Yorkshire Subterranean Society



Taking in the Three Peaks



Purpose built SRT wall

Monday, 24 April 2017 12:39

Sima de las Puertas Illamina (BU56)

In 2008 the YSS negotiated access for the caving world and organised the frst official trip to this gem of a cave for nearly twenty years.


Saturday, 23 August 2008 - Saturday, 13 September 2008
Recently I was very lucky to join a YSS expedition to the Sima de las Puertas de Illamina (BU56), which at a depth of just over 1,400m is one of the deepest caves in the world. The cave is located in the Spanish Pyrenees only a few miles from the deep and popular Reseau de la Pierre Saint Martin.

The entrance was discovered by Jean-François Pernette and I. Ortilles in 1979. That day Pernette reached a depth of -92m after passing the extremely narrow meander N. In the following two years, expeditions followed in which many famous French cavers participated; such as J-F Pernette, Richard Maire, Serge Fulcrand, Gerard Bouteiller and Georges Marbach. They pushed the cave to a depth of -1338m; making it the deepest in the world. Fred Vergier dived the terminal sump of the cave and two following sumps. In 1986 and 1987 a Bulgarian expedition dived three more sumps, stopping before sump 7. This fantastic achievement brought the depth of the cave to -1408m.

I had wanted to visit the BU56 for years but it is very difficult to obtain access to the cave, which is located in the Navarra National Park. The Spanish authorities handle access and will only grant it to expeditions planning to undertake further exploration. In this case, Colin Grey and Mick Jordan had applied for a permit to visit the cave with the aim of diving the un-dived sump 7.

Preparations for the trip began earlier in the year. Many meetings were held and slowly the number of cavers participating in the trip grew to around 30. The BU56 is a serious undertaking. There is only one entrance, located at an altitude of 1,960m and the trip to the sump involves a 16km roundtrip involving around 400m of entrance pitches with some awkward meanders and around 3000m of up-and-down progression once in the cave. And that’s not forgetting the walk-in to the entrance, which takes around 3hrs with over 900m of ascent! All in all, the BU56 was to the Gouffre Berger what King Pot is to Tatham Wife. A whole different kettle of fish, but a fantastic challenge!

My adventure began on the 23rd August, when I set off from Huddersfield with Jason Mallinson. We arrived at the campsite in Zuriza late on Sunday night, but still in time for a couple of beers! Here we met up with Simon Richardson, Bean, Mark Helmore ‘Mad’ Phil Rowsell and Emma Heron. The main expedition wasn’t starting until the following weekend, but it was the job of our small group to try and get all the gear up to the entrance and through the entrance series to the start of the big stuff ready for a bottoming trip on the 1st September.

Monday 25th August
While Jason and I had a bit of a lie-in to recover from the journey down, the rest of the group went to carry some gear to the entrance. At around midday, we followed them up with the intention of dropping the first few pitches down to Meander ‘N’ – the first supposedly ‘big’ obstacle at around -80m. The walk-in was very pleasant through spectacular karst scenery. It was a bit of a slog in the midday heat, especially as it started with around 600m of ascent and we were carrying heavy packs, but after around 2.5hrs the entrance was reached. The entrance itself is located on a terrace from where there are awesome views down towards France. The other group had done an excellent job of marking out some of the more complicated sections of the route over the sharp lapiaz.

Jason and I then started rigging and ferrying the rope bags down to Meander N. After the initial couple of pitches the rock improved and a very pleasant series of pitches led down to the start of the meander. We then took one bag each through this, which was no where near as bad as we were expecting, with a few narrow sections and plenty of short climbs but nothing that could be classed as tight. We then exited the cave and set off back to campsite, pleased with the day’s efforts.

Tuesday 26th August
There was certainly a sense of déjà vu as we trudged back up the hill to the entrance, once again laden with 25 kg packs full of rigging gear and diving cylinders. The plan today was for Phil Rowsell and the rest of the group to finish rigging the entrance series down to the start of Meander Oprimido – the next big obstacle located at around -397 m. Jason and I were to follow with some diving cylinders and other gear.

Phil’s group set off early, but we still caught them up at the entrance and so we had a very enjoyable couple of hours sunbathing to allow them to progress with the rigging. But alas, this went far too quickly and we were soon once again setting off into the depths of the BU56.Progress was easy, with some teamwork to get the delicate diving gear through Meander N. The fine entrance series continues after this, with some very pleasant and spacious pitches quickly gaining depth. However, we soon caught up with the other group at the top of the 65 m pitch, where Phil was putting some new bolts in to improve the rigging. Bolting the cave and improving the rigging was one of the ‘secondary’ objectives to the trip.

At the bottom of this, a fun little squeeze led to a continuation of the pitches. Close to the final 78m pitch, most of the group began the ascent to daylight while Phil, Jason and I continued on. However, some confusion with the route meant we rigged down to the 78m and then decided to head out as time was getting on and we wanted to leave the hill in daylight. So, a speedy prussic out from -314m soon had us back on the surface in the glorious sunshine.

Wednesday 27th August
Today, most of the group had a rest day while Jason, Phil and I carried up another heavy load to the entrance, managing to get the walk-in down to 2hrs.

Thursday 28th August
The plan today was for Jason, Phil, Emma and I to finish rigging the entrance series and get some gear through Meander Oprimido. Once at the entrance quick progress soon saw us down to the top of the 78m pitch, each of us laden with lead and multiple bags. The 78m pitch was superb, being in a large rift. Thankfully, it was split with around 4 or 5 rebelays to make the ascent more bearable.

Close to the bottom, it is possible to swing off into the start of Oprimido. From this point, we each took a bag through the Meander. We were all a bit nervous about Oprimido, as the description said it would take around 2hrs with a heavy bag to traverse around 300 m of passage. Eek!

Thankfully it was no where near as bad as we expected, and actually proved to be a very enjoyable and varied section of passage with lots of short climbs, a few rope climbs, a few narrow bits, some crawling and easy traversing. The first 200m was in a jagged, loose and dry fossil passage, a kin to something out of Daren Cilau. The final 100m or so is in a fine, high and clean washed rift ending in a couple of pitches.

We carried on for another 15mins to where the big stuff started at around – 450m, dumped the bags and then headed out. It probably only took around 25mins to negotiate Oprimido on the return, and we were soon back on the entrance pitches. Back on the surface food was consumed and bivvy sites located ready for sleeping at the entrance. We were treated to a spectacular sunset…..a fine end to a successful day. There was certainly no other place I’ve have rather been!!!!

Friday 29th August
The advantage of bivvy-ing at the entrance became apparent as we set off down the entrance series soon after 9 am, rather than midday as had been common on previous days. Quick progress with more bags soon had us at the start of Oprimido with around 8 large bags. We each took one through to the gear stash. Jason and Emma then carried on down the cave to see what happened next while Phil and I returned through Oprimido to get some more bags. We returned through with two bags each……so Oprimido can’t be that bad!! We also re-rigged some of the climbs on the way with new rope.

At the gear stash, we dumped the bags and carried on downstream to meet the others. A very pleasant section of passage followed with plenty of scrambling over boulders, large streamway and cascades as well as a few sections of crawling and climbing to bypass sections where the streamway became too low. We caught up with Jason and Emma at – 570m just before Salle de Arcaute. Very pleased with the day’s efforts, we set off out reaching the surface around 2.5 - 3hrs later. We were certainly getting used to the entrance series by now, having negotiated it nearly 4 times. Once back on the surface, the only thing separating us from many well deserved beers was the walk back to the car park….which was quickly (well, fairly) negotiated!

Saturday 30th August
All had a welcome rest day to prepare for the next weeks efforts. By now, many more cavers were starting to roll in to camp ready for the bottoming trips.

Sunday 31st August
A day of packing personal gear and food ready for the first bottoming trip. Phil, George North (who had just arrived that morning!) and I then headed up to the cave to bivvy ready for entering the cave early on Monday morning. A very pleasant evening stroll had us at the entrance with around 30mins of light to set up sleeping spots and eat some malt loaf and custard before bed.

Monday 1st September
We awoke to a glorious sunrise, the last for a couple of days! After breakfast, the bags were packed and we left the sun-soaked surface at around 9.30 am. The now familiar entrance series passed by as a blur and we were soon manhandling our large bags through Oprimido. I had bought a Meander Maxi for the trip, which at 48L was a beast of a bag, certainly not fit for Yorkshire potholing but ideal (just!) in this cave.

At the gear stash, bags were repacked and we continued on with two bags each. Around 45 mins later we arrived at the furthest point reached on Friday, picked up another bag and continued on. The next stretch to the camp in Salle Roncal involved lots of short climbs, pleasant streamway and boulder slopes. A short section of crawling was not welcome considering we were carrying 7 bags but we eventually arrived at the steep 80 m climb up into Salle Roncal, a massive 500 m long chamber where it was difficult to see the walls or roof. There was certainly a lot of sweat as I trudged up the loose slope with 3 bags to the top of the chamber. A fairly steady descent of around 110 m brought us to the camp at around -815 m at around 6 pm.

After a very welcome brew, we each set up our sleeping spots (Phil spotted an excellent spot which I quickly levelled with some digging) before tucking into some food. Tonight’s meal was Beef and Potato casserole. Around 2 hrs later, Simon, Bean and Mark arrived with the Dutch team.

Tuesday 2nd September
After a reasonable nights’ sleep (a bit chilly), Phil, George and myself got ready for the bottoming trip. We left camp at around 9am, thankfully with just one large bag each full of ropes and rigging gear as well as some diving gear. At the end of the chamber, a short decorated section led to a pitch down into Canyon Roncal – a superb section of clean washed and sporting streamway with plenty of cascades, a short pitch and plenty of deep pools one of which required a tensioned line to get across dry. A further pitch at the end of this led to another large section of passage adorned with beautiful 3m long straws (Salle Paquiza).

We soon arrived at a 30m or so long section of deep water. Phil changed into his wetsuit and went to have a look. By now, Simon and co arrived. Phil then bolted a traverse line in an attempt to keep people in furries dry but we all still got wet up to our chests (neck for some people), but you quickly warmed up in the following passage which quickly arrived in the massive Salle Ukerdi – a very impressive section of passage with lots of boulder hopping. Once again, the walls and roof were pretty much out of sight.

At around -1000m, a short section of crawling (which sumps dramatically in wet weather) led to a steep ramp up into another massive passage (Salle Belagua) with plenty of huge gour pools and calcite flows. The passage continues massive with lots of fantastic formations and plenty of boulder hopping and steep slopes up and down. Dropping back into the streamway, a massive cobbler-floored tunnel was followed until we once again climbed back into massive chambers.

At around -1,200m or so, the river was met again and this crashed down into Canyon Belagua. Here, a short pitch up led to the start of around 150m of traversing on a balcony high above the river. The final section was pretty blank, around 20m above the streamway with just the occasional stalagmite to grab a hold of. This was a particularly impressive and atmospheric spot. Unfortunately, a lot of faff here placing new bolts and swapping ropes around (we were running out) meant that the Wessex lads turned back while Phil, George and I continued on.

At the end of the balcony traverse, a spectacular and airy pitch dropped us back into massive, sandy-floored passage. More boulder hopping quickly led to the final pitch and a deep lake chamber, where unfortunately we had to turn around due to running out of rigging gear. It was now around 6pm. We set off back to camp which we reached around 3hrs later, after a 12hr trip. I have to admit I was feeling annoyed that we hadn’t made it to the sump, as this was probably my last chance as I was having to leave on Sunday. However, I decided to return to the bottom the next day with Team B (Jason, Beardy and co) to help carry some diving gear and finish rigging to the sump. So, after a quick meal of Beef and potato casserole, I crawled into my pit and had a much better nights sleep, dreaming of sump pools surrounded by dancing ladies and a bar!

Wednesday 3rd September
I awoke fresh as a daisy and ready for another trip down to the bottom. Jason, Lee Langdon, Keith Mason and Dave Ottewell left the camp before 9am, and Beardy and I followed on around 45mins later. Back in the sporting Canyon Roncal, I was really glad of my decision and was loving the caving even more. We caught up with the others just before -1000m and I was quickly thrown to the front to lead the way, with Jason following behind placing a few more markers to make it easier for later teams. It wasn’t long before we arrived at the brilliant balcony traverse, where Jason re-rigged it on new ropes with the aid of Phil’s new bolts. The final pitch was soon reached and re-rigged before Jason swam across the lake to set up the Tyrolean. This allowed the rest of us to keep dry.

Once past this, more sporting streamway and some traversing led to the 15m pitch up into a large fossil gallery. Jason re-bolted and rigged this before we followed him up. A pleasant section of very sandy and large fossil passage then led down to a window overlooking the streamway. Keith and I were now at the front, and made the mistake of dropping down too early via an exposed climb. We then entered what I can only describe as ‘the sewer series’ of the BU56, with neck deep canals and scary looking streamway eventually leading to a sump. We then waited for the others, but they didn’t arrive. Setting off back out, we soon met up with the others and Jason showed us the ‘correct’ way to the sump, which was reached a few minutes later.

I was ecstatic to reach the sump…..an impressive, broad circular sump pool with crystal clear water. The gear was dumped and we said farewell to Jason (who was going to remain here for a few nights) before heading out. The journey back to Salle Roncal took around 3.5hrs, making a 10hr roundtrip. Unfortunately, my extra night in the cave wasn’t exactly planned for, but my mates Tom and Si (ULSA) agreed to fit me in by zipping their two sleeping bags together…..a cosy night was had!

Thursday 4th September
After breakfast, I packed up my gear, grabbed some old rope to fill the maxi bag and set off on the long journey out. The slog up to the top of the boulder slope in Salle Roncal proved to be a rather unpleasant start to the day, but following this I soon had a steady pace going and enjoyed traversing this section of cave once again, although it was quite eerie being on my own. I didn’t meet anyone else until the bottom of the 65m pitch where I encountered a pair of legs squeezing through the squeeze found at the bottom of this. After a quick chat and some filming (Team D had a video camera), we said our farewells and I continued with the ascent.

The surface was reached at around 4pm, after a steady 7hr trip, and a total trip time of around 80hrs. Unfortunately the weather had deteriorated somewhat, and as I made my way off the hill heavily laden with two rather large bags I was beginning to wish I was back in the cave. Needless to say, the weather soon improved and around 1.5hrs later I caught up with Helen Blyth and David Magdalena, and scrounged a lift back to camp. A celebratory meal in the bar provided a fitting end to a fantastic trip, certainly one of the best foreign trips I’ve ever done, being up there with the Gouffre Lonne Peyret which I had done with Tom in 2007.

This was to be my last trip underground before flying back to the UK on Sunday morning (many, many thanks to Tom and Simon for giving me a lift). I still hadn’t heard from Jason when I had left, but everyone should be out and the cave de-rigged as I am writing this.

The BU56 certainly provided a very memorable and breathtaking caving experience, and is definitely one to do if you get a chance, being much better than the PSM through trips and providing more of a ‘caving trip’ than the Berger and many others can. Even though the water levels during the expedition were much lower than they normally are, I can still understand why the discoverers of the cave wrote about it: “Emotion guaranteed".
Hmmmmm, what to do in 2009!!!!.......

Mike Bottomley


There are many club organised caving weekends, with a mixture of easy and difficult caving.  Over the past few years we have given lots of people the opportunity to experience caving with our "Try Caving" events.  These are quite popular and quite a few people have subsequently joined the club. We have YSS members caving most weekends so it is easy for new cavers to tag onto the easier caving trips and find people to help with more training.


Old School House
Austwick Road
Helwith Bridge
North Yorkshire
BD24 0EH

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