A miner has died underground in Western Australia's Goldfields, again raising questions about BHP Billiton's safety record.

Yesterday morning, a truck plunged 18 metres down a shaft at the Perseverance nickel mine near Leinster.

It took rescuers almost 24 hours to get to the 45-year-old truck driver, who was already dead.

Last July, the WA Minister for Mines launched an investigation into whether the mine should be shut down after three workers became trapped underground in two separate rock falls.

BHP Billiton says it will investigate this latest incident and has suspended operations at Leinster.

Wayne Isaacs, president of Nickel West, the BHP Billiton division which operates the Perseverance Mine, says the earlier investigation cleared the company of wrongdoing.

He says those two events are in no way related to the latest death.

But Steve McCartney, from the Manufacturing Workers Union, says BHP has kept the results of that inquiry secret and the Leinster nickel mine is unsafe.

"We believe BHP has still got endemic safety problems," he says.

"And most of those safety problems are based on a lack of communications, and also workers' ability to put forward safety concerns without fear or favour, without it impacting on their future employment."