A corner of Son Doong, the world’s largest cave in the central province of Quang Binh

The information has been announced recently by the central province of Quang Binh’s People's Committee.

Previously, the plan of overtaking the Great Wall of Viet Nam, a stalagmite wall of nearly 100m high near the end of Son Doong, and passing through the cave by the British Royal Caving Research Association, was given to Oxalis Company, the only local tour operator granted the right to offer tours to Son Doong. The plan was developed by selecting passing locations, which had little effect on stalactites and environment inside Son Doong.

In particular, the 65m section crossing the wall with vines only lays on the ground width of 0.5 m and they move one by one that should have less impact on the emulsion layer on the base stone. After much consideration, Quang Binh authorities directed concerned agencies to conduct the tour according to this plan.

Survey results by Quang Binh Department of Natural Resources and Environment said that the installation of ladders in Son Doong Cave is a technical solution that can affect the geological processes, but not significantly. When erecting the ladder to cross the wall, there are three boreholes that hold the top of the ladder, including two old boreholes by the British association when discovering the cave.

The ladder’s body has only one point leaning on the wall of stalactite but is lined with rubber padding to avoid impacts on the wall. The 65m-long slope on the top of the ladder continues with rope, which is used for visitors to climb up to the top of the wall, with 23 boreholes to lock the ropes, including 15 previous boreholes by discovering teams.

According to Oxalis, the pilot tour through Son Doong lasted for four days and three nights (reducing one day and a night than the old route), conducted from May 21 to August 31, with nine tours and the number of guests at 188 people, bringing about high efficiency. Guests did not have to go back to the old road to exit the cave and make it suitable for visitors so that they feel comfortable.

The assembly of ladders for the wall has taken effect in the case of unexpected floods, as visitors can overcome the wall to escape, without waiting for a few days until the water recedes. The route also helps increase overall conservation effectiveness across the whole route, as minimising direct impact when guests do not have to return to the old road.

For the above reasons, Quang Binh allowed Oxalis Company to officially run new tours through Son Doong Cave from 2018, with a time of four days and three nights.

In 2017, 740 people registered to participate in the tours to discover Son Doong - the world's largest cave.