OUCC Proceedings 6 (1974)

John Forder

Grid Ref. 5062 9739

On the summit ridge of the Sierra de Cuera are many open shafts, some of them of considerable depth, though most are choked at the bottom. The expedition entertained some hopes of establishing a connection between one of them and the Cueva La Boriza, which seems to take percolation water from a considerable area. Since the 1970 expedition had enough work in the low level caves, not much attention was paid to the shafts at the top of the mountain. However, one cave entrance, The Torca La Manga had been examined.

Situated in a depression near the summit of Pena Blanca, the entrance is an archway, some 5 - 6 metres wide and 4. metres high, emitting a cool draught. Just inside this arch, the floor fell away in a pitch of 20 metres, which had been descended to a steeply sloping pile of scree. At the bottom of this, after 30 metres, another pitch of 14 metres had been met. Since a minimal amount of tackle had been taken up the mountain, this was the limit of exploration. Because the hole was draughting strongly and did not choke off immediately, Torca La Manga was a high priority for the 1971 expedition.

The first party managed to descend the second pitch and reached a narrow opening which emitted a draught strong enough to extinguish the flame of a carbide light. A large tackle dump was established at the mouth of the hole, and it was with high hopes that the second descent was made.

The first pitch leads to a large, steeply sloping rift, 20 metres high and 1 -2 metres wide, with no solid bedrock discernible until the head of the second pitch - 14 metres - where the slope flattens out into a small chamber. This pitch is situated at the end of another rift, perhaps a continuation of the first at a lower level. After a few metres of straight, high passage, a similar rift was met at right angles to the passage. To the left the passage chokes off after a few metres, whilst to the right it narrows down to a small hole, not especially tight but very awkward because of the number of sharp projections. Just beyond, the passage opened out a little to reveal a third pitch of 3 metres, a long narrow slit in the floor of a small chamber. Again the constricted nature of the pitch, combined with the sharply eroded rock, made the descent tricky. At the bottom the passage widened out once more and a fourth pitch followed almost immediately. This dropped 7 metres through boulders jammed in the floor, and the passage below widened to 3 metres. Yet another short pitch of 10 metres was encountered after a short distance, leading to a circular chamber, approximately 12 metres in diameter and 13 metres high.

On the far side of this chamber was a low, wide arch, which looked like the start of a horizontal passage. It proved to be the entrance to another, somewhat larger, chamber, perhaps 17 metres in diameter with the roof arching overhead to a similar height. Hurrying across this chamber, the explorers found that it was completely choked at floor level by scree which had evidently fallen from an aven of uncertain, though considerable, height. The walls of the chamber were examined by spot beam, but no way on could be seen. The draught which had promised so much could only be felt as gentle waves of air, which presumably filter through the rubble covering the floor.

We had hoped to realise a potential of 720 metres. We had to be content with a mere 80 metres.