Here are the prices achieved per ton sold versus cost per ton...

Here are the prices achieved per ton sold versus cost per ton mined, half year at a time...

Dec 2008: $96 $45
Jun 2009: $68 $59
Dec 2009: $72 $51
Jun 2010: $82 $47
Dec 2010:$119 $61
Jun 2011:$145 $59
Dec 2011:$133 $55

Hard to read much into cost variations. Variations in waste mined versus ore and new project stages being commissioned while others are ageing. $55 seems a safe assumption for the near future.

Even the more pessimistic forecasts put IO prices > $100, with a floor being set due to the cost of production in China. I think there is a sentiment issue with Fe and China growth at the moment. But remember that Chinese authorities had been applying the brakes pretty hard via bank reserve requirements - so now there is plenty of depth to the accelerator pedal should it be needed. I feel very bullish about China's growth prospects for many, many years to come.