Rio Tinto has reported a 50 per cent drop in net earnings for the 2008 calendar year which includes an asset impairment charge of $8.4 billion, mostly attributed to a write down of its aluminium business.

Rio Tinto has reported a 50 per cent drop in net earnings for the 2008 calendar year which includes an asset impairment charge of $8.4 billion, mostly attributed to a write down of its aluminium business.