This a typical "cant bat, cant bowl" position. (a)Coal is already being railed from Emerald to the coast as is Iron Ore from the Pilbara to the coast. By adding value in Australia there is an overall benefit in our Government supplying the infrastructure. The mega smelters & steel processing plants you refer to are mostly Chinese Government owned & operated. If that is OK with the current WTO trade regime for China, then why not for Aus?
(b) If what you say is true, then why do we not convert our molten alumina into aluminium castings; particuluarly for global auto manufacturers?
We have the timber on all other countries because we can produce high rade iron ore & premium met coal much cheaper than china or other steel makers. It is simply a matter of adding Aussie value.
Saudi Arabia nationalised its oil/petroleum in 1973 and look at them now! It is just in the process of floating a fraction of its national oil processor for a world record IPO price and Saudi individuals have enjoyed one of the highest living standards in the world.
Perhaps the Populists will latch on to this opportunity and "Make Australia Great" ?