AREA XX: Moc Chau

MC1 Hang Co Du

The entrance of the cave, located behind one of the most remote Thai houses of the village of Tac Ngoang is a porch. After crossing a small river, which emerges from underneath boulders on the right and disappears into the left wall, one arrives in a high and wide gallery with large grey and white formations. After about 30m the water is reached again which gets deeper and deeper. The ceiling comes down and at the left side one can see a slope behind boulders which might lead to a fossil level (not checked). After a remarkable turn, a small impenetrable boulder choke is seen, out of which the water emerges. This choke can be bypassed through a dry passage with on the right, which seems to act as a overflow. After crossing two deep and muddy basins, one arrives at the final boulder choke, which seems to be formed recently, as the rocks were very sharp and unstable. Behind this collapse there is a chamber where the roof dips down and forms a sump.
MC2 Hang Nghiem

The entrance of this cave is a paleoresurgence from the Bo Co Ban sink-resurgence system, 6km from Moc Chau towards Son La. The actual resurgence lies a little more upstream in the valley at the level of the river. The 6x6m porch is followed by a wide gallery, which is often visited by villagers. There are a lot of old formations, some of them are party dissolved again. This ‘tunnel’ is about 300m long and stops on flowstone that is completely blocking the way on. No draft could be felt, except maybe the airflow caused by bats…