Taconite

Today was our day off. To discourage biking if any sort, our bikes we're locked up in a hotel storage room. Our only task was to enjoy loafing around in Duluth.

Duluth has the furthest inland port on the planet. Lake Superior features violent storms, so a sheltered harbor is important. The St. Louis River, bearing lots of sediment, flows into Lake Superior and deposits the sediment. This has formed a long peninsula called Minnesota Point that shelters the ports of Duluth Minnesota and Superior Wisconsin.

The Minnesota Point peninsula reminds me of Florida barrier islands.

Two hundred years ago the harbor was more of a 4 to 10 foot deep swamp than a usable harbor. Starting in the 19th century, channels were dredged to create the harbor. As ships got bigger over time, the channels were made deeper and wider.

There are actually two peninsulas, Minnesota Point and Wisconsin Point, that almost meet. Water from the St. Louis River flows into the lake through the gap between the peninsulas.

The location of this gap presented a problem for Duluth. If ships entered through the gap, they would pass right by the Superior harbor before reaching the Duluth harbor. This would give Superior a huge advantage. The solution was to dig a canal through the Minnesota Point peninsula to create a shortcut to Duluth harbor.

The peninsulas have a natural gap and a man made canal.

Work on the canal started in 1870. The folks in Superior realized that the canal would take away some business from their harbor. They pulled some strings and asked the war department for an injunction to stop creating the new canal.

The people in Duluth got wind of the injunction. Before the war department could officially notify Duluth not to dig the canal, the citizens of Duluth grabbed picks and shovels and frantically finished a shallow canal. Once the canal was started, the powerful flow of the St. Louis River made the canal much deeper and wider literally overnight. By the time the injunction from the war department was served it was too late, the canal already existed.

This was great as far as providing an easy way for ships to enter Duluth harbor, but the canal turned most of Minnesota Point from a peninsula into an island. A bridge over the canal was constructed to provide access to Minnesota Point.

The bridge is a lift bridge. Instead of opening like a draw bridge, the whole span remains horizontal as it is lifted. Today the bridge is powered directly by the city's AC electric grid, but for 80 years it will was powered by hundreds of 2.5v batteries. During that 80 years the bridge never failed to open or close.

The bridge in the down position. Cars and pedestrians can cross to Minnesota Point.

The bridge in the up position to let ships entered and exit Duluth harbor.

These days Duluth and Superior cooperate and the army corps of engineers maintains both harbors.

The first building ever built by the army corps of engineers is in Duluth next to the canal.

Two of the main cargoes shipped out of Duluth are grain and iron ore. There are lots of huge grain elevators around the harbor.

The iron ore is shipped in the form of taconite pellets. To make these, the raw iron ore is crushed and the iron is extracted with magnets from quartz and other waste rock. The iron is mixed with clay and baked into pellets. The taconite pellets are easy to transport and have a higher iron concentration than the unprocessed ore.

The Canadian ship Cedarglen leaving Duluth with a load of taconite pellets.

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