Rio Tinto said it was too early to say whether a proposed new biomass power plant could secure the future of its primary aluminium smelter in Britain, which is expected to close in September.

“A feasibility study is taking place … no decision has been made and it would take quite a few years before it would go ahead,” a Rio Tinto spokesman told Reuters.

Referring to the proposed power plant, which would comprise huge wood-burning furnaces, he added that it would not solve the problem of securing the future of the smelter.

The 135,000t-per-year Anglesey smelter in Wales is set to close in September when its current power contract expires.

Rio could stop this from happening if it manages to secure an extension of its power terms or an alternative supply at favourable rates.

The Wylfa nuclear power station in Wales, which provides its electricity, is set to close around the end of 2010.

The company is looking into the possibility of a stand-alone casting and re-melting facility at the site, although such an operation would require a much smaller workforce, writes Reuters.

Kaiser Aluminum also holds a 49% stake in the Anglesey operation.