The Building Tradesman Newspaper

Friday, March 28, 2014

Big crane, big job

By The Building Tradesman

One of the largest cranes in North America is operating at the Humboldt Mill, which is the largest construction employer in the state.

Lundin Mining brought in a 1,400-ton Terex Demag CC6800 crane to the mill, one of three such cranes operating on the continent. The maximum lift height for the crane is about 400 feet, but it can be configured to reach more than 700 feet.

“The crane is being used to help construct three fine ore bins,” said Crane Network News. “The bins are built outside the mill in five sections and lifted to the mill piece by piece.  They are connected together, similar to a Lego set.  Each completed bin is 30 feet wide about 150 feet tall, and will hold four million pounds of ore.” It took 85 trucks and nearly a month to construct the crane

Work at the Humboldt Mill, in western Marquette County, is expected to be complete later this year. Built in the 1950s, the mill processed ore and other metals but has been unused the last two decades. Now the building trades are refurbishing the mill to accept ore from Eagle Mine, about 65 miles away. Expenditures at both the mine and the mill are expected to total about $800 million. Construction employment at both is expected to peak at about 500.

The Eagle Mine is the only one in North America devoted to nickel extraction. It is expected to produce 360 million pounds of nickel, 295 million pounds of copper and small amounts of other metals over its eight year productive life. Some 330 jobs will be created during the mineral extraction process, which is expected to start in late 2014.

Ore that is mined will be crushed and separated into nickel-copper concentrate at the Humboldt Mill, and the material will then be taken by rail to a smelter and last to a refinery before the metals are ready for use by manufacturers.