COPIAPO, Chile -- Barring last-minute complications, rescuers plan to reach 33 trapped Chilean miners by daybreak Saturday morning and then make a critical decision that will determine how soon afterward to have them above ground.
Mining Minster Laurence Golborne said Thursday that a drill was within 300 feet of where the men have been stuck since a mine collapse Aug. 5. It is the closest of three competing drilling operations racing to reach the miners, who remain huddled in a 600-square-foot refuge about 2,300 feet below the mine entrance.
At the current rate, the Schramm T130 drill should reach the miners between midnight and dawn Saturday. But officials cautioned that the final stretch is perhaps the most delicate, because the rock is weakest structurally above the cavern where the men are gathered.
Engineers won't decide until after the hole is completed whether they will fully or partially line it with metal tubing. The decision will follow a close inspection with video cameras.
The tubing is thought to be the best way to ensure that the walls of the hole don't collapse on top of the half-ton metal capsule that will be used to lift the men to safety. But the strategy comes with the risk that the tubing could get stuck.
Sources with the mining ministry said the preliminary consensus is that the metal sleeve will only be necessary for the 350 feet or so closest to the surface, where the rock appears to be less stable than deeper down. Such a partial lining would take one to two additional days before the rescue could begin, while placing a casing the hole's entire length could take at least a week, Mr. Golborne said.
Excitement was building Thursday among family members at the prospect that their loved ones will soon emerge. Their entrapment is thought to be the longest in mining history prior to a successful rescue. Dozens of miners' family members have kept vigil at the mine, camped in tents near the entrance.
"I'm anxious, but I'm very excited to think I will soon be touching him and embracing him," said Norma Sanchez, whose 19-year old son Jimmy is the youngest trapped miner. Asked whether she preferred that the entire hole be partially or completely lined with metal tubing, Ms. Sanchez said she preferred "the fastest" option.
Ms. Sanchez said families have been told that each miner will be allowed to have three relatives present when they are pulled to the surface in the capsule called "Phoenix," a process that will take 30 to 60 minutes per miner.
A medic and an engineer from the rescue team are to be lowered to test and advise the miners before their rescue begins. The miners have already begun aerobic exercises to prepare for the change in environment, officials said.
For the ride up, the men will also be given special glasses to protect their eyes -- which have been in near-continual dilation and could prove vulnerable to sunlight. As they are lifted, the miners will wear belts similar to those worn by astronauts to measure their vital signs.