Relatives of the trapped miners reacted with disbelief and anger to news a robot had malfunctioned.

The robot sent into the Pike River Mine was operating outside of its primary role when it broke down.

The Police Commissioner Howard Broad echoed the feelings of all involved in the Pike River disaster, as it was revealed drilling on the mine bore hole was still hours from completion.

Families have viewed footage of the Pike River mine blast this afternoon. Lawrie Drew, father of Zen Drew, said the footage was difficult to watch.

Signs have been erected around Greymouth in support of the 29 miners and contractors trapped in the Pike River mine.

Sending a robot into the Pike River coal mine where 29 men are trapped was always a "long shot", an expert says.

The Defence Force robot was 'the bright spot' for those waiting on the rescue of 29 trapped miners and news it failed was 'a kick in the guts', the Grey District Mayor says.

"The families are frustrated, we are frustrated, the country is frustrated," John Key said after four days of waiting for a rescue effort.

The level of toxic gas in the Pike River mine is still too high after for rescuers to be sent in.

A robot sent into the Pike River mine malfunctioned when water fell onto it.

Pike River Coal says work on evaluating the impact on its West Coast mine of Friday's explosion is "down the line", as it focuses for now on finding the 29 men unaccounted for.

If you haven't got time to read all our in-depth coverage of the Pike River Mine disaster, here's a quick summary of five key things you need to know today.

The families of 29 trapped men trapped after the Pike River mine blast are being updated on progress.

The sun smiled on Greymouth yesterday, but faces were grim and the sadness here was palpable.

The day before he went down the mine for the first time, Joseph Dunbar turned 17.

A scientist says temperatures inside the Pike River mine may have soared higher than 1200C during the blast.

Drilling on a new borehole into the Pike River coal mine is in its final stages, with 20m of the 162m tunnel to go.

An Aussie mine expert recalls when rescuers were within metres of 12 trapped miners, only to be recalled due to "off the chart" gas readings.

Keep up with the latest updates from the Pike River mine, where 29 miners have been trapped since Friday's blast.

Rescuers plan to send a Defence Force robot into the Pike River coal mine where 29 miners remain trapped after an explosion on Friday, one gas levels drop.