The robust share price performances are also being fed by a positive broader sentiment on the sharemarket. There are two factors at play here.

The first is increasing hope that theUS central bank will take a more aggressive position on lowering interest rates. The second - and much less reliable - reason for market optimism is being generated by the slightly toned-down rhetoric inDonald Trump’s latest trade war tweets.

Both these positives could prove fragile.

However,the forces that are specific to iron ore are based on supply and demand fundamentals which are proving tenacious.

Many had forecast that the disruption in iron ore supply that began with theVale tailings dam disaster in Brazil in January would be on its way towards a resolution. It isn’t.

Courts and regulators have taken control and the timing of the restoration of supply seems no closer - or at least no clearer.

At the same time pressure on all mining companies to reassess the safety of their tailings dams is intensifying.

Major investors,led by the Church of England have banded together to form what they have called the Mining and Tailings Safety Initiative. This week it released a name and shame list of companies that had not responded to its request to provide details of their tailings facilities. This investor group accounts for assets under management of $US12 trillion ($17 trillion). BHP and Rio have produced audits of their tailings dams over the past couple of weeks.

Meanwhile,heavy rainfall during the current quarter in parts of Vale’s operations has only added to the supply disruptions.

Citi Research's New York-based analysts said this week’s iron ore rally came on the back of an increasing likelihood that Rio may not make some contract deliveries of higher grade ore for July and August.

But while supply is constrained,the demand side of the equation is not easing which is leading to continued depletion of stockpiles in China.

In a note to investors Macquarie said,"Chinese port stocks,one of the most watched indicators in the iron ore market,have fallen further to under 110 million tonnes,indicating a 25 million tonnes drawdown since the end of April 2019. It further noted that,"the falling inventories at ports suggest consumption continues to outpace seaborne arrivals".

The size and frequency of Chinese government stimulus packages is playing a big part in the continuing high demand for steel - whose major ingredient is iron ore.

And just how the latest round of China-US trade talks play out will also be a major factor determining China stimulus.

Few,if anyone,is predicting that iron ore prices will remain at these elevated levels for another year but right now the forces that are pushing the price higher appear stronger than those that could bring it back to earth.