FILE PHOTO: The General Motors assembly plant in Oshawa, Ontario, Canada November 26, 2018. REUTERS/Carlos Osorio/File Photo

(Reuters) - General Motors Co will respond by Jan. 7 to a Canadian union’s proposals for keeping an Ontario auto assembly plant open, the head of Canada’s largest private sector union said on Thursday.

Unifor head Jerry Dias told reporters after meeting with GM executives in Detroit that the carmaker did not “unilaterally slam the door” on the union’s efforts.

The Oshawa plant is scheduled to shut down in December 2019 but Dias said the “solutions are plentiful” to save it, without going into specifics. The closure is part of a wider restructuring by GM announced in November that will close five North American plants and eliminate 15,000 jobs.

“Our argument to GM today is that they truly have gone too far,” said Dias, who represents most unionized auto workers in Canada.

The Oshawa plant closure, which affects 2,973 assembly line workers, would end more than century of vehicle production in the city east of Toronto.

David Paterson, a spokesman for GM in Canada, described the meeting as “constructive” and said the automaker would get back to the union by January 7 or earlier.