighters transport iron ore across the Great Lakes
May 29, 2019· The DSPA celebrated a successful year, with iron ore tonnage totaling million tons, 60 percent of the total tonnage shipped from the Port of DuluthSuperior. It was a 23season high in iron ore tonnage. More than 100 freighters transport iron ore across the Great Lakes, a combination of and Canadianflagged, and international carriers.