For a commodity that symbolises strength, iron ore is looking ever weaker. On Monday, the Australian benchmark price of the steelmaking ingredient sank to $87.10 a tonne, taking the year-to-date fall to 35 per cent. The price is now just 40 cents above a five-year low.

The reason for the sharp plunge in the first half of the year was clear. The big three global producers – Vale, Rio Tinto and BHP Billiton, which all depend heavily on iron ore for their profitability – have drastically increased production and shipping volumes in 2014.

Most of this material has gone to China, which consumes about two-thirds of global seaborne iron ore. This “tsunami of supply growth” that has pushed the market into surplus has now stalled temporarily, according to Chris LaFemina, head of European metals and mining equity research, at Jefferies. The trouble is now on the other side of the equation: demand.

“The sentiment in the Chinese steel market has weakened a bit,” Mr LaFemina said. “When steel companies know that there is a plenty of iron available they can afford to wait. That pushes the price down.”

Chinese macroeconomic data published on Monday support the idea of flagging demand for industrial commodities. Factory sector growth fell to a three-month low in August, according to an HSBC survey, while the government’s official purchasing managers’ index also fell over the month. The numbers suggested that China’s stimulus measures were not yet sufficient to compensate for the weakness in the country’s property sector, a big user of steel – and thus iron ore.

iron ore charts

With steel mills already well-supplied, and port sheds heaving with ore, the China Iron and Steel Association has urged factories to run down their inventories, rather than restocking, in anticipation of iron ore prices continuing to slide. That could happen unless the Chinese growth rebounds, says Melinda Moore, commodities strategist at Standard Bank.