AREA 17: Muong Trai
MT1 Ban Men 1
The entrance of this fossil cave is located on the left bank of the Suoi Trai at about 40m above the river. The entrance porch gives way to a cave with large dimensions heading west. On the left side, a slope brings you to a step, followed by a pitch of 14m. The bottom of this pitch is choked with dry mud. On top of the pitch, a fossil chamber leads to a small second entrance. The main passage leads to a place where the ceiling is very low compared to the rest of the cave. The floor is covered with pebbles and small rocks. In the ceiling, there are several irregular avens, which might be interconnecting. At the end, the ceiling is too low to continue, but the cave goes on. In order to continue, one should dig its way through the pebbles, which can easily be done. Halfway the cave, a passage higher up goes north to a large chamber, from where a lowering passage starts which stops after about 15m.
MT2 Ban Men 2
The entrance, a low horizontal fissure, is located about 200m
from Ban Men 1, in the direction of the village, at about 20m
above the river. A fossil gallery, 2m high and 5m wide of about
50m long ends suddenly in front of some
formations. Here, a pitch goes down to
-15m where a small horizontal part is found. Villagers told us that in summer, one can hear water when throwing stones into the pitch.
MT3 Ta Sai 1
The entrance is located on the right bank of the river, 100m upstream of the bridge in Xa Muong Trai. It is an underground meander of 10m.
MT4 Ta Sai 2
The fossil entrance is found to the north-east of Ba Ta Sai, about 40m up the slope. It s an old, richly decorated fossil cave, about 10m long. It might be connected to MT3.
MT5 Muong Trai
The entrance is located 60m up the slope in the south of Xa
Muong Trai. A boulder slope gives into a decorated chamber
(30 x 30mē) without continuation. When going down the slope, a
way on the right side can be found behind a boulder. The narrow
passage gives into a joint, which leads to a too narrow
continuation. Uninteresting from speleological point of