The days of spot iron ore trading above $US60 a tonne may be coming to an end.

The most heavily traded September iron ore futures contract on the Dalian Commodities Exchange is currently down close to 4% at 419.5 yuan. On Wednesday evening, the spot price for 62% grade ore fell to $US62.58, according to Metal Bulletin’s iron ore index (MBIOI62).

The decline, likely to be the third in a row, is weighing on Australian iron ore miners with BHP Billiton, Rio Tinto and Fortescue Metals off by 1.94%, 2.20% and 6.97% respectively.