Operations at a mine in the New South Wales Hunter Valley have shut down after a contractor was crushed to death by a coal truck.

Emergency crews were called to Glencore's Ravensworth open cut mine near Singleton just before midnight on Saturday (AEDT).

A spokesman for the Construction, Forestry, Mining and Energy Union (CFMEU) says preliminary investigations indicate the trainee pulled out from a give-way sign onto the mine's haulage road and her vehicle was run over by a fully laden coal truck.

Glencore says the woman was killed when her four-wheel drive collided with a dump truck.

The truck driver was taken to Singleton Hospital suffering shock.

All operations at the mine have been shutdown while police and NSW Government mine inspectors investigate the incident.

The CFMEU also has representatives on site.

In a statement Glencore says its "primary concern is for the safety, care and welfare of our employees and we are providing all possible support for the families of the people involved".

Staff at the mine are also being offered counselling.

The state's Minister for Resources, Chris Hartcher, says a full and detailed report is being prepared for the coroner.

"I would like to personally extend my condolences to the families, co-workers and employers of those involved in this tragic accident," he said in a statement.