Locked-out workers at a Rio Tinto Alcan Quebec smelter will have to move their picket line after the company obtained a court injunction ordering employees to keep their distance.

The Quebec Superior Court injunction requires workers to move pickets by 150 metres, and limit gatherings to 20 people.

Rio Tinto Alcan (RTA) sought the injunction Monday night, on the second day of a lockout at the company's Alma, Que. aluminum processing plant.

The injunction was needed to make it easier for company managers to access the smelter as needed, without confronting unionized workers "protesting illegally," said Rio Tinto Alcan spokeswoman Claudine Gagnon.

About 200 managers are expected to maintain reduced production at the Saguenay region smelter.

The managers are capable of running the smelter at two-thirds production for up to a year, Gagnon said.

More than 700 unionized workers were locked out early Sunday morning after rejecting RTA's final contract offer last week. Their collective agreement expired at midnight Saturday.

The Syndicat des Métallos d'Alma, which has been negotiating with RTA since Oct. 4, disagreed over subcontracting conditions. The union sought guarantees that retiring workers would be replaced with unionized hires.

RTA wants the option of subcontracting some work.

On Monday the Alma union accused RTA of hiring outside replacement workers during the lockout, contravening Quebec labour laws. Union officials said they observed snowmobiles and helicopters ferrying several people to and from the smelter.

The smelter is a major employer in Alma, a town of about 30,000.

Alma's mayor has pleaded publicly for both sides to relaunch negotiations.