Xstrata and Glencore are one step closer to a $30 billion merger.
Shareholders in both companies were expected to cast ballots Tuesday to decide if Glencore has the green light to take over the mining giant.
The president of the CAW/Mine Mill Local that represents workers in Sudbury said the union will co-operate with the merger.
"[It’s] not our first time we've been through a merger," Richard Paquin said.
"We will do the best we can for our members and for this new company."
While workers in Sudbury are on board, unions and government officials in other places like South Africa said they plan to challenge the potential merger, Paquin said, adding it could delay any decision that comes from Tuesday's vote.