(CNN) -- Communications and supplies are flowing efficiently between rescuers and 33 trapped miners in Chile, according to authorities.
The miners have been trapped for a total of 20 days with minimal food. A probe sent by rescuers found the men alive on Sunday, but it could be three to four months before a hole can be drilled that will reach the men, 2,300 feet below the earth's surface.
In the meantime, the miners are asking for certain objects to be sent down to make surviving in the cave easier for them.
Officials have sent down playing cards, and the miners have asked for religious figures, such as statuettes of saints, to be delivered to them, Health Minister Jaime Manalich said Wednesday.
A crucifix has also been sent down. The miners intend to designate an area in their shelter as a shrine, Manalich said.
They have also asked for a Chilean flag.
For their part, authorities are focusing on the mental and physical health of the miners.
Chile is asking NASA to send a team of two or three experts on nutritional and psychological issues, Manalich said.
Based on a survey of the miners, three or four of them are showing signs of depression, such as not sleeping and feeling mentally uncomfortable, he said.
Also, according to medical records, there are at least nine miners who would be too overweight to fit through the proposed shaft to rescue them, Manalich said.
The miners are believed to have lost about 8 kg (17 pounds) so far during their time in the mine, and officials expect that the overweight miners will be able to be rescued by the time the shaft is completed.
"Believe me, they will lose weight," Manalich said.
What the miners eat and how much will be monitored by officials.
Rescuers hoped to have tubes in place later Wednesday to constantly pump oxygen and drinking water into the shelter where the miners are.
To create a routine, officials are having the 33 split into two shifts, one which will sleep while the other works or has leisure time.
One thing that officials have not explicitly told the miners is how long they may be trapped before a rescue. On Wednesday, however, President Sebastian Pinera gave them some clues in a conversation.
Pinera told the 33 that they would have to celebrate Chile's independence day -- September 18 -- inside the mine. He also told one of the miners, who is Bolivian, about a meeting between the presidents of both countries in late November. Pinera said he would invite the Bolivian miner to accompany him.
The miners have been trapped inside the San Jose copper and gold mine since an August 5 cave-in.
Family members had cheered Sunday when Pinera held up a handwritten note pulled from the mine. The note was tied to a probe authorities had lowered earlier Sunday.
Written in Spanish in red ink, it said simply: "We are fine in the shelter, the 33 of us."
CNN's Karl Penhaul contributed to this report.