Grotte des Portes de la Nuit

The entrance, the size of a badger's sett, leads after about fifteen metres of crawling to a gallery 3 metres high that ends in a small chamber. Beyond, a very narrow meander reaches a small active stream at -60 m. After 50 metres, one crosses a shaft whose bottom is an impassable boulder choke. The galerie du courant d'air is traversed over several possible levels of progression; at the end of the handline, before descending, a narrower gallery about thirty metres long leads to a chamber that forms the bottom of a shaft. The gallery then continues for a few metres before ending at a squeeze. After about 120 metres, a hollow has been dug in the floor to allow passage under a boulder, but it is not passable. In the galerie des Bleus, a widening is reached quickly; above the rope is the salle des bleus, and on descending one can follow the fault for about ten metres to a narrow, muddy passage to be dug open. Higher up, a meander with steps becomes narrow.

After the narrow passages, one reaches a gallery that is very pleasant to traverse and particularly rich in speleothems.

At the intersection, take the right. Follow the gallery, seeking the best passage over several possible levels of progression. The passage in opposition above a void of several metres has been equipped with a handline; a rope has also been installed to reach the bottom of a small chamber. At the end of the handline, before descending, a narrower gallery about thirty metres long leads to a chamber that forms the bottom of a shaft, which a fixed rope allows one to climb. One must then climb back up, pass a narrow passage to descend again where another squeeze presents itself (no difficulty for a person of standard build). The draught is always present; it will be necessary to enlarge to search for a possible continuation.

In the entrance zone, take the low passage between the blocks opposite. Behind, a very narrow meander starts on the left that allows one to reach a small active stream at -60 m; the most obvious continuation climbs. After 50 metres one crosses a shaft (impassable boulder choke at the bottom) to pass the chatière des égoutiers (a very muddy flat-out crawl). The gallery that follows gives access to 2 systems: on the left the réseau des Bleus, on the right the réseau du courant d'air.

In the galerie des Bleus, one must pass above a collapse by a ledge on the right; the passage is not difficult but exposed, it is equipped with a handline. a knotted rope and etriers allow one to climb back up opposite to continue the progression. If one progresses by moving upwards, following the handline, one reaches a rope that allows one to pass a short vertical passage. 10 metres after the rope, one finds another that allows one to climb 7 metres to find oneself beneath a pile of blocks; it should be possible to pass through it to reach the gallery that is reached with the first rope.