'Unprecedented' task to save miners
The effort to save 33 Chilean men trapped deep in a mine is an unprecedented challenge, mining safety experts said. It means months of drilling, then a harrowing three-hour trip in a cage up a narrow hole carved through solid rock.
If all of that is successful, the freed men will emerge from the earth and "feel born again," said an American miner who was part of a group dramatically rescued in 2002 with similar techniques. But that rescue pulled men from a spot only one-tenth as deep.
"They're facing the most unusual rescue that has ever been dealt with," said Dave Feickert, director of KiaOra, a mine safety consulting firm in New Zealand that has worked to improve China's dangerous mines. "Every one of these rescues presents challenging issues. But this one is unique."
First, engineers must use a 31-ton drill to create a "pilot" hole from the floor of the Atacama Desert down 2,200 feet to the area in the San Jose mine where the men wait.
Then, the drill must be fitted with a larger bit to carve out a rescue chimney that will be about 26 inches wide - a task that means guiding the drill through solid rock while keeping the drill rod from snapping or getting bogged down as it nears its target.
Finally, the men must be brought up one at a time inside a specially built cage - a trip that will take three hours each. Just hauling the men up will itself take more than four days - if there are no problems.
"Nothing of this magnitude has happened before; it's absolutely unheard of," said Alex Gryska, a mine rescue manager with the Canadian government.
Gryska said he is confident Chile's state-run Codelco mining company, with its vast expertise in the world's top copper-producing nation, would successfully drill the hole out. But he said he is worried about the three to four months officials say it will take to do so - and the key role the miners themselves will play in their own rescue.
Chilean officials said the miners will have to remove upward of 3,000 tons of rock as it falls into the area where they are trapped. There is little danger to the men - the area includes a shelter and about 500 metres of a shaft outside that. But as the rock starts to fall a month from now, the men will work in non-stop shifts to remove it with wheelbarrows and industrial sweepers.
"The thing that concerns me is welfare of workers, their mental state. That will be real tough," said Gryska. "From a health perspective, it's hot down there. They're talking about working 24/7 in 85 degrees for two months. Their mental state for that work will be critical."