Iron discipline key for Los 33

They may not take kindly to being called fortunate, given the fear and discomfort they endured for 70 days.

But from the moment they were trapped underground, the 33 men in the San Jose mine benefited from crucial strokes of good luck. The rockfall that trapped them struck at noon local time on August 5, when they were having lunch in a reinforced rescue shelter.

At any other time in a normal working day, they would have been spread throughout 6km of tunnels - many would have been killed.

When the dust settled, it emerged that the miners had access to a kilometre of what seemed to be stable areas of the mine. That section contained several vehicles, whose batteries they used to power torches. One truck, which had been driven by a former footballer, Franklin Lobos, also contained a small supply of bottled drinking water.

Their next piece of good luck involved the type of mine they worked in. Copper mines are inherently safer than coal ones, which emit potentially deadly methane. So although ventilation shafts had been blocked, the men knew that the only way the remaining oxygen was going to be used up was by them breathing it. Time was on their side.

Perhaps most crucially, the 33 miners had a small quantity of emergency food in the corner of their rescue shelter. They also had leftovers from the lunches they had brought down at the start of their 12-hour shift at the small, privately-owned facility in the Atacama desert, an hour's drive from the northern city of Copiapo, where most lived.

Realising that the sheer depth at which they were trapped meant it could be days, or even weeks, until they were located, the men embarked on a rationing system. They would eat just two teaspoons of canned tuna and a biscuit every 48 hours. Each of these "meals" was to be washed down with two sips of milk. It was hot in their underground prison, about 30C, but they were able to avoid dehydration by supplementing their bottled water by digging a makeshift canal in the floor. As a potential last resort, they also drained the radiators of their machinery.

No one yet fully understands the mood in the mine during the ensuing 17 days. A second rockfall, on August 8, closed off a further hundred metres, adding to the sense of foreboding. There is believed to have been bickering over the rationing, which some deemed too rigorous. But in subsequent letters, "Los 33" say they've vowed never to publicly discuss any tensions that arose.

It seems likely, though, that in the stressful conditions, leaders emerged. One such man was Luis Urzua, 54. The eldest son from a large Catholic family without a father, he was a natural authority figure.

Urzua is believed to have decided they had a straightforward choice: perish separately, or work together to defy the odds. The key to getting themselves out alive, he believed, would be la solidaridad (solidarity).

Urzua instigated a system under which none of the 33 could begin eating their tiny meals until all had received food. He organised them into three groups, who would venture out, in shifts, to search for signs of any approaching rescue.

At the behest of Laurence Golborne, Chile's Mining Minister, and a President who had pledged to spend anything it took to get the miners out alive, experts from the state firm Codelco had assumed responsibility for the search. Using maps of the sprawling mine, they drilled several exploratory boreholes, sending listening devices into areas where they believed survivors might be alive.

For two weeks, nothing. Then, on August 23, came a breakthrough. A probe found its way through a wall metres from the rescue shelter. It returned to the surface with a note attached. "Estamos bien en el refugio los 33," it read (all 33 of us are well inside the shelter). Those first words had been scrawled in capitals on a scrap of paper by Mario Gomez, the oldest of the miners.

A camera was sent down the borehole. It showed the group peering eagerly out of the darkness, shirtless, unshaven and sweltering, but their eyes blazing with euphoria.

The rescue teams realised they had two major problems. The first was how to keep the men supplied with sufficient medication, clothing, meals and drinks to keep them alive during an operation they initially believed might not be over until Christmas. The second was harder: how to ensure the men remained psychologically sound.

A communication system was designed by Miguel Fortt, a Chilean expert in mining rescues. He called it "la paloma" (the dove). It consisted of a 3m-long PVC tube which would be lowered via cable.

At first, each "dove" took four hours to arrive from the surface, and would contain bare essentials: glucose drinks, vitamin and mineral supplements. Later, the system was improved. The PVC was swapped for metal tubes, a further two boreholes were drilled, and journey times improved to 20 minutes. That allowed camp beds, communication equipment and clothing to be sent.

To maintain morale, the rescue team received advice from Nasa, which is used to helping grown men live together in confined spaces for extended periods. There were dominoes, books and letters and tape recordings from their families; their diet was widened to include tea, sandwiches, fruit, and hot meals.

Organised by Urzua, the men were divided into three groups, Grupo Refugio, Grupo Rampa and Grupo 105 - named after the "shelter," the "ramp" and "Level 105", sections of the mine where they slept. They then established a working shift pattern. When off duty, they slept, exercised and sent video, audio, and written messages to their families. Lights shone from 7.30am until 10pm, mimicking daylight. Urzua used the bonnet of a mine vehicle as his desk, and sent up maps.

He wrote for each of the men an official job description. Some became "palomistas," unloading the regular supply of "doves". Others would patrol the mine to check on the structural integrity of its walls. Jimmy Sanchez, the youngest, was the "environmental assistant", who monitored conditions with a handheld computer that measured oxygen, CO2 levels and temperature.

They would shower each morning under a natural waterfall, using supplies of shampoo to clean off the orange-coloured mud that found its way almost everywhere. The more religious men would take part in a daily prayer organised by Jose Henriquez. Others would listen to poems written by Victor Zamora, the group's in-house poet.

Many developed skin infections, and almost all will now require extensive dental treatment. Medical teams at the surface also found themselves clashing with some of the miners, whose natural machismo led them to consider the daily conversations with psychologists to be undignified.

At one point, in mid-September, some of the miners effectively went on strike, refusing to speak to their medical handlers. The psychologists withdrew TV and music. When the men agreed to speak with them again, a delivery of cigarettes arrived in a "dove".

By that stage, three drills - Plan A, Plan B, and Plan C - were cutting through the rock to reach the cavern. By early October, they knew breakthrough was imminent. And last weekend, the Plan B drill broke through. The final stage of their journey to freedom could at last begin.

Slick operation:

Overall:

Estimates for the rescue operation alone have soared beyond US$22 million ($29 million). The entire rescue operation was meticulously choreographed. No expense was spared in bringing in top drillers and equipment - and boring three separate holes. President Sebastian Pinera put his mining minister and the operations chief of state-owned Codelco, the country's biggest company, in charge of the rescue. Officials first said it might be four months before they could get the men out; it turned out to be 69 days and about 8 hours. The final operation took 22 hours, 37 minutes.

Capsule:

The miners made the ascent inside a capsule called Phoenix - 4m-tall, barely wider than their shoulders and painted in the white, blue and red of the Chilean flag. It worked exactly as planned.

Journey:

After a quick pep-talk from rescue workers who had descended into the mine, a miner would strap himself in, make the journey upward and emerge from a manhole into the sun. The miners were monitored by video on the way up for any sign of panic. They had oxygen masks and sweaters for the jarring transition from subterranean swelter to chilly desert air.

Glasses:

The miners wore wraparound style Oakley sunglasses designed to minimise heavy glare. Using the darkest lens with a grey base and black iridium coating should help the miners' eyes adjust to bright light after being dilated so long.

Cameras:

The rescue went so well its managers abandoned a plan to restrict images of the operation. The images beamed to the world were extraordinary: Grainy footage from beneath the earth showed each miner climbing into capsule, then disappearing upward through an opening. Then a camera showed the pod rising through the dark, smooth-walled tunnel.

Presentation:

The miners emerged looking healthier than many had expected and most of the men emerged clean-shaven. Chilean pride and colours were conspicuous and the President greeted miners with hugs at the top.

Aftermath:

Chile has promised that its medical care of the miners won't end until they can be sure that each man has readjusted.

- AP/Independent