News and cave exploration around Matienzo during 2024
A map with area names can be found here.

Section links    • Easter  • Whit • Summer • Autumn • Christmas / New Year

January / February

   The annual exploration permit was received on February 15th, so the majority of activity by the MCP before then was revisiting sites and administration.

Housekeeping
   Simon and Diane's extensive work over the Christmas period resulted in a 9.5Gb set of photos, Survex centre lines and videos. Together with Paul 'Footleg' Fretwell's collation and overview of the Four Valley's System Survex material, the documentation (photos, videos and survey centre lines) has now been updated. Possibly the best files to view are the Four Valleys System Survex 3d file, the video of the Trident Passages by Si and Di and their latest Trident Passages survey (a pdf from Therion). There is also a transcribed WhatsApp chat about the area in the January / February logbook. Within the download were also photo, video and Survex data for other explorations.
   The new material for of all these - 0059, 0081, 0107, 0260, 0429, 0603 Near the Bar Pot, 0670, 0713 Aguanaz, 0814, 0816, 1018, 1232 Cueva de Germán, 1488, 1551, 2099, 4534 Two Way Cave, 5162, 5362, 5396, 5397 and 5398 can be found within the links list below.
   Sam Davis has contributed photos taken last summer in Cueva-Cubío de la Reñada (#0048), Cueva las Cosas (#0084) and El Cubillón (#2538)
   The Matienzo pre-Easter meeting was held at the YSS hostal at Helwith Bridge on February 17th. Over 20 people attended.
   A practice Easter logbook is available here. The hope is that activities can be digitally, remotely and promptly logged through computers and devices.

Southern sector
   Pete Smith has drawn up a new survey of the popular Cueva de Jivero 2 (#0017), and the site 1111, "Jivero 2½". The nearby Cueva del Selvijo (#0028) was re-explored and re-surveyed by Pete, Juan Corrin and Andy Quin. Last visited in 1995, the main purpose of this four-hour trip (by the same survey team) was to take more passage dimensions for Survex. Leads for a later visit were noted.
   The "Colectivo Piezo" group from Madrid have continued work in Cueva Coquisera (#0039), surveying routes found above the Popcorn Climb.
   Vicente from the Espeleo Club Tortosa has published a pdf showing the finds in Cueva Vallina (#0733) over 2023 and provided a couple of videos showing Novadome and Tocadome exploration. Survey data and drawings are to follow and should be assimilated and available through the Easter update.

Eastern Mountains
   Known holes close to site 0898 near La Colina were documented, but not explored: new sites 5399 and 5400. Higher up, site 2339 was photographed.

Cubija
   As this January / February update was being finalised (in time for Easter), a water trace from a sink in Cubija valley (near Regatón) had not yet been successfully concluded. Detectors have been placed in the Riotuerto Inlet in Cueva Molino and Fuente el Escalón (Penny's Cave).

The list below shows links to those 37 sites which were extended or newly discovered over January and February, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned using a GPS.

Arredondo 0733 Vallina, Cueva;
Cobadal 2099 dig; 5396 cave; 5397 cave;
Cubija 0670 shaft; 0814 shaft; 0816 shaft;
El Naso 0059 Molino, Cueva del;
La Colina 0898 cave & shafts; 5398 cave; 5399 cave; 5400 cave;
La Secada 0081 Carcavuezo, Cueva de; 0084 Cosas, Cueva las; 0252 Decepción, Torca la (top entrance); 0260 shaft; 0603 Near the Bar Pot; 1018 dig; 1232 Germán, Cueva de; 1488 cave; 1551 shaft; 4534 Two-way Cave; 5362 shaft;
Llueva 0114 Llueva, Cueva;
Moncobe 2538 Cubillón, El;
Muela 2339 cave;
N Vega 0280 Escalón, Fuente El; 0429 shaft;
Ozana 0017 Jivero 2, Cueva de; 0028 Selvijo, Cueva del; 1111 cave;
Riaño 0105 Riaño, Cueva de; 0107 Hoyuca, Cueva;
S Vega 0039 Coquisera, Cueva de; 0048 Reñada, Cueva-Cubío de la; 5162 shaft;
San Antonio 0713 Aguanaz, Fuente;

January / February logbook

Introduction
   Over 30 cavers visited Matienzo and, along with partners and children, this meant nearly 50 people were visiting the area, with a lot camping behind Casa Germán. The weather was reasonable given the early Easter with some days of drizzle and rain. Water levels were quite low for the time of year and the camping field behind Casa Germán was wet when we arrived but did not deteriorate too much. The many strong winds amused some locals looking out of their window at the tents blowing about and the campers battening them down. Tents mainly survived or were repairable, but some decided to cut their losses and purchase a big new blow-up tent from Decathlon.
    Our permit application area for 2024 did not change from that issued in the last few years, and it arrived in good time for Easter. In our newer area to the NW more work is still needed in the Hazas de Cesto and Ribamontán al Monte areas as far as the N642/A-8 motorway.
   During the Easter period many of the possible leads were checked out that had been highlighted for attention for some years. Unfortunately, most did not go. Several leads that did go were not surveyed and were left with open passages for the summer. Unusually, only six sites made up our survey work for Easter adding up to just under 1.5km of new passage, but the amount of work involved was large due to the nature of the passages and sumps found. As well as new passage, 19 new sites were identified.
   The main finds this Easter were in the Four Valleys System where over 860m were added making the system now almost 75km long. The work involved a lot of very difficult diving as well as dry work in Fridge Door Cave (1800) using the Boob Tube entrance (5000), and some very good finds in Cueva de Riaño (0105) in an area not examined for many years. This shows that there are still good finds to be found in caves looked at and surveyed many years ago.
    On this theme, Cueva del Selvijo (0028) first found in the 1970s and re-surveyed in 1995 was looked at again by a crack team (all past pensionable age). They pushed and surveyed the system adding 350m. It seems possible that a link to Cueva de la Loca 1 (0019) will be completed - work in this cave found what appears to be new passages after a wet flat out section. These will be pushed and surveyed in the summer.
Research Work
   The work of Dr Peter Wynn of Lancaster University continued in Cueva-Cubio del Llanío (3234) looking at phosphate levels in cave seepage water (i.e., from stal etc) with sample water collected for transport back to Lancaster. This project has tentatively established a correlation with surface temperature and should lead to being able to use deposited phosphate in stalagmite for paleotemperature work.
    A sink in the Cubija valley near Regaton was tested, but the dye did not appear in Cueva del Molino (Agua, 0059), or Fuente el Escalón (0280) as was expected. A retest seems to be needed with consideration of other possible resurgence targets.

S O U T H E R N   S E C T O R

   In Cueva Vallina (0733), three trips looked at the Shatter and Dangerous Chambers to try and link them and confirmed parts were "dangerous" with loose boulders. Two new passages were found (89m surveyed) and some "question marks" checked and connected. There was also a trip with children and to take photographs. Survey results from the 2023 Catalan work in Vallina II were received and will be used to update the survey. While in the area of Vallina, three surface sites were noted and information on these will be passed to the relevant club.

South Vega
   The Colectivo Piezo group from Madrid are resurveying and pushing Cueva de Coquisera (0039) and updated survey information is regularly received from Ángel San Juan Gálvez. They asked about the location of Phantom Passage which is on our survey but which they couldn't find. Access to this area was checked out by our team, confirming it is past the 95m pitch up the left wall to an extension and pitch where the said passage is found by a difficult traverse each side halfway down the pitch. A section near the bottom of the website description has links to the latest information received. A photographic trip in this large cave also took place.
   The leads found in 2023 at the bottom Cueva de los Tablons (0242) were checked out with a view to pushing, but it was found the main draught in the final chamber goes down between big boulders and not in the 2023 leads - those did not look a good prospect and had no or little draught. To dig in the chamber would be a massive project.
    A more correct grid reference for Cuevas de Copudia (0265) was obtained, substantially shifting the position of the cave.
   Four sites, high above the La Vega valley, were checked out. Of these sites, 1341 could not be found and it was thought it is likely to be the same site (shown in wrong place) as site 1272 as the description is similar. Site 1272 was dropped on a cool day and found to have a small draught but be choked with clean washed boulders. This would be worth an easy dig to check the draught and prospects on a hot day. A new site, Torca de Hiedra (5405), was found a few metres north of site 1321 on an upper bench. The site had ivy growing down the back wall and was 10m deep to a choke with sheep bones. Site 1875 was found with the slab of rock and fence posts still in place as shown on the old web photo. It was descended and thought worth a dig. A few stones were removed from the base of the pitch, but a large boulder prevented further progress. The draught was checked but it failed a smoke test, so a poor prospect.
    A tourist trip into Cueva-Cubío de la Reñada (0048) took place.
    Carlos Lamoile reported that there was a continuing route to another pitch at the base of La Cuevuca (0177) – this is still to be checked out.
    A 5m long undescended rift (5418) was found and estimated to be 3 to 4m deep.

Alisas and Las Calzadillas
   The shaft 2052 at Alisas was examined with agreement with club G.E. Pistruellos. (The site had been found by the MCP when the area was in our permit some years ago.) The shaft was found to be shorter than stated with about 25m to a tight section and then an estimated 15m drop below. The tight section was too small to safely push through, so it needs more work to progress or a very thin person to get down and return safely.
   Three known sites were checked out at Las Calzadillas, but site 1209 Cueva de Selvijo could not be found at the GPS location. Sink 2930 shows promise as the landowner says it acts as the main sink for the area. The site has a good draught with some slabs obstructing the entrance, so it needs digging to explore. Shaft 3638 was located down near the dry streamway and is well positioned for linking to site 0258. It needs a further trip to push and resurvey the cave.
    A new 6m long cave (5419) called "Plant Pot Cave" was found situated in a sandstone bed.

Cubija valley
   Work continued in the downward rift at the strongly draughting dig 0813. More work is needed in the summer with at least three people to make spoil removal efficient.
    Two new sites were located. Site 5402 was not descended but, although not previously recorded, the shaft had an old bolt installed at the top! Site 5403 is a dig in a narrow rift that continues for 1-2m from where stones bounce down a slope to what sounds like a small chamber below. Some work is required to get down this drop.

El Sedo and Ozana
    A trip was made into Sima-Cueva del Risco (0025) to install a safe route into Arco Gallery. This required a 15m bolt climb that now provides a safe way up to the high levels in Risco, without needing to trust bolts put in 30-odd years ago. A free hanging pitch was rigged back down, and a return trip is planned to investigate leads in the upper levels.
    A resurvey and push in Cueva del Selvijo (0028) showed what looking at some of the early finds from the 1970s can produce. It also proved that some older members can still show the younger contingent how to find cave passage, although they did allow one younger member to push a horrible, muddy, wet, flat out crawl that needs more work in drier conditions. Over five trips, 350m of new passage and survey were completed. In addition, a new, second entrance (5401) was located and a likely third (5404) in the same jungle-filled depression was found but not yet pushed.
    The water from this cave flows to the resurgence Cueva de La Loca 1 (0019). A trip to push the wet crawl towards site 0028 was made. The low and wet lead was pushed through and, after another small standing height chamber then another low and wet section, a 5 x 20m chamber / passage estimated at 10m high was found. No significant draught was noted but a number of leads were seen. No survey was made but it seems this area must be very near site 0028. This area will be pushed and surveyed in the summer.
   Two trips with children were made into Cueva de Loca II (0020) when bones and "fossilised poo splat" were examined (likely a young badger or stoat).
   There was also a tourist trip into Cueva de Jivero 2 (0017).

Mullir
    Shaft 2967 was found to have a 3 x 1m top and be 10m deep. On a wet day it was taking a little water that was sinking with a slight draught. It would be worth a dig to check prospects if up on the mountain looking at other sites.

N O R T H - E A S T   S E C T O R   I N C L U D I N G   T H E   F O U R   V A L L E Y S   S Y S T E M

La Secada
   In Torca la Decepción (4732), the top of the Small Slam pitch was re-rigged with a "Y" hang and a new stainless bolt to add to the single existing one. The high location allowed easy access to a possible passage on the west wall. This was found to be a small aven closed at the top (mixed corrosion) with a drop joining the main pitch 10m down. Lots of eroded stal make it clear that this is an old passage that has been re-excavated, probably by flood water from a bedding just a few centimetres high. Opposite this is an area of cobbles and mud and what looks like a possible old phreatic passage infilled with this mixture. There are no prospects in this small area.
    A trip to check out leads on the way to Armageddon found a high level boulder chamber on the SE of the passage just before End of the World Way. This chamber links two access climbs that, on the survey, had looked like links to a high level oxbow. Any route through boulders has not been pushed. A lead next to End of the World Way was found to be a climb up a mud slope to a large space beyond. This will require bolting to access. Some small finds and links in the Morton's Fork area were recorded, but not surveyed.
   At Bingo (0880), the excavated drop at the end of the dug passage has a pool of water that does not drain away despite pushing in a bar some 60cm in several spots. This would need a big dig even if this is the way on. This site has been abandoned for now and renamed Patrick's Folly. However, not to give up in this area that clearly has a large old cave below, the adjacent site 0874 was dug. On the first day this had a strong outward draught, but much less on the second day possibly due to debris being dropped down the dig. Digging is difficult due the nature of the fill. Plugs and feathers proved useful and a lot more work is now needed. Enough material was removed to allow the use of an endoscope to show the dig does not open up for at least 1.5m.
   Cueva de los Tres Niños (0565) was hard to find in undergrowth. In the cave it became clear that some roof falls had occurred with a lot of big new blocks on the floor making the main chamber area dangerous. However, the 50m pitch near the entrance is worth a push.
    About 100m away in La Cuvia (0086) it was reported that the route down between boulders into the main chamber had changed and a way down could not be found. A possibility is that boulders have moved and if so, could be associated with roof falls in Tres Niños.
    Cueva de la Orilla Mijeo (0091) was checked out for leads but none of interest were found. Shaft 1222 could not be found at the GPS location. Shaft 1231 had been reported at 10m deep, but found to be only 2m to a dug slot to chamber with soil roof. One lead is a crawl with a rock roof and mud floor which could be dug, but there is no draught. The entrance squeeze to cave 1506 was dug out and a dig at the end of the high level passage worked on, but more is required. In the lower level there were no obvious ways on. The site was photographed. Photographic trips were also made to Cueva las Cosas (0084).

Riaño
   The main work this Easter was in Fridge Door Cave (1800) using the Boob Tube (5000) entrance. The pushing occurred over three periods: the dry sections explored in February then March and early April, followed later in April by Jim Lister and Mark Smith diving. In addition, the old (1800) entrance was checked out for a possible dig to connect to Cueva de la Espada (0103) where a bat was noted (large, but no type given - greater horseshoe bat?). The only possible dig is at the bottom down a slot, but it was flooded. We know it takes time for the water to drop so it needs digging in a longer spell of dry weather.
   The five dry trips using Boob Tube (5000) found it wetter than usual and muddy after sump 2. Crown Prince of Denmark's New Clothes was pushed and surveyed from the end into a passage with many stalactites. After 8m, a pit was noted but it closes down. About 12m of passage follows but gets smaller and slopes down. It may continue through a 30x40 cm slot, but no draught was felt. In the same area the east-west intersecting chamber heads up towards the west where it also slopes down and ends in a mud dig. A few other leads were looked at but not pushed. On a later trip climbs and drops were pushed and two new areas were found and surveyed. A trip was made to push leads in the Matienzo Hash House area. Several climbs and ramps were checked using bolting and a new 15m pitch was found, it is still to be surveyed. In Low in Knickers the end was pushed in two places but only 14m was found. In total, 207m was surveyed by the dry teams.
   The two divers were self-contained, mainly as almost everybody else had gone home! Seven trips were made to push the sumps and dry passages beyond. On the way to the sumps a side passage was noted just before station 11. It was an easy dig in a descending tube, partially filled with rock debris, draughting outwards. It was partially dug and looks easy to excavate - solid wall could be seen about 5 metres ahead. On another trip they bolted up to the formations in Diamonds in the Sky aven, but found no way on.
   Diving started at the sump 4 dive base. Mark dived sump 4 and found it was restricted with a thick silt floor. An initial duck reached a sizable chamber / airbell then, by diving a further 20m of sump, a large cross rift was reached that was dug to an airbell with no open dry continuation. The left wall was followed in the sump but ended back in the same airbell. Jim dived and with his hood remove in this second airbell heard the sound of running water from a small inlet that required digging. Both divers scaled a mudbank in the first chamber / airbell, falling down the slippery slope occasionally and dug in a small alcove which was blind. Another more interesting mud ramp on the left in the chamber was climbed with combined tactics (after slipping down mud for 7m) to reach the top of the aven 16 metres up finding a 2×7m well decorated passage that quickly closed down.
    On a later trip, a sandy dig led to a well decorated chamber with a draughting dig just past the formations. At the second air bell in the cross rift, the team dug open the inlet where running water was heard. This entered 40m of walking sized passage to sump 5. This sump was found to be restricted with undercuts, and was 6m long to a walking sized passage. The streamway continued through sumps 6 & 7, with a muddy walking streamway between. Sump 8 was blocked by mud a short way in, and needed underwater digging. On another trip sump 8 was dug and passed to a walking sized stream passage for 50m to sump 9. Side passages in this section closed down.
    Sump 8 needs more digging out as the divers found the slope slumping in on them. This made route finding difficult, requiring a lot of digging to get through, both in and on the return - not a pleasant sump! On the next trip, sump 8 was found slumped in and blocked. Maybe flood conditions will wash out some of the material?
   The finds below and above water up to sump 8 were surveyed and some photos taken. The divers found about 300m of new cave. The dig past the formations in the airbell in sump 4 was dug and passed to a low and narrow passage needing more digging to continue. (A video of the divers' activities can be seen here.)
    In correspondence with Prof John Gunn about the helictites and other numerous formations in the airbells in sump 4, he thought they suggested some connection above the sumps, so some change of air must occur. If this were not the case carbon dioxide levels would not be low enough to cause a CO₂ reduction in the water drops and hence precipitation of calcite.
    In Cueva-Cubio del Llanio (3234), as part of the Lancaster University water chemistry project, water samples were collected on two trips. Unlike last year, the samples were partly treated in the cave meaning vast quantities of water did not need to be taken out of the cave and transported to the UK in Peter Wynn's car!
    Using the SubPhone entrance (4536), the Ski Slope area was visited as partly a trip for some of the expedition member's children and also to photograph the area.
   The other main find in the Riaño area was in Cueva de Riaño (0105) itself. Over three trips, 408m of previously unsurveyed and new passage was found at an inlet 50m upstream of where the entrance series meets the main cave. The inlet reached a rift and a 'downstream' passage. This was pushed heading away from the rest of Riaño. The way on was initially tight, but soon became wide at ceiling level, it went 100m until partly blocked by calcite at a drop back down into the stream. This lower passage was forced for around 50m in a tight, unpleasantly muddy, immature passage that is still continuing in a similar vein and with a good draught. At this point the team realised that were now going upstream. Checking, it turned out that the downstream water at the start of the rift disappeared almost immediately, meaning that what was thought was the upstream part of the rift was probably a later interloper bringing in water. More work is needed in this area in the summer.
    It was noted that the Upper Series east side had a very flat roof just past La Playa and still has the scallops on it from the original flow direction. A climb up and over a large greasy boulder halted progress and needs a fixed line to be left in. The metal work at the top of c4 Up To Glory needs to be replaced.
   A new site, Cueva GeeBee (5406), was found and is a vertical slot filled in with rubble. The slot continues back some 1.5-2.0m with a window over the remaining rubble showing the narrow cave may continue with a lot of work. Another hole was investigated up the hill from 5406 - possibly site 0256. The hole is a 2m wide shaft, about 8m deep covered with a sheet of aluminium, and filled with rubbish at the bottom. It is worth an easy dig to see if it has prospects.

N O R T H W E S T   S E C T O R

Solórzano
   Nacimiento del Campiazo (1106) near the riding centre, was dived by Mark Smith who found the entrance to this resurgence had collapsed and no dive line was visible. The blockage was dug out and the 2002 line was found a little way in. Visibility was poor but was dived to the end boulder collapse. It needs clearer visibility to look for a way through boulders. Also, the entrance needs digging and stabilising as the sandstone bed forming the roof looks pretty unstable.

Quebraduras
    This area above and to the east of Solórzano was checked out for new sites. The area is heavily wooded with a few open fields and undergrowth in depressions makes searching difficult. Six new sites were examined. The most promising was site 5411 with twin holes in a deep depression. The steep slope was descended using two ladders as a handline. One hole contained a rift that appears choked at high level. A 7m shaft was opened up on the rift which needs gardening before exploring. The second hole is a free hanging 5m drop with one possible way on underneath a bridge towards the 7m shaft. At this point stones tumble for a few seconds. It will need more work to progress this way on.
   In the field on the opposite side of the track from 5411 is Field Dig (5410). This is a slot (30x12cm) under a 1m rock face that goes down at an angle. It was distoed at 4.8m. It would be an easy dig but has little to no draught on a warmish day.
    Just in the wood north of 5410 is Almost a Cave (5409) where a 2m rock face goes into corner with another rock face forming a cave entrance, but the continuation is a spoil filled slot only a couple of cm wide. It looks like it may be a fault / joint in line with the depression just over the south side of the track.
    A 6m deep shaft 5409 is next to the track and has been used to dump rubbish, straw and other waste. No hole or prospect was found at the bottom.
    A dig (5408) in a long, jungle-filled, double depression was found at the base of the eastern section. It may have a slight draught but requires digging to continue.
    Further to the north, a small cave (5412) was found on the side of a wooded depression. It is 2.3m long to a dig in a rocky floor. It is restricted but would dig, although no draught was felt.

Hazas de Cesto (west)
    The cave 4939 proved difficult to find in dense vegetation in an area of ravines and gullies. It was entered on a second visit and found too tight at a "T" junction. There was no draught on a warm day. Another cave (5416) was found on the north side of a large shakehole with dense undergrowth and standing water in the bottom. The cave is 2m long to a roof fall blocking the way on.

El Rincón
   Next to the road to the motorway from El Rincón and before the bends, cave 5417 was dug out for 2 - 3m to a right hand bend. A very low passage continued about 2m to the roof lowering with a possible bigger space beyond. Further progress will need digging out the fill from the entrance. It had a slight draught out on a cool day.

Beranga
    The resurgence 4937 on the west of the road from Hazas just prior to the motorway was first partly explored, but not surveyed, in 1977 and is now back in our permit area. The tree trunk that had been put in hole to make it stock proof was partly removed with a chain saw. However, it seems other rubbish and spoil had been dropped into the hole prior to the tree trunk being placed in and this fill has blocked the way down a small passage into the rest of the cave. It now needs digging with a spade to make the area below the tree trunk big enough so a person can turn around and dig out the spoil. This will now be done in the summer.
    Some interesting features show up on the LIDAR map of the woodland to the SW of 4937 and these were checked out. Thick undergrowth made for difficult going with no trace of any limestone showing from the road to the top of the wood. The LIDAR features seem to be large mounds of earth and clay with no prospects.
    Above and to the south of 4937 was a shakehole full of tyres that looked like a good prospect, but after removing some tyres only soil and clay were found.
    Again using the LIDAR map of the area, a depression beyond Bus Stop Cave (5336) was checked but it proved negative.

Ribamontán al Monte
   This area is shared with the Club Montaña y Espeleología La Cambera.
   At Villanueva, Cueva de Covachera (5036) was dug having first checked that the badger had not returned to its den. Comfortable hands and knees crawling leads to a dig with a good draught. One metre of fill was removed to a right turn, but unfortunately only a space 30cm x30cm over solid fill for at least two metres was revealed. It's probably not worth visiting this dig again. A large shakehole past the end of Covachera was checked out but was found to be full of old roof tiles and bricks and is not worth pursuing.

Moncobe
   The following was carried out with the agreement of the club G.E. Pistruellos.
   At El Cubillón (2538) a trip was made to survey extensions (Third South Passage) found last year and tie in a floating survey as well as dropping a tantalising pitch where water is heard. The area was found to be very, very muddy, and the pitch would need a lot of work in squalid conditions to push. Surveying of 141m was completed to link in known passages.
    Cave 3754 was found with a little jungle bashing after a number of failed attempts in previous years. The team started removing the fill which is now 4m long to a slight lifting of the roof with boulders in the floor. This cave requires more work as it has a good draught. Some work was done removing undergrowth to make access to the cave easier.
    At the dig 4480 in the "4474" valley, four trips were made, some solo. Work progressed on enlarging the passage encouraged by a good draught. More work is now needed at this promising site.
    The shaft 4474 was searched for and the conclusion is that it has been covered by a big collapse on the true right wall. The collapse 4972 first spotted in 2019 was found to be much enlarged and needed a return visit with a ladder to investigate. Unfortunately, after some work, it was decided that the hole wasn't going anywhere so the site was left safe and well-covered.

Ideopuerta
The dig 2751 was checked out and it was confirmed it looks interesting and is worth a further return visit for a serious digging effort.

Easter Expedition report by Phil Papard, 8th May 2024

Extras
   New material has been received from Phil Parker - photos for sites documented at Easter 2023. These are sites 3011, 3012, 3406, 3472, 3720, 3736, 5227, 5328, 5349, 5350, 5351, 5352, 5353, 5354, 5355, 5356 and 5357 (which are not included in the list below.)

   The Memoria de Exploración Vallina 2023 from the Vallina Exploration Group has been pored over and their explorations embedded in the Vallina survey and description. There were seven trips through the year, some with large numbers of cavers, e.g. a December trip had 17 cavers entering the system. Three batches of survey data (24-01, -02 and -03) produced a total of 837m of new passages. Important, continuing extensions were made at the top of the Novadome along with smaller passage near Cobra Passage and the Vimanai Aven climbed to link with the top of the First Abyss. Also inspected and pushed with some prospects for further extension were La Pita, Bathtub Passage, Stream Passage (Rioja Reserva), 600 Ptas Passage, Road to Nowhere, a pit in the Road to Glory, Second Abyss, Tocadome and Waterfall Inlet.

   Possibly the most important expedition document - the logbook - was made available (in the cloud) for completing online. Anybody with the link to this Google Docs file could add or alter material just like using a word processor. A trial online logbook and Help file were also available. It would appear that the digital logbook was almost completely successful and an auxillary, stand-by paper logbook was never needed. The online logbook was backed-up at least once a day.
   The main advantages seem clear:
   • Available anytime, anywhere by anyone with the link.
   • Legible entries and easy to amend and correct.
   • "Copy and paste" info from emails and other sources is better then "Print, cut and paste" into a paper logbook.
   • Able to include drawings and photos.
   • Well-written entries can be used verbatim in site descriptions and reports.
   • Easily searched for particular sites. Very useful for report writing and updating site descriptions.
   • When finished, a pdf version is put online as the final version. There is no need to scan paper pages. This pdf version is also searchable, unlike previous logbooks where the pages are scanned jpgs.

   A couple of impressive photos of Swirl Chamber in Cueva Vallina by Sam Davis have been published on Facebook. Copies are linked from the base of the Vallina page (#0733).

New surveys and survey updates (in hand)
Description		Drawn survey	Survex centre line
0028	Selvijo incl #5401	complete (JC)	0028
0105	Riaño	in hand (JC>PF)	0105
0252	Decepción	complete (PP)	0252
0733	Vallina	complete (JC)	0733
1800	Fridge Door	complete (JL, TR, JC)	1800
2538	Cubillón	complete (AR>DA, SC)	2538
5289	Colorao, T. de	complete (GS)	-

The list below shows links to those 87 sites which were extended or newly discovered around the Easter 2024 period, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned using a GPS.

Alisas 2052 shaft;
Arredondo 0733 Vallina, Cueva; 1721 shaft; 4340 Tantas Noches, Torca de; 4808 cave; 5413 shaft;
Beranga 4937 resurgence; 5336 Bus Stop Cave;
Cubija 0071 Mostajo, Torca del; 0813 dig; 0892 Regaton, Torca del; 5402 shaft; 5403 dig;
El Naso 0059 Molino, Cueva del;
El Rincón 5417 cave;
El Sedo 0025 Risco, Sima-Cueva del;
Hazas de Cesto (west) 4939 cave; 5416 cave;
Hornedo 5353 cave;
Ideopuerta 2751 dig;
La Azuela 5289 Colorao, Torca de;
La Rasa 0662 Tonsillitis Pot;
La Secada 0084 Cosas, Cueva las; 0086 Cuvia, La; 0091 Orilla Mijeo, Cueva de la; 0229 shaft; 0249 cave; 0250 shaft; 0252 Decepción, Torca la (top entrance); 0565 Tres Niños, Cueva de los; 0874 dig; 0880 Bingo; 1222 shaft; 1231 shaft; 1506 Road Show, The; 3536 cave; 4732 Decepción, Torca la (bottom entrance);
Las Calzadillas 1209 Selvijo, Cueva de; 2930 sink; 3638 shaft; 5419 Plant Pot Cave;
Moncobe 2538 Cubillón, El; 3754 cave; 4480 dig; 4972 collapse;
Mullir 2966 shaft; 2967 shaft;
N Vega 0280 Escalón, Fuente El;
Navajeda 4112 Cuesta de la Encina, Cueva de la;
Ozana 0017 Jivero 2, Cueva de; 0019 Loca 1, Cueva de la; 0020 Loca 2, Cueva de la; 0028 Selvijo, Cueva del; 5401 Selvijo, Cueva del (entrada 2); 5404 dig;
Quebraduras 5407 shaft; 5408 dig; 5409 Almost a Cave; 5410 Field dig; 5411 shafts 2; 5412 dig;
Riaño 0105 Riaño, Cueva de; 0107 Hoyuca, Cueva; 0256 shaft; 1800 Fridge Door Cave; 3234 Llanío, Cueva-Cubío del; 4173 Shelob, Cueva; 4536 Sub-phone entrance; 5000 Boob Tube; 5227 Sin Sendero, Cueva; 5406 GeeBee, Cueva;
S Vega 0039 Coquisera, Cueva de; 0048 Reñada, Cueva-Cubío de la; 0177 Cuevuca, La; 0242 Tablons, Cueva de los; 0265 Copudia, Cuevas de; 1272 shaft; 1321 shaft; 1341 shaft; 1875 shaft; 5405 Hiedra, Torca de; 5418 rift;
San Antonio 5414 rift; 5415 cave;
Seldesuto 0035 Arenal, Cueva del; 0258 Calleja Rebollo, Torcón de la;
Villanueva 5036 Covachera, Cueva de;

Easter logbook

Introduction
   After the Easter feedback was published, Guy Simonnot responded with additional information about some of the sites close to the Matienzo - Arredondo ridge and others, including one new shaft. Jim Lister provided information about an ongoing dig above Fridge Door Cave in Riaño. The Colectivo Piezo group is continuing to re-explore and push routes in Cueva Coquisera: information is provided by Ángel San Juan. A possible Bronze Age skull has been found in a cave above the base of the Bencano valley, Moncobe.

S O U T H E R N   S E C T O R

   The shafts, caves and digs found in the early years (from 1979) were plotted on 1:5000 maps and given grid references without the use of GPS positioning. It's inevitable that some (or most?) of these will be in the wrong place on modern, digital maps. Some grid references may be out by many tens of metres, even 100m or more. The consequences are that documented sites may not be found, may be mistaken for another, or duplicated. To add to the confusion, vegetation grows, farmers cover holes and entrances can collapse - or open up!
   Around the Matienzo-Arredondo ridge, sites 0611 and 1148 couldn't be found, although the nearby 1147 was spotted. The "small earthy depression" seen at site 1153 appears to contradict the original 1996 description - "unexplored sloping hole". Site 5324, first documented in April, was named, photographed and a 20 - 30m depth estimate made. New site 5420 (SCD 3639) was discovered but not yet explored.
    Lower down towards Arredondo and possibly associated with Cueva Vallina, site 1721 was originally explored - down 32m to a choke - by the Spéléo Club de Dijon in May 2023. Also previously explored is site 5413, first documented by the SCD as SCD 2649. Torca de Tantes Noches (#4340) had another "20m added" in June 2023.
   There appears to be no let up in the work in Cueva Coquisera (#0039) by the Colectivo Peizo group. Survey material and descriptive jpgs have again been received and can be viewed from the cave description page.

N O R T H - E A S T   S E C T O R   I N C L U D I N G   T H E   F O U R   V A L L E Y S   S Y S T E M

   Back in April, as a break from cave diving, Mark Smith and Jim cleared material from site 3302 in Riaño (over the northern passages in Fridge Door Cave, #1800), gaining some 5m of low passage in the left hand entrance.
   A short article by James Carlisle and Juan Corrin, "Climbing the charts in Matienzo" appeared in Descent 298 accompanied by an inside front cover photo in Cueva-Cuvío del Llanío (#3234) by Sam Davis. Based on the Easter finds in Fridge Door Cave and Cueva Riaño (#0105), the length of the Four Valleys System has risen to 74861m to become the 40th longest in the world. Celebrations may be premature as Footleg has realised that, with some of his meticulous surveying (back and forward bearings some 10 or so years ago), some leg lengths have been counted twice in Survex. A re-calculation of the system length will occur when all these legs have been identified.
   Inspired by Simon Cornhill's and Diane Arthurs' productive surveying around the Trident Series in Hoyuca last Christmas, Paul 'Footleg' Fretwell has taken up the Four Valleys System Therion drawing reins again after an 11-year gap. The current overall progress with Therion can be seen here and the individual pdfs are distributed on the Carcavuezo, Llueva and Hoyuca description pages. The "Surveys" sections for the three caves within the Google Earth file have also been updated.
   The underground survey work in The Sewers of Doom in Carcavuezo back in 2022 has also been processed and connected to the Carcavuezo and Four Valleys System Survex files.

W E S T  &  N O R T H W E S T

   In the Bencano valley site 3754, a possible Bronze Age skull has been discovered. Cultura has been informed of the find.

Extras
   Phil Papard has updated the full list and highlights of potential explorations for the summer, also available off the front page.
   A different way of showing site entrance positions is through a 'Leaflet' map where the map background can be altered. Quick and easy to update, the Leaflet map can always be found off the Latest Updates page, the more detailed Maps, Photos & Docs page or from the Publications & Maps drop-down menu on page 1. This map is best viewed on a PC rather than phone or tablet. A link to this map ("Site entrance in context") is now provided at the top of every grid-referenced site description.
    Three extra facilities are included within the CAVES dropdown menu on the front page:
• a random site selector for lucky digs or trips
• a browsing page
• a list of sites with no grid reference. This may eventually lead to fewer site duplicates.
• 'Matienzo 1985' video digitised and put on YouTube. It is thought to be worth digitising as it shows equipment, people and passages from nearly 40 years ago. The quality is poor as the digitised tape is a third generation from the original VHS-C tapes, but some people with their carbide lights are recognisable!
• 'Connections: Matienzo 1986' A 38 year-old expedition video, filmed and edited in 1986, the year of the main connections within the Four Valleys System. Slightly better quality than the 1985 expedition video - it also has added sub-titles. Main caves visited: Azpilicueta, Reñada, Carcavuezo, Hoyuca. As with the 1985 video, because of copyright restrictions, the video cannot be viewed from Facebook.

The list below shows links to those 17 sites which were extended or newly discovered around the May, June 2024 period, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned using a GPS.

Arredondo 1147 cave; 1148 shaft; 1153 cave; 1721 shaft; 4340 Tantas Noches, Torca de; 5324 Valla, Torca de; 5413 shaft; 5420 Labio de Hierba, Torca del;
La Secada 0081 Carcavuezo, Cueva de;
Moncobe 3754 cave;
Riaño 0105 Riaño, Cueva de; 0107 Hoyuca, Cueva; 1800 Fridge Door Cave; 3302 cave; 5000 Boob Tube;
S Vega 0039 Coquisera, Cueva de;
Seldesuto 0611 cave;

Whit logbook

Introduction
   About 45 cavers visited Matienzo, spread over six weeks. The weather was mixed with a few days of drizzle but generally quite dry. (Rupert, based to the south in Arredondo and hoping to dive in Cueva Vallina, had a different experience. See Extras, below.) There was one very hot period where campers suffered in the morning if the tent was not in the shade! The diving team of Jim and Mark had to come out prior to everyone else, as also happened at Easter, due to Jim's holiday rotas. However, next year this will not be an issue due to retirement.  As was the case last year we had a good number of younger cavers join the expedition and they did a lot of good work. There was one spell of illness that affected a significant number of the team, and which may have been covid. The illness was fairly minor but did make people feel ill for some days and tired for a little longer and so did curtail some caving.
    This summer was dominated by finds in caves first explored almost 50 years ago, with almost 1.5km in Cueva de Riaño (0105) and over 300m in Cueva de la Loca 1 (0019). The "resurgence" (now called Nepa Hole, 4937) is on the left of the road to Beranga from Solórzano just prior to the motorway bridge. It was first found and sketched in 1977 was finally entered again, extended to 121m and surveyed. These finds, along with over half a kilometre in Fuente Aguanaz between sumps 1 and 2 and other work added up to over 2.7 kilometres of new surveyed cave this summer. Elsewhere, a site found at Easter (2 shafts, 5411) was pushed to 95m to a possible dig.
    Cueva Vallina (0733) was extended at the high level passages and climbs at the end of the Sunday Stomps. Rupert continued the work pushing the downstream sumps. In addition, the Catalan cavers have been pushing mainly in Vallina II and this will appear in an updated survey. However, there seems to be an anomaly in the survey data (both Catalan and UK) that needs to be sorted out before the survey drawing can be updated.
    Twenty new digs and caves were found and recorded. Some have been pushed but work (pushing, digging etc) for a number is still needed. About 62 sites were visited, and 120 trips were made during the expedition. With the finds in Cueva de Riaño and some more passage found in Vaca Bypass (5368) these brought the length of the Four Valley System up to over 76km.

S O U T H E R N   S E C T O R

Arredondo
   Pushing in Cueva Vallina (0733) continued over five trips in the high level at the end of Sunday Stomps that was found at Easter 2023. Ha! Aven was climbed and leads pushed. It was noted there is a lot of loose rock and care must be taken in this area. A drop down below the pitch had been fitted with a pull-back belay. It looks as if it's been pushed but not fully on the survey. If it is a pull-back, it seems it must lead to lower levels. This is not on the survey and needs to be looked at and surveyed.
    A new pitch, TLC Aven, further west than Ha! Aven was bolted to a chamber. (video) From here Far Left Passage and a traverse was bolted. This area is very loose but there were no good prospects on this side. A sandy crawl leads to some nice formations and then flat out to some loose chambers a further traverse and a crawl to a big drop. This drop is near to the original bolted climb at the end of the Sunday Stomps. Some possible leads remain but do not look very promising. Survey work suggests an error that may be in the original survey or the 2024 ones – a resurvey of the area may be needed to solve this problem.
    The Catalan cavers organised by Espeleo Club Tortosa undertook pushing and bolt climbing work in Vallina II around the Tocadrome and Novadome as well as Bathtub Passage. Also, a climb near the start of Vallina II was started to try and link to Cueva de la Rasa (5135). The details of the work and survey undertaken by the group is not reported here but will be reported on the website when available.

South Vega
   Four new sites were found and recorded (5421, 5422, 5423 and 5424) all have some potential and need further fully equipped team (ladder and digging gear) investigation. Aerial photos (drone work) around Torca de la Vera Negra (0036) was completed and a new GPS for shaft 0338 taken. Future caving members (i.e. children) were taken into both Cueva del Comellantes (0040) and Cueva de Coquisera (0039) and some cave diving training took place in Cueva del Comellantes.

Trillos and Las Calzadillas area
   The Tomb of the Oil King (5369) was checked out but after rigging the pitch it was realised that the entrance had been sealed up with big boulders that had fallen in stopping any progress. The team tried going over the traverse line and carrying on (instead of going down into the big boulder chamber) into 5-10 metres of cave but were then stopped again by more sandstone boulders.
    The sink 2930 was draughting out cold air, suggesting higher entrances. The cave lies at 180m elevation above passages in Torcón de la Calleja Rebollo, (Toad in the Hole, 0258). The hole was cleared of mud to reveal a couple of large boulders needing gear to remove. A good view down a 30cm diameter showed the hole to be about 5m deep hole entirely within mud. Further progress will therefore require serious shoring to continue. With this in mind, the hole was blocked with large rocks in order to make it child and animal proof.

Cubija and North Vega
    The strongly draughting dig 0813, next to the road above the final farm house in Cubija, was dug on a number of occasions. Good progress was again made on this longer-term, promising dig.
    A trip was made to look at the ancient "wall" at the end of Cueva del Molino (0059) and, on a family trip in Cueva de Rascavieja (0077), a quick look at both chokes was made. The choke on the right (with the green string) was blowing a gale - and has got to be worthy of a bit more attention!
    It was noted during a photographic trip in Torca del Mostajo (0071) that the route to some good formations is well trodden with many reflective markers in place.

El Sedo, La Colina, Cubilla and Ozana
   At El Sedo, three sites (Cueva de la Carrasquilla (0011); Cueva de la Puerta (0024) and Cueva del Alzado (1261)) were checked out for GPS accuracy and all three were re-surveyed and photos taken.
    In Sima-Cueva del Risco (0025), the route to Upper Arco passages, via the pitch climbed at Easter was used to check out the Disneyland area with only a small extension made. It is not clear where the original route and traverse is located, and a resurvey next year will help. The old survey to the NW marks passages left unexplored and even ends in dotted lines close to the Dambuster Series. Plenty still to be done here, and access via the new up-pitch is now relatively safe and simple.
    On Mullir ten sites were checked out. A new GPS of shaft 1767 and photo of the entrance was taken. Shaft 3600 was found to be 10m from the base of the doline and was dropped for 10m to a 6x1m rift with a slight inward draught. Stones can be dropped down a 20cm slot for further 10m. The nearby shaft 3601 was confirmed as being a tiny slot down 2m to a choked floor with no real prospects.
    Seven new sites were found and recorded. Scabious Pot (5429) is a 6m drop to a ledge and a further 7m to a choked floor with no way on. Hazel Doline (5430) is a 20m diameter doline about 10m deep full of hazel trees. Stones dropped at the west end suggest there may be a pitch at the bottom. It needs rope and gear to check out this lead. Shaft (5431) was a 7m blind pot. Top Hole (5432) is an 8m free climb down to a choke with small holes continuing below, but was not thought worth pursuing further. Three further depressions (5433, 5434, 5437) that need extensive jungle bashing with gear to enter were located but not fully checked out, but prospects did not look good.
    At Ozana, Cueva de la Loca 1 (0019) was pushed following on from the Easter finds and 358m of new passages surveyed over four trips. A bypass to the duck was found and it was clear the Easter Chamber area is quite complex. A possible connection to Cueva del Selvijo (0028)was seen up a muddy climb needing protection to push. It was noted that the present surveys put the downstream in Selvijo lower than the upstream in Loca 1 where the water is expected to flow to. It's not clear where the error lies but a surface survey of the entrances was made to ensure their location is not the problem. Near the entrance chamber a small hole in the ceiling was noted through which daylight could be seen, it approximately lined up with a small rift (5436) that was located on the surface. This hole was entered to a stoop through the rift around a left corner to pop out into some new chambers. In this area the draughting Bedding Dig (5435) was found.

N O R T H - E A S T   S E C T O R   I N C L U D I N G   T H E   F O U R   V A L L E Y S   S Y S T E M

La Secada
   Cueva de Carcavuezo (0081) was looked at with a view to future work to extend the western area to Cueva de Volvo (0098). The normal entrance was blocked with logs but later dug out, and an entrance below in the flood overflow channel was found and used. The main objective was for the team who had not been in the cave before to familiarise the routes through the cave. It was noted that the route up the rifts to the Western Series is not well marked and the traverse line needs some work to extend and probably replace - it is important that teams take cows tails if using this route. Inlet 2 was pushed and was thought to be worth digging. On the way to the Eastern Series, new passage with several chambers and a good draught was found at the start of Afternoon Stroll. These finds are still to be surveyed.
   The area on the west side of La Secada has many strongly draughting sites that have been dug over the years and is a key prospect area between the Four Valleys System and the North Vega System. It was decided to try to be more focused and the very strongly draughting Socks (1017) was chosen as a site to concentrate on following on from the work Lloyd and his team had done over the last few years. Over eight trips, the entrance shaft was opened up and the top mud slope dug to steps and a flat area to make hauling of spoil easier. Good progress was made, and it was noted the main draught is not from the crawl in the bottom chamber but from between boulders at the bottom of the entrance rift. Stabilizing work here is needed and a little more work on the bottom of the entrance shaft is required. This is likely to be a long term dig, but it has the advantage of being in a very key area with good prospects, easy access and, in hot weather, in the shade with a good cool draught!
    Just to the east of Socks the sites 1015 and 1016 were checked. They draught, but much less than Socks, and it was noted that they look like they would connect if dug.
    The draughting dig 2101 above the road to Fuente las Varas, just past the first hairpin bend, was dug on five occasions. The team dug down to reach a small chamber with a draughting rift in the floor that, after removal of rocks/spoil, was descended to a passage with one way leading up-slope, appearing to be an inward route for water. The other way leads down-slope to a draughting rift that will be the target for digging in 2025. The site is now 20m long and 11m deep.
    A trip was made to Cave 415 (0415)to check out some question marks for the survey currently being drawn up. The rope in the first chamber up to the higher level crawl is in a bad state and is knotted to cover a bad rub section: it needs to be replaced.

Fresnedo
   Cueva del Torno (2366) was visited on two occasions to familiarise team members who had not been in the cave before. Route finding was difficult as the description names do not all appear on the survey making it hard to follow. Some key features (such as the traverse) are not shown on the survey. Access to this site is important if we are to link it to Cueva de Riaño (0105), so it would be useful to annotate the survey. Some of this could be done at a meeting with members who explored the cave and so able to follow the survey / description.

Riaño
The main explorations were in Cueva de Riaño (0105). There was some initial work to change a number of worn aids and to check the geology of some key areas, as well as prospecting new passages. Over another seven trips, 1375m of new and previously unsurveyed passages were found. The finds were north of the fracture area after La Playa and inlets off the streamway. This led to a maze that may have been visited before by one person - there was only one set if foot prints. The area ended in boulders and surface signs (snails and bat claw marks, etc) with some leads still to push. Other leads reached a passage with a large aven and, in the opposite direction, an 8m pitch and traverse above. The main route in this area was followed and surveyed to over 200m with side passage leads, to reach a chamber again with signs that it is near the surface.
    A side passage (Mouse Print Passage) is a fine abandoned walking route which meanders with some small side passages. It draughts and lowers to crawling on dry mud. Broken snail shells in the low section and whole snails in the chamber at the start were found. The locations with surface debris were looked at and pushed but no connection was made. A surface location and dig now seems to be the best option – more SubPhone location work?
    Pessimist Passage and Redeeming Feature areas (see survey when published) were pushed to chambers and climbs needing bolting to possible further passages. These included a waterfall flowing into the far end of Redeeming Feature with what seems to be caveable passage at the top, needing a 6m bolt climb. In addition, two trips with future hard cavers (i.e. children) were made into some of the middle sections and the streamway was traversed with pitches climbed.
    Two trips into Vaca Bypass (5368) investigated a pitch just past the Mayonnaise Escalator. The pitch was dropped 10m to a ledge and then 10m to a 5x2.5m area with a passage that looks like an old stream way needing a small person with no SRT gear to push. At this point, one of the team had a lucky to escape as a large flake became dislodged narrowly missing his back and head. While rigging Crackpot, a climb up was made into the rift leading two ways, the right to stalagmites and a crawl with roots on the left wall. An attempt was made to locate this potential entrance but the whistle blown in the cave could not be heard on the surface. Better location aids are needed (SubPhone and or radios).
   On Footleg's Therion drawing (August 2024) of the Hoyuca entrance series (which includes data up to 2013), there are a lot of question marks and possible links that could be looked at and pushed.

N O R T H W E S T   S E C T O R

San Antonio
   Fuente Aguanaz (0713) was the diving target of Jim and Mark who had to come out prior to the main expedition due to Jim's holiday rota. Their aim was to look at the final sump and adjacent boulder choke. This was reached and inspected but found to be impassable.
    However, on the way out, they discovered an inlet passage near sump 1 and so other diving projects were dropped when this new passage was found. Over 6 further trips, the team pushed and surveyed more than 500m of new passage. It started off in the main Aquanaz streamway, through boulders and gravel to reach several chambers, including Wobble Rock Chamber and some passages requiring crawling. Notable features included a rumbling slot, a narrow, tall passage needing opening up, and a chamber with a streamway sound. A walking-sized passage with a cobbled floor and a large chamber with a climb and a potential new route were also discovered. Water levels were high on one trip but lowered soon after.
    Over the next few trips these finds were surveyed, rock blockages removed, and the tight lead opened up. A 16m high aven was found and bolt climbed over two trips (bolts ran out on first). At the top, they encountered a stream passage in a large boulder choke and ascended into a large void. They bolted to the right-hand passage due to water flow. Beyond a narrow slot, they saw a solid passage ending at a blank wall, with a roof passage requiring 3-4 metres of bolting to gain access. They climbed a loose boulder ramp, reaching a caravan-sized boulder, but did not continue further due to the unstable choke. Another solid cave section requiring descent through an unstable choke was noted. More rigging will now be needed for further safe exploration next year.
    A planned push of shaft 5350 was foiled by aggressive vegetation.

Cobadal
   A lot of work took place in this area high up to the south of Cobadal via access from the Alisas - La Cavada road. The main activity was at cave 3685 where, over three trips, the entrance squeeze was opened up and work done to drop down into a second small chamber with a boulder roof. This will need scaffolding or similar to allow digging in a draughting, boulder floor where the way on is visible. The site was surveyed.
    The nearby shaft 3684 dropped into chamber followed by a shaft into choked chambers. All very spikey rock. The site was surveyed out and abandoned as having no serious prospects.
    A site in woods with a rock face and potential cave at the base was looked at. This seems to be part of a feature which probably includes 3687 and may be on a fault. Four new sites were located in the area. A shaft (5425) was descended part of the way down only and measured at 7.9m to a boulder floor. Three large, wooded depressions were noted all with little prospect but recorded (5426, 5427 and 5428) to avoid members rechecking them.

N O R T H E R N   S E C T O R

Quebraduras
   This wooded area to the east of Solórzano is difficult to prospect due to the undergrowth. The twin shafts (5411) found at Easter were pushed down both drops in the entrance depression. The pitch to the south dropped through a small slot into a constricted rift and a 4m pitch into a chamber. Several climbs in the chamber were looked at but were all very loose and no progress was made. The site was surveyed to 95m and the second drop laddered. A possible dig was noted after some exploration from the pitch base but it is likely to lead into the first cave, above the final chamber.
    Field Dig (5410) was dug a little to get a better view down the hole and it was measured at over 4m deep, but the view is still restricted. To gain entry a lot of soil would need removing and it would need work to make it animal proof. There is a small outward draught but it's not worth a dig being in a field. A look with an endoscope would be a good idea to check if it has any real prospect.
    Three new sites were identified. Sofa Hole (5439) was descended over a sofa to drainage pipes and a choke at 5m. Nothing Hole (5440) and Number Plate Hole (5441) were checked but they had few prospects.

Beranga
    The resurgence (4937) now called Nepa Hole due to the leaches present, was finally entered, pushed and surveyed over two trips after a 47 year delay since its first exploration in 1977.
    First the entrance below the tree stump had to be dug out and a boulder removed. The entrance crawl led to a small chamber with the stream flowing through. The stream contained water scorpions and leeches. The cave went upstream, through a small tube, past a column, and to a chamber after moving a few rocks. This chamber had a boulder choke that was the previous limit, being some 72m fromthe entrance. There were a few possible leads but only one went any distance.
    This was pushed with the blocks ahead taking a lot of work to pass. A small member of the team pushed through and, with working from both sides, the route was made passable for the whole team to crawl into a small chamber. This had a fairly strong draught coming from a sandy tube and that was followed to a boulder choke, at the end of a flat-out crawl. There is a draught here but digging will not be easy at this point. The cave was surveyed to 121m, of which 50m was completely new.
    The team also brought out a leech, in a specimen jar, for Terry to identify.

Summer expedition account by Phil Papard, 14th September 2024

Extras
   Trying to dive in Cueva Vallina puts a different slant on the weather. Rupert Skorupka wrote, "When I was there in July, on a trip when Pedro, Jim and Mark were giving me a chuck into Vallina, we had to stop at the Rio Rioja as the streamway was in flood. The water level remained high for 10 days, and there was another flood on my last day which caused the Ason to flow under the bridge above Coventosa - usually unheard of in the summer. During my August visit, the level had dropped but was still higher than normal. On my first dive through the downstream sumps, a wall of foggy vis was met coming in from Vallina 2, due to the receding flood from one week previous. The forecast was then for a big thunderstorm, which did not materialise thankfully, but in 10 days , there were 4 days with some rainfall. Normally in summer this would make no difference, but as the ground was saturated, any rain caused an effect in the cave streamway. Maybe I was just unlucky with my timing, Im hoping for bettter luck in October."
   For more than 4 decades, Pete Smith has housed the tackle belonging to the Matienzo Caves Project. Outside of expedition times (about 10 months of the year) he has given out and collected equipment from groups working within the permit. Without this facility, it's uncertain how cavers arriving outside the main expedition times would have had such easy access to the range of caving equipment. Our thanks must go to Pete for his staying power and the use of his ground floor! The tackle is now stored elsewhere behind a combination padlock.
   Steve Martin has resigned as Tackle Master. He's carried out this role since 2013 diligently working to ensure that Matienzo gear is looked after: organised, cleaned, collected and returned, audited and topped up as necessary throughout the year. With his caving contacts, he's been the recipient of a number of gifts of rope and other items, which have been put to good use within the expeditions. Thank you Steve!
   So we're looking for someone (or more than one person?) to take over the tackle master role, or parts of it.

New surveys and survey updates (in hand)
Description		Drawn survey	Survex centre line
0019	Loca 1	in hand (JC)	0019
0024	Cueva de la Puerta	complete (PS)	0024
0028	Selvijo with Loca 1 (above)	in hand (JC)	0028
0105	Riaño	in hand (JC>PF)	0105
0107	Hoyuca	Aug '24 version	0107
0415	415	in hand (CSF)	0415
0713	Aguanaz	in hand (PP)	0713
0733	Vallina	complete (JC)	0733
1261	Cueva del Alzado	complete (PS)	1261
2101	dig	complete (ND)	2101
2366	Torno - redraw	in hand (JC)	2366
3684	shaft	complete (ND)	3684
3685	cave	complete (ND)	3685
4937	Nepa Hole	complete (JC)	4937
5368	Vaca Bypass (in #1800)	complete (JC)	5368
5411	shafts (2)	complete (JC)	5411

The list below shows links to those 66 sites which were extended or newly discovered summer 2024 expedition, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned using a GPS.

Arredondo 0733 Vallina, Cueva;
Beranga 4937 Nepa Hole;
Cobadal 2071 dig; 3684 shaft; 3685 cave; 3687 dig; 5425 shaft; 5426 depression; 5427 depression; 5428 depression;
Cubija 0071 Mostajo, Torca del; 0076 Campo, Cuvia del; 0813 dig;
El Naso 0059 Molino, Cueva del; 0077 Rascavieja, Cueva de; 0248 Cuevona, La;
El Sedo 0011 Carrasquilla, Cueva de la; 0024 Puerta, Cueva de la; 0025 Risco, Sima-Cueva del; 1261 Alzado, Cueva del;
Fresnedo 2366 Torno, Cueva del;
Garzón 5150 Gusnardo, Cueva del (LC226);
Hornedo 5350 shaft;
La Secada 0081 Carcavuezo, Cueva de; 0415 cave; 1015 dig; 1016 dig; 1017 Socks; 2101 dig;
Las Calzadillas 2930 sink;
Mullir 0228 shaft; 1767 CM-7, Sima; 3600 shaft; 3601 shaft; 5429 Scabious Pot; 5430 Hazel Doline; 5431 shaft; 5432 Top Hole; 5433 Twin Holes; 5434 Bramble Hole; 5437 Vegetation Rift;
Ozana 0019 Loca 1, Cueva de la; 0020 Loca 2, Cueva de la; 5435 dig; 5436 rift;
Quebraduras 5410 Field dig; 5411 shafts (2); 5439 Sofa Hole; 5440 Nothing Hole; 5441 Number Plate Hole;
Riaño 0105 Riaño, Cueva de; 0107 Hoyuca, Cueva; 5368 Vaca Bypass;
S Vega 0036 Vera Negra, Torca de la; 0039 Coquisera, Cueva de; 0040 Comellantes, Cueva del; 0338 shaft; 5421 dig; 5422 shaft; 5423 dig; 5424 cave;
San Antonio 0713 Aguanaz, Fuente;
Secadura 0117 Boyones, Los; 3742 resurgence;
Trillos 5369 Tomb of the Oil King; 5438 cave;

summer logbook