'We are well', read the note. But now for the long wait to be rescued

The miracle came in the form of the opening two words of a short note, scribbled in red ink on a crumpled piece of paper. "Estamos bien", the note read. We are well.

For nearly three weeks, relatives of the 33 Chilean miners trapped 700 metres underground in a passage the size of a small apartment had hoped against the odds that their loved ones would be located.

But now the miners themselves face a gruelling four-month wait underground as engineers desperately try to bore through millions of tonnes of collapsed rock to reach them in a rescue attempt that has gripped Chile and shone a spotlight on the safety record of its vital copper mining industry.

Engineers yesterday began reinforcing a shaft no thicker than a grapefruit which is the men's lifeline, and only contact with the outside world.

The miners were cut off from the surface when the spiralling access tunnel at the San Esteban gold and copper mine in Copiapó collapsed 18 days ago. They managed to make their way to an emergency shelter but rescue workers had no idea whether anyone from the group was alive until late on Sunday evening when, after a series of failed attempts, engineers finally managed to drill a probe into the chamber, sparking scenes of intense joy for colleagues, loved ones and rescue workers on the surface.

Images broadcast from a camera that was lowered down the shaft showed some of the miners stripped to the waist and waving. Health officials say the men have lost around 8-9kg and began using the newly drilled shaft to send them desperately needed packages of food and hydration gels in plastic tubing.

The trapped miners were able to alert rescuers to their presence by tying a note to the probe confirming that they were all alive. A series of previous attempts to find the men had failed, leading to fears that they would never be located.

The discovery that everyone was alive was a brief moment of intense jubilation for the hundreds of relatives who have gathered at the mine in the Atacama Desert, holding prayer vigils in the hopes that their loved ones will be rescued.

The Chilean President Sebastiá*Piñera, who travelled to the mine over the weekend, held the note up for reporters yesterday morning and announced: "Never have so few words brought such happiness to an entire nation."

Rescuers sent Chilean miners still alive 18 days after a cave-in supplies of saline and glucose through a narrow drill hole on Monday, and now face a months-long, half-mile dig to save them.

For the relatives – who celebrated with barbecues and prayers to St Lorenzo, the patron saint of miners – the initial euphoria will now turn to an agonising wait as rescuers battle to reach the trapped men. "The wait is very different now," said Elias Barros, 57, whose brother is among those trapped. "It is a wait free of anguish. This isn't over but we are much more hopeful it will end happily."

The miners now face the extreme psychological pressure of having to live for months underground in cramped and stiflingly hot conditions with no sanitation or natural light.

Over the coming days engineers hope to drill a second small shaft to send communication equipment so that the men can talk to their loved ones, something which psychologists say is vital for maintaining the men's sanity. They will also dig a third 26in shaft which will eventually be used to rescue the men.

Andres Sougarret, the chief engineer in charge of the rescue operation, said the larger drill needed to create the third shaft has to work at a much slower rate. "Our initial estimate is that it will take three, four months," he said.

It is not yet clear whether the 33 miners are aware that they face the prospect of months before being rescued. But early indications suggest that they are prepared for a long wait.

Mario Gomez, the eldest of the miners at 63, sent a note up to his wife, Liliana, which read: "Even if we have to wait months to communicate... I want to tell everyone that I'm good and we'll surely come out OK. Patience and faith. God is great and the help of my God is going to make it possible to leave this mine alive."

Mr Gomez's note gave rescue workers their first indication of how the group had survived so long underground. When the access shaft collapsed the men headed to an emergency shelter where they rationed out the small supply of food kept there. They used a truck battery to keep their flashlights going and had to dig wells to retrieve water and drink from drilling equipment.

Mr Gomez's note also showed some criticism of the mining company saying it "had to modernise".

Chile has the largest copper deposits in the world and relies heavily on its mineral and metal wealth. Roger Moody, an expert who runs Mines and Communities, a website which monitors mining companies and the impact they have on workers, says Chile has a comparatively good reputation for safety.

"Unfortunately Chile doesn't really keep very good statistics but generally the country is thought to have a relatively good safety record," he said. "There have been accidents and fatalities but nothing like on a par with countries like Colombia or China."

Davitt McAteer, assistant secretary for mine safety at the US Labor Department under President Bill Clinton, told NPR radio that the toughest challenge for the 33 men was to survive the psychological pressure of being trapped for so long underground.

"Miners are resilient as a general rule, but that's a long time to be underground," he said. "Whether it's weeks or months, it's going to be a difficult time."Sandro Rojas, a 42-year-old miner who has four relatives among those trapped, was one of those waiting anxiously on the barren hillsides above the mine which are now littered with Chilean flags. He said he dreamed of seeing his brother again. "I'm going to tell him I love him and smother him with kisses," he said. "To be honest, I don't know if I'll be able to speak I'm so excited."