Unions hope the proposals put to management at Tara Mines will "remove the threat of layoffs".
SIPTU, Unite and Connect trade unions representing workers at the mine held "intensive talks" with management over the last two days.
Boliden Tara Mines last week said it would temporarily suspend operations at the mine and lay off 650 workers, due to factors including a decline in the price of zinc, high energy costs and general inflation.
It said it made the decision in response to unsustainable losses and in the long-term interests of the mine.
Speaking following this morning's meeting, the unions said that they submitted a document of 12-14 pages detailing their alternative proposals to the company's plan to place the mine into "care and maintenance".
John Regan from SIPTU said that there were "a lot of suggested ways forward that hopefully will deliver savings to the company and also improve the operation, in terms of how material leaves the mine".
He said that the company had a lot of questions around their proposals and have now agreed to give it "two to three days, maybe into next week", before it comes back with a reply.
Mr Regan said everyone had participated "very positively", including management.
The unions have asked Boliden Tara Mines to reply to their proposals on a short, medium and long-term basis.
"This is not just a quick hit and a quick fix," Mr Regan said.
"This is a long term set of proposals that is going to benefit the mine going forward and hopefully remove the threat of layoffs."
'Haemoragging money'
Unions say their proposals aim to address areas where the company has been "haemorrhaging" money around energy and fuel.
"We have up-front suggestions on all of that and it should bring in savings of between €70-€100 million in our view. Hopefully that will deliver enough to extend the mine until at least the end of the year," Mr Regan said.
Unions said the company informed them during the talks that they had €35 million remaining from a loan they sought from the parent company in April, which would last until the end of August.
"If our savings come in on top of that, we are most certainly looking at a positive outcome. That gives us production into the end of the year and beyond."
Unions said they made proposals on the running of the mine on a medium to long-term basis, which they said involved "everybody in the mine", "from the top down".
"They have to perform their duties in a different way. There is inefficiencies there and we believe we have put in proposals that's going to improve efficiencies and ultimately output that is going to keep the company very viable."
Proposals involving IDA grants and EU funding were also suggested, as well as a change in the royalties the company has to pay the State.
Mr Regan said that a submission has been sent to Enterprise Minister Simon Coveney, covering IDA grants, royalties the company has to meet every year and EU funding in the form of just transition.
He said that Tara Mines was an extraction company like Bord na Móna and that the Just Transition fund should be available to Tara Mines.
Unions say they are seeking a "very considered", and "full and frank response" to what they have put forward.
They are also keen that the parent company Boliden in Sweden is involved.
'Full and considered response'
Boliden Tara Mines said it will now review the proposals and provide a "full and considered response to the trade unions at the earliest opportunity".
It thanked the representatives for their proposals and the "constructive approach they have taken".
In a statement following the meeting, the company again reiterated that the losses being experienced at the operation in Navan were "unsustainable" and "required urgent action to stem the large cash outflow".
It said the decision to enter care and maintenance on a temporary basis was taken "to safeguard the long term future of the mine".
A date for the next meeting has not been set.
