A union representing workers at Tara Mines has said that negotiations with management have failed to agree a path forward.
SIPTU says that management has reneged on a commitment to an independent facilitation process, and it has now made an application to the Labour Court for assistance.
The union condemned what it called an "abject failure" by management at Boliden Tara Mines after weeks of negotiations failed to agree a facilitation process.
Around 600 workers were temporarily laid off after the mine in Co Meath was placed into a period of "care and maintenance" during the summer.
The company said that the temporary closure of the facility was due to factors including the price of zinc and high energy costs and that the decision was taken to safeguard the long-term future of the mine.
SIPTU has said it is a "national scandal" that workers have been temporarily laid off for 130 days, with a total of around 2,000 workers affected, including those directly employed at the mine.
The union said that management had originally agreed to an independent process to resolve issues which would assist the reopening of the mine, but that it "has now reneged on that commitment".
SIPTU sector organiser John Regan said that the company had confirmed, in a letter, its intention to stick with its own facilitator, "thereby ruling out the joint facilitation process for which the Group of Unions has called".
Mr Regan said that the group of unions is now urgently seeking a date for the reopening of the mine, an outline of voluntary redundancy terms and a request for a hearing of the Labour Court.
In a statement, Boliden Tara Mines said it does not believe a referral to the Labour Court is necessary at this stage, but it said it will participate fully in the process.
The company said it will continue to engage with unions and hoped issues around the facilitation arrangements can be resolved quickly.
Boliden had committed to the development of a rescue plan to address operational challenges, which involved holding a series of workshops attended by management, employees and unions.
"We believed the arrangements for the workshops were agreed by all parties and we have agreed that the workshops should have an independent facilitator. We hope to resolve the issues regarding these arrangements swiftly, as we believe the workshops will be of benefit in the development of a rescue plan".
The operational issues were one of a number of factors behind the company's decision to temporarily close the mine.
Boliden has said that ultimately, the reopening of the mine will be influenced by external market conditions, but the development of a rescue plan will help to expedite the reopening process.
