Australia on Wednesday (Sept. 30) announced a cut in its iron ore price forecast for 2015 from $54.40 a tonne to $52.90, due to increased supply and weak demand growth.

The Australian Ministry of Industry and Research said that "increased supply - mainly Australian supply growth - will lead to a fall in the price of marine iron ore in 2015 and 2016."

In its quarterly commodities report, the Australian Ministry of Industry and Research said that global iron ore trading volume was expected to increase by only 15% to 1.4 billion tons in 2015, the slowest growth since 2001, but Australian supplies increased by 6% to 762 million tons.

As construction activity passes through the summer downturn, China's steel demand usually picks up from September. But the slowdown in China's economy has already hit industrial activity, and steel consumption has continued to decline this year, following the first decline since 1981 in 2014.

Iron ore reported $54.70 a tonne Wednesday, which is now higher than that at the beginning of 2015.