Unions say there has been engagement from management at Tara Mines in Co Meath during a conciliation hearing at the Workplace Relations Commission (WRC) in Dublin.
However, the union say that no agreement has yet been reached and the meeting is continuing.
It follows a protest by workers at the facility which management has warned could jeopardise plans to safeguard the operation.
Boliden Tara Mines is set to suspend work at the facility next Friday, 14 July, with the temporary layoff of 650 workers.
Speaking on his way into the meeting, SIPTU Sector Organiser John Regan said he hoped the WRC hearing might address some of the welfare issues for workers.
"We have to have a way back. People have to know what way they're going to be called back and the method that that's going to come about with," he said.
"We're there to do business today and we're hoping that the company are in a conciliatory mind, because they haven't done that up to now."
Representatives from Boliden, including Chief Executive Gunnar Nystrom, also arrived this morning but did not speak to the waiting media before the hearing.
Mr Regan added: "It's all to play for today and if it doesn't work out, we will be going on to the Labour Court."
He said he hoped for an early hearing there, next week.
Mr Regan said: "The cliff edge is on Friday, and we would always be looking to prevent that happening. Even an extension on the 14th (July) would be helpful to keep engagement going but I can't see the company being interested in that."
He said there might be a role for the Government to see if they could push back on this deadline.
As protests at the site by some workers continue today, he said there was no split in terms of what workers want.
"I don't think there's a split. The workers are very clear. They're very angry. They're extremely annoyed with the company and management have not played ball with them and they are showing their frustration and their anger in their protest at the gate."
He added: "That's not a workforce you want to be bringing back in. You need to do the welfare issues. You need to give the supports and you need to make sure you have a skilled workforce coming back."
The company has previously said it is acutely aware of the difficulty and disruption the decision to go ahead with the temporary closure has had.
It said financial losses at the mines have been driven by factors including a drop in the price of zinc, high energy prices, general cost inflation and operational challenges.
