Cliff's Natural Resources has notified federal officials it could lay off workers at two Minnesota taconite mining companies, and two more in Michigan.
The notice sent Thursday puts workers on notice at Hibbing Taconite in Hibbing and United Taconite in Eveleth that layoffs could occur in 60 days.
The company had already announced potential cuts at Northshore Mining in Silver Bay, a non-union company that doesn't require the advanced notice.
Cliff's spokeswoman Maureen Talarico says the announcements sent this week don't mean layoffs will happen.
"It's a legal requirement that the potential exists -- the potential -- for layoffs in the next 60 days. It does not mean layoffs will occur," Talarico said.
Talarico says Cliffs has so far avoided cutting its workforce.
"Right now, in Minnesota, there have been no layoffs. At United we went down to a 32-hour work week beginning on Sunday, for a three-month trial period, in lieu of layoffs. At Northshore we've cut out some contract work and some overtime, trying to reposition people."
Talarico says the size of potential cuts hasn't been decided yet.
However, the company notes that its customers - steel companies - have been shutting down blast furnaces because of the global economic downturn.