The families of 33 trapped miners are in high spirits after a surge in the drilling of escape tunnels raised hopes that the men's rescue may come sooner than scheduled.
Relatives smiled, hugged and yelled "Viva Chile!" as officials reported one of the rescue drills made twice the progress Tuesday than had been expected.
They promised the families that preparations for the rescue effort on the surface would be ready by Oct. 12, and said they are planning for the possibility the miners could be pulled up nearly a month ahead of the official schedule.
But the officials also urged caution, warning that unforeseen problems could slow the work.
A siren sounded at 5 p.m. Tuesday in the camp where families have held vigil since a rock collapse blocked the mine's exit shaft Aug. 5. At first, no one knew what it meant, just that it was good news.
Then, rescue workers came down to report that the "Plan B" drill had reached 984 feet deep, nearly halfway to its goal, after advancing 243 feet Tuesday, more than twice as fast as expected.
At that pace, barring complications, the drill could break through to the miners in about five more days, and be reinforced with a metal sleeve even before Oct. 12.
We're "happy for this depth they reached. We needed just this kind of attitude," Alberto Segovia told The Associated Press. His brother Dario has been trapped in the gold and copper mine for 54 days.
Three drills are pounding through hard rock below the Atacama desert to reach the miners. "Plan B" is a U.S.-made T-130, operated in consultation with a team from Somerset, Pennsylvania, that had experience in the 2002 Quecreek mine disaster, where a similar tunnel was carved to pull out nine trapped coal miners.
Many observers had put their bets on "Plan C," a towering oil-industry drill with the power to rapidly carve a separate tunnel to a spot slightly less deep. Now it looks like either drill might be the one to reach the miners first.
Above ground, the government is rushing to set up a field hospital and a huge stage where the media can observe the rescue from a distance.
The first rescue capsule has already arrived, but workers still need to attach it to a huge spool of steel cable. These and other tools will be ready in 15 days, Interior Ministry official Cristian Barra promised Tuesday.
Barra and the rescue operations chief, Andre Sougarret, stressed, however, that just because the tools will be ready doesn't mean the rescue will happen so quickly.
There could be setbacks in the drilling, they warned, especially as the drills pass through collapsed sections of the mine or rock layers that aren't well mapped. Staying cautious, Barra said they are sticking with the official date of early November for now.
"We in 15 days will be prepared to be able to do the rescue at any moment. This doesn't mean it will happen in 15 days, but all the installations will be in place," Barra said.
If the "Plan B" drill maintains its current speed, President Sebastian Pinera may be able to keep his promise of hugging each surfacing miner and still leave for Europe on a previously scheduled trip Oct. 15-22.
But Sougarret also advised caution, saying he expects the unexpected when it comes to hard-rock drilling.
"I must insist - we have had problems in which we have had to pause the machines for more than four days at a time because of some problem with the drilling," he said. "We don't completely know the geology, we're passing close to open spaces in the mine, and so I can't confirm until we are very sure that the rescue can happen more quickly."
"We still have doubts," he added. "... It's prudent to keep talking about the first days of November."
The government said the Strata 950 "Plan A" drill reached 1,667 feet Tuesday morning. Once it breaks through to 2,306 feet, this drill will need to start over again, widening the hole to its final diameter of 28 inches so that the metal sleeve and escape capsule can pass through.
The other two drills are already carving out holes this wide, and making quick progress: the T-130 "Plan B" drill reached nearly halfway to its 2,047-foot goal Tuesday evening, Sougarret said. The "Plan C" Rig 421 oil well drill has carved out 361 feet of its 1,959-foot goal.