Galmoy Mines in County Kilkenny is to close by 2011 - 221 jobs will be lost.
Chief executive Stefan Masson said today that the closure was largely due to the fact that the mine will be exhausted by then.
He said the news would not come as a shock to staff as redundancies were part of an expected 'wind down' process. Masson also said the price of zinc was down 50% on last year's prices with the dollar exchange rate and the international markets having an impact on prices.
The trade union SIPTU said it had negotiated a redundancy package for 221 workers at Galmoy.
The union says intensive talks concluded early this morning with a deal, which will include a package worth 6.75 weeks pay per year of service. The first 36 redundancies will take place this year.
The Galmoy mine is located approximately 30 km to the northwest of the city of Kilkenny. The workings of the underground mine are accessed through a decline from surface. Mine production is primarily carried out by room-and-pillar and by bench-and-fill methods.
The primary metal produced is zinc, with lead and silver obtained as by-products.
Galmoy is owned by the Canadian Lundin Mining Corporation, which is a diversified base metals mining company with operations in Portugal, Spain, Sweden and Ireland.