It wasn't that many years ago that Australia exported next to no thermal coal to China. Those exports now account for 13 per cent of all Australian exports.

That's what's at risk if China returns to where it was less than a decade ago and imports no thermal coal.

As it ramps up its use of nuclear, wind and solar power it may well be in a position to do it.

It would take the shine off Tony Abbott's boast that Australia's coal industry had a "big future, as well as a big past" and render out of date the business models of Australia's thermal coal producers.