Wellington - Up to 36 coal miners were missing after an explosion tore through an underground mine on New Zealand's remote west coast Friday, with fears of another blast frustrating rescue efforts, police said.
The explosion at the Pike River coal mine, on the South Island's west coast, occurred just before 4:00 pm. Two miners survived but there had been no contact with any others, the mining company's chief executive said.
Police said a specialist mine rescue team was at the scene but could not go underground because the blast knocked out power to the mine's ventilation, meaning there was a risk they could ignite trapped gases.
"There's been an explosion, they don't know what's caused it, they can't just go charging in there and put other people at risk," police spokeswoman Barbara Dunn told Radio New Zealand.
The ventilation system, which police said they were concerned had been compromised by the power outage, would also normally supply air to any surviving miners.
Reports said families of the miners were gathering at the mine, which lies at the heart of New Zealand's coal industry about 50km northeast of Greymouth, as rescuers prepared to work through the night.
There were conflicting reports about how many miners were still underground, with Pike River Coal estimating 27 in the mine shaft but police putting the number at 36.
"There are 36 tags still on the board at the mine. Those miners have not yet been heard from," Dunn said.
Pike River Coal chief executive Peter Whittall said the miners were about 120m beneath the surface. They had started the afternoon shift about an hour before the blast.
Whittall denied reports a body had been removed from the mine shaft.
"I've not had any reports of that at all," he told TV3. "We've had two miners who've walked out of the mine and they're currently being spoken to and treated on the surface.
"We've had no communication with anyone else underground at this stage."
Police said the two survivors, who were treated at hospital for moderate injuries, told rescuers three more miners were making their way to the surface, although there was no immediate confirmation they had emerged.
The mine, which began production last year, has a 2.4km access tunnel running beneath the Paparoa mountain range to the coal seam.
Police said the mine's remote location and the lack of power was complicating the rescue operation.
Ambulances, medivac helicopters and rescue workers were on the surface ready to treat any injured miners, with ambulance officers saying they were preparing for a long operation.
Grey District mayor Tony Kokshoorn told Radio New Zealand he was praying the miners were still alive.
"We're just keeping our fingers crossed but it's not good," he said.
A total of 33 miners were successfully rescued last month after surviving more than two months in a tunnel 622m below the surface of Chile's northern Atacama desert.
New Zealand Mining Minister Gerry Brownlee said the government would put whatever resources were needed into rescuing the miners.
"Their priority will be getting people out," he said. "I certainly feel very sympathetic to (their) families, it's a dreadful situation for them to be in.
Brownlee said the mine was well built and had good ventilation "so I hope that will be helping".
But Fairfax Media's stuff.co.nz website said the mine had been plagued by delays before production started last year, including a collapsed air ventilation shaft.
The South Island's west coast was the scene of the country's worst mine disaster in 1896, when an underground explosion killed 65 miners at the Brunner mine.
The mine involved in Friday's explosion lies at the opposite side of the Paparoa Ranges to the site of another disaster in 1968, when a blast killed 19 people at the Strongman mine.
The mine is jointly owned by New Zealand Oil & Gas and two Indian companies - Gujarat NRE Coke and Saurashtra Fuels Private Ltd.
It is one of only a handful of underground coal mines in New Zealand, which produces about five million tonnes of coal a year, according to the main industry body.