* Rescuers prepare to drill escape shaft
* Rescue workers send miners aid down narrow hole
* Miners unaware extraction may take four months (Adds NASA consultation, details, quotes, Venezuela accident)
By Alonso Soto
COPIAPO, Chile, Aug 24 (Reuters) - Rescue workers prepared on Tuesday to install a drill to dig an escape shaft for 33 miners -- trapped for 19 days deep in a Chilean mine -- who may not see the light of day until Christmas.
Engineers started sending hydration gel and medication through a narrow bore hole on Monday to keep the miners alive during the long rescue effort and and have set up an intercom.
To avoid hurting morale, the miners have not yet been told how much longer they may be underground.
Now engineers must build a concrete platform and erect the drill, which will bore a shaft 2,300 feet (700 meters) straight down around 2 feet (62cm) in diameter, and plan to use a pulley to lower a cage to evacuate them one at a time. They hope to start drilling the escape shaft by the weekend.
The government has contacted NASA for advice on how to keep the miners healthy with space mission-like rations and help them cope with the extended time in a confined space that lies ahead. It is already one of the longest periods trapped miners have survived underground.
Regional superintendent Ximena Matas said it would take a couple of days to assemble the drill. Rescue workers say it will take three to four months to dig the escape shaft.
For a TAKE-A-LOOK [ID:nN22135549]
FACTBOX-Major Chile mine accidents [ID:nN06266599]
For graphic, see: link.reuters.com/kes76n
Relatives of those trapped, who have been living in plastic tents at the mine head in a makeshift settlement dubbed Camp Hope, are elated but face a long wait.
Maria Segovia, a 48-year-old street vendor whose brother Dario is among those trapped, said she and her siblings would take turns staying at the mine during the rescue.
RELATIVES PREPARE FOR LONG-HAUL
"It will be difficult to leave this behind, because though it's hard to believe, it has become our home," she said, overlooking a tiny tent where she has slept since the Aug. 5cave-in. "The wait is different now, though. We are much more relaxed and I know my brother won't crack down there."
"Even though they haven't told them how long the rescue will take, they are strong, they are miners, and they know it won't be easy to get them out," she added.
"This is going to teach the world about survival, about the will to live."
The miners' relatives have sent letters down to the miners, tucked into emergency provisions, to help them cope with the psychological strain. Mining Minister Laurence Golborne made the first intercom contact with the miners on Monday.
"We are well. We're waiting to be rescued," Luis Urzua, mine shift leader, told Golborne from below as the trapped miners applauded, cheered and sang Chile's national anthem.
Rescuers and family members were heartened by the remarkably good condition of the miners, whose first request was for toothbrushes. The men have stripped off their shirts to help cope with heat down in the mine.
The accident in the small gold and copper mine has turned a spotlight on mine safety in Chile, the world's No. 1 copper producer, although accidents are rare at major mines. The incident is not seen having a significant impact on Chile's output.
The miners are 4.5 miles (7 km) inside the winding mine. They abandoned a sparse 540-square-foot (50 square metre) refuge, an area the size of a small apartment, which contains two long wooden benches, opting instead to stay in tunnels because of ventilation problems.
They tried to escape via a ventilation shaft soon after the accident, but found that a ladder was missing. The shaft later caved in.
Ventilation and tanks of water helped the miners survive. They rationed out the provisions they had, eating two mouthfuls of tuna and drinking half a glass of milk every 48 hours. Health officials estimate they may have lost about 17.5 to 20 pounds (8 to 9 kg) each.
Health officials have advised the miners should try to exercise to stay fit and avoid any complications during the eventual rescue.
President Sebastian Pinera has fired officials of Chile's mining regulator and vowed a major overhaul of the agency in light of the accident.
Analysts say the feel-good factor of finding the miners alive, coupled with the government's hands-on approach, could help Pinera as he tries to push through changes to mining royalties that the center-left opposition had shot down.
In another mining accident in the region, a cave-in at a wildcat gold mine in south Venezuela has killed seven people and trapped others, officials and a miner said on Tuesday. [ID:nN24263878] (Additional reporting by Antonio de la Jara, Simon Gardner, Molly Rosbach and Juana Casas; Editing by Jerry Norton)