The mining business first successfully tested an autonomous drilling system (ADS) in 2008 at its West Angeles mine. Those 11 ADS-enabled drills have now drilled more than 5,000km.

The autonomous drills provide a significant safety advantage by reducing the number of employees exposed to potential hazards and fatigue levels, as well as limiting exposure to dust, noise and vibration. All of the autonomous drills are monitored remotely by operators in Rio Tinto's operations centre in Perth, more than 1,500 km away, and to date have operated injury free.

The automation of drilling has increased productivity because of the increased number of hours the machine operates as well as the numbers of metres the drill achieves per hour.

Four additional drills, retrofitted with ADS technology, were recently deployed at Rio Tinto's Yandicoogina mine in the Pilbara, adding to the existing seven autonomous drills at the West Angelas mine. A further nine drills will be deployed by the end of 2018, bringing the total fleet to 20.

Rio Tinto managing director, Planning, Integration and Assets, Iron Ore, Kellie Parker said: "The expansion of our autonomous drilling fleet delivers significant productivity gains and enables us to drill more safely, accurately and consistently. We are already reaping the benefits.

"The deployment of additional rigs, operated from our operations centre in Perth, offers significant advantages as part of our integrated system, which optimises our autonomous trains, trucks and drills and provides increased operability and flexibility.

"As pioneers of automation and innovation, we continue exploring new technologies to ensure Rio Tinto remains a leader in the global mining industry."

Parker concluded: "Throughout our automation journey we are committed to working closely with our employees providing opportunities for new roles, new skills, redeployment and retraining."