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Last updated: Thursday, 20 January, 2005 1:07

Explorations at the end of Priory Road

By Martin Beale   8 January 2005
Cavers: Martin Beale, John Stevens
Time: 13h17m
Cave: Agen Allwedd
Areas explored: Bunker, Cathedral, Iles Inlet, Birthday Surprise and MOAB
Photos: Plenty (also linked in the report)

The weekend of January 8/9 was a stormy affair. Little branches had been blown off the trees making the drive down to Anwens bakery quite treacherous. The horizontal hailstorm on Saturday morning dampened our desire to walk over to Aggy. Moreover, this weekend, everyone seemed to be ill. Tom and Arthur were definitely ill, John was starting being ill and I was finishing with being ill. Despite this, John and I were still up for going caving down in Priory Road.

As we were getting changed, two cavers knocked on the door asking for Martin: they had come to help Martin with the dig. I met these guys and was quite perplexed as I had never seen them before. Still, if they wanted to dig with us, I was more than happy. A minute later Martyn Farr walked through the door of Whitewalls and all became clear: the unknown cavers were on a trip with Martyn to the North Wing of Aggy.

We had a chat with Martyn about his North Wing effort (which by all accounts is looking very promising) and about the end of Priory Road. Yet again, Martyn was enthusiastic about a slanting roof tube that drafted well in The Bunker area (Stuart France had also been enthusiastic about a roof tube at the top of the 6 metre pitch down into The Bunker). He reckoned that this area was worthy of further investigation. Martyn was a little less enthusiastic about the MOAB choke up which they had driven a scaffolded shaft years ago. Martyn was well interested in the Testo and suggested that such modern technology should be applied to caving more widely. The Testo had not exactly covered itself in glory on previous trips, but it was worth giving it another go.

Armed with the alluring prospect of good drafts in Aggy (with the changeable weather) and the promise of some exploratory caving to parts of Aggy that had not been visited in years, we trooped off out of Whitewalls and towards Aggy. John walked leaning forwards into a howling gale. Neither of us spoke: it was futile, you couldn't hear each other in the wind and the only thoughts in our heads was the misery of the weather. Waterfalls were pouring off the Llangatock hillside and out of strange little holes in the quarry face.

There was surprisingly little draft in Aggy given the tempest unfurling outside and there were a surprising number of bats. The bats were hanging all over the place off the roof of the entrance series.

We stopped part way along the entrance series and used the crowbar to remove a rock that had been partially blocking the way through in the first choke. The way through is now luxurious once more.

Southern Stream Passage was really going for it. This passage never floods, but we could really tell that the water was up and part way down the passage this seemed to initiate a reasonable draft. It was actually quite difficult to crawl in the stream as the water was muddy and you couldn't see when your hands were about to disappear down a pothole: most disconcerting! I was glad to get out of SSP (in the standard 1h10m!). We took a draft reading from the Testo at the point where Gothic passage becomes cobbly and splits to go to Maytime in one direction and Priory Road in the other direction. We got a reading of 0.2m/s in a passage of about 0.5m by 1.5m (volume flow rate 0.15m^3/s) here. The draught was quite noticeable and was presumably caused by air being dragged along by the rapid water in Main and Southern Stream passages.

We took Priory Road gently and looked at the features we saw as we went (as opposed to the usual mad dash to Severn Beach). We ascended into The Cathedral (up a great thrutchy little tube) and investigated the right hand (west) branch. This forms a beautiful arching passage in fantastic rock. All too soon the passage ascends a bouldery slope and meets a horizontal roof tube coming in. We could feel a draft at the end of this passage and the Testo confirmed this. Sticking the digicam into the roof tube seemed to show that the tube continued for some distance. We tried to dig out some of the mud from the area so we could better see what was going on ahead. We only had a chisel with us, but still made some progress. Unfortunately, we were stopped by a larger rock that was clearly going to require crowbaring out. John had a look at a passage that went back (towards The Cathedral entrance) from this terminal area and built a little cairn at a spot where he thought he could see back into the main Cathedral. On returning to The Cathedral, we trained a torch on an obvious potential high level passage and were somewhat disappointed to see John's cairn: this was clearly not the way on to greater things! Leaving The Cathedral, we were however quite excited as we had the prospect of a lead at the top of the boulder pile in the west nave.

We rested and ate some food at Severn Beach. It seemed odd to be sitting there surrounded by a massive spoil heap and not to be digging. There was a somewhat tense atmosphere as we contemplated the push forwards towards Sick Parrot Chamber.

The crawl into Birthday Surprise is not as tight as I remember: familiarity with the crawls into Glevum Hall seems to have numbed by senses regarding tight spaces. In Birthday Surprise, the first thing I was interested in was a vertical shaft going down through boulders on the right hand side. This shaft certainly dropped down through the breakdown into a horizontal sand filled area. There was slight airspace here and the ground was all sandy, but this did not look like a very promising place from which to attack OyDC: the air wasn't hugely inspiring and it would be difficult to remove spoil up the shaft (which is not straight) into Birthday Surprise.

We continued along Birthday Surprise to the drop down into Sick Parrot Chamber. John advanced feet first while I dropped in head first (having a bit of recent experience with this drop). It is a tight little way on from here to Sick Parrot Chamber, but it is thankfully not very far.

Depending on how you look at it, Sick Parrot Chamber is either a historic monument, a mess or a biological laboratory. There was an octopus shaped fungus that had oozed out of a jumper in a plastic bag (possibly the cure for cancer), there was a beautiful calcite like formation of pure white fungus on the floor near the start of MOAB (from which an AIDS vaccine can presumably be derived), the wood hereabouts has completely rotted due to some weapons grade biological agent - you can crush the wood in your hands.

John was absolutely and totally fascinated by the equipment left in Sick Parrot. There is all sorts of equipment here in various states of decay with the occasional rotting jumper or old Mars bar thrown in for good measure (we found one down there with a sell by date of 1992!). There is a sizeable amount of scaffolding in reasonably good condition at Sick Parrot. The bizarre thing about the chamber was the complete lack of crowbars. We found one metal prodding stick and a spade whose wooden handle had completely disappeared (assumed rotted). I was fascinated by the kibble trays and set about liberating two of them in order to extend their useful life down at Severn Beach instead: I succeeded in this quest (these can always be moved back to Sick Parrot when the MOAB diggers renew their onslaught).

John had an explore up the scaffolded shaft in MOAB. Whilst he was doing this, I pretended to be busy with the testo and the camera. He seemed to be away a long time and must have climbed quite a distance for I was running out of things to occupy myself with. Eventually some small rocks tumbling down the shaft indicated that John was coming out (either in or out of control). I was pleased to see him abck with me in one piece.

John started off down the drop into The Bunker. On the last trip, I hadn't been too happy at the prospect of this drop, but John assured me that it would be OK (and the walls were actually quite solid). It is only a 6 foot drop and leads immediately to a

tight squeeze through a triangular shaped slot. John lowered himself into this feet first. All seemed to be going well, but then it was clear that he wasn't happy. He just didn't seem to be able to get his hips through. His concern was that if he couldn't get his hips through then his shoulders certainly wouldn't get through. He eased himself out and looked quite worried (what chance would I have if a caver of John's calibre couldn't make it through this squeeze?). After taking his helmet off and taking a couple more goes (where it looked like he really was losing confidence in making the squeeze), his shoulders and head finally disappeared down the hole. He then retro-dug the hole before I squeezed through.

It is quite surprising when you get to The Bunker as the rock changes from being the red bedded limestone to the fine scalloped grey limestone that you see in the Aggy entrance series and Spaderunner. The passage onwards is a rift type passage that slopes down. There are many little tubes in the side of this passage (and we were looking for tubes as apparently one of these takes a great draught). John found a mouldy bat dropping which he was pretty interested in. It is quite a short distance to P6. When I looked down P6, I could see the bellows: at last I had reached the end of Aggy! P6 has a couple of roof tubes in it. There is a narrow roof tube about 1m back from P6 and a larger tube that opens out directly over the drop. The larger tubes had some scuff marks at the bottom and looked eminently climbable, the smaller tube was also alluring, but was definitely narrower and probably too small to climb. We descended P6 on a knotted rope down to The Bunker proper.

The Bunker itself is a fascinating place. It is another historic monument. The floor of the P6 chamber is filled with the bellows which are amazing (these are no longer strong - presumably the wood is decaying). I was quite stunned to find stals in The Bunker. There is a drooping stal on the wall (as seen in Darkworld) and a beautiful white stal that drips from the ceiling to the floor (with a drip of water right at the end of the stalagtite). Apart from the stals, The Bunker is essentially a very dry and sandy feature. The amazing thing about the end of Priory Road is that Priory Road is an extremely dry feature all the way to the end and then right there at the end, there are two wet features (the stals in The Bunker and the wet mud layer in Grolsch passage). A tube leads from the bellows down into the sand dig (which we didn't follow). Another passage leads north from the bellows. We elected not to follow this either.

We did a little draught test with the testo in The Bunker. We couldn't find any draughts in the horizontal passages down there. However, when we stood at the bottom of P6, there was a definite and substantial draught falling down the aven (the likes of which I had never felt before in Priory Road). The draft measured 0.2m/s on the testo which was very substantial for such a large aven (it isn't possible to measure the volume flow rate, but it is substantial - more than 0.1m^3/s). This was extremely alluring and so an ascent of the aven was called for.

I led. The starting moves were a strange and insecure bridging affair that soon led to foot and hand jamming (what a stroke of luck!). I jammed my way up for about 5m up to a very good thread (in situ - there are other good protection threads here). Given my position (at the deep end of a remote passage in Aggy!), I decided that this was as high as I would go. It was really tempting to climb higher as it was clear that a few back and footing moves up beautiful rock would gain me height and a better view of the roof tubes that surely lay above. I decided that this ascent would have to wait for another day. At my high point, I could see a reasonably large tube heading off up and right (does this join the top of P6?) and it seemed that there might be a small tube above the thread (I couldn't see round into it). It also seemed that there might be another tube heading up and left about 3-4m above my head: again I couldn't reach into this tube. I was happy to have seen that this aven is promising and climbable and carefully jammed back down to John (who was spotting me).

At the top of P6, we testo-ed the two roof tubes. The roof tube that is directly above P6 is the larger (and looks climbable) but I measured no draft there. However, there was a substantial draught going up the tighter roof tube about a metre back. This draught measured between 0.2m/s (in an opening of approx 0.5m by 0.3m giving a volume flow rate of 0.03m^3/s) on the testo and you could feel it on your hand. It seems a shame that the larger roof tube is not the one that draughts. It is possible that the larger roof tube links to the smaller roof tube in some way higher up (there is only one way to find out!).

We took some final draught measurements at the drop from Sick Parrot towards the Bunker. We measured a very feeble draught (at best 0.02m/s) going down the drop (in a 0.4m by 0.4m passage => volume flow rate of 0.003 m^3/s). The left side of the MOAB choke draughts a lot more strongly than the area where the shaft has been dug (we measured about 0.08 to 0.16 m/s in a passage of unknown dimensions). Was the MOAB shaft dug in the wrong place? It is interesting that the strongest draught in MOAB is in the area closest to the roof tubes that clearly draught well.

John had a look down the long dig into MOAB (squiggly bit). He didn't get to the end of this due to the unstable nature of the place [photo2]. This dig would probably require quite a bit of work to bring it up to modern health and safety standards.

After a final look at Sick Parrot, we exited with a kibble tray each that we left in Severn Beach. At Severn Beach, we grabbed the digging tools and transported these out to The Cathedral. I measured a slight draught of 0.02 m/s in one place close to the floor at the end of Grolsch passage (I get the general impression that draughts like to follow the lowest ground in chambers and passages).

We had a look at Iles Inlet on the way to The Cathedral. The scallop marks on the wall here indicate that Iles Inlet is actually an outlet. Iles Inlet is made of beautiful water washed rock (just like The Bunker) and has two pits at the end. It is assumed that one of these pits could lead to a way under a phreatic arch to a continuation beyond the current blockage. This would most likely be a bucket and spade job. Iles Inlet was an interesting feature. It is surprising that we haven't looked at it before.

John and I tried to make some progress in the passage that led to the roof tube at the west end of The Cathedral, but after 2 hours and about 1m of progress, it became clear that the mud ahead just met the roof. Photos that I had taken earlier were misleading. We concluded that the draught had come from a small tube in the roof and had then done a switchback along a wall to where we measured it. This was all a bit disappointing as we had been expecting great things from this lead.

It was getting pretty late by the time we were tromping up SSP. We stopped at the dead bat to take some photos and then exited the cave at about midnight (thankfully the water had gone down a bit on the way out and conditions weren't too grim on the surface: still I enjoyed having a pair of thermal gloves and hat waiting for me at the exit).

It was really good to have an exploratory trip for a change and we discovered a lot of new information on the trip. The Bunker is clearly a very interesting area that will repay further exploration. We really need to understand what is going on with the draughts and roof tubes down there. Plans are afoot....

Martin Beale , Bristol, 14 January 2005


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