Through-trip!

Cueva de la Marniosa

In the early 1970’s a group of students from Lancaster University Speleological Society (LUSS) touring Northern Spain heard about some caves near Tresviso, Eastern Picos de Europa.  In 1975, their first year visiting caves of Tresviso, they explored upstream, into the Sobra valley and found a crack in the side of a cliff that is Cueva de Marniosa.  They explored this cave down a few pitches and along some well decorated fossil passage to a high rifty passage with a small streamway in the bottom. Over a kilometre upstream, the streamway ends at the impressive Hall of the Mountain King chamber- a 50 m x 20 m chamber with a height of over 50 m.  The whole cave has a length of 5 km and a depth of 290 m.  Over the next 40 years a few extra bits were added, but other caves in the area were more interesting.

During the summer expedition of 2018 a small group were tasked with surface prospecting in the brambles, bracken and beech at the head of the Sobra valley and found a number of surface shafts. One of the surface shafts, Cueva del la Silvestre, descended a series of pitches to an impressive large 45 m deep, 20 m diameter shaft.  From the bottom of this shaft several ways on were found.  A few days later, on the final day of the expedition, more pitches and climbs were descended and a message from the past was found: LUSS.  A short walk upstream and the explorers entered Hall of the Mountain King.  Much to the chagrin of those involved the 500 m deep traverse of Silvestre to Marniosa would have to wait until next year…

Cueva de la Silvestre to Cueva de la Marniosa through trip (Lydia Leather)

We got to the Silvestre layby at about 11am, kitted up and started walking down the track. This time round it was a lot easier to find having been well travelled. Stu’s white tape on silver birch trees was not so great in the day light as it had been the night before. Whilst we were doing the through trip, Joe and Rob where diving the sumps in Wet Willy and had stolen Alastair for the day to carry for them. As Stu and I weren’t carrying much we took two of their bags down for them (on the basis that Rob would later repay us with a create of beer, but failing that, dancing bear coffee liquor).

The Silvestre entrance had been rigged the day before down to waterfall chamber, where Bob needed to re-bolt before we continued on with the through trip, so Bob and Arwel headed in whilst the rest of us followed behind. The day before Stu had found the jaw of what we think is horse, to match the skull he’d found the year before. Now Bingo (see photo for scale) lives happily in the entrance chamber.

Following through the rest of the cave, Rob who hadn’t been in the cave before grew increasingly more impressed at the fact that it was indeed a cave. We took our time marvelling at the finest bolder I’ve ever seen that sat in the middle of the stream way and is a conglomerate, at first I assumed it was originally the floor of the streamway and had been eroded away, but not all that convinced, think it might just be a boulder.

When we reached Bob an Arwel, there was a short wait for the bolting to be finished before we could reach the bottom of waterfall pitch 
When everyone was down waterfall pitch we left the diving team and their bags and continued on. From waterfall chamber we continued up the aided climb and through into old stream way rift passage. This continued on (picture below), getting slightly small in places (for Bob and Stu) and down climbs and eventully leads to a junction, left being the way on and right being Hall of the MountainKing.

As Stu and I hadn’t been before we went to Hall of the Mountain King which is an aven roughly 50m in height and 20m width, with a mud slope to the left of the chamber and 2 water inlets coming in through the aven above to the right. Here was where we stopped to take a group photo.

From Hall of the Mountain King back to the Silvestre junction we followed the stream and continued down the active passage way. The passage follows onward with multiple down climbs, some more exposed than others. Eventually the passage follows a fault and here the bolder choke began. Alastair Gott had been in Marniosa the day before and placed reflectors along the bolder choke which were extremely helpful and saved a lot of time as there are multiple ways along the choke in which you can go wrong. When the choke ends, the passage re-joins into stream way and this follows straight towards the bottom pitch of Marniosa

We headed up the muddy pitch out of the streamway, where Bob showed us “the boulder” which must not be touched or moved in anyway as it was wedged right between the wall and multiple boulders which became the false floor of the next slope.
Following this onwards the passage is very well decorated series of chambers (see photos), with various calcite flow slopes and formations, including this flying pizza like disc thing… Eventually reaching the bottom of a 22 m pitch. From here there’s 3 more small pitches until eventually you get into the old cheese chamber and we were at the Marniosa entrance. The trip in total took 6 hours and we got out with plenty of time to spend in the bar drinking celebratory beers and eating local cheese. Rob and Joe eventually turned up and kept the promise of buying Stu and I a dancing bear coffee liquor.

The times they are a changin’

by Howard Jones

Brief history

In the 1970’s LUSS were caving in Northern Spain, inland from Santander. They learned about a village where cheese was made and matured in caves. Nearby a resurgence cave fed a hydroelectricity scheme. Add in some high mountains in the vicinity and it was Xmas for cave explorers. Tresviso was first visited in 1974 and cavers from LUSS and other clubs, both UK and foreign, have been visiting ever since. The resurgence cave (Agua ) has been surveyed in excess of 15km and Sima 56 was pushed to a depth of 1169m. Vertically they have over lapped, horizontally they are 4km apart. If joined they would establish a world class system, and maybe through trip!

The Village

Tresviso is a lovely village of some 25 houses sat at the top of the Urdon gorge. The families used to be subsistence farmers living off the proceeds of goats and cheese. When we first arrived in vast numbers and camped just outside the village, we must have swamped their existence. Yet we were absorbed into their company without rancour and have been so ever since.

When the track from Sores was improved to a road village life changed and nowadays many villagers leave in the winter a return in the summer. There are far more visitors than before and life in the village has changed for ever.

Arrival

In the 70’s there were two ways to Tresviso. A track came in from the village of Sotres some 10k away which could usually be passed by a land rover, though was sometimes blocked by rock fall. The other way in was up from the Urdon gorge, a 6k march with 900m of ascent. The bus from Santander would drop us at the bottom and the nightmare ascent would begin. For many of us this was our introduction to Tresviso expeditions and it was brutal, staggering up this donkey track in the mid-day heat with your caving gear on your back. As a way of making you cave fit it was ideal. Hopefully the expedition land rover had made its way in via Sotres and you could unpack your tent, home for the next 9 weeks.

10 years ago, the track from Sotres was engineered into a metalled road and saloon cars can now drive to Tresviso. This has changed a lot of aspects of Tresviso life, not least cavers can drive to Tresviso and no longer sweat up the track!

Accommodation

In the 70’ we would camp in a field just above the village in a sloping field which had been harvested early. Water was gained from a trough and flies were a problem. A big communal cooking tent was used to store food, you slept in your own. Life was pretty basic and there was little incentive to hang around camp all day. Evenings were spent in the bar, a red wine often lasting all evening for an impoverished student.

Nowadays we stay in a hostel in the village. Bunk beds, electricity, hot water, an oven all make life a lot more comfortable. A store room downstairs is used to leave gear in from year to year which makes logistics much easier. Some things have not changed though, evenings are still spent in the bar.

Technology

Caving in the 70’s meant wet suits, carbides (stinkies) and texolex helmets was all we knew. Over suits were proofed cotton which ripped to bits in rifts, under suits bought second hand from the air force which for some reason had short arms and legs. Harnesses were homemade or the dreaded Whillans which rearranged genetalia. In short caving gear was a mixture of home made or adapted from other uses.

Petzl changed all that and LED and battery technology has made life underground much safer and pleasant. Cave photography and surveying can now be undertaken for hours without the risk of imminent exposure, with better results to boot.

Weather

Snow fall has decreased remarkably over the 40 years. The days of digging out the White house door and cave and mine entrances are largely gone. In May 2019 there was little snow at Andara (top camp area) and by September there was none. A few shafts are still snow plugged, but this must be yearlong. The river caves of Agua and Marnioasa are thus drier and safer and the tracks and roads keep in better condition.

Cave names

One of the joys of exploring caves is you get to name them and the passages within. In the 70’s Bob Dylan songs were popular and a quick glance at the Agua survey proves this to be the case. As time moved on other influences have been reflected.

I was always surprised that the Spanish caving authorities allowed us ( and other foreigners) to come and explore their prime areas, surely in years to come the next generation would be appalled that so many of the world class Spanish caves had been explored by non-Spanish teams, and yet despite changes to the permission rules we are still allowed to keep control of “our area” 40 years on.

However, the Spanish cavers have got their own back by renaming our caves! The Cueva del Agua is now Nacimiento, which is very confusing to us old timers.

Tresviso 2019

Andara (Eastern Massif) viewed from Tresadura (looking South) (Phil Walker)

The 2019 expedition is only 5 weeks away. Hopefully some interesting blog posts will be created, but firstly, as per previous years, a bit of a brief overview of expedition:

Overview & brief history:
The Picos de Europa is a range of mountains 20km inland from the northern coast of Spain, forming a westerly extension of the Cantabrian Mountains. It consists of three main areas, the Western, Central and Eastern Massifs.

  • The Western Massif is to the west of the Rio Cares and has been explored by a selection of clubs including Oxford University Caving Club (OUCC), Seccion de Espeleologia Ingenieros Industriales (SEII), York University Cave and Pothole Club (YUCPC), Sociedad de Espeleologia Geologicas (SEG) and Speleo Club de Paris (SCP). This now includes the area under exploration as part of the Ario Caves Project.
  • The Central Massif is between the Cares Gorge and the Rio Duje and has been mainly explored by the Speleo Club de Seine (SCS).
  • The Eastern Massif is to the East of the Rio Duje. Lancaster University Speleological Society (LUSS) were exploring the Eastern Massif from the early seventies to 1987 with the help of SEII.

It was the Eastern Massif (or Andara) that drew the attention of LUSS in the early 1970s. In the early years exploration was mounted from the mountain village of Tresviso and exploration was dominated by the resurgence cave Cueva del Nacimiento (Cueva del Agua) located at the foot of the mountain range. The resurgence flows into a canal that contours the Urdon gorge with an average flow of 2 m3/s and the cave behind the resurgence leads to >12 km of surveyed passage and a height gain of over +534m.

The catchment is some 40 km3 and includes caves such as Torca Jou Sin Tierre (CS-9) at -1203m deep and Torca del Cueto de Los Senderos (Sima 56) at -1169m deep.

Morning Chamber, Cueva de La Marniosa (Joe Daniels)


In the late 70’s LUSS pushed Cueva del Nacimiento to around the 11km and +300m mark, but after several years the cave was abandoned as all the major routes sumped and no continuation could be found. LUSS then turned their attention to the Andara region higher up the mountain range and sought caves that would drop into the Nacimiento system and hopefully create a record-breaking >1500m traverse. They found a number of deep caves around this ‘top camp’ area; Sara, Tere, Flowerpot, Dosser’s Delight and Sima 56 were all pushed to respectable depths but a
connection remained elusive.


The discovery of newer and deeper systems, plus improved GPS, have changed the figures slightly but a connection between the deep potholes and resurgence would create; a cave in the top 10 worlds’ deepest, deepest in Spain and potentially one of the the deepest underground traverses in the world.

Top EntranceAreaAlt(m)Current Depth (m)Vertical Range (m)
S-33 Torca de la Hendida Samelar2100-4521620
CS-9 Torca Jou Sin Tierre Cueto Senderos 2074 -12031594
Sima 56 Cueto de Los Senderos Cueto Senderos 1975 -11691495
T82 Karen – 2.6 Sara Grajal (Sara depression) 1880 -5911400
T145 – Pozo Castillo Mazarassa 1870 -3091390
2.24 Tere Grajal (Sara depression) 1820-7921340
FT39 Compromisso Mazarassa 1820-3131340
T169 Flowerpot Pico Boro 1785-7231305
T173 Dossers Delight Pico Boro 1706-8311226
T190 Septrin Pico Boro 1696-1801216
3.2 Torca Branarredonda (Fallen Bear) Samelar 1589-4561109
T510 Cueva Entre Cuetos Sierra del a Corta 1305-117825
T69 – Pozo Motilla Sierra del a Corta 1248-70768

Table: Potential depth if connected to Cueva del Nacimiento (2017).

Note: There are at > 70 sites at higher altitude than CS-9 that would surpass -1600m deep through trip, with some close to -1800m depth.

Survex – Mountain range looking E-W

Expedition Dates
• 31 st August 2019 to 14th September 2019 – main expedition dates

Objectives
The expedition has several goals. The following are a few primary objectives:

Cueva del Nacimiento

  • Jurassic World – The Sandy dig, draughting lead, now only an hour from camp
  • Pina Colada Bypass – calcite aven to climb
  • Joe’s Crack – continuing shaft behind Death Race camp.
  • Teeth of Satan – Wet Aven – +30m aven with draft and calcite squeeze, requires enlarging.
  • Dan’s Big Room – unexplored section of maze in area of Dan’s Big Room, Peanut Chamber and Winter Gardens
  • Parting Friends – a dive of the Parting Friends sump is planned.
Pena Coloada Sump (CUeva del Nacmiento) (Rob MIddleton)

Cueva de la Marniosa

  • Beyond Sump 2 – undescended 6m pitch
  • T20A Silvestre – Marniosa – first through trip to be completed
  • T20A Silvestre – upstream leads, heading toward the Valdelafuente

Secondary Objectives:
Time and resources permitting there are several secondary objectives that will be attempted:

Downstream Marniosa (Joe Daniels)


Sistema Castillo
A large mine and natural cave complex in the Minas de Mazarrasa area. Pozo del Castillo series was explored to – 292m depth in 1983, with either a howling draft or roaring waterfall beyond a constriction at the limit. The potential of the cave is significant but currently a collapse prevents getting to the end. Pozo Natacha series ends at -309m depth and is close to the same point in Castillo.

  • Pozo Del Castillo – shoring and bypass of rock collapse Castillo remains a major lead, if we can get past the blockage! In 2018 the snow level had dropped and possible to get into the next section.
  • Pozo del Castillo – other entrances. FT16 entrance snow plug would appear to be the same blockage in lower Castillo passage. Snow plugs are reported further into the cave, so another entrance must exist!
  • Pozo del Castillo – surveying of Natacha upper series and locating possible surface entrance,


Valdelafuente / Sobra Valley

  • Re-locate draughting surface entrance on Valdelafuente, close to 80m aven beyond Sump 1 in Cueva del Marniosa,
  • Yorkshire Inlet in Cueva del Marniosa. Exploration of col above aven

Sierra del a Corta

Above the furthest reaches in Nacimiento is the Sierra del Corta. A heavily wooded area with a number of promising leads, that could potentially drop into Nacimiento and provide an easier route into the back-end to aid exploration at the far reaches.

  • T554 – large 100m shaft on the Sierra del a Corta, this requires some digging at the bottom,
  • Al2 – a drafting shaft not yet bottomed. Jurassic World in Nacimiento appears to be heading directly towards this site,
  • T294 Oh What Pot (La Gobia) – continuing passage,
  • Surface prospecting close to vicinity of Terror Firma in Nacimiento. Terror Firma is only 40m vertically and 200m horizontally from some parts of the surface in the Sierra del a Corta region.

Other

  • Locate and descend FT43, this draughts strongly. It is almost directly above Boulder Chamber in T87 Mazarrasa and would provide bypass to collapse at T87 entrance.
  • Prospecting on Hoyo Oscuro and Hoyo Evangalista. Highest entrances on the mountain range.
  • Mine 2.32a – there is large unexplored level (with tram lines) leading to unexplored passage.
M6 Toll Bypass, Cueva del Nacimiento (Arwel Roberts)

T20A Silvestre Pot exploration log

Extract from various sources on exploration of Silvestre Pot (Alistair Gott)

Part 1

Sobra valley is part of the stream catchment for cueva del marniosa, very little was known about the stream sinks until 5 days ago. Cueva del marniosa is one of the two well known stream caves in the Tresviso region.

Imo furlong, Stu coxon, Derek Cousins and Alastair Gott started the ball rolling by doing some gorse, bracken, karst and bramble wading. Finding various areas of interest. Aided greatly by stu’s verbal sonar “boop” and imo’s “cooweep”. Both of these sounds really carry in the woods.

A return was on the cards for the next day, without a drill, we descended a cave named cueva donga. Down various sections to a constriction. Kelda Jones, stu coxon, bob the juggler, Adam Spillane and Alastair Gott were present on this day.

The third day we returned with a drill, 5 ropes of various sizes, a keen biologist called Will Burn and breaking gear. With 2 objectives descend IM2 “practice pot” and cueva Donga. AG descended practice pot and placed 2 bolts in plain clothes and SRT gear, realising his rope did not reach the bottom, he returned to the surface and kitted up.

Whilst AG and SC descended practice pot, the “other two” KJ and WB had a dig to connect donga via the stream sink and collect biological samples, putting many bugs into alcohol for further analysis.
After getting bored with that they went for a wander and found another hole which needed investigating. Rigging a rope from a tree Kelda fearlessly descended…

Practice pot was going well, bolts being placed and the Derbyshire digger (AG) doing what he does best and digging at 30m depth, (after surveying) finding approx 6m more passage to a mixed mud and rock constriction. AG and SC got bored with this, surveyed it and returned to the surface.

KJ1 “silvestre” had reached a leafy ledge and needed some bolts, AG and SC joined Kelda (KJ) and Will (WB).

Part 2

About 4.30pm AG and SC were teaching KJ how to place a bolt. KJ was desperate to descend.

AG found himself at the base of the shaft, I would say the shaft is approximately a tenth of the size of eldon hole, similar width to length proportions. At the base approx 10m down, AG then put a bolt in to rebelay the rope to help rigging the y-hang. The rock here was quite hard to place a bolt, but in two places it was possible to place. despite the cherty conglomerate. Below this, AG rigged a rebelay and told KJ and SC that it was ok to descend. Three leads were immediately obvious. A wet lead “upstream”, a dry lead and the downstream lead. The chamber leading to these leads was approximately 10m by 10m.

All upstream leads have been left to further expeditions.

KJ was still keen, despite AG’s protesting. Rigging a handline down a 3m climb, her first bolt placement, the drill ran out of battery for further bolts.

KJ climbed down even though AG said if she descended he would leave her, AG soon excitedly followed, keen not to miss out. “Fear of missing out”

KJ, SC and AG then found themselves in a bit of stompy stream cave approximately 30m long. Ending in a gaping hole to the unknown. With no battery they returned to the surface.

All four of us returned to the hut, including Will Burn our callout. AG had a celebratory shower, 1st shave of the Expedition (Gott to look good for the photos!) and wolfed food down, lovingly cooked by the other members of the expedition. Potentially Helping with the washing up (can’t remember) AG was feeling pleased with himself. But tired.

Part 3

We returned again on Monday. The trio were together again Kelda Jones, Stuart Coxon and Alastair Gott, this time as surveying team.

Sir Phillip of Thirsk had said we needed some “adult supervision” so we were joined by Bob the Juggler and Jason Gotel, who immediately became the rigging team. Storming through the cave they excellently rigged 7 pitches, of varying length. At the start of the day, sir Phillip said we could only take the Crap rope. So we left 200m of brand new rope at the “hut” and cracked on. As it happens, JG and BTJ (Bob Cockeram) did a very good job, all the ropes were actually the right length.

The surveying team only followed the way on and did not survey the numerous sinks joining the flow on the way. They caught up with the rigging team at the head of the seventh pitch, “electronica pitch” the PDA ran out of battery at this point and the rigging team had swapped batteries in the drill to ensure they could reach the bottom. Rigging style by Jason Gotel was classic “by the book” rebelays to keep the cavers out of water. Top work.

The 58m rope landed on a ledge with space for 5 or more people, the pitch remaining was estimated at 17m by Bob the Juggler. At this point drill battery was low, it was suspected that the drill batteries were cold, and could get the remaining half a hole needed to rig the pitch. Therefore JG and AG each had a drill battery under their armpits to warm up. It worked, and a bolt was placed to complete the 70m ( ish) “electronica pitch”.

Part 4

Electronica pitch is a fantastic pitch, with white lines running through the rock, and approx 14m wide and 30m long chamber, straight down not unlike some of the Yorkshire style places, i would say the equivalent in Derbyshire would be the NCC shafts in terms of vertical walls, except electronica is bigger.

Without surveying, the team continued downstream, the dimensions of the chamber close down to a rift type development with cherty conglomerate ( approximately 1 and a half body widths wide) much like the entrance pitch. The team found an ethical problem with a bridge of rock glued together by mud and calcite, the team decided it was quite dodgy, so two sandstone boulders were chucked at it to see if it would collapse. It didn’t, but there’s a video made by Stuart Coxan, which may get posted up later.

The team, then continued downstream to a point where the stream drops down a pitch. The remaining 50m rope was left for futher exploration the next day.

Part 5

A return was in order for Tuesday, objectives were to continue exploration and survey electronica pitch.

AG did a sterling job of forgetting the drillbit and also forgetting the waterproof protection for the surveying tablet he had borrowed from “sir Phillip”. Eeeeep!

AG ran back up the hill via the muddy track when he realised he’d forgotten the drill bit and called “sir Phillip”, who dispatched Adam Spillane in a car to deliver the drill
Bit. The team then descended to the head of electronica pitch, where AG realised his error with the tablet and tried to “make do” with a zip-lock sandwich bag.

Having no experience with surveying pitches AG then tried to survey on the way down, but soon realised that he wouldn’t be able to download the shots till the base of the pitch. The team today consisted of Alastair Gott on tablet and Stuart Coxon on disto shooter. Bob and Jason continued the rigging.

At the base of electronica, AG tried to download the shots from the disto with a damp tablet. Every time he tried to select the download button the sandwich bag decided to touch the first shot collected at the top of the pitch to start the survey. Needless to say this method was dispatched rapidly. Mars bars were extracted from what looked like a dry bag, and the tablet was turned off and enclosed within, it turns out this was a “damp bag”. So the tablet was not much better in here. Rice to the rescue for the second time on “the holiday”.
Surveying continued with disto and book, noting the legs of the mostly north trending rift. Any bad LRUDs (left right up down) or forward legs were noted for deletion later.
AG picked a permanent marker which it turns out is not as good as pencil! Another lesson learnt!

We had done so well the day before of hiding all the old rope in the cave, so “sir Phillip” deemed that we could take 100m of New rope. Mmm, we hid this in the cave as well!

At the base of the “water fall junction” pitch we found at the continuation of electronica, we found three ways on.

Straight on, 23deg is the direction of hall of the mountain king in cueva de la marniosa. Some 300m distant from the head of electronica, we were closing the gap…

Behind left (dry but descending) and behind right (wet pitches) were also leads.

We progressed two leads, picking the dry options, straight on and back left. Leaving the wet option for the end of the day. JG and AG went for straight on and BTJ and SC picked back left.

BTJ rigged with SC as support, and used up the rest of the 50m old rope, phew! The pitches ended in a sump.
JG progressed the straight on lead, with AG stopping at a climb he didn’t like, JG reckoned 180m of passage, paced. The lead took a slight trickle of water, but nothing more, it was exceptional fossil passage with popcorn formations.

The team made a decision to exit the cave, it being after 7pm.

It has been reported that hall of the mountain king only takes a slight trickle of water…

Part 6

Today was a day off for Alastair Gott, Stuart Coxon, Kelda Jones and Jason Gotel. AG getting up at midday + 30mins. Coffee and tea straight off then a spot of brunch in the bar before decamping computer, tablet and disto to the bar for investigation. Some data sorting required. A lovely leisurely day starting in the sun, turning to mist/cloud.

Bob the juggler, Dave “mate” Collins and “Gay” Dave powsland were dispatched today to investigate the wet lead and the dry 23 deg lead (to marniosa).

The wet lead was pushed by bob the juggler to land in water. It is assumed this is a sump.

Dave Powsland entered the 23 degree passage, and investigated for some way before retuning to some hot food cooked by Dave mate. The three returned in time for dinner, rather than the 10pm time that we’ve been returning on other days.

Tomorrow Jason Gotel plans a return for the through trip, a team will probably be assembled. Otherwise we will savor the treat for next year…

Part 7

Silvestre through trip to marinosa, did the lead killers make the through trip? Find out at hidden earth 2018 in one week.

Updates

Pozo del Castillo

After 30 years of a blocked snow plug, preventing access to the lower reaches of Castillo, the snow plug has melted.  The previously scary boulder held up by snow, is now held up by air and luck.  A 100 year old winch has now been revealed, and more large scary boulders.  The ‘pitch’ has been dropped down under the snow plug into continuing passage, but not currently bearing any relation to the descriptions from the 1980’s French description.

A second trip explored further under the snow plug to arrive at some Screwfix through bolts…. FT16 explored in 2017.  It’s not clear how this has happened, no survey detailing such a connection, quite possibly a link revealed by the receding snow.  More work to do….

Cueva del Marniosa

Following a successful set up trip by 2 divers, a team of 4 passed Sump 1 to reach Sump 2 and get 2 divers into the new passage found last year.  The 2 divers explored 185m of passage before hitting a 6m pitch.  Logistics of exploration at such a remote site prevented further exploration.

SUSS updates: https://ukcaving.com/board/index.php?topic=23537.0

Article on recent expeditions published

The 2018 expedition is now only 4 weeks away. A few red tape problems have now been resolved and everything is set, including last minute equipment orders, turning over the shed looking for old equipment and herding everyone into position.

The latest edition of Descent (No 263 – Aug/Sep 2018) includes an article on Tresviso exploration, giving an overview of the recent work by the team, and is well worth seeking out a copy. Available from 4th August.

https://www.wildplaces.co.uk/

Tresviso 2018

Prospecting for caves (Sam Deeley)

Expedition Dates

  • 1st September to 15th September 2018 – main expedition dates

Objectives

The expedition has a number of goals.  The following are a few primary objectives:

Cueva del Nacimiento

  • Jurassic World – Terror Firma – multiple avens and climbs,
  • Pina Colada Bypass – a 3-10m rift leads off from the Pina Colada sump.
  • Joe’s Crack – un-descended shaft behind Death Race camp.
  • Teeth of Satan – Wet Aven – +30m aven with draft and calcite squeeze, requires enlarging.
  • Dan’s Big Room – unexplored section of maze in area of Dan’s Big Room and Winter Gardens
  • Parting Friends – a dive of the Parting Friends sump is planned.

DR traverse (Chris Jones)

Cueva de la Marniosa

  • Beyond Sump 2 – a dive of sump 2 and exploration beyond is planned

Pico Boro (SUSS)

SUSS are also involved and will take on responsibility for exploring either  Flowerpot on the Pico Boro area.

  • FlowerPot – re-rigging and exploration of leads
  • Surface sweep and logging of entrances in Sara Depression (around camp)
  • Surface sweep and logging of entrances in Pico Boro area


Secondary Objectives:

Time and resources permitting there are a number of secondary objectives that will be attempted:

Sistema Castillo

A large mine and natural cave complex in the Minas de Mazarrasa area.  Pozo del Castillo series was explored to -292m depth in 1983, with either a howling draft or roaring waterfall beyond a constriction at the limit.  The potential of the cave is significant but currently a collapse prevents getting to the end. Pozo Natacha series ends at -309m depth and is close to the same point in Castillo.

  • Pozo Del Castillo shoring and bypass of rock collapse Castillo remains a major lead, if we can get past the blockage!
  • Pozo del Castillo – other entrances. FT16 entrance snow plug would appear to be the same blockage in lower Castillo passage.  Snow plugs are reported further into the cave, so another entrance must exist!
  • Pozo del Castillo – surveying of Natacha upper series and locating possible surface entrance,
  • Pozo del Castillo Natacha 1983 series. Attempt to get small, skinny person through current limit, otherwise derig and survey.

Pozo Castillo (Chris Jones)

Valdelafuente / Sobra Valley

  • Re-locate draughting surface entrance on Valdelafuente, close to 80m aven beyond Sump 1 in Cueva del Marniosa,
  • T20 (Sobra Valley) – sandstone sink above Hall of the Mountain King in Cueva del Marniosa,
  • Yorkshire Inlet in Cueva del Marniosa. Exploration of col above aven (also close to T20),
  • Upstream series in Cueva del Marniosa. Large black voids above the streamway,  if leads head to the South this is up the Valdelafuente

Sierra del a Corta

Above the furthest reaches in Nacimiento is the Sierra del Corta.  A heavily wooded area with a number of promising leads, that could potentially drop into Nacimiento and provide an easier route into the back-end to aid exploration at the far reaches.

  • T554large 100m shaft on the Sierra del a Corta, this requires some digging at the bottom,
  • Al2a drafting shaft not yet bottomed.  Jurassic World in Nacimiento appears to be heading directly towards this site,
  • T294 Oh What Pot (La Gobia) – continuing passage,
  • Surface prospecting close to vicinity of Terror Firma in NacimientoTerror Firma is only 40m vertically and 200m horizontally from some parts of the surface in the Sierra del a Corta region.

Other

  • Locate and survey General This may be another way into T87 Mazarrasa, bypassing entrance collapse. (most likely T88 Suerte or T89.  T88 draughts strongly at junction inside)
  • Locate and descend FT43, this draughts strongly. It is almost directly above Boulder Chamber in T87 Mazarrasa and would provide bypass to collapse at T87 entrance.
  • Surveying of Nacimiento top entrance series. There are a number of unsurveyed and minor leads in the area,
  • Prospecting on Hoyo Oscuro and Hoyo Evangalista. Highest entrances on the mountain range.
  • Mine 2.32a – there is large unexplored level (with tram lines) leading to unexplored passage.

2017 Summary

Cueva del Nacimiento – Jurassic World – Terror Firma

The ‘final’ aven at the end of the cave was climbed to over 40m, a split in the aven was followed to a new height of 534m above the entrance, but closed down.  The second aven remains unclimbed and is ongoing 

Cueva del Nacimiento – Jurassic World – Pterodactyl Crumble

Another aven at the end of the cave was explored upwards before reaching horizontal passage for another 60m, then finally closing down. 

Cueva del Nacimiento – Death Race 2000 – Joe’s Crack

Initial constriction was passed and the passage continues down another 35m, to head of undescended 12m pitch.  The passage heads under the Death Race chamber, toward the Death Race pitches.

Cueva del Nacimiento – Teeth of Satan – Wet Aven

The Wet Aven was not attempted on this trip, in part due to 2 trips getting lost on the way to the far end and running out of time to climb.

Cueva del Nacimiento – Other

180m of passage found near Death Race passage.

A new aven (+30m) found near P Chamber in Death Race passage, continues.

Cueva del La Marniosa

Sump 1 was dived and the 80m aven beyond was climbed to approx. 47m.  The rock is extremely poor and no obvious continuations could be seen at the top of the aven, using powerful lights.

The Marniosa team diverted attention to trying to dive Sump 2,  an undived sump, discovered in 1987 and unvisited since.  A rather ambitious trip saw two cavers reach sump 2 and allowed one diver to pass sump 2 (30m long t 5m depth) to surface in stream passages.  A further 40m of cave was explored and still continues, before safety concerns forced a retreat.

 Pozo Del Castillo.

Pozo Castillo continues to be surveyed (2km +) and leads explored, attempting to bypass the 1987 snow collapse.  The rediscovery of FT16 and the lower snow levels, allowed further progress in the system, but a sump was encountered at -110m.

Pozo Natacha (a series of pitches in Castillo, rather than a separate cave) was pushed past it’s 1983 limit, down a tight right to the head of a tight 20m pitch.  This pitch head would need serious enlargement before further exploration can continue.

Other exploration

Torca del Carneros was (re)discovered and surveyed.  This lies on La Mesa, above Tresviso, and probably would be connected to caves draining away from Tresviso toward the San Esteban valley.

Fallen Bear was also rigged ready for further exploration in 2018.  The bulk of the cave is a steeply descending ramp, similar to Nacimiento, and contains a number of leads of potential.

Summary:

In total over 2km of cave was surveyed in 2017.  Exploration of Nacimiento continues and has now pushed the height to over 534m from the entrance.  A logistical challenge that is not proving to get any easier, despite fixed camps toward the end of the cave.  Trips to the far end require 4-5 nights of camping, and advanced camps at the far (far) end now need to be considered.  Passing the second sump in Marniosa is a major achievement and unexpectedly has surfaced in passage heading away from Nacimiento and into the mountain, possible towards a hypotheses trunk route that may also feed the upstream sump in Nacimiento.  The rigging of Fallen Bear, and discovery of some new leads, opens up further possibilities of closer deeper systems lying between Nacimiento and the deep potholes high on the mountain.