BHP Group Ltd. said iron ore output in its first quarter rose 2% from the year before, as concerns grow that moves by major miners to ramp up production of the steel-making material may lead to over-supply.

Global miner BHP beat first-quarter iron ore output estimates on Thursday, spurred by easing of bottlenecks at its Western Australia operations amid efforts by China to revive its grappling property market and faltering economic growth.

The Australian mining giant said it produced 64.6 million metric tons of iron ore in the three months through September, up 2% on a year earlier. Copper production rose by 4% to 476,300 tons, the company said.

Thursday said that copper production rose 4% in the first quarter due to higher grade and recoveries at Escondida, while Western Australia iron ore output climbed 3% driven by the completion of debottlenecking work at the port.