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I recently took a trip to northern Minnesota, and decided it would be a good chance to look at a bit of history and how it affects the way things are made today. It’s a long journey from mine to model, and as engineers, architects, etc., we rarely see what is at the very beginning of the process. Seeing where raw materials are from can help us really appreciate the entire modeling process and the structures that are built from it.

Northern Minnesota plays a vital role in construction and manufacturing throughout the country. Most people think of Minnesota as just this cold place that has snow all the time.

Minnesota Mining: Iron Ore and Taconite

If you think of a company like 3M, you probably think of Post-It notes. However, did you know that 3M stands for Minnesota Mining and Manufacturing? 3M began back in 1902 in Two Harbors, Minnesota, on the Lake Superior north shore. Although 3M went on to other things as we know today, mining has been a large part of northern Minnesota’s industries for decades.

Minnesota is the largest producer of iron ore and taconite in the United States (90% of the total). Even though nearly all the high-grade natural iron ore in Minnesota has already been mined, the advances in technology have found that taconite, which is a lower grade iron ore, is being mined daily and used in everyday products.

What can we do with taconite? It is believed that every American born will need more than 20000 pounds of iron in their life. The iron mined in Minnesota along with other locations in the world are processed into steel, which make up several products you use every day, including vehicles, appliances, bridges, construction of buildings, agriculture, transportation, power generation, infrastructure and more. Back in war time efforts, mining of iron was critical for building military equipment.

So maybe you are asking yourself why is this such an interesting topic for me? As a person that grew up in southern Minnesota, I was always enamored by trips up to the north shore of Lake Superior, not just to see the big lake but also the trains and ships that delivered the ore from point A to point B.

In the past, I have visited both open pit mines (Hill Annex Mine and Hull Rust Mahoning Mine (First image below)) and underground mine (Tower-Soudan Mine (second image below)). All are still available for touring and two of them are State Parks. The Tower-Soudan mine will take you down in an elevator shaft about 2400 feet down. In comparison, the One World Trade Center is 1776 feet tall.

Hull Rust Mahoning Mine in Bemidji, MN

Tower-Soudan Mine in Tower, MN

Mining  and Ore Transport

After the ore has been mined from one of these locations, it needs to be shipped to be processed into steel. This is where the big locomotives come into play. The largest ever steam locomotive ran these railroad lines, it was a 2-8-8-4 Yellowstone steam locomotive. The length of it would be equivalent to about a 12-story building. There were other smaller engines as well, but if a large load needed to be moved you needed something with power.

Over the years, steam engines dropped off leading to diesel engines that we have today. Whenever visiting the Duluth, Minnesota area, I would always be on the lookout for those maroon and gold engines of the Duluth Missabe and Iron Range Railroad (DMIR). All these trains were heading to Lake Superior to drop off to the next set of transportation, the ore ships.

2-8-8-4 Yellowstone Engine, The Depot Museum, Duluth, MN

Conductor view of the cab of the 2-8-8-4 Yellowstone, The Depot Museum, Duluth, MN

EMD SD-18 Diesel Engine, The Depot Museum, Duluth, MN

Duluth, MN: Aerial Bridges and Ore Ships

When driving to Duluth, Minnesota from the Twin Cities, it is pretty much flat land until you come to Duluth. You come upon the big hill going down and you see a beautiful view of the harbor of Duluth and of Lake Superior. Off in the distance you see a strange type of bridge that most people have never seen before.

The Aerial Lift Bridge, initially built as a ferry bridge back in 1905, became what it is today – a vertical-lift bridge that lifts to a height of 135 feet in about one minute. The span is 390 feet across. So why is a bridge like this needed? For the ore boats of course. These ore boats can be over 1000 feet long and can be about 112 feet high just clearing under the lift bridge. Take a look at the ship’s schedule to see a live camera look at boats coming through.

Aerial Lift Bridge in Duluth, MN

Now Duluth is just one of the ports on the north shore, but it probably is the most accessible spotfor tourists to see the large ships. Two Harbors and Silver Bay have additional ore dock locations for trains to drop off their loads onto the ships. After loading the ore on to these large ships, where to next?

Ore ship loading taconite in Duluth, MN

Large ore ships would transport taconite or iron ore across the Great Lakes to Gary, Indiana, Cleveland, Ohio, or other steel-making towns. The pellets are brought to the steel mills and melted down into steel.

A company such as Gary Works in Gary, Indiana on the shore of Lake Michigan, would take the iron ore or taconite and go through the process of steelmaking and finishing. Hot-rolled, cold-rolled, and galvanized sheet products are produced for those industries I specified earlier to complete the process.

Gary Works USS facilities layout, Gary Indiana

Conclusion

In the future, I would like to visit one of these steel plants to really finish that journey and see the process complete. In the end as you have been reading, you may have wondered why such a topic for a blog post. I think it is interesting to see that process from where it starts to when you are sitting at your computer.

While working on that next construction or manufacturing project you are designing, you can really get a feel of the work involved in building from the raw materials.

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This blog is written by Sr. MEP Technical Specialist Phil Charlson. If you have any questions or just want to chat, please email us at whyATG@atgusa.com or reach out to us on LinkedIn.

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