Pre-tax profits at the company that operates Tara Mines almost doubled last year to €19.3m, new figures show.
The mine - Europe's largest and the world's fifth largest zinc mine - employs 691 people.
Filings just lodged with the Companies Office show that revenues at the Swedish-owned Tara Mines Holdings and subsidiaries fell 10pc to €174.1m last year.
The Swedish firm warned the Labour Court last year that without a reduction in labour costs, 2013 would be loss-making for the mine and that the savings were necessary to secure additional capital investment for the operation.
Management and unions reached an agreement on costs at the Labour Court that will result in the company investing €110m in the operation to maintain the mine's operation to 2018 and beyond.
The new accounts show that the firm recorded the profit from an exceptional €24.7m gain from changes to the firm's pension scheme.
Production at the Co Meath mine began in 1977. It produces between 2.4 and 2.5m tonnes of ore a year, resulting in 400,000 tonnes of zinc and lead concentrate.
According to the directors' report, the mine has reserves through 2019, confirming that metal prices for zinc was lower last year while the average price for lead was higher than 2012.
The pre-tax profit takes account of €44.8m in the non-cash depreciation costs. Numbers employed fell from 717 to 691 with staff costs decreasing from €62.7m to €58.4m. Directors' remuneration stood at €429,000.