Mining giant Rio Tinto has loaded 200 million tonnes of iron ore with its fleet of 53 driverless trucks.
Rio, the world's largest operator of autonomous trucks, said the milestone was reached at Yandicoogina mine in the Pilbara last month.
Chief executive of iron ore Andrew Harding said the autonomous truck fleet delivered significant savings in maintenance, tyre life and fuel.
"These new technologies bring value and productivity benefits through decreased variability, improved schedule efficiency and early identification of bottlenecks in the system," he said.
It comes 13 months after the GPS directed trucks completed the loading of 100 million tonnes in April, 2013.
Iron ore prices tumbled 13 per cent in May to around $US94 per tonne.