Rio Tinto cuts 2021 iron ore shipments forecast on labour squeeze

A tight global supply chain also added to its troubles, the company said.

"There are some clear headwinds from recent regulatory tightening (in China) and the transition may lead to some near-term volatility," Rio said.

Iron ore prices have nearly halved since hitting a record peak in mid-May, with demand hurt by China's steel output curbs and a sharp slowdown in the country's property activity due to a regulatory crackdown.

Still, Rio Tinto shipped 83.4 mt of the steel-making commodity in the three months ended September 30, 2 percent higher than the 82.1 mt shipped last year.