The miners rescued so far appear to be in better physical health than expected

'Given the size of this group, it's almost a guarantee that we're going to see cases of post-traumatic stress disorder, sleep disturbances and clinical depression,' said Sheryl Bishop, a social psychologist and expert in survival in extreme conditions at University of Texas Medical Branch in Galveston, Texas. 'They may look fine now, but they could have flashbacks and nightmares six months from now or even later.'

Chile's health minister, Jaime Manalich, said the miners' physical ailments were the same ones the men had described before the rescue began. Two men will undergo major oral surgery for teeth infections or abscesses. Another miner who is recovering from acute pneumonia suffers from a lung disease common among miners called silicosis and came up with a special oxygen mask as a precaution, wire services reported.

'I have to humbly admit that the miners' health is more than satisfactory,' Dr. Manalich said.

The miners' remarkable feat of surviving as long as they did was probably buttressed by the initial decision of a few individuals to quickly take on leadership roles.

That likely helped to make the group cohesive and stable -- and gave them hope.

Later, when they knew that help was on the way, the trapped miners probably benefited from having to take on a vital task crucial to their rescue: clearing debris so that the rescue shaft could be drilled.

'It gave them something concrete to do, and that gave them the psychological stamina to endure the wait' Dr. Bishop said.