COPIAPO, Chile — Just 35 inches (90 centimeters) around the waist — that’s how skinny Chile’s 33 trapped miners have been told they need to be to squeeze through the escape tunnel, the health minister said Wednesday.

Dr. Jaime Manalich said rescuers are applying a holistic plan to support the miners’ well-being during the months it may take to carve out the tunnel, including exercise and other activities to keep them from gaining weight.

“We’re working to determine a secure area where the miners can manage things. The space they’re in actually has about two kilometers of galleries to walk around in,” he said.

“We hope to define a secure area where they can establish various places — one for resting and sleeping, one for diversion, one for food, another for work,” he said, adding that specialists have reviewed each miner’s condition, based on the information they sent up to the surface, and “we can say that they are all healthy, with just a few minor problems.”

The health minister also said that as of Wednesday, the miners are getting more nutritious food in the form of cans of a milk-like drink that has been enriched with calories and protein, and tastes like chocolate with vanilla. It will be days yet before they can have solid food, he said.

The escape tunnel will be about 26 inches (66 centimeters) wide — the diameter of a typical bike tire — and stretch for more than 2,200 feet (688 meters) through solid rock. Rescuers also have to account for the space of the basket that will be used to pull the miners to safety, leaving little margin for error.

Even before rescuers contacted the men, the self-imposed rations were meager: Two spoonfuls of tuna, a sip of milk, a bite of cracker and a morsel of peach every other day.

That iron discipline kept all 33 miners alive for 17 days on just two days’ worth of emergency rations. And the same strength may be needed while they wait for rescuers to dig a tunnel wide enough to get them out — an operation that Chilean officials say may take until Christmas.

“The way that they have rationed the food, just as they’ve performed throughout this crisis, is an example for all of us,” Mining Minister Laurence Golborne said Tuesday after talking with the miners at length the night before through an intercom system lowered into their underground refuge.

Chilean President Sebastian Pinera spoke by phone Tuesday with Luis Urzua, the 54-year-old shift foreman who has been the miners’ leader underground.

“You will not be left alone, you have not been alone. The government is with you all, the entire country is with you all,” Pinera said.

Jorge Barahona isn’t surprised Urzua, his cousin, has led the men through such a precarious situation.

“All the guys with him have an experience of surviving, their work is survival,” said Barahona, standing around a campfire Wednesday, warming his hands as the sun peeked over the mountains.

Urzua’s father was killed when the foreman was just a teenager, and he immediately took charge of his younger brothers and sisters, developing his leadership skills early in life, his cousin said.

“He’s the leader of everything down there,” said Barahona, who doubts any of the miners would question his direction. “They know before something like this happens that there is somebody who will always lead.”

The miners were plunged into darkness by the Aug. 5 collapse of the main shaft of a gold and copper mine that runs like a corkscrew for more than 4 miles (7 kilometers) under a barren mountain in northern Chile’s Atacama Desert. They gained contact with the outside world Sunday when rescuers drilled a narrow bore-hole down to their living-room-sized shelter after seven failed attempts.

“It’s been like a heart that’s breaking, but we’re thankful they’re all alive,” bore-hole driller Rodrigo Carreno told The Associated Press as he prepared to leave Tuesday. “We did everything we could to save them, and in the end we succeeded.”

The miners said they conserved the use of their helmet lamps, their only source of light other than a handful of vehicles whose engines contaminate the air supply. They fired up a bulldozer to carve into a natural water deposit, but otherwise minimized using the vehicles.

The miners can still reach many chambers and access ramps in the lower reaches of the mine, and have used a separate area some distance from their reinforced emergency refuge as their bathroom. But they have mostly stayed in the refuge, where they knew rescuers would try to reach them.

The room has become stiflingly hot and stuffy. Leaving it allows them to breathe better air, but wandering too far is risky in the mine, which has suffered several rock collapses since the initial accident. It’s also spooky, since headlamps can illuminate only small areas of the vast space.

Three 6-inch-wide (15-centimeter) shafts are serving as the miners’ “umbilical cords” — one for supplies, another for communications and a third to guarantee their air supply.

Family members who have maintained an anxious vigil outside the mine were encouraged to send down notes. First was Lila Ramirez, answering the “Dear Lila” letter from her husband, Mario Gomez, that thrilled the nation when the president read it aloud Sunday, providing the first details of the miners’ survival.

“I wrote him just now and told him to be very patient, that we’re all camped out here, following his every heartbeat. That he shouldn’t become desperate, and that he try to be extremely tranquil,” Ramirez told the AP.

With each passing day, the families have been praying for their trapped husbands, fathers, brothers and boyfriends in tents surrounding the mine entrance, where cold nights end in a chilly fog. There’s a bonfire to keep warm, and barbecue and other food donated by the local government in a common tent.

“We’re not going to abandon this camp until we go out with the last miner left,” said Maria Segovia. “There are 33 of them, and one is my brother.”

In one more week, the men will have been trapped underground longer than any other miners in history. Last year, three miners survived 25 days trapped in a flooded mine in southern China. Few other rescues have taken more than two weeks.