DYO – In search of the Pinnacle Series

On Sunday we ventured into Dan Yr Ogof in search of the Pinnacle Series. On our previous trip to DYO we’d passed an entrance to the series and acknowledged that a return trip was likely. We were looking forward to playing in the ‘The Playground’ and admiring the walls of the ‘Painted Chamber’.

To make swift progress we decided to wear wetsuits which would enable us to swim through the Green Canal instead of taking the longer route through the bypass or the higher, slower route above the canal in the rift. Brendan reckoned that this would save us at least 20 minutes! Richard and I still question whether wearing wetsuits actually did save us 20 mins, given that:

  1. it took at least 10 mins to squeeze into the quite old and slightly small wetsuits.
  2. the extra physical effort of wearing a wetsuit whilst climbing, crawling and walking most certainly slowed our progress by 10 minutes.
  3. it took at least 10 mins and the help of Richard to remove said wetsuit.

Anyway, since Richard had spent the previous evening mending the 25 cm wide tear in the rear of his wetsuit, we weren’t going to opt for furry suits at this point. When we saw the water level in the Lakes (the first wet bit in the cave) I was additionally happy that I had chosen to wear mine. Do you recall the Lakes? well it is a 3 m wide passage that on Sunday was neck deep in water with quite a significant flow. Normally one shuffles up one side of the passage and then at the well-chosen spot crosses to the other side without putting ones foot in the deep channel in the middle of the passage – the problem being that you have no idea where this is. This is less important when wearing a wetsuit because you are more buoyant and don’t mind getting wet! However, my leap of faith didn’t exactly go to plan because the flow rate was such that I couldn’t get my feet on the floor again, so I ended up hanging onto the opposite wall of the cave until Richard managed to sink my legs somehow.

After the Lakes we headed for the evil little climb. It was on this climb that Richard’s rear proved to be too large for his newly stitched wetsuit….. I think this will be the wetsuit’s last trip.

Anyway, the Green Canal was enjoyed by … eerrr me … and then after the Rising and the descent up and down on ropes (which is hardwork wearing a rather warm wetsuit) we arrived at Pinnacle Chamber. Remember we pass through here just the other week.

The Pinnacle Series was located directly above and to the right of Pinnacle Chamber. Richard climbed up a tube that was the obvious way into the Series, but we didn’t follow because the climb was a bit tricky at the bottom and Richard dislodged a rock that didn’t exactly fill us with confidence to follow on. We were sure that there was another easier route into the series, so we allowed Richard to make his way through the upper series and then we walked the bottom series with the proviso that we would meet back at Pinnacle Chamber in 30 mins. We hunted and hunted for the way up from the bottom and called to Richard regularly, to no avail. After 30 mins we arrived back at Pinnacle Chamber and found that Richard had only been able to progress in that direction for a miniscule distance because there was another slightly tricky rope climb that he wasn’t going to scale alone. So, we helped Richard down and then again went in search of the missing link from further up the passage. This passage, called North Bypass, was fairly pretty, which was good because we never found the other entrance and so we weren’t able to play in The Playground or admire the Painted Chamber. We did spend about 2 hours in that chamber searching though …. so we gave it our best shot.

Rachel at North Bypass
Richard at North Bypass
Shaun at North Bypass
North Bypass

All pictures are courtesy of Brendan who took his small camera this time … with only 3 flash guns …

Maybe next time, after a few more discussions with other cavers we’ll find the way in. But, before we do, I must cut the arms of the wetsuit off at the elbow and the legs of the wetsuit off above the knee. That would make life so much more comfortable.

To the Far North

Those boys from Dudley Caving Club have figured out that if they need sherpas for caving wilderness photo shoots, then we are the bees knees. Not only are we young, strong and willing to carry large, heavy black boxes, but we also make fine models and carry pork pies to share. So, into Dan Yr Ogof we went. What a delightful cave. Within 10 minutes of the carpark, you’re up to your neck in freezing cold water and climbing awkward rifts with no footholds. After that it’s relatively plain sailing for all of a few metres before entering the long crawl which continues for about 10 km (or so it seems). Once past there, the situation improves a little.

In the large chamber after the long crawl, we decided to temporarily stash the quiche that Brendan had carried into the cave on Keith’s behalf. We decided that it would not last much longer in it’s cardboard box if it continued any further. We also figured that a snack at this point in the cave on the return journey would be most welcomed. The quiche and it’s rather crumpled box was stashed behind a rock and we continued.

We took the passage to Crystal Pool, that led into Elliptic Passage, which led to a crawl that drops you into Bakerloo Straight. From here we went through Thixotropic Passage (a little bit muddy), into the Abyss, up a ladder to trenchways, then through Go Faster (stomping walking passage), through Go slower (big stomping passage with huge boulders in the bottom) and then into Rottenstone Aven and through to the Rising. We took the rather scary chain-linked ladder up to the Windy Way, and then down the 14 m pitch onto the Great North Road.

Richard heading up the 14 m pitch into the Windy Way. Courtesy of Brendan Marris

The Great North Road carried on for a fair while until we came to Pinnacle Chamber, a place that marked the start of the part of the cave that we actually came to visit!

Pinnacle Chamber. Courtesy of Brendan Marris

We meandered through The Meanders (funnily enough whilst we were wearing Meanders) and then went through to the Mostest. These two final destinations were really quite pretty. The Meanders is a fabulous piece of stream passage with a really high roof – we took lots of complicated photos there.

Keith in the Meanders. Courtesy of Brendan Marris

The Mostest has lots of pretty formations, the best of which was probably an entire wall covered in white flowstone, below which the passage floor was a mass of creamy cauliflower-type things in the water.

The Mostest. Courtesy of Brendan Marris
Flowstone in The Mostest. Courtesy of Brendan Marris

We took the best part of 100 photos, ate the pork pies and then started the long journey home. By the time we got to the quiche we were hungry and therefore, despite it having seen better days, the entire comestible was consumed. It was good – although it was not the best timing given that we were just about to start the long crawl. We made it through and out the lakes and were back at the cars by 8 pm and after 10 hours in the cave! After consuming cake (sorry no pictures), we retired to the Gwynn and ate. We even had room for dessert, how could anyone say no to one of these ….?

Brendan and his strawberry pavlova

On the morning after, we considered opting for a sofa Sunday. It nearly happened, but unfortunately someone uttered the words let’s go and off we went. With ankles and wrists slightly damp in yesterday’s caving gear we walked up to Top Entrance of OFD and headed in for a bimble around. One point to this trip was to locate a particular rock formation that required photographing for one of my colleagues. Unfortunately I had forgotten to ask exactly where it was and I only had a conceptual description of what it looked like, along with a half an idea of where it was near from one of Brendan’s pictures! After a good 3 hrs wandering around the cave (not all in search of the rock formation) we located the rock about 100 m from the entrance. A nice trip was had and it left us suitably knackered, which meant that the weekend was probably over. Another weekend, another set of aching muscles.

BoB(ing) along

The sunny weather this weekend promised good caving but the rainfall during the week meant that sump conditions were likely to be poor. To improve our chances Andrew and I waited until Sunday for our digging trip into BoB in DYO. We were not disappointed, the dive conditions lived down to our expectations although on the up side the water was warmer than winter.

the-trusty-rock

We found the same rock that we had previously used to measure the height of the water and since it worked last time we decided to use it again.

mud-bank-before-digging-out

attacking-a-mud-bank

At the dig face Andrew made quick progress with the sand and silt layers. Unfortunately it soon became apparent that with only one person to move the spoil progress was going to be slow however fast he dug. Work at the dig face was abandoned in favour of cutting a channel through some of the mud banks that make moving the spoil hard work. Good progress was make in between checking the rock.

moving-spoil-a-the-bottom-of-the-slope

Whilst digging the face a draft was felt through the tunnel leading to the dig so prospects for future trips look good. If we can get another person in to help progress should be good.

pigs

DYO BOB Digging

After a week of undramatic weather Andrew and I planned a trip into BOB in DYO. We planned to meet Bernie in the car park for a chat about the tape on the way to Corbels inlet before hand. The result of this chat was that we can’t (as we expected) cross the pool that is taped off owing to the delicate nature of the water born formations that are forming. He did however point us in the direction of some passage that doesn’t appear on the survey that may bypass the taped off pool. We will have to go and look some time…

Whilst chatting to Bernie we also met Gary, a Welsh section trainee who was coming along with us into BOB. As we moved the kit to the entrance via the rope drop a shower started. With the river issuing from the cave showing signs of increased flow flow from the hilltop sinks we decided to keep a close eye on the water levels in the cave during the trip. After kitting up at the usual spot we dived through in poor vis, the route on under the aven offered no improvement and a search of the side walls of the flooded section of the aven also proved fruitless in the conditions.

bob_climbing_waterfall_gsh

After climbing up the aven we all headed into Gwynn Saunders Hall to show Gary around. Having three of us allowed Andrew to use more photo gear but we still need bigger flashes to do the place justice. After photographing the waterfall, the duck and the phreatic passage we went up the slope to the dig.

bob_view_to_duck

With three of us working spoil movement became easy, one person dug, one towed the spoil trug along the tunnel and the third dragged it to the mud slope and dumped the contents to be removed by the next flood pulse. A careful eye was kept on a rock we had placed on the waters edge in the passage below and when the water started to rise around it we called it a day.

bob_view_from_t_junction

DYO Corbels chamber

Having spent the Saturday attending the CDG AGM near Crickhowell I was looking forward to a day underground. As I was just recovering from a cold I had the previous week, diving was out so a dry trip was planned into the Corbels inlet in DYO with Andrew. The aim of the trip was to carry a length of thick walled hose pipe into the inlet to set up as a siphon so that we can drain the static sumps in the passage.

corbels_crawl2

Turning up in the car-park, we parked out of the way of the tourists to change before strolling into the show cave with the pipe. Corbels chamber is close to the entrance but still required us to wade through the lakes before doing a short section of dry caving that includes a good variety of passage. The water levels were low and the water was warm (if your wetsuit fitted well; like mine LOL ) with very little flow. On the way in we took our time and admired the plentiful formations.

formation_off_corbels_crawl_21

The final passage into Corbels chamber is a bedding crawl with beautiful formations to each side before a final thrutch up into the chamber itself.

formations_off_corbels_crawl1

In the chamber we quickly found Corbels inlet passage; our chosen target. This passage like the rest of DYO has been tapped to guide cavers clear of the formations thereby protecting them. Halfway up the passage towards the sump we found that the route ahead had been tapped off. We had no alternative but to abandon the plan and retreat so that we could consult with the Cave Access Committee to see what the next move will be.

hose_in_corbels_chamber2

We made our exit to a sunny day. Waterproof seat covers were put in place and we drove along the valley to the SWCC hut to change out of our wetsuits away from the show cave customers before the drive back home. On arrival we found two happy looking pigs.

pigs_shot1

Back in BoB

All the snow melt has cleared, the rain stayed away and a trip into Battle of Britain in DYO was on. Our aims were to repair the equipment cloths line, line laying and do a smoke test. We were also desperately keen to get some pictures for Pete as we both know how much he likes them.

Andrew and I arrived at DYO and carried some kit up to the entrance before returning to the car to change. We had arranged to meet Bernie who appeared out of the cave and handed over a smoke kit. We agreed to let the smoke off at 2pm and synchronised watches.

The water was at the normal level and clear. After diving through to Hard Cheese, Andrew set about repairing the cloths line and I set off to lay some line out in a Southerly direction across the bedding plane. The idea being to create a large target to hit on a planned future dive from the outlet from Gwynne Saunders Hall. Unfortunately the bedding thwarted any attempt to head South and the line ended up trending WSW (ish). Progress was made over floor pots connected by phreatic windows until 20 m of line had been laid at which point a final belay tied on to the same point as an old bit of line. This turned out to be Andrew’s old final belay from 20 years ago when he was trying to find the way on before the dry stuff in BoB was found. On that trip he had gone about 6 m beyond the belay but with no new belays available had turned the dive.

Out of the water and in the dry passage at the SW corner of Gwynne Saunders Hall where we had felt a draft on a previous trip the smoke test kit was prepared. We started the test just before 2pm by lighting a jos-stick (sp?) to satisfy ourselves that the smoke was blowing away from us and into the cave beyond where Bernie and his team would be waiting to try and spot where it came from. Once we were happy with the direction of the draft we lit several of the smoke pellets and retreated to a safe distance. The smoke was running up the rift well and not blowing back into BoB. We made our exit to the sunshine.

Speaking to Bernie later he reported that no smoke or smell was detected. This is a disappointing result. A lot of smoke went up the rift in BoB and it must have gone somewhere but we don’t know where. The two passages we were looking at may be connected and the result could be down to the direction of the draft but with the amount of smoke that went up the rift the link looks unlikely unless there is an large alternative passage connected to it.

It was a very good and useful trip, the only downside was that Andrew’s camera flooded. So no pictures. (Tish, I have the phone number for the Samaritans for Pete if you haven’t got it.)

Dan Yr Ogof, that sinking feeling….

Building up the shots for the photo library of the Dan Yr Ogof cave means that we do get to go to some obscure places, and this trip was to be no exception. The aim was to go to Productus passage, a Phreatic tube high above the Green Canal that contains lots of glutinous mud.

Richard in Productus Passage above the Green Canal - Dan Yr Ogof
Richard in Productus Passage above the Green Canal - Dan Yr Ogof

En route to the Green Canal we stopped off to look at the pretties in Flabbergasm Oxbow and also provided action sequences for Keith’s video as we went through the Long Crawl. On reaching the Green Canal I carefully wrapped my SRT tackle bag in a life jacket to ensure that I did not befall the fate of Keith, but I hadn’t got 10m along the canal before I realised that bag had come away from the life jacket and was now at the bottom of the canal! After a couple of minutes treading water in search of the bag we carried on and shared kit to get up to the passage 20m above the Green Canal.

Richard viewing a straw column in Productus passage
Richard viewing a straw column in Productus passage

The passage takes its name from a prominent fossil marker bed. The roof of this passage is so thin in places that it collapses and the shale band above drops down to form small chambers. It is in these small chambers that some beautiful arrays of straws and formations are found.

Keith in a shale collapse Chamber in Productus Passage
Keith in a shale collapse Chamber in Productus Passage

DYO Battle of Britain rematch

With the weather still holding we headed to South Wales and the Dan Yr Ogof cave system. Our aim was to give the Battle of Britain series a better looking at and maybe findout what has caused the change in water flow in DYO. This time Andrew avoided the snuffles and after a quick carry in we both dived through on the line placed last time. In the Hard Cheese Airbell the dive gear was stowed and we climbed up into the passages beyond, quickly reaching the place I turned at last time. Andrew’s memory of the passage up to this point was as poor as mine had been last week.

andy-in-hard-cheese-airbell

Andrew dekitting in Hard Cheese Airbell

At the point where it looked like the roof comes down to the water we followed the in-situ dive line along the right hand wall (North wall) around a slight curve. At this point Andrews memory of the place started to return. The line was originally put in place to mark the route through the passage using the available airspace. After several meters of swimming we entered Gwyn Saunders Hall where a waterfall lands from a rift high above in the roof.

colin-behind-waterfall-gwyn-saunders-hall

Colin behind the waterfall in Gwyn Saunders Hall

We skirted the pool in the middle of the Hall and scrambled up the bank to the South West to look at Lake Zero; this is the route via which the water from the upstream cave enters Battle of Britain series. The water in Lake Zero was clear, unlike the water in the pool we had just climbed out of which was very cloudy. Further up slope from Lake Zero was a tall sand bar which came close enough to the roof to reduce us to crawling. Dropping down the other side of this we found the other entrance into the sump that connects Lake Zero with Lake One; the water was clear.

colin-eye-hole-zero-to-one-sump

The flood overflow for the sump between Lakes One and Zero

Having looked at the sump we climbed another sandbank that this time did hit the roof, leaving only a small opening to crawl through to reach the end of the Hall. At the most Westerly point of the chamber, next to some formations there was a notable draft.

colin-top-gwyn-saunders-hall

The formations were the draft is…

Returning down the sandbanks we had another look at the water colour and levels. We then looked at the sumps in the canal passages to the South of Gwyn Saunders Hall and the passage out.

colin-canal-exit-gwyn-saunders-hall

Canal passage South of Gwyn Saunders Hall

Before heading out we had a look at a bedding crawl below the climb up at the shelved passage and followed it to two sumps. This passage is not marked on any of the surveys we have of the area but we think it is very close to the Hard Cheese Airbell. The dive back through to the resurgence cave was uneventful.

colin-surfacing-after-trip

Surfacing after the dive out

Conclusions

We think that the water levels in the main cave area are responding much more quickly to rainfall owing to sand deposits in Gwyn Saunders Hall. The sandbank between Lake Zero and the flood overflow exit from the sump is restricting the flow rate in times of high flow. We also think that there may be a partial blockage in the sump passage that leads between Lake Zero and the pool in Gwyn Saunders Hall. When the flow rate increases these two restrictions are causing the water level in Lakes One up to Four to rise as the water backs up and fails to flow into Gwyn Saunders Hall at the normal level.