The 64m machine can excavate 10-12m a day on a typical deep copper ore body, twice the rate currently achieved with conventional tunnelling methods.

Rio head of innovation John McGagh said the capability to double the excavation rate was an important step for underground mining.

“This investment offers the possibility for a significant improvement over conventional drill and blast practices,” he said.

The machine – designed and developed by Rio in partnership with Aker Wirth over the past four years – is the first of three new underground excavation systems being developed as part of Rio’s Mine of the Future program to improve construction and operation of underground mines.

The TBS is controlled on-board by a team of 12 operating all functions, and is supported by three underground haul trucks.

The on-board team also receive logistical support from an above ground crew of roughly 15 additional people.

Northparkes managing director Stefanie Loader said the TBS trial was not only an exciting opportunity, but also a chance to improve safety across the company.

“Importantly for Rio Tinto, it provides an opportunity to introduce fundamentally safer processes into the underground mining industry,” she said.

The trial phase will run until about July, with an expected distance of 1400m.

The company will conduct a comprehensive critique of the performance of the machine following the trial.

If the new system proves successful, Rio plans to integrate the technology into its other underground mining operations internationally.

Rio shares were down 1.4% to $A65.75.