Grotte du Sergent

Past the 4 x 2.5 metre porch, one progresses along a 4 x 4 metre gallery. At 280 metres from the entrance, a junction forms the main access to the North network. Continuing along the main gallery, after a low passage, one reaches the “salle du Grand Pilier” (391 metres from the entrance). Shortly after, a 3 metre step gives access to the galerie du Réservoir, which ends at a sanded-up sump at 575 metres from the entrance and at a depth of -83 m. From the “lac des Parresseux”, a gallery with a section of 2.5 x 2 metres leads 60 metres further to the “lac du Bain”. Beyond the Bournier sump, 280 metres of fine active galleries lead to another sump.

One crosses the “salle des Sept Colonnes” then “la Grille”, a barrier of stalagmites.

The “lac du Bain” may sump after rain; in low water, it dries up entirely. As soon as one hears the sound of the stream, climb back up into the joint and look for a passage between blocks that opens into the continuation of the joint and then into the “salle du Lac”, where the Bournier sump begins.

The Grande Branche (from the entrance to -82): a simple but exposed climb for people who are not confident sometimes requires belaying. One then progresses by looking for the most obvious passage; one successively crosses the “lac des Draperies” then the “étroiture de la Boîte à Lettres” before arriving at a junction chamber. From there, two routes are possible to reach the Bournier sump: a chaotic low gallery, or the “Grande Diaclase”, which is reached by a high passage between the blocks after a 5 metre climb.