Dubai: The head of Aluminium Bahrain (Alba), owner of one of the world's largest aluminium smelters, said on Tuesday he was optimistic the company would receive the needed approvals for its $2.5 billion Line 6 expansion project this year.

"I am optimistic that we will get approvals in 2015," Chief Executive Tim Murray told an industry conference in Dubai. "We are pushing as a management very hard for this move forward," he said.

The proposed opening date for Line 6, which will increase Alba's annual capacity to around 1.3 million metric tonnes, is dependent on final approval for a gas pricing structure being received from the Bahraini government.

Murray could not give an update on whether or not a financial adviser had been picked by the firm for the expansion.

"This will be announced when the project is announced," he said.

In April, Alba told Reuters it was close to making the selection after having whittled down its choice to two banks.

The gas price Alba currently pays for its existing operations rose to $2.50 per million British thermal units on April 1 and gains 25 cents every year to 2021, with each increase costing Alba an additional $30 million.

The plan will make Alba the largest single-site aluminium smelter in the world by boosting per-annum production by 400,000 metric tonnes at a time when demand for the metal is growing.