An NZ Mines Rescue member wants the public to understand what the rescue team members are going through.

One of the miners who died at Pike River told a friend he feared for his safety in the month before last week's explosion.

"What gave armchair critics the right to criticise and worse - accuse the rescuers of deliberately sitting on their hands?"

Broadcaster Maggie Barry, whose cousin Michael Monk was lost at the Pike River mine, understands when people asked counsellors "funny" questions.

Up to 500 relatives and friends of the Pike River miners travelled to the mine today, which one mother described as "very healing".

Grey District Mayor Tony Kokshoorn wants the mining industry to learn from past mistakes and has called for a royal inquiry.

Heroism probably involves an instant calculation of known risk against likely benefit.

The riches of the Paparoa Range were enticing, but the cost of extracting them was greater than anyone imagined, writes Grant Bradley

Superintendent Gary Knowles has been at the helm of the Pike River disaster, unable to provide answers to the questions the world wanted answered. Next, delivering news no one wanted to hear.

The face of the country's worst mining disaster since 1914, Pike River CEO Peter Whittall, has fronted in the most trying of circumstances.

Experts suggest a split-second gas outburst may have overwhelmed the Pike River miners before they could respond to any alarms.

"We pray that their moment of fear becomes eternal peace," said Monsignor Gerry O'Connor during an emotional tribute to the Pike River miners in Greymouth.

Families of the dead men due to be bused to the Pike River mine tomorrow will still go, despite a third explosion at the mine this afternoon.

There has been a third explosion at the Pike River mine this afternoon. The blast occurred at 3.39pm and lasted for 23 seconds.

As the West Coast struggles with the emotional cost of the Pike River tragedy, chairman John Dow has reassured the community there is still a future for the mine and the company.

A third robot that has gone 1575m into the Pike River coal mine has detected debris and destruction indicating Wednesday's blast was much more violent than the first one.

Check times of church services for the miners, and tell us about services in your area.

It is likely to be several more days before operations will start to stabilise the Pike River mine so that the bodies of 29 men can recovered, police say.

The GAG unit flown for the Pike River coal mine recovery effort is 'no gimmick' and has been used successfully in Queensland mines, the head of an Australian miners' union says.