The Aughinish Alumina plant in Co Limerick recorded a pretax profit of $15.6 million (€12.2 million) in 2013 following the closure of its defined benefit pension scheme, according to accounts filed at the Companies Office.

The profits for the Shannon estuary-based alumina refinery, owned by Russian aluminium giant Rusal, mark a turnaround on the operations performance in 2012, when it dipped into the red and had a $10.4 million (€8.1 million) pretax loss.

The main activity of the company is the production and sale of alumina, which is extracted at the plant from bauxite, and then exported outside the EU for further processing to aluminium metal.

The accounts for Limerick Alumina Refining Ltd and its subsidiaries show turnover increased in 2013 to $608 million, up from $586 million the previous year. The cost of sales also rose, from $589 million to almost $613 million, meaning there was a gross loss of $5 million. However, it was brought back into the black by a curtailment gain of $25.4 million triggered by the closure of its defined benefit pension scheme.

The company employed some 450 people during 2013, the same number as in the previous year. It paid tax of $3.2 million on its activities.

Since the end of the accounting period the group has entered into an agreement with resources giant Glencore to provide volumes of alumina from 2014 to 2016 to Glencore.

Limerick Alumina Refining Ltd is wholly owned by Rusal Aughinish Holdings Ltd, which is incorporated in the British Virgin Islands.

Its ultimate parent is United Company Rusal, which is the world's largest aluminium company. Its shares are traded on the Hong Kong stock exchange, with secondary listings in Paris and Moscow, and it is controlled by Russian billionaire Oleg Deripaska.

United Company Rusal reported in August it had returned to profit for the first time in five quarters, with Mr Deripaska suggesting the global aluminium industry had “turned a corner”.