Workers have begun installing a casing to protect the top stretches of a rescue hole that will be used to evacuate 33 men trapped in a Chilean mine.
In the next 48 hours, steel pipe will be lowered into the first 96 metres of the shaft, which curves down 622 metres to the miners below, and a winch structure will be installed to lower and raise the half-tonne rescue capsule capable of rescuing one man at a time.
But while officials still believe they can begin raising men to surface by Wednesday, Chile's mining minister said Sunday morning that it is hard to estimate how long preparations will take -- and the extrication may not start until Thursday.
"We're still talking about Wednesday, but it's difficult to calculate," Laurence Golborne said.
The order of evacuation has yet to be decided, but the miners have been jockeying to be the last to go up, Mr. Golborne said.
The men have spent more than two months in hot and humid conditions, but they have been exercising, have been supplied with ample food and are in good condition, Chilean health minister Jaime Manalich said Sunday.
"They aren't patients. They are healthy," he said.
Engineers decided Saturday that such a casing should be installed; that work is expected to finish by Monday. Crews will then begin erecting a metal structure above the shaft that will hold the capsule and winch it up and down. Construction of the winch structure will likely take another full 24 hours.
Following that, crews will conduct two trial runs, sending an empty capsule up and down the shaft. A further two trial runs will be conducted with a rescue crew member inside before two people are lowered to the bottom to assist in the evacuation.
The extraction could then begin when the tests are complete, likely sometime Wednesday, Chilean mining minister Laurence Golborne said late Saturday, hours after waiting families at the San Jose mine cheered the drill's success and workers sprayed bubbly in celebration.
Marching through a gauntlet of jubilant family members, many of them extending hugs and kisses to the men whose 33 days of drilling finally opened a route to safety for their trapped husbands, boyfriends and sons, Jeff Roten, a service technician for Schramm, the manufacturer of the drill, said workers should have little trouble pulling up the rescue capsule.
"It will come up really easy," Mr. Roten said.
The reason for his confidence: the drill bit -- which is encased in a unit called the "hammer" -- is 66 centimetres, or 26 inches, in diameter; the capsule intended to carry the workers is just 53 cm, or 21 inches.
The two people that will be sent down -- a Codelco miner and a naval medical expert -- will remain at the bottom to assist with the evacuation, which could take as long as an hour per person, or a day and a half in total.
Although 16 people are working on the final rescue effort, officials have so far declined to notify the two already selected to descend into the mine.
"It's a question of family," said Mr. Zepeda. "It's emotional. For the families [of the two] it's the same as being one of the trapped miners."
Despite the continued uncertainty, Saturday's breakthrough sent a wave of optimism cascading over the families who are at the site waiting, many living in tents in a small makeshift settlement on the mine's loose rock that has been called "Camp Hope."
"The day they found them alive, it was a great party. But now, it's the same feeling but it's even happier because we really have hope," said Gaston Enriquez, whose brother Jose is trapped below.
Drillers watched a live video feed Saturday morning as the drill bit punctured the last bits of rock into the part of the mine accessible by the 33 men.
"It's overwhelming. It's very much overwhelming. A goal has been met today that will forever change some lives," said Jeff Hart, the driller with U.S. company Layne Christensen who was at the controls when the drill broke through to the miners.
It took 33 days to complete the operation, through brutally hard rock that chewed through five hammers. Normally on a well of this depth, companies use just one.
"Every metre is difficult. Every one fought us. It was a hard fight and in the end -- mother nature, we won!" Mr. Hart said.
Mr. Hart worked on what was called "Plan B," one of three drills operating in different locations in hopes one would succeed. The Plan B drillers credited their success to the fact that they were able to follow a previous, smaller hole that had been drilled to lower supplies. The other drills, including one owned by Canadian company Precision Drilling, had the more difficult task of drilling blind.
In the last few days, the noise of the drill had echoed so loudly below ground that the men had difficulty sleeping, and had to be supplied with earplugs. The response when the drill broke through was jubilant.
"They told us they could see the hammer and then the nose came out. That made us very happy. And then the bit started appearing and when they saw that -- then they all started celebrating," said drilling operations manager James Stefanic.
"They've been participating in helping us clear out all the cuttings when we drill, and that made it nice because it got them involved, too," he said. "They were part of this whole effort, part of the team. And they were a lot of help, too. So when we finally got this done, it was their victory, too."
- with files from Eva Salinas