In four days, experts dived to a depth of 77 m and discovered the unknown cave system.
On March 31, Phong Nha – Ke Bang National Park Management Board cooperated with Oxalis Company to share the plan of diving survey, exploring underground river in Son Doong cave – the largest cave in the world. The performers were a team of five British cave diving experts, the team leader was Mr. Martin Horoyld, an expert of the British Royal Cave Association (BCRA), three other members of the top 5 best cave diving experts. world and a device coordinator.
Divers said the group is equipped with many specialized equipment such as flashlights, underwater camcorders, ropes, air cylinders … The whole device is transferred from England, weighing hundreds of kg. Each dive costs an estimated $ 53,000.
The objective of this trip is to find the underground cave connecting Son Doong cave and Thung cave, 600 m apart. According to Nguyen Chau A, director of Oxalis, the plan for this diving dive was from 2009 when the survey team found that the underground river in Son Doong cave ended at a sinkhole and raised doubts about an underground river. connected to Thung cave.
Mr Howard Limbert, an expert from BCRA, who found 500 caves in Vietnam, said: “We find out whether there is a connection between the two caves. If there is a physical connection, Son Doong cave will confirms the position of the world’s largest cave in both volume and length “.
Journey of underground river exploration starts from 1/4 to 4/4. Each diver must wear two compressed air cylinders on his body when wriggling in narrow caves and many nooks and crannies. They also use the circulatory system, reusing the air instead of releasing it to dive for hours.
Rick Stanton, who rescued the Wild Boar kids team in Thailand, said: “April 3-4 is the best time to dive, the river level in the cave is low, the weather is cool and cool. Good underwater look. ” Due to special geographical conditions, Son Doong cave has its own climate system, with clouds formed from underground rivers flowing below.
In the early days, the divers said that the connection point was at a depth of 25 m, but when measuring the river bed by wire, the bottom of Son Doong underground river was at a depth of 93 m, exceeding the limit of compressed air diving tanks. usually brought by the group.
On April 2, diving expert Chris Jewell dived 60 meters but could not find any path. On April 3, diving experts Rick Stanton and Jason Mallinson continued to search for a way to make the journey.
The passage was thought to be accessible by divers, while Jason had reached a depth of 77 m, the maximum limit for a pneumatic diver. Chris Jewell traces the path left by Jason and finds the dome of the new cave at a depth of about 60 m. Due to poor visibility, they were unable to measure the size of the cave. It is through the combination of scuba diving that experts can find the next way.
This dive therefore therefore takes more hours, most of the time devoted to pressure relief (divers stop at depths for a period of time before returning to the surface of the water to allow the body to adapt to the pressure). This event has also become the deepest cave dive in Vietnam ever.
Jason said that when he dived to 77 m, the cave was deeper, unable to see the bottom of the cave, the visibility was only 2-3 m. “At that time we realized the depth could reach more than 100 m. The problem of Son Doong is that the cave is so large that it makes it difficult for us to explore. I’m sorry because I couldn’t see the scale of the underground cave, we wanted to map the cave to show the results of the work, ”Jason said.
An underground cave system was discovered located at a depth of 60 m, the deeper the deeper the extension. This discovery makes Son Doong cave more mysterious with experts and scientists.
The expert team is expected to return here next year with more specialized equipment to reach a depth of more than 100 m.
Currently the depth of the cave has been increased to 500 m from the cave entrance and this is not the final figure. In addition to Son Doong cave, divers also surveyed the area of Nuoc Mooc stream in Phong Nha – Ke Bang National Park and also had to stop due to a depth of more than 74 m.