Company officials said the tower's construction took 11 separate lifts via a Liebherr LR-13000 crawler crane - one of North America's largest units featuring a lifting capacity of 3,000 short tons (2,722 tonnes). The crane is scheduled for disassembly this month.

"This represents a significant milestone in the construction process as the furnace tower was the key critical path item in facilitating the advanced start-up date for the commercial production of HBI," Cleveland-Cliffs said, adding that it is ahead of schedule on the project and is now eyeing a production start date in the first half of next year.

"I am proud that this portion of the project was accomplished in record time, and also completed with an industry-best environmental and safety record with 1.7 million man hours," president and CEO Lourenco Goncalves added.

The facility, which was first announced in April 2018, is targeted to produce about 1.6 million tonnes annually of customised HBI; it will also supply the domestic regional market that is currently being served exclusively by imports.

Once in operation, the company said it expects to be the sole producer of HBI in the Great Lakes region of North America.