GREYMOUTH, New Zealand — Relatives of 29 miners still missing two days after an underground explosion were given a tour of the site Sunday in order to better understand the situation, including how toxic gases are preventing a rescue attempt.
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Nothing has been heard from the men who were deep in the mine near Atarau on South Island when a massive blast ripped through it late Friday, but officials insist it is still a rescue operation.
"This is a search and rescue exercise, with the major emphasis being on rescue," police superintendent Gary Knowles, the rescue controller, told Sky News television. "As the days go on we still maintain that faith. Until such time as someone can prove to me that the situation has changed, we're doing our best to bring them up."
But with levels of dangerous gases still fluctuating within the mine tunnel, it was too dangerous to send in the rescue teams that have been on standby since the explosion.
A buildup of poisonous gasses, which could be coming from a coal fire smoldering deep underground, could generate another explosion, officials said.
Fresh air is being pumped down an open air line into the mine but there is evidence of heat underground that concerns the rescue officials.
"Something is happening underground, but what it is we don't know," said Peter Whittall, chief executive of Pike River Mine Ltd.
He said his talks with two men who escaped from the mine Friday had revealed no fresh information. Both were only part of the way into the mine when the explosion occurred and didn't know where the explosion initiated.
Anguished relatives have been desperately waiting for news or for rescuers to enter the mine to find their loved ones. They were taken on a two-hour tour of the site Sunday morning.
"It was obviously quite an emotional thing for them to go up there, where their family members are still underground," Whittall said. "They were very appreciative of that and have a lot better understanding of what we're talking about."
But even the tour couldn't allay the families' fears as they awaited word from their loved ones in the tunnel.
"It was good to see the layout of the place, but it's still hard," said Laurie Drew, whose 21-year-old son, Zen, is one of the missing men. "We just want to be there when they walk out."
He said the mine has refused requests for the families to wait at the mine entrance.
Mine experts on Sunday began drilling a six inch-wide (15 centimeters) hole from the mountain above to test for levels of deadly gasses in the center of the mine.
Knowles said the hole — which must dig down through 500 feet (150 meters) of rock — could break through the mine wall overnight. The team will then lower listening devices into the mine to hopefully hear sounds of live miners, as well as gauges to assess the air quality.
"Teams are on standby and at the first opportunity, day or night, they're going to go down in there," he said.
But he could not say how long a rescue operation would take, given the unstable gas levels.
"There's no timeline for this type of operation," he said. "It could take a day, it could take weeks."
Police have said the miners, aged 17 to 62, are believed to be about 1.2 miles (two kilometers) down the main tunnel.
Electricity in the mine went out shortly before the 3:45 p.m. Friday explosion, and that failure may have caused ventilation problems and contributed to a buildup of gas, officials have said.
Whittall said the blast was most likely caused by coal gas igniting.
Two dazed and slightly injured miners stumbled to the surface hours after the blast shot up the mine's 354-foot (108-meter)-long ventilation shaft. They have declined to speak to media.
Comparisons are being drawn to the Chilean mine accident, where 33 men were rescued from a gold and copper mine after being trapped a half mile (one kilometer) underground for 69 days.
But mine safety expert David Feickert said unlike the Chilean mine, Pike River officials have to worry about the presence of methane. He added, however, that the Pike River mine has two exits, while the mine in Chile had only one access shaft that was blocked.
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. The vertical ventilation shaft rises 354 feet (108 meters) from the tunnel to the surface.
Whittall said the horizontal tunnel would make any rescue easier than a steep-angled shaft, once safety is established.
Each miner carried 30 minutes of oxygen, enough to reach oxygen stores
in the mine that would allow them to survive for several days.
Australian and British citizens were among the missing men, and
Australia sent a team of mine rescue experts to assist the operation.
The 2-year-old Pike River mine is working the largest-known deposit of hard coking coal in New Zealand, about 58.5 million tons.
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.