MOORHEAD, Minn. (AP) — American Crystal Sugar says it plans to lock out its 1,300 workers at five Red River Valley sugar mills and hire replacements if a new labor agreement isn’t reached by Monday.

The Moorhead-based company is the largest sugar beet producer in the U.S. It’s negotiating with its union to replace a seven-year contract that expires at midnight Sunday. Local union president John Riskey says he can’t remember the last time the company threatened production workers with a lockout.

The union says the company’s proposal would hurt seniority rights and allow American Crystal to contract union work to outside firms. Company spokesman Brian Ingulsrud tells the Star Tribune (http://bit.ly/pbkeZ5 ) the company has to have a contingency plan in place for the beet harvest which begins in mid-August.