A Rio spokesman confirmed that an employee passed away last night following an incident at the Channar mine near Paraburdoo.
Police were called to the site at around 12:30am this morning.
A 32-year-old man from the Perth suburb of Landsdale received fatal injuries while working on a drill.
The Department of Mines and Petroleum have been advised and a report will be prepared for the Coroner.
“We are devastated by this terrible tragedy and the loss of our workmate’s life, who was a highly valued and greatly respected member of our Paraburdoo team," Rio Pilbara Mines managing director Michael Gollschewski said.
"This will have a lasting impact on family, friends and colleagues and our thoughts are with them at this most difficult time. We are fully supporting the family, as well as our people at Paraburdoo. We continue to assist the relevant authorities with their investigations.”