Northern Lao - European
Cave Project 

Laos 2009 Expedition to Houaphan and Oudomxay

Expedition date: 11.-25. January 2009

EuroSpeleo Project FSUE


  Joerg Dreybrodt (coordinator), Michael Laumanns, Helmut Steiner

    Francois Brouquisse

    Dave Clucas

    Lica Ersek

    Torben Redder


Oudomxay Team:     Siegfried Moser (DED)
    Vandy Somvang (PTO)

The Laos 2009 team had a very successful expedition to Oudomxay and Vieng Thong in Northern Laos. The most significant finding and major highlight since the expeditions started in 2002 is the exploration of the Chom Ong cave system 25 km Northwest of Oudomxay town. The system stretches along a 4 km long mountain ridge and has a parallel running and interconnecting fossil and river passage. It was in just 5 days explored to a length of 13.5 km with several wide open side passages remaining. It ranks now as the longest cave in Northern Laos and is one of the top 20 in all Laos. The typical passage dimension is 20-25 m width and 20-30 m height. Two huge overlaying halls mark the connection of river and fossil passage with each 100m lenght, 30 m width and ceiling heights of 30-50 m.The cave is a trough cave and can be entered near the stream inlet and left at the outtflow. The full traverse takes 3.5 hours with additional 3 hours return walking time from Chom Ong village! The cave was pushed at the last day in a 15 hour trip to it current length. 

The cave is currently developed as a cave for ecotourism. We received full support from the provincial tourism office in cooperation with Mr. Siegfried Moser from the German Development Service while staying in Chom Ong village. The director invited us during the farewell diner to return again to Laos and promised a Oudomxay province cave entrance directory.

The visit of Vieng Thong yielded 3.7 further caving km with Kokai cave as most remarkable finding The expedition visited this area with the main objective of a systematic search and documentation of caves along the road. The project spent one week and found several river caves within walking distance. The longest system Tham Nam Mai, known from 2007,  was completed within two days. Lica Ersek, who works as postdoc at the karst group of Prof. Gideon Henderson at Oxford University, extracted two stalagmites to investigate the climate change of the region out of the speleothem data. Approval of the National Park authority was given prior to the extraction of the relative small stalagmites. The expedition spent the last two days in a remote area 75 km North of Vieng Thong. Tham Kokai turned out to be rather big after a 50 m crawl. The main passage continued with a width of 20-25 meters and 15 m height straight into the mountain with hundreds of meters of dry sinter basins filled with sinter pearls of 3-5 cm diameter. The cave ends currently at a narrow 15 cm wide window with strong wind and a big passage behind. It is blocked by sinter formations and needs manual widening.

Total 15 km of caves have been mapped during the 2 weeks. The project will return again to Oudomxay in January 2010.

The Team 2009