COPIAPO, Chile — Trapped nearly half a mile inside the earth and facing perhaps four months before rescue, 33 Chilean miners began accepting food, water and oxygen from above ground Monday as rescue teams worked to gauge their state of mind and brace them for the long wait ahead.

Through a newly installed communications system, each of the men spoke and reported feeling hungry but well, except for one with a stomach problem, a Chilean official said. They requested toothbrushes.

It was a positive sign, and Chile’s president said the nation was “crying with excitement and joy” after engineers broke through Sunday to the men’s refuge. It had been 17 days since a landslide at the gold and copper mine caused a tunnel to collapse and entombed them more than 2,200 feet below ground.

Still, doctors and psychological experts were trying to safeguard the very sanity of the miners in the months to come, and said they were implementing a plan that included keeping them informed and busy. The miners reported that a shift foreman named Luis Urzua had assumed leadership of the trapped men.

“They need to understand what we know up here at the surface, that it will take many weeks for them to reach the light,” Health Minister Jaime Manalich explained.

Engineers worked to reinforce the 6-inch-wide bore hole that broke through to the refuge, using a long hose to coat its walls with a metallic gel to decrease the risk of rock falling and blocking the hard-won passage through the unstable mine.

The lubricant makes it easier to pass supplies through in capsules nicknamed “palomas,” Spanish for dove. The first of the packages, which are about 5 feet long and take about an hour to descend from the surface, held rehydration tablets and a high-energy glucose gel to help the miners begin to recover their digestive systems.

Rescue teams also sent oxygen down after the miners suggested there was not enough air in the stretches of the mine that run below where the main shaft collapsed.

The shelter, a living-room-sized chamber off one of the mine’s lower passages that is easily big enough for all 33 men, is far enough from the landslide to remain intact, and the men can also walk around below where the rocks fell. Actual food will be sent down in several days, after the men’s stomachs have had time to adjust, said Paola Neuman of the medical rescue service.

Rescuers also sent down questionnaires to determine each man’s condition, along with medicine and small microphones to enable them to speak with their families during their long wait.

Meanwhile, an enormous machine with diamond-tipped drills capable of carving a 26-inch-wide tunnel through solid rock and boring at about 65 feet a day was on its way from central Chile to the San Jose gold and copper mine, outside Copiapo in north-central Chile.

Engineers were also boring two more narrow shafts to the trapped men, but stopped Monday just above their refuge while they made sure that the lifeline was fully secure. Only when these three shafts are complete will they begin carving out the tunnel large enough to fit a man, Mining Minister Laurence Golborne said.

“We cannot be 100 percent precise, but the idea is to establish three or four points of contact so that we can guarantee better life conditions to our comrades down there,” he said.

Besides their immediate physical needs such as medicine to restore their raw stomachs and sleep cycles, the rescuers were preparing psychiatric counseling. A first step was the questionnaires, which were also intended to help identify their natural leader — someone who can ensure the men are keeping busy and mentally focused.

Above ground, rescuers and family members thought that might be Mario Gomez, who at 63 is perhaps the oldest of the veteran miners down below. Gomez’s letter to his wife, Liliana, which the miners tied to the drill bit, was full of expressions of faith and determination, revealing to the world that the miners were holding strong.

“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,” Gomez wrote, scrawling the words on a sheet of notebook paper. “Patience and faith. God is great and the help of my God is going to make it possible to leave this mine alive.”

But Urzua, 54, was the shift foreman at the time of the collapse, and Golborne said Monday that “it seems the miners respect hierarchies.”

The men already have been trapped underground longer than all but a few miners rescued in recent history. Last year, three miners survived 25 days trapped in a flooded mine in southern China, and two miners in northeastern China were saved after 23 days in 1983.

The miners’ survival after 17 days is very unusual, but since they’ve made it this far, they should emerge physically fine, said Davitt McAteer, who was assistant secretary for mine safety and health at the U.S. Labor Department under President Clinton.

“The health risks in a copper and gold mine are pretty small if you have air, food and water,” McAteer said.

Mine officials and relatives of the workers were determined not to give up hope that the men were safe below where the tunnel collapsed Aug. 5 at the mine, about 530 miles north of Santiago, the capital.

Rescuers had drilled repeatedly in an effort to reach the shelter, but failed seven times. They blamed the errors on the mining company’s maps. According to Gomez’s note, at least some of those earlier probes were close enough that the trapped miners heard them. The eighth attempt finally worked.

Gomez wrote that the miners used vehicles for light and a backhoe to dig a channel to retrieve underground water. And while his message focused on faith and love for his family, his frustration also showed through. He wrote, “This company has got to modernize.”

Chile is the world’s top copper producer and a leading gold producer, and has some of the world’s most advanced mining operations. But both the company that owns the mine, San Esteban, and the National Mining and Geology Service have been criticized for allegedly failing to comply with regulations. In 2007, an explosion at the San Jose mine killed three workers.

President Sebastian Pinera said Monday that “there is not going to be any impunity” and said investigations were under way.

Shortly after the accident, Pinera fired two top executives of Sernageomin, Chile’s mine safety regulator, after reports that the mine had reopened too soon, and without real security improvements, after a fatal accident three years before.

The miners’ relatives are suing and claim the miners were put at risk in a mine known for unstable shafts and rock falls. Company executives have denied the accusations and say the suits could force them into bankruptcy.