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Steel Dynamics

Boldt Role:

Rotary hearth furnace foundation construction

Key Points:

Boldt's history in the mining industry, collaboration and BoldThinking were central to the success of the project. The radius foundation was poured during the winter with 4,200 cubic yards of concrete and over 500 tons of reinforcing steel. Preassembly of Symons Flex-Form panels ensured the project's quality while keeping it on schedule.

Steel Dynamics

Mesabi Nugget

Hoyt Lakes, MN

When facing unique challenges of the frigid, open-pit site of the world’s first commercial iron nugget plant, it’s helpful to have BoldThinking® on your side. BoldThinking is the way Boldt approaches owner’s needs with flexibility and imagination, and much of both were used on Steel Dynamics’ Mesabi Nugget project, which estimates production at 500,000 tons per year.

As the project started, Steel Dynamics turned to Boldt for the first and most important foundation of the direct reduced iron plant project; the 33-foot wide, 240-foot-in-diameter, ring-shaped foundation of the rotary hearth furnace.

The challenge of working with a radius foundation was made easier using Symons Flex-Form panels, which were delivered preassembled to the correct radius. The panels helped form the foundation’s 4,200 cubic yards of concrete, poured vertically over 500 tons of reinforcing steel during winter conditions.

Boldt’s close coordination with Ulland Brothers, Inc., the earthwork contractor, proved to be paramount as portions of the foundation design were changed as work was progressing; down 37 feet and blasting rock down to discharge pit foundations.