The Toronto-based company says there are currently 100 construction personnel on site, a number that will swell to 350 later this year.
Eagle also has 70 staff and is recruiting to fill about 220 positions by the third quarter of 2014.
Eagle was formerly owned by a subsidiary of Rio Tinto PLC (NYSE:RIO), which sold it to Lundin for US$325 million in cash.
The mining project, near Marquette, Mich., on the south shore of Lake Superior, is about 340 kilometres west of the Canada-U.S. border at Sault St. Marie.
Lundin announced Wednesday that its deal with Rio, announced last month, closed ahead of schedule.