Rio CEO Sam Walsh tells The Australian that short-term factors like restocking and the cyclone season are behind the December spike from $115 to $145.

“We’re seeing an unusual situation at the moment where there’s some nervousness from the steel mills in relation to supply. I’m sure it will settle down after the cyclone season,” Mr Walsh said.

Even if Walsh is wrong, it shows that companies are reluctant to invest further in Australia’s mining boom.

In the short-term it doesn’t matter with AUD/USD breaking through 1.0500 and no significant resistance until 1.0570/80.