The two sides met for the fourth time with a federal mediator in an attempt to end the impasse. The company said in a statement that the union’s proposals were not consistent with the company’s final offer.

“The parties remain far apart,” the company said in a sentence highlighted in bold face. Brian Ingulsrud, American Crystal spokesman, said the company would have no comment beyond the statement.

Union spokesman John Riskey said Friday the outcome was disappointing, but not surprising.

“We came prepared for genuine negotiations and with positive proposals to help bring an end to this stalemate,” Riskey said.

About 1,300 union workers have been locked out since Aug. 1 at plants in North Dakota, Minnesota and Iowa. Unemployment payments for most of the workers in Minnesota will end in the next month. North Dakota workers were not eligible for unemployment.

The company has been using replacement workers at all of the plants.

The union said Friday it offered detailed proposals “addressing management concerns” on health care, drug testing and the role of seniority and qualifications in promotions. The company said the workers continued to demand wage and pension increases “significantly above” those contained in Crystal’s final offer.

“American Crystal listened to the union demands, received the document provided by the union that detailed their demands, and evaluated it,” the company said.

Riskey said the company leaders made it clear they are unwilling to compromise.

“But this lockout cannot and will not end unless there is cooperation at the bargaining table,” he said.

No further talks are scheduled.

American Crystal Sugar, the largest beet sugar processor in the country, has said it believes its contract package is a fair one, with a 14 percent pay increase over five years and increased pension, leave and vacation benefits.

Workers have backed off some of their earlier complaints on health care but are focusing on provisions covering job security and seniority.

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