United Steelworkers members, including those represented at a mine on the Iron Range, unanimously gave leaders authority to call a strike against ArcelorMittal should contract negotiators fail to produce results for about 15,000 workers across the nation.

ArcelorMittal is the largest iron mining and steel producer in the world. It has 18 facilities in the United States and employs about 300 union workers at the ArcelorMittal Minorca Mine in Virginia, Minn.

Company and United Steelworkers (USW) officials confirmed Tuesday that contract talks are ongoing in Pittsburgh after the Monday strike vote.

If a strike is called, union members would receive 48 hours notice, said Harold Anderson, president of the USW Local 6115 in Virginia.

Steelworkers labor contracts expired Sept. 1 for both ArcelorMittal and for U.S. Steel, which operates the Keetac mine and taconite plant in Keewatin and the Minntac mine and plant in Mountain Iron. The bulk of 16,000 union workers at U.S. Steel nationwide authorized a possible strike on Sept. 10.

Workers at both companies agreed to continue negotiating beyond the Sept. 1 contract expiration in the hopes of reaching an agreement. But tensions have remained high as the days drag on with no contract resolution.

ArcelorMittal officials said Tuesday its plants continue to operate in a “safe and orderly fashion.”

“It is important to note that this is not a declaration of a strike, talks continue this week and we continue to work diligently to reach a mutually agreeable conclusion,” the company said.

Sticking points in the negotiations include proposed health care, pay and retirement concessions, especially because union members made concessions during the industry downturn in 2015.

Now the industry has rebounded and many facilities are near or at capacity.

“Now that the company is generating enormous — even historic — amounts of cash, it is an insult that bargaining progress has been hindered by management’s unrealistic concessionary demands and unfair labor practices,” said USW International President Leo W. Gerard in a statement.

David McCall, negotiation chair and director of USW District 1 in Ohio, said that ArcelorMittal’s represented workers “are uniformly fed up with management’s attempts to reduce, eliminate, undermine and weaken contractual protections and benefits hard-won through generations of collective bargaining. ArcelorMittal can easily afford to negotiate fair labor agreements with us.”

Anderson, from Virginia, Minn., noted that the vote for a possible strike “was 100 percent unanimous” across all 13 USW local unions representing ArcelorMittal workers.

Similar pushback was seen by union workers at U.S. Steel, which has hundreds of workers in Minnesota.

U.S. Steel spokeswoman Meghan Cox said in a recent e-mail to the Star Tribune that the company believes its revised proposal for a six-year contract “is in the best long-term interest of all U.S. Steel stakeholders.”