Matienzo Caves Project 2017

News and cave exploration around Matienzo during 2017
A map with area names can be found here

   Dr Peter Wynn from Lancaster University is planning the 3rd International Cave Monitoring Workshop to take place around Matienzo 20th - 23rd April. The overall theme of the workshop will be to develop a series of best practice protocols for monitoring the hydrology and meteorology of cave systems. Specific topics will cover data logging and instrumentation, high resolution drip water sampling, in-situ water chemical analysis, in-situ precipitation of carbonate and cave surveying. There is a website and a first circular. Anyone interested in participating in the workshop should contact Peter.
   Guy Simonnot (Spéléo-Club Dijon) has contributed surveys for Hoyo de Rotura and Cueva del Mar (with a description).

January & February

   The end of January saw photos taken in Cueva del Mar (0004), Cueva-Cubío de la Reñada (0048), Cuvia del Campo (0076) and the entrance to Cueva de Bollón (Volvo, site 0098). The Cueva de Carcavuezo area was visited: a small whirlpool was seen as one of the sinks and, although the overflow channel and entrance were completely clear of branches, the route into the cave at the base of the entrance climb was found to be choked.
   In February, a team on a walk from Alisas down to the bottom of the TV mast track, via Trillos and La Rasa, relocated a number of holes and found some possibly new undescended shafts. (Sites 1677, 1108, 1077, 1081, 1083, 1096, 4502, 4503)
   Surveys from the Christmas 2016 explorations by Simon Cornhill and Diane Arthurs in Torca de la Espina (0128) and Sprog on a Rock (0710) along with Torca del Hombre (3115) from early 2014 are now online. Phil Papard has scrutinized the separate surveys for the four caves of the Cubija (North Vega) System and produced a combined survey showing over 22km of cave passage.

  The list below shows links to those 19 sites which were extended or newly discovered over January & February 2017, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned with a GPS.

Alisas 1677 cave;
Cobadal 710 Sprog on a Rock; 3115 Hombre, Torca del;
Cubija 71 Mostajo, Torca del; 76 Campo, Cuvia del; 243 Cubija, Cubío de; 774 Morenuca, Cueva de la; 892 Regaton, Torca del;
La Rasa 1108 Cable, Torca del; 4502 shaft; 4503 shaft;
La Secada 81 Carcavuezo, Cueva de; 98 Bollón, Cueva de;
Muela 128 Espina, Torca de la;
Ogarrio 4 Mar, Cueva del;
S Vega 48 Reñada, Cueva-Cubío de la;
Trillos 1077 dig; 1081 shaft; 1083 shaft;

Juan Corrin, January, February 2017


   This year, Easter corresponded to a dry, sunny and warm fortnight in Matienzo! This was a real bonus for campers and the Latimer's extended family who were erecting a new roof on their new holiday home acquisition in La Vega. Just under 3km of new cave was found and surveyed, mainly in Cueva Fresnedo II (0841), Cueva-Cubío del Llanío (3234) and Fuente Aguanaz (0713). Eighty-seven new caves/sites were located and just under 700m of resurvey work was completed, mainly in the South Vega System where there is little modern survey data.
   Two diving projects took place. Rupert Skorupka continued the re-lining and pushing of the downstream sumps in Cueva Vallina (0733), but was hampered by poor visibility at times due to tourist cave traffic in the main Rio Rioja stream stirring up sediment. Due to this problem, the pushing of the dry passages above sump 6 was not pursued but will continue later in the year when diving is not taking place. The team of Jim Lister and Dan Hibberts worked in Invisible Cave (3283) where a short extension was abandoned as it was found to be both polluted and significantly silted up. The divers turned to the adjacent Fuente Aguanaz (0713) where they found a major extension beyond sump 1. One of the key primary objectives completed this Easter was to continue with the "Alto Asón" water tracing exercise. One key test was completed from El Cubillón (2538) with a positive test to Fuente Aguanaz (0713). This, and the new passage found in Aguanaz demonstrates the very large potential for this cave system.
   During the expedition, an International Cave Monitoring Workshop took place in Matienzo organised by Dr Peter Wynn of Lancaster University. Dr Wynn has had two PhD students working in our area at Cueva de Asiul (0061) and Cueva de las Perlas (0074). Paleoclimate records have been established, from selected stalagmites and cave monitoring, for key periods of human history including 40,000 years ago, when Homo Neanderthalensis disappeared. Andy Quin managed the logistics of the workshop greatly helped by the mayor of Matienzo and the loan of the old school building for the meetings. Various field excursions were made and members of the Matienzo Expedition helped out on some of these. The workshop attracted academics from institutions across Europe and as far away as the USA and SE Asia, and will have helped strengthen the knowledge of both Matienzo and the Alto Asón area as one of the key karst areas for such study.

Southern Sector
   At Cueva Vallina (0733), Rupert continued his diving work and all the sumps up to sump 6 were checked. It was found that the re-lining carried out last year was in good condition. However, the old line in sump 6 was found not to be in the best place and needed a new line placing. This was done up to the main inlet and connection with the dry extensions. However, what should have been some of the best visibility available due to the exceptional dry weather was ruined by silt from the Rio Rioja steamway caused by tourist cavers going to Vallina II as well as, to a lesser extent, Matienzo cavers travelling to the extension above the sumps. We stopped our work in the extensions to allow the water to clear, and the tourist caving group were also asked not to go into the steamway. However, some of the tourist group did not follow our request and made more trips, but did later agree to stop. It was noted in Reñada on a trip to sump 1 that, although the water in the main steam when first met was clear at the sump, cloudy water from Vallina was just beginning to come through. This issue caused a delay in the work and prevented a push beyond the inlet in sump 6. Gear was stored for a push later in the year. Only one trip went to the dry passages above sump 6 to begin to bolt across the traverse above the start of sump 6. More bolts are needed to complete this traverse.
   In Cueva-Cubío de la Reñada (0048), the lower passages of the South Vega System, the end of the route found last year at the west side of Stuffed Monk Passage was pushed over a traverse into 55m of new passage - side passages are still to be surveyed and pushed. In the Stuffed Monk area over 500m was re-surveyed as part of the South Vega System re-survey project. The possible by-pass to Sump 1 was dug to a small extension and surveyed (47m of new and previously unsurveyed passage) but the digging was difficult due to the very sticky clay needing each spade load to be pulled or scraped off. The passage is seen continuing low over the fill, but a lot of digging is needed. This site is worth a dig (tray left in) and a check should be made in good draughting weather. A high-level lead in the entrance series was investigated via a rigid extension ladder and bolting, but no significant passage was found. As part of the International Cave Monitoring Workshop members of the expedition took three delegates to Stuffed Monk Passage and Anastomoses Hall to look at cave geomorphology under Prof John Gunn's expert tuition.
   In South Vega, two new caves were found and pushed to chokes (4504 and 4506). The latter lies over the entrance passage in Reñada. Three undescended shafts (4508, 4509 and 4510) were located. A new small bedding cave (4519) was found draughting. The entrance needs digging out but it is possible to see on for about 5m. Eight known sites were checked out, five were found to be choked shafts (2260, 4199, 4167, 4197 and 4198). The first two were choked. Two - 1858 and 0853 - need more work (digging and a further drop to rig) to progress and one (1441) could not be found.
   At Seldesuto, the rock blocking the entrance to Torcón de la Calleja Rebollo (Toad in the Hole, site 0258) was removed. The draughting Root Tube Cave (4520) was extended by digging but more easy digging is needed. Nearby, a new site (4521) was found where rocks rattle down through boulders, but the site was not dug. Sites 1565 and 1566 could not be found, possibly due to location errors and site 1862 was found to have lots of dead animals dumped in it. Torca de Corcada (0780) was located and found to be still open and draughting.
   At Alisas, site 4364 was pushed 7m to a choked chamber; 4365 was found to 8m deep to a dig in boulders and site 1075 was pushed 25m to a choke. At Las Calzadillas a new hole (4511) was pushed 5m down a slope to a dig needing snappers. A nearby shaft (3638) was re-visited and pushed with the view to a possible connection with Toad in the Hole (0258) but, although a draughting small lead requiring opening up for at least 3m was found, no connection was made. The site needs a resurvey.
   Two known sites were visited on the slopes of North Vega: Cueva de Acebo (0433) was capped to get around a corner, but it was found too small beyond and site 0434 was re-surveyed to 143 m (an extra 68 m) but needs snappers to make more progress. A small resurgence (4590) was noted 150 SE of Fuente de las Colmenas (0363).
   On El Naso, the re-survey work at 415 continued, including dropping a pitch, but it was not clear whether it had been pushed previously. Work will continue on this project. Four new sites were located: 4505, 4512, 4513 and 4514. All need more work (descending and digging) to progress. Known sites 3138 and 2379 were pushed to chokes with little prospects. Sites 4022 and 2377 were found and pushed, but need capping to progress. Site 2375 was dropped 15m in two pitches to a choke with an aven above. Site 0496 was noted to have a warm draught indicating a likely near-by source.
   As part of the International Cave Monitoring Workshop, the traverse from Cueva Oñite (0027) to the Toca del Sedo entrance of the Sistema del Risco (0025) was made, again looking at cave geomorphology with Prof John Gunn.

The North-East Sector including The Four Valleys System
    In La Secada, despite flooding since last summer, the entrance to Cueva de Carcavuezo (0081) was found to be open and accessible for the summer expedition. In the area to the north and east of the "Mushroom Field" a number of sites were checked out and located with GPS as many old positions were estimated from maps, including sites 0869, 0870 and 0880. Sites 2709 and 1552 were located and confirmed they are not the same - new GPS readings were taken and both are worth a closer look and push. Site 1553 was GPS'ed but the old location was found to be correct. Site 0260 was re-explored - but this area needs looking at again in some detail. Nearby site 0252 was opened up and descended but needs capping to make progress - it draughts well. Five new sites were located: 4522 - 3m deep that could be dug; 4532 - a draughting hole that could be dug; 4507 - a 2m deep with no way on; Badger Hole (4535) - an old short remnant 4m deep with a fill floor and Two Way Cave (4534). This is an old remnant going both ways from a skylight entrance. It was surveyed to 26m with an easy dig in a side passage heading to the north which needs checking out in good draughting weather. The entrance to sites Cueva Seta (0093) and the nearby 1744 could not be found. They seem to have been filled in as the location should have been accurate given the nearby barn that is clearly marked on the map.
   Near the far end of Fresnedo II (0841) three pushing trips were made to the Block Chamber and the Rio Lastras Inlet area via The Howling. This required use of a scaling pole to get up a waterfall in poor rock. In total, 628m of important new passage was found in this area.
    A 13-year-old boy from Fresnedo told us about a "through-the-hill" cave he knew about. A meeting was arranged - and it turned out to be Cueva Fresnedo I (0126).
   In Cueva-Cubío del Llanío (3234), the Mitre Passage area was pushed in dry conditions - much better than last year. This resulted in a major breakthrough with 1056m of new passage found with leads still left to be examined. The Mulu Manners tunnel heads towards the passages to the west of the Road to Torno in Cueva de Riaño (0105)and, at the closest point, is about 100m away. At the start of this key extension, passages to the SW entered an area with tree roots and what appeared to be a small draughting hole near the surface. Ron Taylor's "Subphones" were used to locate this point and the depth was estimated to be about 6m to the floor at the molephone station, indicating that approximately 4 to 4.5m of digging was needed to the highest point seen in the cave. As the trip to this point is awkward and takes some 1.5 hours, a dig was started (site 4536 - Subphone Dig) and it is now a little over 2m deep following a channel in limestone which then dips vertically down forming walls on about a third of the dig, with clay/sandy fill forming the rest. A 1m drill inserted in the base seemed to hit either loose fill or a part void about 60cm down. This site will be dug in the summer and if successful will give a better entrance to this key extension and help to get a link to the Four Valleys System to bring it to well over 60km.
   Work continued to make the Giant Panda entrance (2691) to Cueva Hoyuca (0107) safe following the rock fall at the first pitch two winters ago and following the work done last summer. However, on close inspection, it was decided that, although the pitch top could be cleared, it looked quite possible that removing the large block adjacent to the rope hang could undermine the massive boulder that had moved down in the original collapse. To avoid working in this area it was realised that, at the bottom of the entrance, an easy dig would gain the pitch away from this boulder and would probably give safe access. Work was started to open up this dig and in doing so the original way down was blocked. So, for now, this entrance is not possible. In the summer, more work will be done on this new access route.
   In the Riaño area, five new sites were located: 4515 - 7m deep to dig; 4516 - 5m to a choke; 4517 - needing snappers to get down a shaft and 4541 and 4542 were found but not descended. Cueva Shelob (4173) was dug with an ongoing passage needing digging to get along a visible but small passage. On drawing up the extension in Cueva-Cubío del Llanío (3234) it is clear that it runs very close to Cueva Shelob and a connection seems possible. Site 4172 was pushed to 7m deep and 12m long but, with no draught, it was thought not to be a good prospect for more work.
   Fridge Door Cave (1800) was looked at but, despite the dry weather, it was flooded below the entrance pitch and so diving was left for the summer when water levels may be lower.

Solórzano and the Riolastras Area
No activity took place over Easter. Work to complete the survey in Cueva del Arroyo de Canastrillas (4046) and push the passage beyond the sump in Cueva de Lolo (del Secretario - 3991 was left for the summer expedition.

Northwest Sector
   As part of the water tracing work, 3 litres of optical brightening agent (OBA) were placed in the steamway at the downstream sump in El Cubillon (2538) on the 23rd April, with detectors downstream of the resurgences of Cave of the Wild Mare (0767), Fuente Aguanaz (0713) and La Riega (0551), the resurgence for the water in Cueva la Verde (4486). On 1st May (and subsequently) the detector at Fuente Aguanaz was positive. The other two sites were negative and remained negative when tested in the following weeks.
   At Hornedo, there was only one trip into Torca la Vaca (2889) via BigMat Calf Hole (3916), to the Mard Arse area. In the event, route finding was a problem and pushing was incomplete. Two new sites were located (4583 and 4584) and pushed to where digging is required. Site 3010 was found to be a 1.5m drop into a rift blocked at both ends.
   When looking for Cueva de Collada (0394) in La Gatuna, a new site, Eastwater Entrance (4537) was found that was explored down between boulders and into Cueva de Collada giving a much better entrance and an extra 49m of passage. This should help pushing this site which seems to be the origin of the Suit Wrecker Inlet and Friday the 13th Passage in the far SE of Torca la Vaca (2889).
   In San Antonio, Dan Hibberts and Jim Lister started diving work at Invisible Cave (3283) reaching sump 9 where gravel had to be dug out under water to allow access for further pushing. On the next trip, the sump was found to be closing down and the water smelt polluted. As both divers felt ill that evening pollution seemed to be confirmed. Attention was then diverted to Fuente Aguanaz (0713). This proved to be extremely profitable as, on the first of three trips past sump 1, an inlet was entered and followed for a considerable distance before reaching a sump. This short sump was dived on a second trip to more passage and a boulder choke where a hole could be looked through into what looked like a higher large passage, but this needed a lump hammer to remove rock to enter. The passage was surveyed for 770m up to the sump on a third trip, but there was no time to push further at Easter and work will continue in the summer.
   Seven new sites were located: a sink to the north of the main road (4565); a 3.5m deep shaft to a small chamber (4566); an undescended 3m shaft needing work to enter (4567); a small cave blocked by silt (4568); a 10m long rift ending in a choke (4569); a draughting blocked shaft that needs digging (4570) and a 3m shaft to sediment fill (4571). Site 3027 was dug and pushed to 12m with more work needed.
   At Garzón, Pipe Cave (4050) was pushed and surveyed to 140m of which 32m was new. Signs of flooding were noted.
   A lot of prospecting work took place at Composdelante, with 35 new sites located (4543 to 4564 (see list below for the links), 4573, 4574, 4577, 4578, 4579, 4580, 4581, 4582, 4585, 4586, 4587, 4588, 4589 and 4592). Just under half of them have some digging potential and 3 shafts were undescended needing work to enter. Of note were 4549 - pushed to 22m deep to a choke; 4553 - pushed to 21m deep to a dig; 4558 - explored to a shaft and tight squeeze with a further shaft and climb to a choke and 4573 - climbed down in a rift to a mud floor and on for 15m to a choke with a draught. Work to open or dig a number of these sites will continue. Dos Perros (2988) was checked and the sump level was found to have dropped to a pool with a passage continuing, but was too narrow to follow.
   In the hill behind the Church at Navajeda, two new sites were found: 4576 - a 3m long tube needing digging to make progress, and site 4575 - a 3m long cave to a dig with the passage continuing. Cueva de la Iglesia IV, as 4575 was later called, was dug over a few days and pushed into a complex area of phreatic eroded chambers with good formations, this was surveyed to 78m and photographed. Unlike the other "Church Caves" this did not seem to have any archaeological significance due, we assume, to the small entrance that needed digging and the use of snappers to enter!
   The following work was carried out in agreement with the Spanish club G. E. Pistruellos.
   In El Cubillón (2538) at Moncobe, the second pitch was re-rigged to remove a rub point and OBA was placed in the sump - later detected at Fuente Aguanaz, as discussed above. A lot of prospecting took place this Easter with 12 new sites located, of these five (4528, 4529, 4530, 4538 and 4539) require digging to gain significant cave; two (4524 and 4533) were pushed to fill blockage with no draught and no real prospect and two are undescended shafts (4526 and 4527). A lot of work went into pushing the new site 4525 including opening up a pitch to a chamber and then capping a draughting rift and surveying the find. But more work is needed and leads remain. Site 3669 was pushed 8m and is now 7m deep to a dig. Four days were spent digging in 4474 where two of three draughting leads were pushed after opening up the entrance pitch to get better access. One led to a further pitch (still to be pushed) and the second to a crawl which, after removal of an obstructing flake, led to more chambers and large passages ending in tight sections. Part of the cave was surveyed but more work and pushing is needed.
    At Ideopuerta, Torca de Hoyo Carabo (Washing Machine Hole, 3420) was opened up over two trips with a lot of digging to remove flood debris. The pitch needed some re-rigging and replacement of the rope. A traverse across the pitch to check the passage on far side was made, but no onward lead or further pitch found. The bottom of the cave still needs to be pushed but it requires two thin cavers to push safely. Four sites were checked out for future work: 3692 and 4483 are worth digging; 3655 was pushed through a tight section into a choked chamber and was not thought to be worth any more work. Although site 3693 draughts well, no way on could be found.
Visiting Revilla on a day off, a 4m long draughting cave to a choke was found in the left bank of the river. This site is out of our area of interest and the information (along with the finds in Moncobe and Ideopuerta) will be passed on to the G.E. Pistruellos club.

Easter expedition article by Phil Papard.

Survey updates
0048 Reñada complete (JC)
0394/4537 Collada new entrance complete (JC)
0434 cave complete (DB)
0713 Fuente Aguanaz complete (PP)
0733 Vallina complete (JC)
0841 Fresnedo 2 complete (JC)
2889 Torca la Vaca complete (JC) (use Chrome)
3234 Llanío (Cold Store) complete (JC)
4050 Pipe Cave complete plan elevation (PG)
4474 cave ?? in hand (AL??)
4506 cave complete (JC)
4525 cave ?? in hand (AL??)
4534 Two-way Cave complete (PP)
4575 Iglesia 4 complete (PP)

   The list below shows links to those 171 sites which were extended or newly discovered over April & May 2017, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned with a GPS.

Alisas 1075 shaft;
Arredondo 733 Vallina, Cueva;
Barrio de Arriba 4587 shaft; 4588 shaft; 4589 cave;
Bustablado 4364 shaft; 4365 shaft;
Camposdelante 2988 Dos Perros; 4543 cave; 4544 shaft; 4545 cave; 4546 cave; 4547 shaft; 4548 dig; 4549 shaft; 4550 shaft; 4551 shaft; 4552 cave; 4553 shaft; 4554 cave; 4555 shaft; 4556 cave; 4557 cave; 4558 shaft; 4559 shaft; 4560 shaft; 4561 shaft; 4562 shaft; 4563 shaft; 4564 shaft; 4573 rift; 4574 cave; 4577 cave; 4578 shaft; 4579 cave; 4580 shaft; 4581 cave; 4582 shaft; 4585 rift; 4586 cave; 4592 rift;
Cobadal 618 Orchard Cave;
El Naso 61 Asiul, Cueva de; 74 Perlas, Cueva de las; 496 Casasierra, Cubío de la; 1235 Roja, Cueva; 2375 shaft; 2377 shaft; 2379 shaft; 3138 shaft; 4022 shaft; 4505 shaft; 4512 cave; 4513 cave; 4514 hole;
El Sedo 25 Risco, Sima-Cueva del;
Fresnedo 126 Fresnedo 1, Cueva; 841 Fresnedo 2, Cueva;
Garzón, Solórzano 4050 Pipe Cave;
Hornedo 767 Wild Mare, Cave of the; 2889 Vaca, Torca La; 3010 cave; 3261 shaft & cave; 3282 resurgence; 4583 cave; 4584 cave;
Ideopuerta 3420 Hoyo Carabo, Torca de; 3692 dig;
La Cavada 551 Riega, La;
La Gatuna 394 Collada, Cueva de; 4537 Cueva Collada (entrada 2);
La Rasa 1096 cave;
La Secada 93 Seta, Cueva; 252 cave; 260 shaft; 415 cave; 869 cave; 870 shaft; 880 dig; 1552 dig; 1553 shaft; 1744 cave; 2709 shaft; 4507 shaft; 4522 dig; 4532 dig; 4534 Two-way Cave; 4535 Badger Hole;
Las Calzadillas 3638 shaft; 4511 cave; 4572 cave;
Moncobe 2538 Cubillón, El; 3655 shaft; 3669 caves; 3693 cave; 4474 shaft; 4483 dig; 4523 shaft; 4524 shaft; 4525 shaft; 4526 shaft; 4527 hole; 4528 cave; 4529 cave; 4530 dig; 4531 collapse; 4533 shaft; 4538 cave; 4539 sink;
N Vega 433 Acebo, Cueva de; 434 cave; 4590 resurgence; 4591 dig;
Navajeda 4420 Iglesia 2, Cueva de la; 4575 Iglesia 4, Cueva de la; 4576 cave;
Ozana 17 Jivero 2, Cueva de; 27 Oñite, Cueva; 376 cave;
Riaño 255 Via, Fuente de la; 2691 Giant Panda entrance; 3234 Llanío, Cueva-Cubío del; 4173 Shelob, Cueva; 4174 shaft; 4515 shaft; 4516 shaft; 4517 shaft; 4518 caves; 4536 Sub-phone dig; 4541 dig; 4542 shaft;
S Vega 48 Reñada, Cueva-Cubío de la; 331 shaft; 333 Azpilicueta, Torca de; 339 shaft; 407 cave; 675 shaft; 853 shaft; 1253 Dead Fox Passage; 1441 shaft; 1858 cave; 2260 shaft; 4167 shaft; 4197 shaft; 4198 hole; 4199 shaft; 4221 Reñada, Cueva-Cubío de la (top entrance); 4504 cave; 4506 cave; 4508 shaft; 4509 shaft; 4510 shaft; 4519 cave;
San Antonio 713 Aguanaz, Fuente; 3027 cave; 3283 Invisible Cave; 4565 sink; 4566 shaft; 4567 shaft; 4568 cave; 4569 rift; 4570 shaft; 4571 shaft;
Seldesuto 258 Calleja Rebollo, Torcón de la; 780 Corcada, Torca de; 1310 resurgence; 1565 dig; 1566 dig; 1862 cave; 4520 Root Tube Cave; 4521 dig;

Additional news
The document outlining water tracing work around the area (since the 1960s) has been updated to June 2017 and supplemented with a map showing the successful traces.


   The weather was somewhat mixed and not as good as at Easter, but water levels were fairly low and so did not hamper exploration. Over 40 people were out over the main summer period when over 3km of new cave passage was surveyed and just under 1km resurveyed. Most resurveying was in the Four Valleys System.
  Thirteen new sites were found and almost 150 visits made to caves and digs in our area, with some good progress made at some important digs. These included a strongly draughting dig at Seldesuto (1298) that is located just to the east of the present end of the South Vega System. It was opened up using over 1000 caps and almost reached a 10m draughting drop needing more work to gain access.

More key events this summer included
- Connecting and completing the installation of the new entrance (Subphone Entrance, site 4536) to Cueva-Cubío del Llanío (3234) with the dig hitting the exact point as predicted by Ron Taylor's SubPhone location at Easter. Using this entrance, over 1km of big passage was explored which runs over Cueva de Riaño (0105) and was left with an open draughting lead that should give the expected link.
- A sump at the end of SW Passage in Cueva de Carcavuezo (0081) was dived into the connection route between Cueva Llueva (0114) and Cueva Hoyuca (0107) and was found to be free diveable. The route from here to Hoyuca is reasonably safe and open, although still tight and a boulder needs propping up.
- In Cueva Vallina (0733) just under 100m of passage was found off the main "trade route" near the start of Avinguda de la Sorra. A diving team (Jim Lister, Ashley Hiscock and Mark "Killer" Smith) worked on upstream Rio Rioja, finding sump 2 closing down in gravel. Sump 3 was pushed to an extensive dry area with 400m of passage heading NE away from the known cave into chambers with lots of leads left for 2018. Meanwhile Rupert Skorupka continued diving in the main downstream sump series with work continuing this autumn.
- Over a third of a km was added to Cueva de Fresnedo II (0841) with leads still left.
- In Cueva de Suviejo (0122), the passage found some years ago heading north was pushed for a third of a km and reached large passage - this passage is heading towards Fresnedo II but still a long way off.
- The underground survey work for site 415 was completed, but the link to Mostajo and Volvo remains elusive.
- The Dingle's new house roof was tiled and shown to be water proof!

Southern Sector
   At Cueva Vallina (0733), the main activity was diving in the downstream sumps that connect hydraulically to Reñada, and in the Rio Rioja upstream sumps that head north and east. In addition, on a carrying trip, an 86m side passage, Galería Jesús Lecue, was found and later pushed and surveyed. This passage was named after a good Spanish friend of the expedition: his funeral took place the same day. This passage goes off near the junction of Avinguda de la Sorra (the sandy passage that leads to Swirl Chamber and Double Dutch pitches area) and shows that, despite many trips through this area, there are still finds to be made near the trade routes.
    Rupert progressed the re-lining of downstream sump 6, getting the gear ready for a push in October when a rebreather will be used. He also resurveyed sump 6A (to the big inlet), clearing up errors in the old survey.
    Jim Lister, Mark Smith and Ashley Hiscock worked in the main upstream Rio Rioja sumps. The main objective was to push sump 2a past where Jim got to last year, but Ash found it was blocked with gravel only a few metres further on. As a lot of work took place preparing for this dive it was decided to look at sump 3 - thought to be a dead end. However, Jim found that the sump turned up and back (not obvious) and it was then pushed through sumps 3 to 5 to an extensive area of dry passages heading NE into the unknown in the direction of Cueva de los Cantones (0865). Some 400m were surveyed leaving open leads for pushing in 2018. "Vallina 3" is a very important find as it opens a new area that was previously barren of cave passages.
    A test of the Subphones was carried out in Vallina at the start of the Road to Glory where Clapham Bypass meets it. This is an important spot as Torca de Rotura (0753) is above this point and some years ago a mass of blow flies were found here suggesting a fairly open link to the surface. Unfortunately, the test was hampered by very heavy rain and thunder (better to be underground!) but showed the revised location on the 2017 map (due to better fixing of the bottom entrance) is more accurate. A re-test in better weather is needed to fix it accurately. The depth reached was approximately 120m and demonstrated the usefulness of the system. Some refinements will be made to the SubPhones over the winter and they should be fully operational for next year - a very important asset for the expedition with respect to both exploration and safety.
    In the Arredondo area, some sites were checked out for possible links to Vallina and work in further years depending on our permit area and extent.
   At Cueva del Comellantes (0040), Ash dived in poor visibility to try and identify the way on in the main water, running lines along both walls at different heights but no further passages were found. This site needs good visibility for future worthwhile diving attempts, as it seems to be unpredictable as to when the site has good visibility. It will be worthwhile to keep a check on the site when we have diving teams in the area.
    In Cueva-Cubío de la Reñada (0048) a few trips were made to familiarise newer members of the expedition with the cave and possible leads for 2018, but no further surveying work was carried out this summer.
    Both Dairy Dig (1189) and Dead Fox Passage dig (1253) were checked out, but a major collapse had occurred in the former and the latter's draught seemed to have changed and the dig needs a lot of work. Both sites were left for work in future years.
    At Seldesuto, the area at the top of the track where it turns east into the field was looked at in some detail. The old dig, 1298, previously excavated with the help of the Espeleo Club Tortosa, was opened up. Over 10 days, and using more than 1000 caps, the small, strongly draughting crack was excavated following the draught and its "river-like" sound. The dig has now reached a wider area with boulders with the draught coming up a drop of up to 10m that will need some work to remove the rocks. It looks big enough to make good progress.
   A previously undocumented small resurgence (4593) was found.
    A lot of holes in this area (including site 0879) were checked out using an infra red camera and it is clear, due to the number of draughting holes, there must be a significant development in this area.
    The old Derbyshire Caving Club site (3318) was opened up and dug, but more work is needed. A new draughting hole/dig (4600) further up the streambed from 1298 was found. This is important as this area is just to the west of the far reaches of Cueva-Cubío de la Reñada and the fault that seems to hinder exploration. There is a considerable area between here and Torca de Hoyón (0567) and Vallina for a major cave system so it will be a key priority for 2018.
    Over 4 trips in Cueva del Arenal (0035) the Foam Dome and the lower boulder/flood-stream area were thoroughly checked out and some 99m of new survey in the lower area completed. No good leads or digs were found in the far west reaches of the cave.
    Torca de Corcada (0780) was pushed by English/Spanish/ French teams, with chocolate cake and tea at the adjacent Robert and Alison's house following the trip. The French team pushed and removed rock in the active passage round several tight corners to the head of a tight pitch needing more work to descend. In the fossil route, the English and Spanish team checked out the end dig and confirmed it will cap out easily. However, the rigging for SRT needs to be sorted out and made safe prior to this.
   In North Vega, Cueva del Bosque (0373) was pushed down a pitch to a chamber with possible ways on. These will be looked at and pushed in 2018.
    In Cubija, Sima de los Hoyos (0072) was visited to take photos of the bear skeleton. The lower entrance digs (3802 & 0813) to Torca del Mostajo were checked out but found to need a lot of clearing of vegetation before any work can be done. In Torca del Mostajo (0071) the end of Wonderland was checked out. However, there was no draught and the suggested (on the survey) dig into upper passages was not promising and not considered worthwhile as it would need a lot of capping. The top of the Golden Void pitch was found to need re-bolting on the next trip as only one bolt was usable. Just past the sandy crawls in the top passage 55m of new passage was surveyed in Sheppard's Bush.
    The entrance to the 1985 extensions in Cueva de Rascavieja (0077) were capped out to make access easier and a guide line put through part of the choke. A new pitch was found at the west end of the second chamber. Rascavieja is a key site given the draught and the large passage that may be associated with the top level in Torca del Mostajo.
    The cave 0387 on El Naso was checked out but the reported draught was not found.
    In Ozana the Jivero caves (0016, 0017, 0018) were visited and native crayfish were spotted, despite the signal crayfish seen on a previous visit.
    Two trips to show new members the area were made in Sima-Cueva del Risco (0025) and Cueva del Molino (0059).
    The resurvey work in 415 was completed with just over 100m added to the previous length. Unfortunately, no good leads were found that could link to the adjacent caves.

The North-East Sector including The Four Valleys System
    In Cueva de Carcavuezo (0081) five trips were made to continue the re-survey work needed for Footleg's Therion survey of the Sistema de Cuatro Valles, with over 1km surveyed. With a re-calculated length of 59101m, just over 500m of the one kilometre surveyed was new and is recorded in the table of finds. An important aim was to check out the end of Strangle W Passage and the possible sump. It was found not to be free diveable but on the next trip it was dived with gear and the 5 - 6m sump then rigged for free diving. This dive emerges in the connection passage to Cueva Hoyuca (0107) and will give a quicker route to this area of the cave. Although open, one boulder needs supporting and it may be possible to enlarge some of the tight sections.
   Elsewhere in La Secada, a few sites were looked at and some dug. At Cueva de los Tres Niños (0565) a high-level passage was checked out but closed down after 30m. At Handy-for-the-Bar Pot, site 0603, the route was pushed to a good draughting dig and the site surveyed to 25m. Subsequent trips opened up the tight sections and secured loose areas with scaffolding, allowing further work to safely take place in 2018. At Torca de JR (0366), over the course of three trips with capping and jack hammering, the cave was pushed and surveyed to 25m. It now needs much more work to progress and other sites in area should be looked at first. Other sites checked out included 1553 and 1552 that were found to be poor prospects; 2709 descended to 2.5m with no real further prospect; a new site 4595 was found, but thought to be a poor dig; a new draughting site 4594 that was dug to 2.26m deep but needs a lot more work. Cave 4180 was surveyed and two bats noted in the cave. Dig 1018 was noted as having a very strong draught. Eight further dig sites in the same area were GPSed (4596, 4597, 4598, 4599, 4601, 4602, 4603 and 4604), with the first three excavated enough to show some prospect and all having a draught. Cueva las Cosas (0084) was visited and re-surveyed but no digging prospects were found. The resurgence 4238 was checked out and, what appeared to be a wall built to close off the cave, was found to be at least 2m of solid fill. As there was no draught on this occasion no significant digging was attempted - it needs checking out again on a good draughting day. The dig "Socks" (1017) was pushed at the base of the shaft to 11.5m where capping is needed to make progress along the draughting route.
    In Cueva Fresnedo II (0841) two trips were made to the Coyote Inlet area where the waterfall (Pepé la Puits) was climbed and upper and lower passages pushed with open leads left for another year. New passage was surveyed for 366m.
    After a gap of many years the open lead (Croissant Passage) found in Cueva de Suviejo (0122) was visited and 330m of new passage surveyed, ending in larger passage and some 500m short of Cueva Fresnedo II. Torca de Fanny (1211) in the Fresnedo area was visited with a view to pushing/digging, but was found to be full of rotting matter and plastic sacks. Apart from the health risk, this would need a lot of work to open up.
    Around Riaño the main and extensive activity was at Subphone Entrance (4536) where, following on from the Easter excavations, a further six digging trips joined this site with Cueva-Cubío del Llanío (3234) giving the needed easier access to the far end of the system. More visits opened up the tight section in the shaft and installed an 800mm diameter tube with lid and access steps to make the entrance secure and safe. Using this entrance three pushing trips were made in Cueva-Cubio del Llanío where large fossil passages and chambers were followed for over 1km, all with a good draught. These passages run above and over the Road to Torno area in Cueva de Riaño (0105) and it is possible that they are related to the high levels that lead off from Pendant Chamber. An open, draughting lead was left to be pushed in early 2018. If, as seems likely, the link is made, it will make the Four Valleys System over 65km long and, if Cueva del Torno (2366) can be linked, it will be over 70km! (YouTube video here.)
    Above the Four Valley System, Chestnut Hole (0102) was re-surveyed and examined to see whether it could be a better entrance to the system than the Giant Panda Entrance (2691) but it became clear that the low and very wet crawl at the bottom would not be a good way in if it could be connected. In the same area Trackside Pot (4517) was snappered open to allow the 18m pitch to be descended, but it was small at the bottom with no draught and no prospect.
    At Fridge Door Cave (1800) the water level below the entrance was low and allowed access to the dive and the far end for Jim Lister. The constriction found previously was capped and a 1.5m wide and 2.5m high steamway was followed for some 31m to a further clear duck/sump. This passage and sump will be pushed and surveyed in 2018.
    With the extensive work at Subphone Entrance, the work planned at Giant Panda Entrance (2691) was not carried out and the entrance remains closed. However, the 6m long tube obtained for the Subphone entrance was cut in two, and the remaining section will be used in the entrance of Giant Panda and should be a relatively easy approach compared to other ways to stabilise the excavated entrance shaft.

North Sector including Solórzano and the Riolastras Area
   At Torca de Canastrillas (4407) more slippage had taken place and it now needs more extensive boarding and scaffolding to make progress.
   Three trips were made into Torca la Vaca (2889) via BigMat Calf Hole (3916) in order to push possible leads in the Frizzington Extension and Mad Arse areas, where in total 260m of new cave were surveyed.
   In the San Antonio area, the far upstream end of Fuente Aguanaz (0713) was checked out to see if the main sump had been missed. The assumed sumped passage shown on the survey prior to the end proved to be correct and it seems all the water does come from the final tight and sharp sump. The best prospect at this end may be by digging above the final sump, but a few people are needed to make the trip realistic. The main find from Easter was not pushed and will be left for Easter 2018.
   The new Eastwater Entrance (4537) to Cueva de Collada (0394) was enlarged to make access easier and was used to push possible leads. Two were examined and found to link back to known passages. More work is needed in this site with a view to progressing in the direction of Torca la Vaca.
   YoYo Cave (Cueva de los Campizos, 3812) was pushed at the bottom but nothing of note found and the cave was de-rigged.

Looking ahead
   Two teams which had been out in previous summers will be out in October this year and will be working mainly in the North Sector (hence the lower level of exploration here during the summer this year).
   Also in October, we expect a team to be working in the downstream sumps in Vallina (0733).
    Early in 2018 and prior to Easter, a small team will visit Cueva-Cubío del Llanío (3234) to push the passages towards Cueva de Riaño (0105).
    With the change in the leadership of the Federación Cántabra de Espeleología there will be a review of allocated areas for 2018. A meeting was held with one of the members and it seems that we have an opportunity to refine our area in order to better align it with the extent of the main cave systems which we are working on.

Summer expedition article by Phil Papard

Survey updates
0035 Arenal addition complete (JC)
0071 Mostajo addition in hand (PP)
0084 Cosas in hand (RBu)
0102 Chestnut complete (JC)
0122 Suviejo complete (JC)
0366 Torca JR complete (JC)
0394/4537 Collada complete (JC)
0415 Cueva 415 in hand (CSF)
0603 shaft / dig (interim) complete (JC)
0733 Vallina complete (JC)
0841 Fresnedo 2 complete (JC)
1189 Dairy dig complete (RBu)
1294 Epiglottis (resurvey) in hand (PS)
1800 Fridge Cave (additional sketch) temporary (JL)
2889 Torca la Vaca complete (JC)
3234 Llanío & Subphone complete (JC)
3812 Yo-yo complete (JC)
4050 Pipe Cave (from Easter) plan & elevation (PG)
4180 cave complete (ND)

The list below shows links to those 75 sites which were extended or newly discovered over June - September 2017, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned with a GPS.

Arredondo 733 Vallina, Cueva; 1758 Orbitolines, Cueva de; 3271 Boueuse, Cueva;
Bustablado 4379 Laverón, Torca de; 4380 shaft;
Cubija 71 Mostajo, Torca del; 72 Hoyos, Sima de los; 813 dig; 892 Regaton, Torca del; 3802 dig;
El Naso 59 Molino, Cueva del; 77 Rascavieja, Cueva de; 387 cave; 1294 Epiglottis Cavern;
El Sedo 25 Risco, Sima-Cueva del;
Fresnedo 841 Fresnedo 2, Cueva; 1211 shaft;
Garzón, Solórzano 4050 Pipe Cave;
Hornedo 2889 Vaca, Torca La;
Ideopuerta 3812 Campizos, Cueva de los;
La Colina 382 Entrambascuetos, Sima de;
La Gatuna 394 Collada, Cueva de; 4537 Cueva Collada (entrada 2);
La Helguera 4407 Canastrillas, Torca de;
La Secada 81 Carcavuezo, Cueva de; 84 Cosas, Cueva las; 366 J.R., Torca de; 415 cave; 565 Tres Niños, Cueva de los; 603 shaft; 1017 dig; 1018 dig; 1552 dig; 1553 shaft; 1655 dig; 2709 shaft; 4180 cave; 4238 resurgence; 4594 dig; 4595 digs; 4596 dig; 4597 dig; 4598 dig; 4599 dig; 4601 dig; 4602 dig; 4603 dig; 4604 dig;
Llueva 114 Llueva, Cueva;
N Vega 373 Bosque, Cueva del;
Ozana 16 Jivero 1, Cueva de; 17 Jivero 2, Cueva de; 18 Jivero 3, Cueva de;
Riaño 102 Castañas, Cueva de la; 107 Hoyuca, Cueva; 383 Fuente de Escobar, La; 1800 Fridge Door Cave; 3234 Llanío, Cueva-Cubío del; 4517 shaft; 4536 Sub-phone entrance;
S Vega 40 Comellantes, Cueva del; 48 Reñada, Cueva-Cubío de la; 1189 Dairy Dig; 1253 Dead Fox Passage; 4593 resurgence;
San Antonio 713 Aguanaz, Fuente;
Secadura 122 Suviejo, Cueva de;
Seldesuto 35 Arenal, Cueva del; 780 Corcada, Torca de; 879 dig; 1298 dig; 1565 dig; 1566 dig; 3318 dig; 4600 dig;


   In October, preparations were made for pushing on in the downstream sump 6 in Cueva Vallina. Rupert Skorupka visited the cave 9 days in succession to take in a rebreather together with all the necessary components. In addition, several depleted cylinders were replaced. A window of perfect weather allowed this to-and-froing to take place without any risk of gear being washed away.
North Sector
    A 4-man team spent about 3 weeks at the end of September and into October mainly exploring around San Antonio and Moncobe.
At Moncobe, most time was spent in site 4474 where, over 5 trips, a bedding plane was excavated and pushed to a draughting continuation. A draughting rift in the roof also has some potential. All the leads in nearby site 4473 were found to choke but a draughting choke has spaces above and needs a return. Over the end of El Cubillón, dig 3901 was capped again but much more is required to open up the narrow shaft. To the northeast of El Cubillón, the shafts at site 4525 revealed about 30m of passage. Up the valley to the east, site 4483 was inspected and found not to warrant further work. Five new holes were documented: site 4639, an undescended 6m drop into a large chamber with possible leads; site 4640, a pair of strongly draughting slots into a narrow rift which may be passable with some effort; site 4641, another pair of draughting holes; site 4642, a hole down through boulders in a small shakehole and site 4643, a collapse at one end of a depression that appears to take water in wet weather. On the same trip, site 2545 was partially excavated to where it was possible to view an enlargement about 4m down the narrow rift.
   At San Antonio, site 3239 was inspected and thought to be a fairly easy, draughting dig. A dig in Cueva Laberinto (site 3268) was found to have slumped in but, after a few hours, was cleared to a small stand-up chamber with a draught.
   Over in Riaño, site 1318 - a shaft explored in 1998 - was found in the middle of a muddy motorway logging track with a similar undocumented shaft a few metres to the north.

    The last 2 weeks in October saw a team of four continuing work in the north and northwest of the permit area and at Las Calzadillas.
    An interesting area to the north of the Entrambasaguas-Riaño road at Hornedo was looked at. The main cave (3261) in the cliff was re-investigated with a dig at the base of the entrance slope enlarged and 15m of passage entered. This appeared to increase the draught in the nearby surface dig, 3915. The latter, very strongly draughting site, was excavated over 3 sessions and about 40m surveyed to a collapse zone. Nearby, site 4583 was found to be a 4m crawl and not worth returning to and site 4584, draughting inwards, was dug with difficulty to 12m length.
    A walk up the valley containing the sink 3010 revealed one small resurgence, site 4605. In an attempt to understand the hydrology of the area, OBA was put into 3010 and a detector in a resurgence, 3282. The trace was negative after 5 hours and, after 4 days, only some patches of colour where seen under UV light - an inconclusive result. Some water temperatures and water chemistry readings were taken at a number of sites.
    To the north of Torca la Vaca, on the opposite side of the river, site 3281 was re-explored and the dig excavated for a couple of metres to where more work is required. The nearby entrance - now given a number (4635) - was photographed.
   A cleared area to the west and south of Cueva de Regato (site 3494) was investigated. Sites 4615, 4616 and 4619 are shallow rifts while 5 holes were left undescended for future exploration: 4617, about 5m deep; 4618 and 4634, about 4m deep and 4621 and 4623, both about 3m deep. Site 4622 was found as a narrow bedding in a cliff while site 4620 is a walk-in, well-developed cave at about 30m long. Draughting digs were found at sites 4630 and 4631, and site 4632 is a 15m long, steeply descending low cave at the base of a cliff. Site 4633 is a small cave at the base of a cliff; site 4637, a mud-floored hole in a field and site 4638, a small resurgence cave. Site 4613 is a 7m through trip in old cave passage and 4614 was excavated until it was found that stronger measures are required.
   Further west, photos were taken in site 4386, Cueva del Palo de la Mesa and, at shaft 4489 towards Navajeda, progress was made down over bags of rotting bones to 3m of descending passage with a slight draught that needs digging.
   At Garzón, a trip was made into site 4069 - "An excellent cave; well worth a trip" - and a dig at the base of the initial entrance slope gave a small extension. Ten other sites were found in the area to the north. Site 4608 is a narrow rift about 9m deep that requires some work before the good echo can be investigated. An 8.5m pitch dropped into a chanber at site 4610 with 5 ways on. It requires some work to reach a floor about 10m below. At site 4611, a small crawl leads to hading passage for 20m to good formations and boulders. The end of a 52m rope was reached in site 4627. This was down over rubbish to a narrow canyon climb down to a short pitch which dropped into a chamber where the cave continues in a very small, tight crawl. At site 4636, a slanting bedding cave descends at about 45 degrees for 25m to enter a small, debris-filled chamber. The draughting passage can be seen to continue for 10m but is too small to enter. Smaller sites were found at 4609, a 2m drop to a boulder floor; 4612, a 2m narrow choked rift and small resurgence at site 4629. Digs were noted at site 4607 (a small draughting hole on the side of a depression) and site 4628 where a possible draughting dig is found about 8m down.
   At previously strongly draughting site 4574, in Camposdelante, a dig was started, although no draught was felt this time and more work is required. Further west, at Barrio de Arriba, the dig at site 4587 was abandoned when an area of collapsed sandstone blocks was encountered. The nearby site 4606 was found as a walk-in rift cave which quickly became more arduous to explore, with difficult traversing in the roof. Over 10 pitches were descended along the passage - all blind, and continuing exploration along a draughting right hand branch will require a thin person. The length of this site was surveyed as 267m.

South Sector
    A large open shaft some 13m deep was spotted as site 4624 and another open hole, 8m deep, was catalogued as site 4625 at Las Calzadillas. Both are undescended. In the same area, site 4626 is blocked at the top by two large boulders.
   The new survey for the long-lost Epiglottis Cavern (site 1294), including its relationship to other caves on El Naso, has been completed by Pete Smith. Peter has also taken a centre line through Cueva Asiul (taking the length up to 95m from 80m) and a drawn up survey will appear in due course.

October expeditions article by Juan Corrin.

Survey updates and new surveys
0061 Asiul complete (PS)
1294 Epiglottis complete (PS)
3261 cave complete (PG / JC)
3915 cave complete (PG / JC)
4606 cave complete (PG)
4627 Inclinada plan & elevation (PG)

The list below shows links to those 64 sites which were extended or newly discovered over October 2017, or which have had surveys, references or descriptions updated, photos or movie clips added, or entrances repositioned with a GPS.

Arredondo 733 Vallina, Cueva;
Barrio de Arriba 4587 shaft; 4606 Grietas, Las;
Camposdelante 4574 cave;
El Naso 61 Asiul, Cueva de; 1294 Epiglottis Cavern;
Garzón, Solórzano 4069 cave; 4607 hole; 4608 rift; 4609 hole; 4610 shaft; 4611 cave; 4612 rift; 4627 Inclinada, Sima; 4628 shaft; 4629 resurgence; 4636 cave;
Hornedo 3010 cave; 3261 shaft & cave; 3282 resurgence; 3915 Garma, Cueva la; 4583 cave; 4584 cave; 4605 resurgence;
Las Calzadillas 4624 shaft; 4625 shaft; 4626 dig;
Moncobe 2545 dig; 3901 dig; 4473 shaft; 4474 shaft; 4483 dig; 4639 shaft; 4640 shaft; 4641 shaft; 4642 dig; 4643 sink;
Navajeda 4489 shaft;
Riaño 1318 shaft;
San Antonio 3239 cave; 3268 Laberinto, Cueva; 3281 cave; 3494 Regato, Cueva de; 3896 dig; 4386 Palo de la Mesa, Cueva del; 4613 cave; 4614 hole; 4615 rift; 4616 rift; 4617 shaft; 4618 hole; 4619 rift; 4620 cave; 4621 shaft; 4622 cave; 4623 shaft; 4630 dig; 4631 dig; 4632 cave; 4633 cave; 4634 shaft; 4635 cave; 4637 hole; 4638 resurgence;

Additional news
   Juan Corrin delivered a short (18 minute) lecture (with PowerPoint) as part of A Golden Age of Cave Exploration, celebrating 50 years of pioneering British cave exploration and science, 1st - 4th December at the Royal Geographical Society, London. This was well received. Anyone who wants to give this talk (or just to view it) can download the files (including a script) here. A YouTube video of the presentation was also put online in August 2018: Matienzo - a Spanish caving area for the connoisseur!
   An update from Laura Deeprose about the ongoing palaeoclimate work in Cueva Perlas: By the end of 2017, after monitoring temperature, CO2 and drip water chemistry for nearly 3 years, the monitoring is revealing some interesting insights into the dynamics of the cave including cave ventilation. The speleothem record work is ongoing but we have successfully found a speleothem covering the period of the Neanderthal extinction at approx. 40,000 years ago. The geochemical record from the speleothem is currently being developed and it is hoped it will provide an indication of how the climate and landscape were changing during the period around the Neanderthal extinction.

   It was with surprise and sadness that we learnt of the death of Michael "Squirrel" Wood. His body was found on 8th December in Ewes Top Moss Pot on Scales Moor which he had been exploring. He had been missing for a number of weeks after becoming increasingly frail.
   Squirrel first came to Matienzo in 1974 and for the next couple of years was often at the forefront of new exploration. His discoveries in Cueva de la Reñada in the early days led to the naming of the downstream streamway as Squirrel's Passage. He also took part in early explorations in such sites as Uzueka and Cueva de la Espada. He found the entrance to Torca Azpilicueta in 1982.
   In recent years, his mobility problems curtailed his caving activities but he did come out to Matienzo on a couple of occasions when he helped to video Cueva Campizo and assisted in surveying the Orillón cave complex and other caves in Ozana.
RIP Squirrel.


   Work continued at site 603 at the top end of the Mushroom Field - a possible back entrance into Carcavueso or the Trident Series in Hoyuca. Over four trips, the entrance route was made more comfortable, facilitating future work. The site draughts strongly in both directions depending on outside temperatures.
   A large specimen of the Quimper Snail, Elona quimperiana (Férussac, 1821), was seen halfway down the entrance shaft in site 0603. This snail is on the IUCN red list and been previously recorded in caves.
    A hunting dog and wild boar fell into a hole high above Seldesuto. An investigation found the shaft to be site 0545, a 60m deep shaft on the southern La Vega slopes. Although there was some talk of arranging a descent while British cavers were still there, in the end it didn't happen. The dog's body was later recovered by a caver from Ramales, taking about 4 hours.
   A small group (Simon Cornhill, Diane Arthurs and Neil "Slim" or "Nez" McCallum) stayed speleologically focused with almost daily underground activities over the Christmas and New Year celebrations (24th December - January 3rd). A delayed return ferry due to bad weather meant a bonus caving day.
   The highlight for the team was the pushing and exploration in Cueva del Bosque (site 0373). This had been left in August at a bouldery dig in a 6 x 10m chamber (Slim Pickings). By the end of the Christmas period, the team had had an "awesome time exploring this superb pothole rivaling the best the Dales has to offer." Over 640m had been surveyed.
   The hole was opened up to provide a p4 into a short passage to a small inlet chamber. Just beyond was Squirrel's Pitch - a magnificent 75m deep, 10m diameter drop. The tortuous rift at the base was followed for 15m to a squeeze and the 10m deep Helmet Trapper pitch. A comfortable descending streamway soon ended at a steep rift to the take-off point for the 50m deep Double Six Pitch described as "another stunning descent in a large, beautiful shaft with the stream falling at the far side". The pitch ended at a 15x8m flat boulder floor with the only outlet being a flatout crawl - Roll Again. This soon met a sizeable streamway - the Río Dado. Downstream, a tedious hand-and-knees crawl was soon encountered, continuing for about 200m to a beautiful aven coated in slippery white calcite and moonmilk - Slithery Turtle Aven. Beyond, the crawl continued for 60m to a sump.
    Upstream in Río Dado, exploration was halted after about 100m at another sump. A passage to the right ended at a very steeply ascending and draughting boulder choke which was forced for 10 - 15m.
    The Survex centre line survey and surrounding caves can be seen on the site 0373 page. Plans are being made to dive.
   In Cueva de Rascavieja (site 0077), about 80m of probably new route was surveyed in the complex, draughting 1985 Extensions. A good draught is now needed to follow any leads.
   The small stream inlet in La Fuente de Escobar (site 0383) was dug and capped over two sessions and the cave surveyed for 42m. The excavations were carried out lying in cold, fast flowing water and an apparent enlargement is visible 3m ahead.
   In Cueva de Collada (site 0394), a sandy crawl was surveyed for 71m off Sex on the Beach and the dig off to the west of White Russian was inspected and partly cleared of rubble.
   A visit to site 1815 to try to (re)locate the draughting hole was unsuccessful, probably due to the cold outside temperature.

December expeditions article by Juan Corrin.

Survey updates and new surveys
0077 Rascavieja need to tie in and align parts
0373 Bosque complete (SC & DA)
0383 Escobar in hand (SC & DA)
0394 Collada complete (JC)

The list below shows links to those 7 sites which were extended over the Christmas 2017 / New Year period, or which have had surveys, references or descriptions updated, photos or movie clips added.

El Naso 77 Rascavieja, Cueva de;
La Gatuna 394 Collada, Cueva de;
La Secada 603 shaft;
Las Calzadillas 1815 cave;
N Vega 373 Bosque, Cueva del;
Riaño 383 Fuente de Escobar, La;
S Vega 545 shaft;