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Taconite is a sedimentary rock mined in Minnesotaís Mesabi Iron Range for its iron content of approximately 25-30%. It is an important source of raw material for making steel.

Before it is loaded onto bulk cargo vessels, taconite is pelletized through a process pioneered in the early 1900s by University of Minnesota instructor Edward Davis. During this process, the rock is ground into powder and the iron is extracted with magnets. The iron is combined with a binder, such as bentonite clay and limestone, and rolled into pellets approximately one centimeter in diameter. Taconite pellets are about 65% iron.

Although taconite was first shipped in 1895, it didnít become a significant source of iron until after World War II, when high-grade iron in the U.S. became scarce. Taconite pellets travel by train to Lake Superior ports (Silver Bay, Two Harbors, Duluth-Superior) and are then shipped to steelmaking centers such as Gary, Ind., and Cleveland, Ohio. You might find iron from taconite in automobiles, building supplies, appliances, and in containers.

In 2010, 4.6 million tons of taconite was shipped from the Port of Duluth-Superior. The taconite industry employs about 3000 Minnesotans.


Tons of bentonite, a type of clay, leaves the Duluth-Superior Harbor by way of Hallett's Dock #5. Much of the commercial bentonite mined in the U.S. comes from an area between the Black Hills of South Dakota and the Big Horn Basin of Montana. It travels to Duluth by train.

Bentonite is mainly used for drilling operations, and to line and seal landfills. With the addition of water, even a thin layer of bentonite, turns into a waterproof coating with consistency of axle grease. Along the North Shore of Minnesota, the mining industry manufactures taconite pellets using bentonite as a binding agent. This clay is also used in making molds for casting molten metal, cement, adhesives, ceramics, and cat litter. Other, more esoteric uses of bentonite include pyrotechnics, winemaking, cosmetics, and laxatives.

2008 Port of Duluth-Superior Stats

1,126 vessels called on the Duluth-Superior port. 69 were oceangoing ships (less than half of the salty traffic of 2007).

Tonnage for the season, which ended on January 12, 2009 was 45,640,002 short tons; 4.6% behind 2007. Despite the global economic downturn and drops in steel production and manufacturing during the latter part of 2008, record coal shipments and the reallocation of iron ore pellets kept the season's traffic relatively stable. Project cargo traffic, which includes wind turbine components and Canadian oil sands equipment, remained steady. The precipitous decline in grain movement, reflected in reduced "salty" traffic, is partially attributed to exceptional harvests in the Ukraine and Australia, which reduced the global demand for American grain.

Commodity Trend Change from 2007
Coal RECORD! Up +6.3%
Iron ore Down -7%
Grain Down -61%
Project cargo No Change No change

The traffic through the St. Lawrence Seaway fell by 5.35% from 2007.

"Weíre in unchartered territory; itís difficult to know where inventories and freight rates will be in the year ahead, what sectors of the economy will recover fastest, where grain markets will be globally, or how many vessels will be in operation to start the season." Adolph Ojard, Duluth Seaway Port Authority executive director, January 2009.

Maritime Transportation:

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This page last modified on March 23, 2011     © 1996 – 2020 Regents of the University of Minnesota     The University of Minnesota is an equal opportunity educator and employer.
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