RIO Rio Tinto Plc

By Rhiannon Hoyle

SYDNEY--Rio Tinto PLC said quarterly iron-ore shipments rose 8% despite weather disruptions, as it ramps up output from its operations in western Australia.

The Anglo-Australian miner reported global iron-ore shipments of 81.4 million metric tons during the three months through June, which was 12% higher than the prior quarter.

Rio Tinto, the world's second-largest exporter of the steelmaking commodity, has been expanding its network of mines and infrastructure in Australia's iron-rich Pilbara region, despite a sharp fall in prices over the past 18 months.

The company also reported a 5% increase in bauxite production, to 10.7 million tons, but said quarterly copper output fell 19% to 134,000 tons.

Write to Rhiannon Hoyle at rhiannon.hoyle@wsj.com