BHP said a thorough internal investigation was underway and the incident had been reported to Western Australia's Department of Mines and Petroleum.
The DMP has been contacted for comment.
The accident is the latest in a spate of serious safety incidents in WA's mining industry this year.
In January a 26-year-old man, working for BGH Mining Resources, died on an exploration lease near Newman.
Last month a 59-year-old died in a rock fall at Norseman Gold's Harlequin mine in the Goldfields.
February also saw Fortescue Metals Group ordered to stop blasting at the Christmas Creek mine following a safety incident with a contractor.