WELLINGTON, New Zealand — Fears that dangerous mine gas could trigger a second explosion stalled rescue crew search efforts on Saturday at the New Zealand coal mine where 29 workers are missing nearly a day after a powerful gas blast struck deep underground.
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Two dazed and slightly injured miners stumbled to the surface hours after the blast shot up the 354-foot- (108-meter-) long ventilation shaft at the Pike River mine on Friday. Video from the scene showed blackened trees and light smoke billowing from the top of the rugged mountain where the mine is located, near Atarau on New Zealand's South Island.
Pike River Mine Ltd's chief executive Peter Whittall said it was not known if the men were alive because nothing had been heard from the 16 employees and 13 contract miners since Friday's explosion at the mine. Repeated attempts to contact the 29 men had failed.
"We can't risk sending men into the mine until we know exactly what (the quality of the gas) is," he said.
A coal-gas explosion was the most likely cause of Friday's major blast, Whittall said.
"There could be another explosion," said mine safety expert David Feickert, who noted that officials don't yet know what caused the original ignition, and rescuers will enter the mine only when it is safe.
Whittall said officials would have enough analysis by later Saturday to decide whether a rescue team can go in, adding that the missing miners would have to deal with such hazards as air pollution, high levels of methane and carbon dioxide, and low levels of oxygen.
Each miner carried 30 minutes of oxygen, enough to reach oxygen stores in the mine that would allow them to survive for "several days," said Pike River chairman John Dow.
"This is a search and rescue operation, and we are going to bring these guys home," police superintendent Gary Knowles told reporters.
A company official had earlier said that five men had come out of the mine, based on information provided by the two men who had surfaced. By Saturday morning, however, officials had seen no sign of the other three men.
Unlike the accident in Chile, where 33 men were rescued from a gold and copper mine last month after being trapped a half-mile (one kilometer) underground for 69 days, Pike River officials have to worry about the presence of methane, Feickert said.
He added, however, that the Pike River mine has two exits, while the mine in Chile had only one access shaft that was blocked.
It could be days before it is safe enough for special teams to enter the mine, said Tony Kokshoorn, mayor of nearby Greymouth.
Electricity went out shortly before Friday's explosion and that failure may have caused ventilation problems and contributed to a buildup of gas. The power outage continued to frustrate efforts Saturday to pump in fresh air and make it safe for rescuers.
Whittall said rescue crews were trying to get accurate gas samples as they couldn't risk sending men in till they had definitive tests.
Damage to the upper part of mine shaft in the explosion meant "we can't get accurate samples," he said. Fresh air was being pumped into the mine, but officials still did not know where the men were.
Energy Minister Gerry Brownlee said gas experts from Australia were flying in to help analyze the gas in the mine. Chile and Australia had both offered assistance, with Australian "Foreign Minister (Kevin) Rudd making it clear that the Australian government would do whatever to help here."
Australian and British nationals were among the missing men, he said.
Kokshoorn was hopeful the missing workers could survive like the Chilean miners, whose rescue — played out on live television — captivated the world.
"We are holding on to hope," Kokshoorn said. "Look at Chile, all those miners were trapped and they all came out alive."
Kokshoorn said his community was "grief-stricken" about the 29 miners missing in the mine and had "ground to a halt" as they wait for news about the men.
"The families out there ... are all rallying together at the moment, we're doing everything we can for them but it's a serious situation down there," he told TV3's "The Nation" program.
"We hope they've (the missing miners) got to ventilated shafts sucking in oxygen. We're praying for them," he said.
Mine rescue teams were "working their guts out" trying to get into the mine and were well trained for emergency situations.
"Incredible" offers of support were flooding in from around the world, including "search and rescue teams from Australia ... airlines around the world ... saying (they'll) bring anyone, anywhere, anything you want. It's just been fantastic," Kokshoorn said.
Whittall had said Friday that 27 were missing, but on Saturday he told a news conference the number was 29 — 16 miners employed by the company and 13 contractors.
The coal seam at the mine is reached through a 1.4-mile (2.3-kilometer) horizontal tunnel into the mountain. The seam lies about 650 feet (200 meters) beneath the surface. According to the company's website, the vertical ventilation shaft rises 354 feet (108 meters) from the tunnel to the surface.
Pike River spokesman Dick Knapp confirmed late Friday the mine had been rocked by a gas explosion, but said its cause was still unknown. It also was not clear if all of the workers underground were together.
Deputy Mayor Doug Truman said the blast was so powerful that one of the workers who came out of the mine described being only a mile (1,500 meters) inside the shaft when he was blown off his machine.
"The mine vents have ... scorch marks — so it must have been a reasonably big explosion," Truman told New Zealand's National Radio.
Brownlee said the explosion occurred about 3:45 p.m. (0245 GMT Friday, 9:45 p.m. EST Thursday), and the last contact with any of the miners was about a half-hour later. That contact was with one of the two men who came out.
The two men who surfaced were taken to a hospital for treatment of minor injuries and were being interviewed to determine what happened, Whittall said.
Whittall said the horizontal tunnel would make any rescue easier than a steep-angled shaft.
"We're not a deep-shafted mine so men and rescue teams can get in and out quite effectively, and they'll be able to explore the mine quite quickly," he said.
While Pike River Coal is a New Zealand-registered company, its majority
owners are Australian. There are also Indian shareholders.
Pike River has operated since 2008, mining a seam with 58.5 million tons
of coal, the largest-known deposit of hard coking coal in New Zealand,
according to its website.
It said its coal preparation plant at the site is the largest and most
modern in New Zealand and processes up to 1.5 million tons of raw coal a
year. It is country's largest single source of coal exports.
The mine is not far from the site of one of New Zealand's worst mining
disasters — an underground explosion in the state-owned Strongman Mine
on Jan. 19, 1967, that killed 19 workers.
New Zealand has a generally safe mining sector, with 181 people killed
in 114 years. The worst disaster was in March 1896, when 65 died in a
gas explosion. Friday's explosion occurred in the same coal seam.