A forensic expert is due to analyse the burnt-out wreckage of a 35-tonne truck in Waihi’s underground Trio gold mine today to find out how its engine caught fire, sparking a major rescue operation on Tuesday.

Father of two Steve Sant was one of 28 miners who hunkered down inside one of three refuge chambers deep underground waiting to be rescued.

Mr Sant has worked for Newmont Waihi Gold for more than eight years, but this was the first full-scale emergency he has been involved in at the mine.

Mr Sant was operating a remote controlled ‘‘bogger’’ when the emergency came through three times over the radio.

‘‘A couple of the boys were going past in a vehicle so I hitched a ride with them,’’ he said yesterday.

‘‘When I first heard it I thought it was drill and I thought, ‘At this time of the morning, on my last shift and I get an emergency drill’.’’

But once he entered the refuge chamber, he and the other miners realised it was far from a drill.

General manager Glen Grindlay said yesterday that a fire in the mine is as bad as it gets.

However, unlike coal mines, there is no chance of a gas explosion.

‘‘Fires are pretty much the worst thing that can happen in an underground mine. The way we ventilate fills the mine full of smoke – it’s just the way it works. We draw [air] from the surface and spread it around. So the smoke is the main hazard as opposed to the fire. It’s probably everyone’s nightmare.’’

On the surface, 30 mines rescue staff were preparing for the operation and a team of six donned breathing apparatus and headed underground.

Mr Sant said he was never scared and there was never any question of if they would get out but a matter of when.

Mr Sant’s wife knew there had been a fire but couldn’t contact him throughout the ordeal.

‘‘They did get stressed out,’’ he said. ‘‘But once they heard my voice on the surface everything was good.’’

- © Fairfax NZ News