The New South Wales Resources Regulator is investigating a heavy vehicle collision at the Peabody Energy-owned Wilpinjong coal mine.
A Hitachi EX1200 excavator collided with an autonomous dozer on May 27, causing damage to the access steps down from the excavator.
Resources Regulator inspectors assessed the incident the following day and did not identify any material breaches of the Work Health and Safety Act 2011. No one was injured in the collision.
The causal investigation will help the Resources Regulator to fully understand the causes of the incident and pass on lessons to the industry to reduce the chances of a recurrence, particularly in relation to the use of autonomous heavy vehicles.
It will release information from its investigation within the next few weeks.
Mobile mining equipment has been rated as the single highest cause of industry fatalities last year, according to the International Council on Mining and Metals (ICMM).
The Wilpinjong mine, which employs more than 500 people, produces thermal coal for domestic and export markets.