Engineers in Chile have begun drilling the rescue shaft through which they hope to eventually free the 33 men trapped in a collapsed gold mine.
The miners have been stuck 700m (2,300ft) underground for the past three weeks.
Officials say it could take up to four months for the tunnel to be completed and the men to be winched out.
Some of the miners have developed fungal infections and body sores in the hot conditions underground.
A huge Australian-made "Strata 950" excavator began work late on Monday.
The machine dug a narrow test hole, and will now drill down to the men, before widening the shaft to about 60cm.
The miners will have to clear thousands of tonnes of falling debris in round-the-clock shifts, although officials say the men are in no danger of being hit.
The rescue shaft is likely to take 90 to 120 days to complete. Then a capsule can be lowered down to retrieve the miners one by one.
Mining Minister Laurence Golborne had said up to 10 options were being considered in the efforts to rescue the men.
But he dismissed suggestions that the men could be out within a month, saying: "Up to now there is no alternative... that would allow us to get them out in 30 days."
At present, rescue workers are using three narrow shafts to send essential supplies to the trapped men, and ensure they have adequate ventilation.
On Sunday, the miners were each able to speak to family members for one minute by telephone.
The supply line which is proving vital to the Chilean miners
Alicia Campos said she broke down as she said goodbye to her son, Daniel Herrero, promising him she would see him again.
"His voice is the same. He's not good, but not so bad either," she said.
Jessica Chille said speaking to her husband, Dario Segovia, had been "a balm to my heart".
The men are trapped in a refuge chamber of the mine, where they managed to take shelter after a rock collapse on 5 August.
One of the men has some medical training and has been able to give his colleagues vaccinations against tetanus. They will be sent flu vaccinations later this week.
Quick-dry clothing has also been sent down, after some of the miners said they were suffering from skin conditions in the hot, wet conditions. Others have been sent mats to sleep on to protect them from the damp ground.
They have also been sent mp3 players to listen to music and a small screen, so they can watch football matches.
Four experts from Nasa are due to arrive at the mine this week at the request of the Chilean authorities, to advise the miners and rescuers on how to cope with their situation.
The team includes a doctor, nutritionist, and engineer and a psychologist.
Nasa deputy chief medical officer Michael Duncan said that while the environment was different to that experienced by astronauts, "the human response in "physiology, behaviour, responses to emergencies is quite similar".
"We think that some of the things we learned in research and operation can be adaptable to the miners who are trapped under the ground," he said.
Mr Duncan praised the responses of the miners and officials, saying they appeared to be well organised.
"They have done a lot for the miners, and in fact the miners have done a lot for themselves underground," he said.
Families of the men have set up a temporary encampment at the head of the mine, which they have called Camp Hope.
The BBC's James Reynolds at the mine, about 800km (500 miles) north of Santiago, says a shrine has been built for each of the miners, covered in photographs, messages and football shirts.