All 29 men presumed dead in N.Zealand mine disaster

photo - AFP

Police said there was now no chance of finding anyone alive, confirming the country's worst mining accident in nearly a century and prompting anguished scenes as distraught relatives wept, shouted and collapsed with grief.

"There was another explosion at the mine. It was extremely severe," superintendent Gary Knowles told reporters.

"Based on expert evidence I have been given... it is our belief that no one has survived and everyone has perished."

Knowles said the explosion, the cause of which was unknown, ripped through the Pike River coal mine on Wednesday, five days after the initial blast trapped the 29 men including two Australians and two Britons.

Prime Minister John Key described the disaster as a "national tragedy" and said flags would fly at half-mast on government buildings.

"New Zealand is a small country, a country where we are all our brother's keeper," he said. "So to lose this many brothers at once strikes an agonising blow.

"Today, all New Zealanders grieve for these men. We are a nation in mourning."

The victims of the blasts ranged from a 17-year-old on his first shift to a 62-year-old veteran. High levels of toxic and combustible gases had stopped rescuers entering the mine in a remote area of New Zealand's South Island.

District mayor Tony Kokshoorn said the incident was the "darkest hour" of New Zealand's rugged West Coast region, a centre of the country's burgeoning mining industry fuelled by exports to Asia.

"It's unbelievable. This is the West Coast's darkest hour. It doesn't get worse than this," Kokshoorn said.

He added that grief-stricken families who have suffered an agonising five-day wait for a rescue that never came, were angry that the dangerous gases had been allowed to build up again.

"They don't know what to do. They just sobbed openly, just fell to the floor. There were people just shouting out, anger," Kokshoorn said.

"The cause was the build-up over the last five days of the gases again and they noticed this this morning. A lethal mixture ignited the entire mine," he added.

Energy Minister Gerry Brownlee said efforts would be made to recover the bodies of those killed.

He announced a series of inquiries aimed at finding out the cause of the mine disaster and preventing any repeat.

New Zealand lost 19 miners in 1967 but the last accident on this scale was in 1914, when 43 died in a gas explosion at a mine in Huntly on New Zealand's North Island.

Stop-start rescue efforts had earlier inched forward when a bore hole into the mine finally broke through, revealing a toxic cocktail of dangerous gases with little oxygen.

A remote-controlled robot -- the second such device after an earlier one broke down -- also travelled about a kilometre (half-a-mile) into the mine and found the helmet of one of the only two survivors, with its headlight still lit.

But rescue efforts were dramatically ended when the second blast shook the pit.

"I was at the mine myself when this actually occurred and the blast was horrific, just as severe as the first blast and we're currently now moving into recovery phase," said police superintendent Knowles.

>> NZealand braces for loss of life as mine rescue drags on