CHIANG RAI, Thailand — Expert divers assigned to the task of saving a youth soccer team trapped in a cave in northern Thailand for more than two weeks looked set to resume their operation on Monday, a day after four people were brought out.
It was not clear Monday morning whether divers had reentered the huge Tham Luang cave complex where the remaining nine people have been trapped for more than two weeks. Heavy rains in the area overnight had eased by Monday morning.
The rescue operation chief said Sunday that efforts were paused overnight because workers used all the oxygen" and needed to reset their air tanks, and he gave a time frame that suggested it could resume Monday morning local time (Sunday night ET).
The four people rescued Sunday are now receiving medical treatment at Prachanukroh hospital in Chiang Rai, around 35 miles away, where the eighth floor has been reserved for the soccer team, their coach and their families — who have maintained a patient vigil by the entrance to the cave while the boys have been underground.
The 12 boys — ages 11 to 16 — entered the massive cave complex on the frontier of Thailand and Myanmar with their 25-year-old coach on June 23. The group became stranded after torrential monsoon rains caused the system to flood and were missing for nine days before being discovered by two British divers early last week.
Ivan Karadzic, a Danish dive instructor who lives in Thailand and who was involved in the rescue effort of the four people on Sunday as a support diver, said late that night that "it went surprisingly well, we were expecting bad things to happen, and they didn't."
"The kids were all totally calm," Karadzic said.
Karadzic said the British divers are the most skilled in the group — "when it comes to cave diving, the U.K. is the best," he said — and acted as beginning-to-end "buddy" escorts for those rescued Sunday.
Those rescued Sunday traveled more than half a mile underwater with the first one coming out of the cave at 5:40 p.m., Chiang Rai Gov. Narongsak Osottanakorn, the head of the rescue mission, said Sunday. He said that four boys were rescued in Sunday's effort.
The journey out of the cave from the chamber the boys and their coach have been trapped takes even experienced Navy SEAL divers as long as five or six hours to complete. Early Friday, a former Thai Navy SEAL diver died after losing consciousness while returning from placing air tanks deep inside the caves.
Narongsak said Sunday that the decision to try and rescue the boys and their coach on was made because conditions inside the cave were the best they could hope for and that water levels were now so low after days of good weather and constant draining that long stretches of the passage were now walk-able.
Karadzic, the Danish diver, said preparations had been made with air tanks and spaces identified for those being rescued to go if needed.
"We surveyed the cave to find good spots that we could say OK, from this route to this route, if anything unexpected or there's a panic, we go here, and in this other part, if any panic happens, this is where we're gonna go," he said.
Part of the route is carved into roughly quarter-mile sections manned by support divers who studied every stalactite or potentially panic-inducing tight squeeze to avoid. "Communication is difficult, so we plan everything," Karadzic said. "We look at all the scenarios."
They were equipped with spare air tanks, regulators, masks and wetsuits, and were prepared to lead the boys to comfortable above-water space if needed, he said, adding that it wasn't necessary.
"There was anxiety when we started our day, but when we saw the first kid ... he was like, no problem at all," Karadzic recalled. "We asked the escort diver, 'Did he do anything?' And he said, 'No, no, no, he's just here.'"
Karadzic was hopeful that Monday's operation would go as smoothly.
"Obviously we need to be careful not to be overconfident," he said. "But it was just incredibly well planned. We thought of everything that could happen, everything that could break, anything that can go bad."
Rain was a concern as preparations were made for Sunday's rescue. Thailand's Meteorological Department said there was a 60 percent chance of rain Monday with thunderstorms forecast throughout the week, the Associated Press reported.