BHP slashes $3bn costs as profits dive 30 per cent MINING giant BHP Billiton has made better-than-expected progress in slashing costs and capital spending under new chief executive Andrew Mackenzie, reporting $US2.7 billion ($2.98bn) in operating cost reductions last financial year and a faster drop in capital spending. The world's biggest miner last night reported a 30 per cent slide in full-year profit to $US10.88bn ($12bn) because of falling commodities prices amid slowing global growth.