Hang Son Doong Extensions 2010

Several leads remained to be checked following the initial exploration in 2009. Some passage dimensions also had to be confirmed due to the disto’s being unable to measure the large distances encountered. The average passage width is 80m and average height 80-100m. Around the swimming pool, and approaching Passchendaele, the passage is over 130m wide.

The Garden of Edam was measured at over 163m wide.

A side passage at ‘In Dog we Trust’ was surveyed for a further 250m over rimstone pools, to a steeply descending gour slope which sumped in all directions at its base. A white scorpion and white spider were noted in a calcite choke.

At the lake near the entrance, a small inlet passage was followed that was partly explored in 2009 to a low airspace section. This was pushed through a low airspace, into an ascending passage with fine flowstone. After 100m, this intersected a larger flood prone passage which ended in a sump after 50m.

From the top of the Great Wall of Vietnam, 300m of passage was surveyed to a relatively small exit. The passage was dry and well decorated with many cave pearls. It was 70m wide. A calcited animal skeleton was discovered on top of a large stal boss. This could be the So’n Duo’ng (mountain cow) of which there are numerous hoof prints in the mud, or possibly a bear as suggested by one of the guides.

The exit was at 165m altitude as measured by GPS, was into an obvious valley, but with no obvious path out, and heavily vegetated.

At the Great Wall of Vietnam, the passage is 199m high.


High Level Cave Development

Dr Vu Van Phai of Hanoi University of Science has identified 5 levels of cave development in the Ke Bang Massif (see below). Level 1 or 0m is taken as the modern stream cave level. Caves explored on this expedition in the area above Hang En suggest there is probably a sixth level at 350-400m above stream level.


Hang Ho Nui was first explored in 2007. At an altitude of over 500m the cave is large and well decorated and 420m long.It is over 300m higher than the river level, which in this case is Hang En at 180m.

Hang Doi, located above Hang Khe Ry is 350m above stream level. It was explored in 2001, is 450m long and 24m deep. The cave has a mud floor with many formations.

The caves explored in 2010, Hang 1989, Hang 1987 and Hang 1990 (named after the year they were first visited by Khanh) are between 350m and 380m above stream level.

Hang 1990 is situated at the end of a valley. A large entrance in a cliff leads down steeply to a well decorated chamber, with many cave pearls. At the end there is extensive calcite and a small drop to a mud floor with no way on. The cave is 60m deep and 690m long.

Hang 1987 is situated halfway up a cliff; this entrance also drops steeply over boulders to a large calcited passage. There are old dry gour pools with unusual mushroom shaped formations. The cave enters a mud floored chamber with a climb up though flowstones to a calcite choke. There are many fine columns. The cave is 916m long and 75m deep.

Hang 1989 is also a large entrance halfway up a cliff. Descending steeply over boulders and flowstone the cave levels out into an extremely well decorated cave. There are many fine flowstones and curtains, as well as an area of extremely large cave pearls. The cave ends in a calcite choke. The cave is 206m long and 62m deep.

These high level caves whilst not as long as the river systems are very interesting for their extensive and often unusual formations.

Deb Limbert


2012 Report


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