By this point, the official wheels were already in motion, requesting additional assistance. A US search and rescue team would arrive at the request of the Thai government, which had also asked for survivor detection equipment.5 Other international teams, such as a contingent of Australian Federal Police divers, a group of Chinese divers and others would follow soon after.
And on Unsworth’s recommendation, the Thai government requested the help of three of the world’s best cave divers—John Volanthen, Rick Stanton and Robert Harper. They all answered the call.
It was in the 1960s that foreign cavers first began mapping the thousands of karst limestone caves, like Tham Luang, dotted around Thailand. They form when rain- and groundwater eat away at limestone over millennia, forming spectacular moonscapes, chambers, tunnels and caves deep inside mountains. The limestone in the Sleeping Lady is between 200 million and 400 million years old, although the caves themselves are younger; Martin Ellis, a British expert on Thai caves who writes books about Thai caves and runs a website devoted to them, estimates that while the limestone is probably from the Permian age, between 299 and 251 million years ago, the cave system is only a few hundreds of thousands of years old, as there is a single, quite small main passage with no really large chambers or high-level old passages.
Back in 1986 and 1987, a survey of the Tham Luang cave was undertaken by the Association Pyrénéenne de Spéléologie, or French Cave Survey Association, a team of French speleologists.6 Two teams of four surveyors undertook those first, early surveys to map out the sprawling, twisting 10-kilometre network of tunnels beneath Doi Nang Non. They faithfully marked out the contours and curves of the Tham Luang system, and included the well-known Pattaya Beach. The team also surveyed the nearby Tham Sai Thong cave.
Ellis published an updated map of Tham Luang, based on the 1986 and 1987 surveys, on his website. He says that initial survey was inaccurate, at least in part because of the equipment that was available for use at the time. ‘On the landscape scale it looks okay—Monk’s Series heads towards Pha Mi [Doi Pha Mee], reached by a right turn at the T-junction the boys didn’t take. The main cave follows the spine of the mountain …’7 In his blog post on 30 June 2018—two days before the Wild Boars were found—Ellis stressed that the French map, on its own, could not be used by rescuers who were looking at drilling down from the top of the mountain to create an alternative escape route for the boys: ‘It was a magnetic survey with no calibration of the compass or correction for declination. The GPS co-ordinates of the entrance could be out by 10 or 20 metres.’
The survey had been undertaken in the days before GPS became a feature of smartphones. Ellis himself had used a handheld GPS unit—not as precise as a professional differential GPS, but more accurate than a phone (or the French survey). And every metre of progress the rescuers could make was valuable as they tried to find their way through the dark, flooded cave in a race against time to save thirteen young lives. The dive line laid by the rescuers who would swim into the cave, for example, was being measured metre by metre, and each and every metre brought the rescuers a little closer to the Boars—or so they hoped.
It’s no surprise that Unsworth and Ellis know each other. Caving isn’t about to challenge football as a global participation sport and both men share a particular passion for the caves of Thailand. The knowledge the pair has of the cave was a crucial part of the success of the rescue mission, as was Rob Harper’s—the British cave diver would arrive in a matter of days from the UK.
Unsworth had used the maps to extensively explore Tham Luang with his friend, Mr Lak. Between 2013 and 2016, he and Lak—who already knew some of the uncharted areas—explored the caverns and tunnels before helping Ellis in surveying the extensions. Ellis, who has only explored Tham Luang a few times, is not a big fan of it as it is too dark and muddy—‘Tham Luang is Vern’s passion.’
In 2016, along with Lak, Harper and another caver, Phil Collett, Unsworth helped Ellis plot out far greater detail for Tham Luang Nang Non, the Monk’s Series of caves and the main cave extensions. In an age of GPS, smartphones and increasingly sophisticated technological aides, the French map was no match for the updated and detailed surveys that Unsworth and his cohort had undertaken for Ellis over the years of exploring Tham Luang but it did provide the foundation for their own contribution. For example, the T-junction, or Sam Yaek as it is known in Thai, is clearly labelled; boulder choke points are marked; and names such as ‘Show Cave’, ‘Monk’s Series’ and ‘Nang Non Series’ provided crucial additional information to the rescue teams.
As the rescue got underway, the Ellis–Unsworth map was found and adopted by Thailand’s Department of Mineral Resources. This map, plus Unsworth’s presence on site—his knowledge of, and passion for, the cave is well known to locals—gave the rescue teams huge amounts of detailed information about Tham Luang.
One of the trickiest aspects of undertaking the rescue operation inside the cave, even for expert cavers, was calculating distances. Much of the information that was being made public about Tham Luang, and the path ahead facing the divers, had been gleaned from divers and rescue workers who had a less-than-complete picture of the cave. Much of it was incorrect.
Ellis is scathing about the distances that would feature in the majority of maps that began to appear in newspapers and on websites. ‘Most press reports have got the distances wrong and confused. My measurements are not estimates, but measured from the survey.’
From the entrance to what became the dive base in chamber 3 was 700 metres. From chamber 3 to the T-junction (Sam Yaek) was another 800 metres. From Sam Yaek to Pattaya Beach (past chamber 8) was 500 metres, and on to Nern Nom Sao, where the boys were trapped, was another 250 metres. Therefore, the distance from the entrance of the cave to the trapped Wild Boars was 2.25 kilometres—less than many of the estimates that were floating around, some of which suggested the boys were as far as 4 kilometres into the cave.
It is true the Boars travelled 4 kilometres from the cave entrance to Muang Lab Lae. But in the early stages of the rescue, few would have known that—and the distance from the cave entrance to Nern Nom Sao was indisputably less than that. Ellis says the trip to Muang Lab Lae (which translates to Hidden City in English) from Nern Nom Sao was another 1750 metres—so at one point the boys had travelled 4 kilometres into the system.
Any lingering doubts about the importance of the Unsworth–Ellis map were put to rest by Chaiporn Siripornpibul, a speleologist with Thailand’s Mineral Resources Department, who told Thai newspaper The Nation that Tham Luang was one of about 4000 Thai cave systems about which little is known; only about 2500 caves across the country have so far been surveyed.8 Ellis, however, says that Thais use the same phrase—sam luet—for a cave that has been explored and a cave that has been mapped, or surveyed, by a caver. His database of Thai caves has 5000 entries, of which 1900 have an associated length—which means someone, at some point, has been inside the cave and recorded at least some basic data. However, there are fewer than 700 caves in Thailand that have been mapped or surveyed by someone who has published in a European language. Without the Unsworth–Ellis map, with all its carefully surveyed detail, the task of searching on the surface for a way to drill down through the mountain—and diverting water away from the caverns of Tham Luang—would have been far more difficult.
Once it was established the boys had turned left, towards Nern Nom Sao, the path was clear. The maps—supported by daily bulletins from the divers and by briefings from on-the-ground experts such as Unsworth and Lak—were like a second meta-guide rope.
In the wake of the near-tragedy of Tham Luang, there were fresh calls for more surveying of Thailand’s huge network of caves to take place.
At 9.30 pm, British Summer Time, on Tuesday, 26 June, John Volanthen, Rick Stanton and Robert Harper left Heathrow Airport on a flight bound for Bangkok. Once they landed in Bangkok, they would take a second flight to the north of Thailand—along with 250 kilograms of diving equipment
—before making the drive up to Mae Sai.
Chris Jewell and Jason Mallinson would bring another 350 kilograms of equipment with them when they later arrived from the UK.
Halfway across the planet, it was 3.30 am on Wednesday morning in Thailand where twelve boys and their coach had been trapped inside the Tham Luang cave complex for more than 80 hours. No one knew if the Wild Boars were alive, and the rain and rising floodwaters were still holding back desperate efforts to find the young soccer team. So while the trio of cavers didn’t know if they were flying in for a rescue mission—or to help retrieve thirteen bodies—between the three of them, they had a pretty good idea of the conditions that would confront them in the cave.
Within the small and tight-knit global community of cave explorers and cave divers, Rick Stanton, 56, and John Volanthen, 47, are widely regarded as two of the best cave divers in the world. Stanton, a former firefighter from Coventry, and Volanthen, an IT consultant based in Bristol, have been involved in some of the highest-profile rescues in the world—and they have dealt with their share of tragedies, too.
In 2004, as members of the South and Mid Wales Cave Rescue Team, Stanton and Volanthen had helped lead the successful rescue of six British military divers trapped in the Alpazat caves, south-east of Mexico City, for eight days. And in 2010, they flew to the South of France to play a key role in the attempted rescue of their friend and fellow cave diver, Eric Establie, from the Dragonnière Gaud cave. Establie had been trapped by an avalanche of soil and silt a kilometre or more inside the cave and, tragically, after ten days, he was found drowned.9
There are many more examples of the pair’s heroism—not that either man would embrace that term—and their commitment to their expertise, which has enabled them to save lives in the UK and all over the world. They have set two records—for the deepest dive (76 metres) in a British cave, back in 2004; and for the longest cave penetration dive that saw them travel 8800 metres into the Pozo Azul cave network in Spain, along with Dutch diver René Houben and British cave diver Jason Mallinson in September 2010, in a dive that took about 50 hours.10 Mallinson would later become an integral part of the rescue effort at Tham Luang cave.
Stanton has even developed two closed circuit rebreather units which, within a closed circuit, remove the carbon dioxide exhaled by a diver and add oxygen, thus extending how far, how deep and how long divers can stay under water.11
Bill Whitehouse, who served as chairman of the British Cave Rescue Council (BCRC) for 35 years before ‘stepping down’ to become vice-chairman for the last four years, knows both men—but particularly Stanton—well. The BCRC is the umbrella body for fifteen regional UK cave rescue teams that swing into action when a dog falls down a mine shaft, a sheep wanders off, or a novice caver goes missing while exploring a local landmark.
The first of those regional groups, which all function as charities, was established in 1935 in Yorkshire. Over the next three or four decades, more were created to cover the entire country. The cave rescue teams, if you add them up, amount to about 900 people. The total number of members of these regional groupings is also pretty close to 900—they provide their own rescue service, and offer the same service to any other unwitting soul who encounters trouble on a walk through a local cave.
‘If something happens to one of us, the rest of us gather round … we don’t just help our own,’ says Whitehouse.
Just a fraction of those 900 people are cave divers, as opposed to cave explorers. (‘No one uses “speleologist” because it sounds pretentious and they can’t spell it,’ Whitehouse jokes.) The BCRC becomes involved when emergency services such as police and ambulance need to be coordinated, or when an international deployment is required, as happened in Thailand.
Whitehouse explains why Volanthen, Stanton and Harper were summoned to Thailand: ‘Vern Unsworth blew the whistle and got in touch with Rob Harper in the UK. Rob had only just returned from Thailand, where he had been caving with Vern. Rob went out because he knew the cave, but more in a support role.
‘The cave rescue world is a very small one, most people know each other, they know each other’s reputations. John and Rick are exceptionally experienced cave divers, they have been involved in rescues and attempted rescues all over the world. There isn’t a formal BCRC cave-diving team—but the members on that team are Rick and John, and Jason [Mallinson] and Chris [ Jewell, both of whom would arrive shortly after]. And Rick and John would be the first people I would call.’
Cave-diving is nothing like diving in open water. When something goes wrong at sea, the obvious solution is the correct one—head towards the surface. But when something goes wrong inside a cave—for example, a wall collapses, or a passage ahead becomes blocked—your options are not only more limited but also far more dangerous. Before you can even surface, you have to do a U-turn and return the way you came.
Adrenaline is the enemy of the cave diver, and an underwater cave is one of the most unforgiving environments on the planet. One panicked or poor decision by a diver can have terrible consequences, and if a panic attacks occurs, the oxygen in a diver’s cylinder can be exhausted more quickly, too.
Although Tham Luang wouldn’t require deep diving by the rescue workers, it still presented difficult conditions to work in, with poor visibility, jagged rocks everywhere and multiple dives through sumps that were sometimes very narrow to negotiate.
In other words, it was still dangerous and if something went seriously wrong, the divers could die. It was that simple. So cave divers are, by and large, careful people and tend to take methodical steps to ensure their own safety. Redundancy is a big thing in diving: where possible, divers will take two of everything they can carry—so if the mouthpiece fails, you use a spare, or if a compass or light is lost, you have another one on hand.
Air tanks are often mounted on a diver’s side, rather than on their backs, to allow them to squeeze through tight spaces. According to Whitehouse, divers tend to follow a ‘rule of thirds’ for their air supply—one third of a tank for the swim in, one third for the swim out, and one third in reserve, in case something goes wrong.
And if something does go wrong, the calculus is brutal.
As Volanthen told the UK’s Sunday Times newspaper in 2013: ‘What you want is nice and boring. Underwater, things happen slowly. If a parachute fails on a base jump, you have seconds to contemplate your fate. If something goes wrong 10 kilometres down an underwater tunnel, you usually have until your air runs out to find a solution or make your peace.’12
Volanthen, Stanton and Harper—who would help oversee the rescue mission mostly from outside the cave—knew what they were up for when they stepped onto that plane at Heathrow. If anything, Tham Luang was less technically challenging than other dives Stanton and Volanthen had undertaken, if only because fewer deep dives would be required.
They would have to dive through sumps—stretches of submerged passages or tunnels within the cave—that are for the most part not much deeper than 5 metres, which pales in comparison to the more complex 100-metre deep dives, which require decompression stops on the way up, they had undertaken elsewhere.
However, the strong currents on the swims into the cave did make the dive tough, as did the very low levels of visibility in the water—less than a metre at times. Rock formations jutting out from the wall as well as stalactites and stalagmites also contributed significantly to the degree of difficulty.
On site, at the cave, the Brits frequently brushed aside requests to speak to the gathering media, maintaining their single-minded focus on those twelve boys and their coach and the cave that lay ahead of them. As Volanthen told a reporter: ‘We’ve got a job to do.’
That job started on 27 June. Stanton and Volanthen made their first dive in Tham Luang cave that evening, soon after their long flight from the UK. The water was still gathering strength, both in and outside the cave. In a reconnaissance dive that lasted three hours or so, the two men had a chance to evaluate conditions in the cave.
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Lak says that on their way back out of the cave after that first, exploratory dive, one of the men yelled, ‘We have to get out now!’ The rising waters suddenly posed a threat to the rescue teams gathered in the cave.
‘This day is what we call “retreat day” because we have to escape out of the cave … I still remember every single minute of it. The cave entrance was full of water. Even at the cave entrance, there are many of staff (mostly soldiers) that were taking a rest or sleeping there, we had to wake them up and evacuate from that area immediately.’
Four days into the rescue operation, the dangers of the flooded cave were still being underestimated.
Thursday, 28 June, was, if anything, worse. Conditions in the cave were constantly changing, and water continued to pour in the cave, now flooded just 200 metres from the entrance. Tham Luang was no longer accessible without diving. But Stanton and Volanthen still ventured inside. In fact, the duo rescued four Thai men from chamber 3.13 It would be months before details of this ‘secret’ rescue would emerge, when Stanton gave a talk to a conference, Hidden Earth, for British cave divers in late September.
At this stage, in those early days of the rescue, Thai authorities had little control over who was in the cave and no one had realised the four Thai water company employees did not evacuate chamber 3 when the waters rose; they had now been trapped for over 24 hours.
Stanton revealed that on 28 June he and Volanthen made their way through three sumps and surfaced in the flooded chamber 3—which would later become the main operations base for the rescue team inside the cave.
When they surfaced, they realised there were already people there. The pair hoped for a moment that they had found the missing Wild Boars, but they soon realised they had instead found four rescue workers.
The Great Cave Rescue Page 4