Time pressures mean cave operation faces daunting decision this weekend
Rescuers dedicated to freeing 12 Thai boys and their football coach from a cave face a daunting decision this weekend over whether to rush the extraction by diving them out before heavy monsoon rains next week or to leave them in place for now.
The ideal scenario would be to drain out enough water with high-tech pumps to make it possible for the football team to either walk, swim or be floated out in lifejackets along the 4km-long dark, twisting corridors that separate them from the main exit.
So far more than 130 million litres have been pumped out this week, but much of the 2.4km corridor between 'chamber 3' - a staging position for the rescue divers - and the Nern Nom Sao slope, where the boys are sheltering, remains fully submerged.
Plan A still remains the high-risk option of teaching them how to use scuba gear in order to dive them to safety, passing through stretches of water as long as 400 metres and as deep as five metres.
However, the death of Saman Kunan (38), a volunteer diver and former Navy Seal, who perished on Thursday night after running out of air during the perilous dive, has thrown a spotlight on the dangers of subjecting inexperienced children to the same route.
According to the 'Bangkok Post', three Navy Seals would accompany each boy along the route. The boys would wear full face masks - similar to the breathing apparatus worn by firefighters - which would be less frightening for novices as it keeps the entire face dry.
Patrick Moret, a mine rescue expert from Cornwall Search and Rescue in the UK, said teaching the boys how to follow the underwater rope guide lines fitted along the passageways would also be a crucial part of their training.
"Really, skill-wise, all they have to do is learn to not let go of this line but they will have to immerse [the boys] in the water and get them practicing breathing in a controlled way without panicking," he said.
"If a child panics it is incredibly dangerous for other divers."
The dive to 'chamber 3' is an arduous five-hour feat for even top professionals. Keeping the boys calm in dark, muddy waters, battling against strong currents for so long, will be a major challenge.
Giving the children medication to make them "almost unconscious" could be a solution, Jani Santala, a Finnish cave diving instructor, told BBC Radio 4's 'Today' programme.
With the proper medication, the child could be "just strapped with the full-face mask and just being like a parcel that professional divers are handling," he explained.
Plan B would be to either find or drill a shaft some 800 metres into the chamber where the boys are huddled. Low-flying helicopters have been hovering over the site in the hope of spotting any natural fissures. However, despite the pilots' best efforts and those of 20-30 teams combing the jungle foliage on the mountain above the cave, no hidden entrances have been discovered yet.
Drilling a sloped shaft through the limestone could be an option, said Thailand's 'The Nation', but it carries the risk of prompting a full or partial collapse of the cavern.
"We want to find the way down. I believe we are close," Thanes Weerasiri, president of the Engineering Institute of Thailand told Reuters.
Meanwhile, The Boring Company, a tunnel construction company founded by billionaire entrepreneur Elon Musk, confirmed that it is sending people to Thailand to assess whether it can help with the rescue.
According to Mr Musk, the company has an "advance ground penetrating radar" that is "pretty good at digging holes" and technology that could "create an air tunnel underwater" to allow the children safe passage.
Plan C is to hold the 13 survivors in situ, keeping them warm and well fed while they wait out the monsoon rains and allow the waters to subside. But this could mean a long and psychologically difficult period of weeks or even months.
Oxygen levels inside the cave have also dropped from 21pc to 15pc, which has added an extra sense of urgency to the operation. Engineers have been racing to lay a pipe into their chamber to provide more air. (© Daily Telegraph London)