United Steelworkers at 3M’s 763-employee Cottage Grove chemicals plant have voted to give strike authorization to union leaders embroiled in labor negotiations with 3M Co.

The company and employees have been in labor talks for several weeks but have yet to reach agreement on how to replace the three-year labor contract that expired last month. Union officials said that the members’ strike authorization might provide the leverage needed to move the company to greater flexibility on issues including weekend pay, work rules and benefits.

“Right before the Labor Day weekend, the members of United Steelworkers Local 11-00418 in Cottage Grove overwhelmingly voted to approve strike authorization for their bargaining committee in an effort to spur the company to have more urgency in talks,” said USW staff representative Brian Ecker. “Negotiations are continuing, and we are hoping to attain a successful resolution.”

3M spokeswoman Fanna Haile-Selassie declined to discuss key elements of the proposed contract that are in dispute.

“We are still in the contract negotiations and still working hard to get a deal done,” she said. “Right now we just want to respect the process. … Our goal is to identify ways we can continue to operate successfully while still providing competitive pay and benefits.”

The prior labor contract covered about 400 steelworkers at the plant.

Union workers have been operating under a temporary one-month contract extension that ends Saturday. Talks with company officials are scheduled to resume Friday, USW officials said.

Union employees have been negotiating with the company since June and have occasionally picketed at 3M Cottage Grove, at various community parades and outside 3M headquarters in Maplewood.

The steelworkers have balked at company plans to adjust weekend wages. Specifics are not yet available on other points of contention.

The 3M facilities in Cottage Grove include a plant that supplies many 3M divisions around the country with various products.

The operation is the city’s largest employer and houses seven 3M divisions including abrasives systems, industrial adhesives and automotive.

The 1,750-acre site also operates a wastewater treatment plant and an incinerator.