At least 230 jobs are on the line at Rio Tinto Iron & Titanium in Sorel-Tracy.
The company's management met with the union this week to present a restructuring plan that could result in significant job losses.
The plan foresees cutting 75 jobs at the Montérégie-region plant between now and September, with another 155 cuts in 2014.
"We are in the process of evaluating the situation and we will meet all of our members at an assembly. We’ll have to take a decision on how to proceed, but I hope there will be room at the negotiation table [for us]," said union president Jacques Boissonneau.
The company maintains that the cuts are needed because of hard financial times.
Rio Tinto’s new president Sam Walsh is looking to cut $5 billion over the next two years from the mining giant’s budget.
Boissonneau said he believes the company is looking to make up for a $14 billion loss last year, which he said was mostly a result of acquiring Alcan.
Rio Tinto Iron & Titanium is Sorel-Tracy’s biggest employer.