SANTIAGO, Chile (Bloomberg)—Chile is tapping the United States' National Aeronautics and Space Administration and domestic Navy on how to maintain the health of 33 miners facing a three-month wait before being rescued from a collapsed gold and copper mine.

Psychiatrists and nutritionists from NASA discussed in a conference call ways to help the miners cope with the physical and mental challenges of being trapped underground for such a long period, Health Minister Jaime Manalich said on Chilean television Wednesday. A delegation may visit the site, he said.

The miners were discovered on Aug. 22 after being trapped 2,300 feet underground since Aug. 5, when the only access to the San Jose mine collapsed. A three-month rescue is “unheard of” in the industry, said Rob McGee, an official at the Uniontown, Pa.-based U.S. Mine Rescue Assn.

“It's being evaluated whether a NASA mission comes in the coming days to review the quality of our operation,” Mr. Manalich said Wednesday in televised comments.

The miners' only contact with the outside world is through 6-centimeter-wide drill holes that were used to discover them and through which they receive food, water and medicine.

“It's extremely fragile,” Mr. Manalich said. “It's truly an umbilical cord.”

Shipping a drill

The mine is owned by Cia. Minera San Esteban Primera S.A. State-owned Codelco, the world's largest copper producer, sent a drill to the site that will bore a hole wide enough to pull the men out. Andre Sougarret, who leads the rescue mission, manages El Teniente, the world's largest underground copper mine in central Chile.

Melbourne-based BHP Billiton Ltd. and Phoenix-based Freeport McMoRan Copper & Gold Inc., which also mine for copper in Chile, form part of the rescue team. Chile provides one-third of the world's copper.

Drillers must bore through the “unstable geology” of the Atacama Desert to reach the miners, said J. Davitt McAteer, who was appointed to investigate the causes of a blast at Massey Energy Co.'s Performance Coal operation in Montcoal, W.Va., that killed 29 people in April.

Freeing the miners is “still a hell of a problem,” Mr. McAteer said in a telephone interview. “Lots of things can go wrong. You've got to be lucky and be good as well.”

The technique of lifting workers from a man-sized hole first proved successful in 1963 after David Fellin and Henry Throne were pulled out of the Sheppton coal mine in Pennsylvania after being trapped for 14 days. A similar rescue effort at a coal mine in Crandall Canyon, Utah, ended in failure after six miners and three rescuers were killed, Mr. McAteer said.

Antidepressants, dominoes

“If you drill too fast, the drill hole will deviate and not hit the target,” said Bruce Kennedy, principal mining engineer at Tucson, Ariz.-based SRK Consulting, which advises mining companies worldwide. “If the ground is fractured up, the drill hole may collapse.”

The trapped miners in Chile have access to more than 1.24 miles of tunnels and a small refuge with benches, Enes Zepeda, director of Codelco's supervisors union FESUC, said in an interview. They are sleeping on the ground with blankets, he said.

Chile's rescue plan will surpass a 25-day rescue of three coal miners in a flooded mine in Guizhou, China, Mr. McGee said in an e-mailed response to questions. Two Australian miners walked free in May 2006 after being trapped for two weeks almost 3,281 feet underground in a gold mine in Tasmania.

Until Christmas

Chile's government hasn't yet calculated how much it has spent on the rescue effort, Finance Minister Felipe Larrain said Thursday.

“The most important thing for us has been the lives of the miners,” he told reporters in Santiago, Chile. “Of course we are going to make sure that resources are used efficiently. But our main objective is to bring the miners back up to the surface in good condition, and we will have the resources we need to do that.”

The Chilean miners have accepted that the rescue may take until Christmas, Chile's Mr. Manalich said.

“Maybe we can help in the psychology of the trapped miners and their families,” Jose Hernandez, who last year embarked on a 13-day mission on Space Shuttle Discovery, wrote in a Twitter posting. He didn't respond to requests to verify the comments.

Chile is enlisting the Navy to help the miners cope with the isolation, Mr. Manalich said Wednesday. The miners will be given games such as dominoes and ludo to stay entertained, he said.

Soaring spirits

So far, the miners’ spirits are high, the minister said. They sang the country’s national anthem in a telephone call with Mining Minister Laurence Golborne and asked President Sebastian Pinera for wine to celebrate Chile’s National Day on Sept. 18.

Former World Cup and Real Madrid soccer star Ivan Zamorano wrote a letter to Franklin Lobos, one of the 33 miners, who played with Zamorano in Chilean team Cobresal. Marcelo Bielsa, an Argentine who oversaw Chile’s most successful performance in the soccer World Cup earlier this year, sent Mr. Lobos a shirt with the signatures of the national team.

The miners’ euphoria at being discovered may turn to depression as they wait for their rescue, Mr. Manalich said. Authorities are preparing antidepressants if needed, he said.

Conflicts may occur when people are trapped together in a confined space for prolonged periods, said Ana Maria Aron, a psychologist at Chile’s Catholic University who heads a unit that helps patients recover from traumatic experiences. The government is doing a good job in giving the miners tasks such as monitoring their health, which helps them feel like they have control over their situation, Ms. Aron said.

“This is a task of great undertaking, without any precedence in the history of medicine,” Mr. Manalich said.

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