The United Steelworkers of America have agreed to keep working under their old contract with Cliffs Natural Resources, at least for another month.

The USW bargaining committee said it negotiated a 30-day extension of its current agreement with Cliffs beginning Oct. 1, along with a rolling 168-hour extension if they go past those 30 days.

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The agreement had originally been set to expire on Oct. 1.

"While our committee has made progress on some issues, we remain far apart on many others," the union said in a message to members. "The company is still insisting on unacceptable and unnecessary concessions. These demands would essentially turn back the clock on decades of progress we've made at the bargaining table."

Meanwhile the union reported that it has resumed contract negotiations this week with U.S. Steel.

Union officials said they had spent a few weeks "gathering feedback from our brothers and sisters in our locals around the country'' and returned to Pittsburgh on Monday, to resume negotiations with U.S. Steel.

"Our bargaining team met among themselves and with company (U.S. Steel) representatives for several hours on Monday, discussing a wide range of issues, including active and retiree health care, contracting out and health and safety," the union said in a message to members. "While significant differences remain on each of these issues, we believe we are making progress, and we will continue to work hard to reach a fair agreement."

Talks also resumed in recent days between the USW and ArcelorMittal, said Tony Montana, union spokesman in Pittsburgh. No breakthroughs were reported.

U.S. Steel, which owns and operates Minntac in Mountain Iron and Keetac in Keewatin, is Minnesota's largest taconite iron ore producer. It also is a co-owner of Hibbing Taconite.

ArcelorMittal owns and operates the Minorca mine in Virginia with about 300 employees.

Cliffs Natural Resources is part owner and operates Hibbing Taconite and owns and operates United Taconite and nonunion Northshore Mining in Minnesota as well as two union operations in Michigan's Upper Peninsula, Empire and Tilden.

In all, about 4,500 Iron Range employees at five taconite plants are affected by the contract talks.