Steel has been one of the most widely used and celebrated architectural material for over 150 years. From the steel frame of the earliest skyscrapers, to the rebar that reenforces nearly all concrete construction, to the renewed interest in rust as an expressive material finish, it seems that architects rely heavily on steel to achieve both functional and expressive aims. Yet rarely do architects have the opportunity to appreciate the material flows and industrial processes that go into the production and distribution of the materials we specify, nor do we have much of an understanding of the economic and environmental impact of these material flows.
This past week I had the opportunity to experience firsthand the global flow of iron ore during tours of the open-pit mines along Minnesota’s Iron Range and the international shipping port of Duluth-Superior. Despite being born on the Iron Range and growing up in Duluth, I was surprised to learn how central a role these two locations have played in the global supply and distribution of iron ore for steel production. In the decade prior to WWII, more than one-half of the iron ore extracted worldwide came from Minnesota mines, with the majority of it shipped to eastern steel mills via Duluth. Duluth Steel foundries such as Clyde Iron Works were instrumental in the the fabrication of the steel equipment that built the Empire State Building, Golden Gate bridge, Panama Canal, and New York subway system. When Iron Range mining hit its peak in 1950, over 80% of all steel produced in the United States was being made from Minnesota iron ore. As the high grade iron hematite deposits became depleted, a series of technological innovations made mining the lesser-grade taconite deposits physically and economically feasible. The invention of the taconite pellet by Edwin W. Davis in 1955 and the development this year of magnetic technology to extract iron particles from previously discarded mining tailings promises to sustain the mining economy of the region for another decade or more. Yet it is not difficult to foresee a point at which the environmental toll of extracting minerals from poorer and more difficult to access deposits will outweigh the economic gains of mining an increasingly scarce resource. This certainly seems to be the case with the tar sands in Alberta.
It’s difficult to know exactly what the future holds for Iron Range mining and the Duluth shipping industry which both rely heavily on the flow of taconite pellets to the developing economies of Mexico and China. Yet it’s safe to assume that the days of iron ore mining are numbered. When this flow of iron ore does come to an end, it will inevitably have significant ramifications for both the local economy and the global supply chain that feeds the construction industry. Perhaps now is the time to invest in renewable and reusable material economies that can sustain us both economically and ecologically in the decades to come.