Tresviso 81

Eastern Massif caving expeditions

by Ken Daykin (originally appeared in Caves and Caving No. 15)

This year’s expedition, by members of LUSS, ULSA, and others, to the Tresviso area was based in the high mountain region of Andara. From here a number of deep shaft systems are known to drain to the resurgence cave, La Cueva del Agua, 1400 metres below and 6 kilometres distant.

Initially we concentrated on the system Tere where exploration terminated in 1980 with the next two pitches tantalisingly in sight at minus -520 metres. The cave went easily at first down a series of vertical shafts and then into a rift where it became very tight. Work with a lump hammer and chisel enlarged the passage so that someone could squeeze through. Disappointment waited on the other side. After a 30 metre freeclimb the cave closed down once more – this time for good. At a depth of 670 metres the stream flowed away in a rabbit-sized passage. In the meantime however another route had been opened up. This descended 50 metres in well proportioned shafts to a long crawl in glutinous mud and water, aptly named The SewerThe Sewer led to an inclined shaft, The Septic Tank, over 100 metres deep. Enthusiasm mounted and we began to talk of bivouacing near the bottom. The cave continued to descend rapidly, down more shafts and into a muddy area. The usual suspicions were aroused… and confirmed. The next pitch finished after 40 metres as a flooded shaft. Not even anywhere to get off the rope! The depth was -792 metres. Although pleased to explore such a deep cave we were bitterly disappointed at it finished so short of the 1400 metres potential.

Whilst exploration of Tere had been drawing to a close, lovers of large dry shafts had tackled up a 1980 discovery, T173, later called Dossers Delight due to its rather pleasant nature. Exploration proceeded rapidly with no shortage of people willing to go down. Many shafts of large dimensions connected by small, awkward but short rifts made it quite a pleasant caving experience. The came to an end at -300 metres, where a 25 metre climb up a massive calcite formation led to a draughting fissure, which was too tight for anyone to penetrate.

During this time a number of draughting entrances had been revealed to us by the local people in an area around Monte de Valdediezma. The Monte de Valdediezma is a heavily wooded area half between Andara and the resurgence. These were enthusiastically explored along with many more, which we found ourselves, in the hope of dropping into the Cueva del Agua labyrinth beyond the known end of the cave. Unfortunately they all came to an end within a depth of 100 metres, mostly choked by calcite.

After we had been in Andara a few weeks we were joined by a small group of Spanish cavers from SEII, Madrid. They set about exploring Flowerpot, a high altitude natural entrance, discovered in 1980 and explored in that year to a depth of -230 metres. They pushed on through several meanders interconnected by pitches to a very tight section above a sump, The Autopista Sangrienta (Bloody Highway). This crawl constricted for 20 or 30 metres, has a very tight section at the end which had to be enlarged with a hammer before anyone could pass. Beyond at minus 350 metres, they came to an enormous shaft, but ran out of rope. At this stage they had to leave as they were due to the western Picos to explore another cave system named Cembaviella. (Two of our members made the trip over and joined in the exploration with them).

Cursing as we forced out large tackle bags through The Autopista Sangrienta we wondered what might be beyond. The large shaft named The Stone-eater by the Spaniards, turned out to be a spectacular 50 metre pitch onto a huge sloping ramp, over 15 metres wide. The amount of blackness around was awe inspiring. The ramp rapidly became a boulder slope, but still so steep that ropes had to be used. Puzzlingly, at the bottom only a small passage led off. This brought us to a 40 metre shaft and then quite quickly to a shaft of 114 metres with convenient ledges enabling us to keep clear of the water. The cave was getting quite deep and people were once again queueing to go down. Bivouacs were planned and dreams of great depth flourished. The cave continued with a pleasant stream down three more pitches and then sumped. Minus 720 metres – we were all shattered – once again our hopes had been dashed. Available side passages were checked out and found to be alternative routes to the same place.

After detackling Flowerpot very little time was left before we were to sail for home. We therefore decided not to detackle Sima 56 which we had left uncompleted the previous year, knowing that we had a lot of work to do down there. Instead we concentrated on surface work, looking for and descending new shafts, hoping to find a new system for next year. Unfortunately all the shafts we descended came to a conclusion one way or another. However we feel that our work in the area is far from finished.

Despite several disappointments, as we packed and headed for home we were pleased with out achievements. Two systems over -700 metres deep, one of these nearly -800 and a third at -300 metres plus another summer spent reinforcing friendships with the people of Tresviso and SEII Madrid.