AREA 31: Tan Lac

TL1: Xom Ton

Development: 284 m
Denivelation: -25m

Water of a small river disappears in an impenetrable passage. The entrance is about three meter above a small river. The walls and ceiling of the cave are completely covered with mud, this means that the cave floods during rainy season. It consists of relatively easy passages, but a slippery floor. Many swallow holes in the floor are present. They give contact with the lower (underlying) narrow active cave system. At the end of the cave a 30 m rope gives access to a ‘window’ to the active river, both sides are too small to pass

TL2: Xom Bo

Development: 104 m
Denivelation: -34 m

The entrance is 30 to 40 m higher than the presumed underground river (level of rice fields). The cave ends in a chamber with muddy floor and two sinks. A warm moist air blows out of the cave.

TL3: Xom My

Development: 104 m
Denivelation: -34 m

Xom My is a river cave through the mountain with 4 entrances. A river disappears in the first entrance. A second entrance is a pitch which gives again access to the river. The third entrance is situated in a large doline. From the third entrance a series of small steps and galleries lead to a sump which can be by-passed by fossil passage 10 m before the sump. A descent leads to a lake in open air: entrance four.

TL4: Bai Vang

Development: 144 m
Denivelation: - 51 m

A vertical shaft of about 40 m gives way to a muddy slope, 10 m lower a small river is reached; in the two directions ending on a sump.

TL7: Lang No 3

Development: 75 m
Denivelation: -12 m

Approximately 30 m up in sidewall of karst cone (halfway up). Starts with a climb of 5m, then a horizontal development up to the final pitch of 6 m. From there on the dry cave develops a few meters more.

TL8: Lang No 4

Development: 40 m
Denivelation: -7 m

The entrance is situated about 15 m above the water level in the sidewall of a karst cone. After going down for 6 m a horizontal cave develops. It stops on a muddy siphon.

TL9: Xom Lo

Development: 387 m
Denivelation: -42 m

This fossil cave is a labyrinth of passages 2 m high. The entrance is a few meters above the base level. Air is blowing into the cave. The cave could be suitable for adventurous touristic caving trips. A few fossil concretions are present. Also archived as Lang No 5.

TL12: Hay Hai

Development: 47 m
Denivelation: -47 m

The entrance to this cave is to be found in the backyard of a house in Hay Hai village. The entrance was opened with spades by the local people, as the entrance had been closed with soil for safety reasons. The cave is a fossil vertical shaft, 0.5 m by 1 m, with water in the rainy season. Halfway, the shaft becomes wider as a shaft from above joins.

TL15: Xom Nghe 1

Development: 20 m
Denivelation: 0 m

The cave develops in a fault parallel with the karst cone outside wall. Shortly after the entrance the cave develops in two directions: to the left it stops on blocks after 8 m; to the right a meander can be followed for about 12 m before it becomes too narrow; wind blows into this small passage.

TL16: Xom Nghe 2

Development: 60 m
Denivelation: -29 m

The cave develops in a fault parallel with the karst cone outside wall. The vertical cave is entered approximately 25 m above the lowest point. The rope is fixed outside the cave, on the right side. After climbing down 3 m, the rope is belayed on a spit and an AN. 17 m lower a second AN allows to reach the bottom, consisting of large blocks.

TL17: Xom Xom 1

Development: 50 m (est.)
Denivelation: -25 m (est.)

The river disappears at several places in sumps. 5 m above the valley bottom an entrance of a cave is found. The passages are narrow, the walls are clean. At several places the water disappears into too small squeezes. But one or a few meters higher up by-passes are found. At about 25 m depth (app. 50 m from the entrance) no by-passes are found anymore. The water falls in the a small chamber and the water disappears into a narrow squeeze.

TL18: Xom Xom 2

Development: 0 m
Denivelation: 0 m

A strong, wet and hot draft could be felt between blocks, but no way to get in. There is very likely a physical connection to the underground river we followed in Xom Xom 1.

TL20: Xom Xom 4

Development: 22 m
Denivelation: -22 m

A fossil 22 m shaft (30 m rope, 2 AN).

TL21: Xom Xom 5

Development: 30 m (est.)
Denivelation: -18 m (est.)

Via a squeeze a 9 m pitch is descended. Under a larger block, which is stabilized with bamboo, a gentle slope leads to a huge block. Below the block a 6 m unstable pitch is dugged out in the sediment. It is a former gold mine. Outside the cave remains of equipment to wash the sediment (to concentrate the heavy metals in the sediment) is found. Local people told us the mining activity stopped only a few years ago.

TL22: Hang Bung 1

Development: 85 m
Denivelation: -58 m

This cave was used as a gold mine. The entrance is a doline. What follows is a succession of small pitches that can easily be free climbed, except the last one that must be equipped with rope (or bamboo). It ends in a too narrow passage with some draft. The mud in the squeeze was removed, the width of the passage led us conclude that only children are able to do so.