Planning and preparation

A logistics camp was established at the cave entrance, which accommodated hundreds of volunteers and journalists in addition to the rescue workers. The site was divided into several zones: restricted areas for the Thai Navy SEALs, other military personnel, and civilian rescuers, an area for the relatives to give them privacy, and areas for the press and for the general public.

An estimated 10,000 people contributed to the rescue effort, including more than 100 divers, representatives from about 100 government agencies, 900 police officers, 2,000 soldiers and numerous volunteers. Equipment included ten police helicopters, seven police ambulances, and more than 700 diving cylinders, of which more than 500 were in the cave at any time while another 200 were in the queue to be refilled. More than a billion litres of water (the equivalent of 400 Olympic-size swimming pools) were removed.

Challengesedit

The point where the boys became stranded was about 4 kilometres (2.5 mi) from the entrance and 800–1,000 metres (2,600–3,300 ft) below the top of the mountain. The route to them had several flooded sections, some with strong currents and zero visibility, and some extremely narrow parts, the smallest measuring only 38 by 72 centimetres (15 in × 28 in).

The journey through the cave to the team took six hours against the current and five hours to exit with the current, even for experienced divers.

From the outset, rescue workers battled rising water levels. In an effort to de-water the cave, a stone diversion dam was built upstream and systems were installed to pump water out of the cave and divert flows that were entering it. On 4 July, it was estimated that the pumps were removing 1,600,000 l/h (420,000 US gal/h) from the cave, ruining nearby farm fields in the process. For a time, well-meaning volunteers inadvertently pumped water back into the groundwater supply. Helped by a spell of unseasonably dry weather, these efforts reduced water levels by 1.5 centimetres (0.6 in) per hour on 5 July, enabling rescue teams to walk 1.5 kilometres (0.93 mi) into the cave. However, heavy rains forecast for 8 July were expected to halt or reverse this process and could even flood the position where the team were trapped.

On 6 July, the oxygen level in the cave was detected to have dropped, raising fears that the boys might develop hypoxia if they remained for a prolonged time. By 8 July the oxygen level was measured to be 15%; the level needed to maintain normal function for humans is between 19.5% and 23.5%. Thai military engineers attempted to install an air supply line to the boys, but the effort was abandoned as impractical.

Optionsedit

As the crisis unfolded, rescuers planned several different methods to save the team and coach. The principal options were to:

• Wait until the end of the monsoon season; with divers providing food and water.
• Teach the group basic diving skills.
• Find an alternative entrance to the cave which could allow for an easier escape; one shaft was discovered that went down 900 metres.
• Drill a rescue shaft; more than 100 shafts were bored into the soft limestone, but no suitable location was found.
• Build an oxygen line.
• Build a telephone wire to communicate.

The diving optionedit

Multiple dangers—the threat of more heavy rain, dropping oxygen levels, and the difficulty or impossibility of finding or drilling an escape passage—forced rescuers to make the decision to bring out the team and coach with experienced divers. The Thai Navy SEALs and US Air Force rescue experts met with the Thai Minister of the Interior who approved the plan. Ninety divers worked in the cave system, forty from Thailand and fifty from other countries. Rescuers at first considered teaching the boys basic diving skills to enable them to make the journey. Organisers built a mock-up of a tight passage with chairs, and divers practiced with local boys in a school swimming pool. Thai SEALs and US Air Force experts then refined the plan to use teams of divers to bring out the weakened boys.

Death of rescue diveredit

On 5 July at 8.37pm, Saman Kunan (Thai: สมาน กุนัน), a 37-year-old former Thai Navy SEAL, made a dive from Chamber 3 to the T Junction close to Pattaya Beach to deliver three air tanks. During his return he lost consciousness underwater. His dive buddy attempted CPR without success. Kunan was brought to Chamber 3 where CPR was attempted again, but he could not be resuscitated and was pronounced dead about 1 am on 6 July.

A member of Thai Navy SEALs class 30, Kunan had left the SEALs in 2006 at the rank of Petty Officer 1st class and was working in security at the Suvarnabhumi Airport when he volunteered to assist the cave rescue. He was posthumously promoted to Lieutenant Commander by the Commander-in-Chief of the Royal Thai Navy, an unprecedented rise of seven ranks. A funeral sponsored and attended by the Thai royal family was held on 14 July. On the same day, he was also awarded the Knight Grand Cross (first class) of the Most Exalted Order of the White Elephant by King Vajiralongkorn. A memorial statue of him may form a part of a proposed tourist attraction at the site.

Another diver also lost his life in Dec 2019 from an infection caught from germs in the cave rescue.