THE world’s biggest mining companies wiped $85 billion (R1.03 trillion) off the value of takeovers struck in the past eight years after prices for aluminium, iron ore and nickel collapsed, according to Citigroup. About 90 percent of their deals since 2007 were written off “raising questions about their capital allocation strategy”, Jon Bergtheil, an analyst at Citigroup, said yesterday. Rio Tinto, the world’s second-largest miner, was worst affected with 34 percent of its asset base impaired, followed by Anglo American with a 23 percent impairment. Aluminium made up $25bn of the charges, followed by iron ore with $10.3bn and nickel with $7.8bn. – Bloomberg