At that price, most Australian miners would be producing at a loss, with the exception of low-cost giants Rio Tinto and BHP Billiton. Miners have already been under pressure on the stock market: Fortescue Metals slumped more than 6% on Wednesday, while BHP and Rio each lost more than 3%. Iron ore prices hit a low of $US47 a tonne in April this year before recovering to rise above $US64 a tonne in