Rescuers worried that trapped miners may risk blood clots and panic attacks as they are hauled to the surface

The 33 miners trapped under Chile's Atacama desert today began preparing for their imminent rescue with a detailed medical checkup and a prescription of aspirin to prevent hypertension or blood clots as they are hauled nearly half a mile to the surface.

Emergency workers sent down special equipment to monitor the men's heart rates, respiration and skin temperature, said Chile's health minister, Jaime Manalich. If the rescue goes ahead as planned they could be winched up in just 20 minutes.

The rescue capsule is expected to rotate up to a dozen times as it rises through the 28-inch escape shaft, and to prevent nausea, the men have been given compression socks and a high-calorie liquid donated by Nasa.

Each escape capsule has been fitted with a two-way communication system and a video camera so each miner's face can be watched by rescuers, but Manalich said that the biggest concern for officials was that the men could suffer panic attacks during the ascent. "This is the first time in many weeks that the miners are going to be completely alone," he added.

The rescue team hopes to start extracting the men on Wednesday after reinforcing the top segment of the escape shaft with steel tubing.

A video inspection showed that most of the shaft, 622 metres deep, was solid rock and did not require a lining, speeding up a complex and often fraught challenge, officials said.

During conversations with the miners tonight, they were asked to help officials agree the order in which they will be hauled to the surface.

Manalich said that several of the men expressed a desire to be the last man out in what he called "a completely admirable show of solidarity".

On further questioning, however, the men revealed the cause of the disagreement: a guaranteed place in Guinness World Records for the longest time a miner has ever been trapped underground. Given the complexities of the current situation, it is a record that many expect to be insurmountable.

A drill reached the trapped men yesterday, 65 days after an accident caused the collapse of the gold and copper mine. The breakthrough triggered celebrations above and below ground, and rescuers cheered and sprayed champagne.

The miners used explosives to widen the shaft for a special capsule dubbed "the phoenix", which will lift them individually to the surface.

The government-led rescue operation has used cameras to analyse the entire length of the shaft. An eight-member team of geologists determined that the tunnel presented little risk of caving in.

All day , a caravan of trucks, vans and buses brought supplies and personnel to the already crowded mountainside. With 20 different companies participating in the rescue effort and an estimated 2,000 journalists at the scene, the problems of feeding and organising the rescuers' village have grown.

Rescuers who descend to the mine will give the trapped men green waterproof suits designed to let their skin breathe as they ascend.

When the miners arrive at the top, they will each receive a pair of Oakley Radar sunglasses in an effort to shield them from direct sunlight. They will then be helped from the capsule and taken down a darkened hallway where doctors, nurses and psychologists will begin a 48-hour evaluation of their mental and physical health.

The miners are under no obligation to submit to the medical proceedings, but will be asked to sign a waiver if they wish to go home immediately.

Police will fingerprint them and check their identities. "The idea is to verify that the people who are inside the mine are in effect the same names that we have all assumed," said Oscar Miranda, a police inspector.