A 25-year-old man has died at BHP's Olympic Dam mine site in South Australia's far north, where emergency services were earlier called to what police described as a "serious crash".
But the mining giant has said the cause of the young worker's death "remains unclear", after emergency services responded to reports a pedestrian had been critically injured at the site about 5:30am.
Police have since confirmed the man, from Two Wells north of Adelaide, was pronounced dead at the scene.
Various details about the incident, including exactly what kind of vehicle was involved, have not been publicly revealed.
But police have confirmed that workplace safety agency SafeWork SA has been notified, and BHP has said it is "engaging with SafeWork SA and SAPOL in relation to the incident".
"We are deeply saddened to confirm that a member of our workforce died this morning at our Olympic Dam site," a BHP spokesperson said.
"The cause of death remains unclear.
"Our thoughts are with the person's family, friends and colleagues, and we are offering all the support we can during this difficult time."
Investigators from SA Police's Major Crash unit attended the scene.
Police described the incident as a "serious crash" and said emergency services responded to reports "a pedestrian had been critically injured in a collision on private property".
SafeWork SA has confirmed it has been notified of the incident.
It said it appeared not to have been work-related but will make further enquiries.
Police will prepare a report for the coroner.