Matienzo 1983

A summary of the cave explorations which occurred in Matienzo during 1983

amended from an original article by Juan Corrin in Caves & Caving 22

With over 6km found this summer, people might be excused in thinking that finding cave passage in Matienzo was as easy as ever. Not so - half of this years length of tunnel was discovered by 'pushing' at the end of known systems; 6 days digging was necessary to enter one extension and the second was gained after 7km of tedious caving.

   The expedition started quietly enough with a small team investigating numerous small, choked shafts on the northern side of the Vega valley. (SRT fans might be interested to know that ladders were used for every one - and not a single bolt). Attention shifted to the other side of the valley, above the South Vega system, where 200m was surveyed in site 37, Cabritilla (and a strongly draughting dig abandoned after hitting solid rock); Squirrel Wood finally (after 10 years of chiselling) slipped through the windy entrance of 'ammered 'ole (457) finding the inevitable choke 25m down; and on Pat Devines birthday, Sima Cumpleaņos (459) was bottomed. Fairly typical of the small finds, a 5m pitch dropped onto rubble with a tight continuation down to a mud floor 13m below. A short series of joint aligned, 1m diameter tubes entered a rift containing an 8m sloping pitch to a 10m long chamber. By this time, most of the team thought 'We've cracked it!', but 10 minutes later all leads were found to choke. Length of this one was 120m, depth 35m.

   Attention switched to bigger things on the southern side of Vega and Torca de Coteron (site 264) was tackled up to continue looking at the many leads. Effort was concentrated on pushing to the west over the upstream sump in Reņada and to the east where a blank mass of limestone needs 'filling in'. The western front was advanced very little; all attempts met with boulders and the only ways appeared to be up or down among them. One passage that did appear to go in solid rock only bent round and dropped back to the start. (At one point in this route both walls of the rift consisted of one foot diameter limestone 'lenses'; the climb up to a higher level continuation necessitated forceful bridging manoevres just to keep the lumps in place). On the eastern front, Bootlace Passage was attacked at a short climb and Battery Passage immediately entered. With an initial strong draught, Battery Passage passes through low crawls, vadose and phreatic passage and 'ends' at chokes or tight sections. Passage direction' is generally north and it almost joins with Matutano Passage, discovered at Easter; length is 0.5km and pushing prospects are excellent.
    In Reņada below, the western side of the trade route was extensively poked into but little progress was made; Sanatogen Passage, heading SW, was re-explored and again little progress made.

   High up on the same hillside, to the east of the South Vega System, site 472 (a newly discovered open entrance) was bottomed at 135m. A central deep shaft has various levels running off on the way down which require pendulum tactics to enter. All ways choke.

   The entrance to Cueva Uzueka (107) lies in Riaņo and its maze like entrance series leads into a streamway which heads generally south east and then east towards Llueva and its eventual resurgence in Secadura. It is along the early section of this easterly passage (Rocky Horror) and beyond, that the cave comes close to the main sink in the Matienzo depression and over the years many attemps have been made to dig out draughting holes on the hillside above the disappearing water at Carcaveuzo (site 81). This year saw the end of Uzueka extended by 2.2km and much excitement and speculation when the passages headed for the surface in Matienzo.
   It was a couple of years ago that John Thorp, on a trip to the end of Uzueka (trying to follow the water between the boulders) clambered up a steep calcite slope on the right of Rocky Horror and came across a 'black hole' which was assumed (with his ailing carbide), to be a pitch down. The first team to reach the spot this year left ladder and rope behind as the drop turned out to be a short clamber down over boulders into a large passage ending at a 31m diameter chamber, 40m above the water and subsequently named 'Camp 1' (no stops as yet). A walking-sized tunnel set off from this and after a couple of climbs the stooping Mace Head Passage was reached. Possibly the best decorated passage Uzueka, this 1m phreatic tube has a profusion of calcite formations with large spikey crystals on the floor. After 200m the way on enlarges and things then start to get out of hand. A 15m high passage leads off into the distance with tubes going off on the sides. After a number of 15 hour trips survey detail shows the Trident Series ending at three points under the Carcaveuso hillside between 30 and SOm above the water and at an aven about 50m below the ground level.

   Two areas around the Matienzo depression have, in the past, failed to yield any large lengths of cave passage. The larger and most difficult to prospect is Muela, which rises to 700m above valley bottom, and the other is the north side of the Vega valley. Some shaft bashing was done on Muela this year - a couple of about 100m depth being the most significant - but the best discovery was found in the second area by extending a pot found in 1978.
    Since its discovery, Dave Howard had been wanting to return to the end of Mostajo (site 71) to scale onto a slope and then up to the roof, 90ft above. This year, Dave, pole, people and enthusiasm came together to attempt the climb. Piers lead the assault, 25ft up leaving the pole behind and clambering on slippery cal-ite up to the roof; a short crawl to the right along the wall met a sandy ledge and a passage with the draught whistling out. After a short distance the sandy floor required digging and half an hour later the team were through and admiring 5ft straws and 18" helictites in a passage some 10m wide. The next day saw a short climb tackled and a protracted dig started some 400m from the entrance. The flat out digging was awkward, not particularly because the floor halfway in was calcite, but because the draught blew sand in the excavators' eyes. On the sixth day of digging, the breakthrough was made. Nicely decorated at its start the passage enlarged to 7m square with much gypsum on the floor and passed numerous pits in the floor until 330m from the squeezes, a hole in the floor about 5Oft deep stopped safe progress.
   The following day, a traverse and climb around and up the sandy walls of the pit gained the continuation, about 350m of similar passage, ending in a boulder floored chamber but with an inviting rift in the roof 10m above.
    Although of no great length at 1300m, Mostajo has carved through the ridge of Enaso and opened up an area which was previously barren of lengthy passage. Incentives to return include undescended pitches off to the side of the main way - routes that could meet a level of development 150m below, or indeed the present 'water table' at 150m depth.

   Cave site numbers have risen from 427 to over 500 during this years explorations and, although none of the caves explored are of great depth or length (Uzueka at 15.65km is the 5th longest in Spain, Coteron the 6th), the series of expeditions over the last 13 or so years have certainly been the most persistant to leave Britain, gradually unearthing the remarkable number and variety of caves around Matienzo.

   As usual, our thanks must go to the Char Parau Committee for administering the Sports Council Grant and to the Spanish Authorities for their willingness in allowing us to continue with our explorations. Also in Spain, Juan Carlos Gutierrez has actively encouraged our work with much discussion and Pete Smith has been the instigator of much discovery by wandering over the area during the winter months. Bob Machin kindly lent a Molephone set to the expedition which was put to good use in the Uzueka extensions.

Iron Age in Matienzo by Peter Smith was published in Cave Science (BCRA Transactions) 10(3) in October 1983