The Marie Cassan river cave
Henri Cassan, 1948
Stationned in Vietnam, the young captain Henri Cassan was a seasonned caver. He had already realised numerous expeditions in France and in North Africa. By 1941, he had conducted explorations in Couserans and Cagire, together with Jean Noir, in Ariège, in the Pyrenees with the Martel-Cigalère abyss, and also in the Vercors. He had met Norbert Casteret in Saint Girons, then he had conducted explorations in Algeria, in Djurdjura, in 1942, on the karstic plateau of Haizer. In 1943, he had followed upstream the underground course of the Tafna river, near Sebdou in Oranie.
With Cassan, the Lao speleology changes of era. In 1948, the technique has evolved. Rubber dinghies replace the Macey’s bamboo raft ; flexible ladders and climbing masts allow to reach the perched galleries; caves are mapped and photographed...
Twenty eight years old, Henri Cassan has two passions : Caving and his young Vietnamese fiancée, Marie, whom he is not long to marry. Henri leads Marie to adventure during a rather unconventional honeymoon.
Cassan is interested by the Nam Nhom, with a beautiful emergence situated in Ban Thathot, about forty kilometers to the northeast of Thakhek. During a two weeks leave, he organizes a raid from Hué, his base in Vietnam.
The emergence turns out to give access to a superb underground river explored and mapped for three kilometers by the small explorers group : Marie and Henri Cassan, Gilbert Sacco and Vo Van Han. The cave is named "Marie Cassan" in honor of the young bride, and a commemorative marble tablet mentionning the names of the fearless adventurers is sealed on the edge of the terminal sump on Monday, December 13th.
In 1948, the explorations of the underground Nam Hin Boun and Xe Bang Fai had been already forgotten, and the longest cave in Indochina was believed to be the underground river of Phong Nha in Vietnam, known over 1.4 km. "Marie Cassan" was twice as long ! (Today Phong Nha develops 8.8 km, and is part of a cave network of 71 km (2011), formed by 32 cavities)
Cassan publishes an account of his adventures, illustrated with the first known pictures of Laos underground. In 1952, the Martel Prize rewards these exotic explorations.
The marble plaque commemorating the 1948 exploration. Prepared in advance,
it is indicative of the optimism of Henri Cassan
Champagne to celebrate the success of the exploration of "Marie Cassan" !
Henri Cassan is on the left, next to Mary
I had decided to make my contribution to the study of the Maha-Xai caverns, already initiated from Thakhek by the captain-surgeon Rachou, with the help of the engineer Roz. But while this team had investigated for lack of appropriate means only fossil - or dry - caves, my plans were to extend my explorations to underground streams, and especially the resurgence of the Nam Nhom that the 1:100,000 map had revealed to me as being the most important.
In addition this resurgence offered all the conditions of a noteworthy accessibility. Located one hour of easy walking from the Thakhek-Nape road, from Nhommarat - a small town that had the carrying mules resources in a station of Laotian fighters - I could transport easily nearly a ton of equipment across a dried rice field to the Laotian village of Ban Thathot. Besides my wife and myself, the team assembled on this occasion included Sergeant Sacco and the firemen Papet and Vo-Van-Hanh. It was to be reduced to four during the exploration not to exceed the capacity of our two inflatable boats, which, to minimize clutter, would take our equipment in tow on car inner tubes with adaptable floors. This precaution was to develop a greater ease of movement and would receive its full justification thereafter...
Excerpt from Cassan H., 1950. Un spéléologue en Indochine. Sciences et Voyages
The porch of "Marie Cassan", before its flooding due to the construction of a dam downstream
Henri Cassan, colonel of the French Army
Corps of Engineers
Marie Cassan, with Vo Van Hanh