Since commencing trial operations in 2008, Rio Tinto haul trucks fitted with Autonomous Haulage System (AHS) technology have now moved more than 1 billion metric tons (mt) of both ore and waste material across five sites in the Pilbara, including the newly commissioned Silvergrass mine.

Last year, Rio Tinto’s autonomous fleet accounted for about a quarter of the total material moved across the Pilbara mines. On average, each autonomous truck was estimated to have operated about 700 hours more than conventional haul trucks during 2017 and around 15% lower load and haul unit costs, Rio Tinto said.

Also, there have been zero injuries attributed to autonomous haul trucks since deployment, the company added.

There are more than 80 autonomous Komatsu trucks currently operating and plans are in place to increase this to more than 140 by the end of 2019.

Rio Tinto Iron Ore Chief Executive Chris Salisbury said, “Hauling 1 billion mt autonomously is an impressive milestone for our business and again highlights Rio Tinto’s pioneering spirit when it comes to adopting revolutionary new technologies which are making the industry safer and more efficient.”

“We are studying future additions to our autonomous truck fleet that we expect will contribute to our $5 billion productivity program, specifically Iron Ore’s commitment to deliver $500 million of additional free cash flow from 2021 onward.”

Last month, Rio Tinto approved retrofit programs to add autonomous technology to 48 existing Komatsu and Caterpillar haul trucks over the next two years. About 20% of Rio Tinto’s existing fleet of almost 400 haul trucks in the Pilbara is autonomous. Once the retrofit projects are complete, autonomous haul trucks will account for 30% of the fleet.

Rio Tinto has been partnering with Komatsu for 20 years and in September deployed the world’s first retrofitted Komatsu autonomous haul truck at its Hope Downs 4 operation.