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What's in the Ships?

Minnesota’s Connection to Both Domestic and Global Markets

In 1970, Congress officially designated the Great Lakes as our nation’s “Fourth Seacoast.” The Great Lakes serve as one of our most important transportation corridors, with movement of more than 200 million metric tons of goods a year, supporting both domestic and international business and trade. Minnesota gained direct access to international deep draft navigation in 1959. The St. Lawrence Seaway winds 2,350 miles (3,780 km) from the Atlantic Ocean to Duluth, Minnesota, and ships gain 600 ft. in evaluation during the approximately eight-day trip.

Minnesota has four ports on Lake Superior – their combined tonnage in 2006 equaled 67.4 million net tons (the net ton, or short ton, equals 2,000 lbs). The largest and busiest Minnesota harbor is the combined Port of Duluth/Superior, which handled a total tonnage of 47,234,022 net tons (of various commodities) in 2006. The Port of Duluth/Superior was the 20th largest U.S. port in total tones moved last year.

What Cargos are the Big Ships Carrying in Lake Superior?

Minnesota’s taconite industry represents 59% (40 million net tons) of the total tonnage shipped from the state. Taconite is mined in Northeastern Minnesota and shipped mainly via the Great Lakes to steel mills in Ohio and Pennsylvania. Although every cargo is important to shippers, iron ore (taconite) for the steel industry is what built the Great Lakes fleet, and remains its mainstay to this day. Iron ore movement from Minnesota ports through the Soo Locks occurs continuously through the federally mandated opening and closing of the locks from March 25 through January 15.

The second largest commodity tonnage shipped on Lake Superior is coal from Montana and Wyoming. It comes into the Port of Duluth/Superior via dedicated 100-car unit trains to Midwest Energy, where it is stockpiled and then loaded onto ships for distribution throughout the Midwest and even overseas. This “low-sulfur” coal is cleaner burning than eastern coals, and is prized for power generation.

Our ports handle limestone, cement, project cargo (machinery and equipment), minerals, clays, salt, packaged goods, scrap iron, rolled steel, and much more. Commodity shipment on the Great Lakes continues to rise each year, especially coal. There is a growing pressure on our transportation infrastructure as both domestic and international trade continue to expand (demand has doubled in the past 15 years, and it is expected to double again in the next 10-20 years). This fact makes the value of the Great Lakes Transportation Corridor even more important.

Cargos are Not the Only Thing Transported on the Great Lakes

In addition to commodities, people, and products, there have been unwanted “stowaways” on the ships moving across the Great Lakes. We call these non-native or invasive species, and they have been known to cause great harm to the environment, the economy, and recreation. This is a major issue that both shippers and carriers are trying to overcome through a number of different initiatives. Biological pollution is not just a Great Lakes shipping issue, and it impacts the environment world wide. One of the most recognizable aquatic invasive species is the zebra mussel, which is widespread and has caused great damage. In addition, we need to become aware that species native to the Great Lakes can become invasive overseas when transported there.

Different Ships Mean Different Cargos and Different Destinations

The Great Lakes has two distinct fleets of ships. One we call “salties,” those ships that are small enough to pass through the Welland Canal (8 Locks in series, lifting vessels with a maximum size of 740 ft. in length and a beam/width of 78 ft. or less past Niagara Falls). The second fleet of ships are called “lakers” and are too large to move through the lock systems out to salt water. These often specialized ships are unique and have contributed to many important innovations in “bulk” commodity handling. In fact, carriers come from around the world to the Great Lakes to learn the best ways to handle and move bulk materials. The largest vessels in the Great Lakes are just over 1,000 feet and have a width of 105 feet.

If you want to learn more about Great Lakes ships and the things they carry, check out these Great Lakes Web sites:

Maritime Transportation:

Topic Highlights:

This page last modified on November 25, 2008     © 1996 – 2020 Regents of the University of Minnesota     The University of Minnesota is an equal opportunity educator and employer.
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