An underground mine worker was struck by mobile plant.

Westgold's emergency response teams attended the scene and rendered assistance to the injured worker.

The Royal Flying Doctor Service flew the worker to Perth but she died in transit.

Westgold is providing support to the family of the worker and employees at Big Bell.

"Our hearts go out to the family of our employee as well as her colleagues," Westgold executive chairman Peter Cook said.

"This devastating news has shaken all of us at Westgold to our core.

"The safety and wellbeing of our people is a priority to us, which is why we will ensure that a thorough investigation is conducted into this tragic incident."

Mine safety inspectors from the Western Australian Department of Mines, Industry Regulation and Safety are on site investigating, in cooperation with Westgold.

Mining at Big Bell has been temporarily suspended and Westgold will remain in a trading halt until tomorrow.

The Minerals Council of Australia said it was deeply saddened by the incident.

"Our thoughts are with the families, friends and colleagues of the worker," it said today.

"The Australian mining industry's core value and commitment is the safety, health and psychological wellbeing of its workforce, where everyone who goes to work returns home safe and healthy. 

"The MCA will continue to assist the commitment of its members and that of the broader industry to an industry free of fatalities, injuries and occupational illnesses."

It is the third death on a WA mine site this year. In July, Michael Johnson died when his bogger fell into an open stope at Saracen Mineral Holdings' Carosue Dam mine. In January, Howard Prosser died in an accident at the Roy Hill iron ore mine.