The youngest of the miners, seventeen years, was beginning his first day on the job. There has been no contact with the miners since a powerful blast sealed in the 29 miners.

A bore hole drilled into the New Zealand coal mine where 29 men are trapped has shown high gas levels and little oxygen near where the miners are believed to be.

“It is not safe to send rescue teams down at this time,” Gary Knowles, the police official co-ordinating the rescue, said on Wednesday.

Officials said air coming from the drill hole showed high levels of carbon monoxide and methane and was low on oxygen, which means sending down rescuers could trigger an explosion.

A robot has also been sent down the shaft of the Pike River mine on the west coast of the South Island to check the tunnel and toxic gas levels after Friday’s methane-fuelled explosion.

Police say the robot, which had stalled on Tuesday after hitting water, has now gone a kilometre into the mine to collect air samples and send back video.