FARGO, N.D. (AP) — American Crystal Sugar Co. and its locked-out union workers headed back to the negotiating table Monday, but refused to talk about the results.

A federal mediation service in Minneapolis said talks between the company and the union representing about 1,300 workers would resume, but didn't disclose the place and time. Workers have been locked out since Aug. 1.

Representatives from both sides did not return repeated phone calls Monday from The Associated Press.

North Dakota state Sen. Tim Mathern, who last week wrote a letter to company and union officials urging a settlement, said he views the silence as a good thing.

"If that's the way they're responding, I think that means they are actually working on an agreement," Mathern said. "It's right down to the wire in terms of wording, I'm sure, and now is not the time to talk publicly."

American Crystal's last offer was a 17 percent pay increase over five years, but workers rejected it over job security provisions, health care costs and language in the contract they say will hurt workers in future years.

The contract dispute involves workers at sugar beet processing plants in North Dakota, Minnesota and Iowa. The factories have been running with replacement workers hired by a Minnetonka, Minn., firm.

Mathern told company president David Berg and union president John Riskey that the lockout has gone on too long and people are suffering.

"People are applying for welfare, applying for Medicaid, applying for food stamps," Mathern said Monday. "They can't feed their families."

The lockout is the first labor impasse in 30 years at American Crystal, a cooperative that accounts for 38 percent of the nation's sugar from beets and 15 percent of overall sugar production.

It's the second time the two sides have met since the lockout. Mark Froemke, a union representative, said negotiators representing workers planned to bring new proposals to the table, but refused to outline the changes.