More than 100 chimneys are being drilled into the mountainside in Thailand in an attempt to rescue the 12 boys and their football coach, who have been stuck in a flooded cave in the northern province of Chiang Rai for the last two weeks.

“Some of the chimneys are as deep as 400 metres... but they still cannot find their location,” Narongsak Osottanakorn, the governor of Chiang Rai province told reporters, according to AFP. The rescuers are attempting different methods to save the boys, as it is deemed too risky to evacuate the team by diving into the submerged passageways.

“We estimate that they are 600 metres down, but we don’t know the exact target,” he said. Osottanakorn said the team lacked the technology to pinpoint the target.

But the rescue team head said they had managed to pump in fresh air into the chambers where the underground cave is located, thus attempting to maintain the supply of oxygen to the boys stranded inside.

United States businessman Elon Musk said that engineers from his firms – SpaceX and Boring Company – were headed to Thailand to see if they could help in the rescue effort. “The Boring Co has advanced ground penetrating radar and is pretty good at digging holes,” Musk said on Twitter. He also offered suggestions on how to improve the rescue effort.

Rescue may take a few days

Meanwhile, Narongsak Osottanakorn said on Friday evening that the boys cannot be rescued immediately, The Guardian reported. The monsoon rains are expected to begin in the region within a day.

“If we face heavy rain, we must bring the kids out,” he told a midnight press briefing. “But if the situation is stable [inside their chamber], we can let them stay.” The governor said the boys’ parents had written them letters, which were delivered 3.2 km into the cave where the boys are sheltering.

On Saturday, Osottanakorn said that the rescuers have a three to four day window. He said the operation to drain water from the 3.2 km path into the cave had been “very successful”. “The next three to four days from now is the most favourable time for the operation and rescue mission using one of the action plans,” he said. “If we wait too long, we don’t know how much rainwater will come.”