Avenc de la Carbonera

The entrance opens at the bottom of a depression about 3 metres in diameter formed by the old charcoal burner enlarged when the thickness of earth and detritus at the bottom collapsed. An opening of 2 x 1 metre allows access to a small chamber occupied by clay and earth dragged in from the surface. At one end opens the entrance of the first pit, 5 metres deep, of elongated section and structured on an E30N-O30S joint, enlarged towards the S side mainly by a developed clastic process. Its base forms a ramp to the entrance of the second pit, 32 metres deep. Down it one descends 13 metres to a side chamber (La Capella) and from this point the pit notably widens its section and the cavity becomes structured on an N-S megajoint. At the bottom of the pit one reaches the Sala dels Cavalls, where it takes on notable proportions (12 x 6 x 15 m.). The floor, on a ramp occupied by small detritus, leads to the entrance of the third pit, 6 metres deep and which can also be descended by a side gallery 7 metres long.

A descent of 2 metres more allows access to a gallery of reduced section that, after another step, reaches the entrance of the fourth pit, 9 metres deep. A short ramp leads out into the final chamber (15 x 5 x 20 m.), in the floor of which opens the entrance of the fifth and last pit, 5 metres deep and the bottom of which constitutes the point of maximum depth of the cavity.

The final chamber is divided by a large elongated block into a lower part constituted by the aforementioned pit and a gallery of 9 metres that leads to a low point choked by clay. A short gallery between the wall and the central block allows a “ramonage” up to the upper side of the block and of the chamber itself.

At the bottom of the second pit, walls covered with concretion in the form of typical hemispheres attached to the nodules. At the W end of the Sala dels Cavalls there is a notable stalagmitic flow of very white concretion.

Down the fourth pit a small quantity of water usually descends. Two metres above the low point choked by clay a temporary water level is observed. On the upper side of the block and of the chamber itself there is a water deposit about 6 metres long, 1.5 wide and 1.5 deep. Still 3 metres higher, another temporary water level is observed located 10 metres above the fifth pit.

An opening of 2 x 1 metre allows access to a small chamber. At one end opens the entrance of the first pit, 5 metres deep. Its base forms a ramp to the entrance of the second pit, 32 metres deep. Down it one descends 13 metres to a side chamber (La Capella). At the bottom of the pit one reaches the Sala dels Cavalls. The floor, on a ramp, leads to the entrance of the third pit, 6 metres deep and which can also be descended by a side gallery 7 metres long. A descent of 2 metres more allows access to a gallery of reduced section that, after another step, reaches the entrance of the fourth pit, 9 metres deep. A short ramp leads out into the final chamber (15 x 5 x 20 m.), in the floor of which opens the entrance of the fifth and last pit, 5 metres deep and the bottom of which constitutes the point of maximum depth of the cavity. A short gallery between the wall and the central block allows a “ramonage” up to the upper side of the block and of the chamber itself.