Last updated: 31-Jan-2025
Black Mountain, South Wales, U.K.
The cave is best approached from the mountain walking parking area at Dan yr Ogof, next to the camping area. Follow the mountain path steeply upwards. After some sheepfolds, the path climbs along the top edge of a forest. Ignore an old quarry track to the right. The path then becomes smaller and zig-zags steeply upwards. Soon, it rejoins the track, and continues up to the left, along the top of the forest. At the top of the forest, the path swings away from the forest wall, and soon bends left then turns a hairpin bend to the right, where another track continues ahead. Follow the hairpin around to the right, towards Tunnel Cave and the main Black Mountain path. 50 metres after the hairpin bend, take a smaller path to the left, which soon passes between two significant shakeholes, then immediately splits. Take the left branch, heading up to the left edge of a small crag. After ascending to the top of the small crag, the path runs between limestone outcrops, to reach a dry valley. It turns right and descends into the dry valley, where the path splits. Take the right branch towards an obvious, large boulder. The entrance lies 10 metres beyond the boulder, in a shallow depression at the edge of another limestone outcrop.
No control is placed over access.
In heavy rain, the Second Pitch and Fourth Pitch can become unpleasantly wet, but remain passable. Fifth Pitch is often too unpleasant in such conditions. In flood, the Terminal Sump and Fifth Pitch can back up to form a lake a couple of metres deep at the base of the pitch.
The entrance drops down between rocks, then drops 2 metres down a wriggle beside a boulder. Footholds do exist, but you have to feel around for them. At the bottom, a low arch in one direction ends quickly at a small inlet, while the other direction increases to walking height, and there is space to kit up. The passage descends quickly to the pitch head of the 9 metre First Pitch. A couple of metres before the pitch, a passage above reaches a ledge of rocks, but is blind.
From the pitch head, the main routes through the cave use P-hanger resin anchors. The first pitch anchors consist of a backup, a traverse anchor, and Y-hang. The route down First Pitch descends 6 metres until it bumps into the wall, and stepping down a cleft then reaches the large ledge at the bottom of First Pitch, where it is best to remain on-rope.
Where the First Pitch route first bumps into the wall, a scramble up boulders underneath the pitch head leads under a very loose ceiling made of boulders (warning, this area is best avoided). In wet weather, this passage is almost invisible behind a curtain of water. The route quickly leads over and under boulders to a loose arch into a blind aven. A very loose pit in the floor has a visual connection back to the start of the boulders.
From the bottom of First Pitch, the 17 metre Second Pitch begins immediately with a backup and Y-hang on the left wall, with a rope rub immediately below it, which does not normally need a rope rub protector, as long as you are careful when moving below it. This drops to a hanging rebelay Y-hang on the left, where two routes diverge. The main route is to descend to the bottom of Second Pitch. An optional deviation part way down may be desired in wet weather, to reduce swinging into the water. The route lands on a small shelf next to a large pillar. On the opposite side of the pitch base are a blind rift on the right, and the main way on along a narrow rift to the left, where the first backup anchor and traverse anchor for Third Pitch are located on the right wall. The main way on immediately reaches the Y-hang at the head of Third Pitch.
Third Pitch has two options. The main route to Fourth Pitch is to descend to a deviation on the right wall, then pendulum into a passage in the left wall 4 metres above the floor, 7 metres below the top of the pitch. There is an anchor on the right wall of the passage. The other option, which does not reach the way on, is to descend all 10 metres to the floor, using the same deviation. The stream flows in from under the way in, and flows out down a narrow rift. The rift is only 4 metres long, and becomes too tight, with visual connections to the wet rift in Fourth Pitch and through boulders up to the main route to Fourth Pitch. From the base of Third Pitch, following the obvious, tall rift away from Second Pitch, up a sandy step and through a shallow pool, reaches a climb up beside boulders. This ascends to a balcony, where a further climb up boulders reaches a boulder choke.
The main route to Fourth Pitch descends a climb and quickly reaches a Y-hang backup. The route descends a rocky climb beneath an aven, to reach the main Y-hang of Fourth Pitch. CUCC Old Flyover soars overhead. The pitch drops to a deviation on the left wall, the closer and lower of two P-hangers. At this point, a wet rift passes back under the way in, which climbs very steeply up cascades to pinch out with a visual connection to the stream passage from Third Pitch. From the deviation, the main route descends to the base of the main part of Fourth Pitch, 20 metres below the Y-hang. The obvious outlet drops down a 5 metre pitch which can optionally be free climbed in dry weather, but is best treated as a pitch. A rebelay anchor is on the right wall at the end of the ledge, which has an optional second anchor for a Y-hang. This lower pitch lands in a chamber at the bottom of Fourth Pitch.
The route into CUCC Old Flyover starts from the rebelay on Second Pitch, and consists of a bolt traverse of 4 resin anchors, landing on a small, sandy ledge. The first anchor is best reached with a long loop of rope, abseiling down from the rebelay, then changing over to prusik up to the first anchor of the traverse. At the ledge, the way on is down an obvious hole in the floor. However, an aven above needs climbing equipment to reach a very short side passage, which immediately reaches a dead end in one direction, while the other direction immediately falls back down Second Pitch. Back on the ledge, SRT gear will normally need to be removed, as the way on drops down a feet-first squeeze where a handline is useful for hauling equipment. The squeeze ends in a very narrow passage. The narrow passage quickly reaches a narrow climb down, which is awkward on the return. A Y-hang backup starts on the right wall immediately afterwards. A short climb then lands at the head of the 47 metre CUCC Old Flyover pitch, one of the largest in Wales.
The CUCC Old Flyover pitch has Y-hang anchors on the right side, and drops to a rebelay Y-hang on opposing walls just a few metres down, where the pitch starts to open up. This is followed by a Y-hang rebelay then deviation on the overhanging wall. Just after the pitch narrows is a Y-hang on opposing walls, below which a blind side passage produces some flowstone, and a large alcove is blind (its sandy ceiling presumably connecting with packed sand on the wall of the pitch). The route then has a deviation on the overhanging wall, the closer and higher of the two resin anchors. It then switches walls, with a Y-hang rebelay at the top of the cleft that leads into the lower pitch of Fourth Pitch, and descends into the cleft. At the ledge at the bottom of Fourth Pitch, it uses the main rebelay for the lower pitch of fourth pitch, at the end of the right ledge leading out onto the pitch. It is best to use both P-hangers to make a Y-hang rebelay, to avoid the possible rope rub that would happen if one anchor failed. This lands in the chamber at the bottom of Fourth Pitch.
At the head of the last drop down Fourth Pitch, a small rift opposite the P-hangers is a crawl leading to a pitch down into the chamber at the bottom of Fourth Pitch. This route is not used.
From the chamber at the bottom of Fourth Pitch, a steep slope of boulders passes the main way on to the left, then a low undercut to the left. Ahead is a short side passage which ascends steeply to a pair of too-tight avens.
The main way on is a rift below a jammed rock, and drops down a hole to avoid a much more awkward climb. The alternative undercut joins from the right, and the combined way on drops down a climb into a larger chamber. High overhead is Loose Slab Aven. Up on the right wall is a bolted climb into a rift, while the main way on is down a hole in the floor on the left side of a jammed boulder. The jammed boulder can be used as an optional backup, or there are unofficial spit hangers on the left wall of the chamber that can be used for the same purpose. The hole in the floor descends a rocky climb to immediately reach the head of the 14 metre Fifth Pitch. This has a backup anchor and traverse anchor on the left wall, then a Y-hang on opposing walls. The pitch can be very wet, especially in wet weather, so there is a deviation 2 metres down on the overhanging far wall.
At the base of Fifth Pitch, the route lands on rocks. The walls are adorned with obvious Lithostrotion fossils, sitting quite proud from the walls. A deep pool is at one side of the pitch base. To its right is the obvious way on. At the opposite end of the pitch base, close to where the route landed, is climb into a short crawl ending at a choke, with a blind alcove to its left.
From Fifth Pitch, the obvious way on is a short climb up into a rift, with a latticework of higher levels and connections between them. The passage quickly reaches a climb down, assisted by a metal ladder, to a scaffolding platform above the sump. The sump is 4 metres deep, undercutting to the left and ahead, with the outlet at the deepest point on the right. This has been dug for many years without success, and the passage extends only about 1 body length in from the sump chamber. In wet weather, the sump backs up considerably, and the water has been known to wash items into the passage before the sump, about 2.5 metres higher. The bottom of Fifth Pitch becomes a lake in those conditions.
On the other side of the scaffolded platform is an inlet, which passes under a rocky climb, then becomes too tight. The rocky climb is 5 metres high, assisted by an unofficial handline. At the top, the latticework of passage above the pitch can be seen more clearly. Continuing away from the sump, a stooping/crawling passage soon reaches a climb up through scaffolded rocks into the base of Enterprise Aven. To the left is a chamber with a choke made from enormous boulders, and a blind inlet in an undercut under the right wall. To the right is a steep ascent into a blind, narrow rift. Up above is an 8 metre pitch into the main part of Enterprise Aven. This can be free climbed with care, but is best treated as a pitch, though any rope left on the pitch is not officially maintained.
From the head of First Pitch, a crazy bolt traverse route starts on the left wall high overhead, then immediately switches to the completely blank right wall, using unmaintained spits and through bolts (hangers required). It reaches a Y-hang in the ceiling above Second Pitch, descends to a rebelay on a buttress on the left wall, then rejoins the main route at the rebelay on Second Pitch. This route is not advised.
Most of this route relies on unofficial through bolts (hangers required).
The bolt traverse used to access CUCC Old Flyover remains the same. At the CUCC Old Flyover pitch, the backup Y-hang and top Y-hang are the same. After descending the start of the pitch, the route instead heads out to the right, to the opposite end of the rift. 1 metre above the normal CUCC Old Flyover's first rebelay Y-hang the first rebelay for this route is on the left wall, at the lip of an overhang. From there, the next rebelay is nearly 2 metres away and 1.5 metres lower down, at the far end of the rift, and is a Y-hang on opposing walls. A too-tight side rift has a visual connection with a later aven. From the Y-hang, a 12 metre descent reaches the mouth of a narrow keyhole-shaped cleft leading into a side aven, with an anchor on the overhanging wall.
The route passes through the keyhole, which is a squeeze while remaining on rope, with another traverse anchor at its far side. Once on the tiny floor of the blind side aven, two more opposing anchors are used for a Y-hang, where a 7 metre descent reaches an anchor next to the main route's Y-hang on the Fourth Pitch.
Loose Slab Aven is a 20 metre pitch, with two rebelays leading to its Y-hang. It may or may not have an unofficial rope hanging on it, and the unofficial anchors cannot be inspected from below. At the top, a climb up reaches a squeeze under a rock into a very narrow rift. The rift ascends little climbs to reach a choke after 10 hard won metres. This choke is several metres below the base of Third Pitch.
At the base of Loose Slab Aven, directly above the wedged boulder above Fifth Pitch, a bolt climb using unofficial through bolts (hangers required) gains a short rift passage that ends in silt. The rift has a very tall aven which is too tight to get into, but looks much larger above. The floor at the start of the rift is not solid, and is formed from rocks jammed into the ceiling of Fifth Pitch, with a visual hole down into it at one point. It is best to remain safely attached to a rope.
From the head of Fifth Pitch, a 3 metre descent lands on a ledge below the lip of the pitch. It may be best to use an unofficial anchor to the right of the main Y-hang's resin anchors, as well as one of the resin anchors, to set up a Y-hang that lands in a better position. The ledge has 5 unofficial hangers which can be used to traverse along the ledge, away from the Terminal Sump. This gains a very low crawl, 4 metres long, passing under a blind aven, to reach a much larger passage where there is a final unofficial anchor. This passage has sand deposits on the floor, and sadly is very short lived, as it slams into a choke. Several avens connect to a later part of the passage. On the left side of the choke, at the top of a slope, a small passage passes a climb up into the choke, then a bedding on the right leading into the choke, before ending in silt. The two routes into the choke unite in an unstable chamber, with holes dropping back down into the earlier large passage. In the ceiling, a bolted aven (climbing equipment needed) reches a short section of passage ending in a higher level of the same choke. The choke lies below the balcony of Third Pitch.
Any ropes and anchors on Enterprise Aven are not officially maintained, and cannot be inspected from below.
From the base of Enterprise Aven, the 8 metre first pitch up can be free climbed, but is best treated as a pitch. It usually has water splattering in from high above. This reaches a Y hang and backup at a ledge of jammed rocks, which can be followed out into the main part of Enterprise Aven, one of the largest pitches in Wales. Enterprise Aven may have an unofficial rope hanging on it. The second pitch ascends 12 metres to a Y-hang at a small, sloping ledge with 2 traverse hangers. At the head of this hang, a rift heading away from the main aven has been bolted across for some distance, but becomes too tight.
From the ledge, the third pitch starts with a pendulum across the main shaft before ascending 11 metres to the next Y hang. A side ledge of jammed boulders has nothing to offer. The Y-hang has a bold step across to the cleft opposite, where there are 2 traverse anchors. Leaving the rope, a short side passage following the cleft's rift, reaches a too-tight aven.
From the top of the third pitch, the fourth pitch climbs up the narrow cleft above. Half way up, a traverse ledge can be followed, without the rope, to yet another too-tight aven. The fourth pitch ends after 11 metres at a proper pitch head with a Y-hang, and one final backup. A rift to the side is blind.
From the head of the fourth pitch, an obvious passage passes beneath a large, wedged boulder to the base of the fifth pitch. The passage continues beyond here, passing through a squeeze into the bottom of another small aven. Ledges above the squeeze close down.
The fifth pitch is 7 metres tall to a Y-hang, but has no ledges big enough to stand on. Back over the top of Enterprie Aven is a ledge of wedged boulders, where a too-tight fracture and solution tube both enter the top of Enterprise Aven. In the opposite direction is the top of the rift above the passage below, and this is the way on, into A Thutch Too Far.
Going any further needs SRT gear to be removed, without anywhere good to stand. This means taking it off and leaving it at the pitch head, but remaining safely attached to the rope using cows tails, so a belay belt might be mis-used for this purpose. A Thrutch Too Far starts off as a crawling sized vertical rift with a narrow gap in the floor dropping back down the fifth pitch, and is quite demanding. A hauling line is useful for equipment. Getting into the passage safely is a difficult task. The thrutch is 10 metres long, and has a small resting spot after 5 metres. Beyond this, it reaches an enlargement, where the way on it to step up to a higher part of the rift, where standing becomes possible. The passage becomes a lot more easy, and soon reaches a water worn section where a stream showers in from a too-tight aven above. A climb up at the far end of this section reaches a narrower passage, which ends at calcited sediment infill, just after a squeeze. The end of this passage is very hard won.
The cave was originally descended using ladders, but is now configured for SRT. There are too many SRT tackle options to list here. See the rigging topo for tackle options. However, if you would prefer to use ladders, traverse lines should be used for safety when approaching pitch heads. Tackle list assumes resin anchors are used rather than naturals. Second pitch has a shorter ladder hang using a large boulder belay that lands on a rock pinnacle. The climb up from Third Pitch to reach Fourth Pitch has become extremely slippery, and one good climber needs to rig a ladder for others. Fourth pitch can theoretically be done with a single 30 metre ladder, but this places the lower part of the climb in the full force of the stream, and mashes fingers against the rock.
| Pitch | Traverse line | Ladder | Lifeline |
|---|---|---|---|
| First Pitch | 6 metres | 10 metres (33 feet) | 22 metres |
| Or free climb the bottom section of First Pitch | 6 metres | 6 metres (20 feet) | 22 metres |
| Second Pitch | 4 metres | 19 metres (62 feet) | 40 metres |
| Or Second Pitch rock pinnacle | N/A | 15 metres (49 feet) plus 8 metre belay | 40 metres |
| Third Pitch | 7 metres | 12 metres (39 feet) | 26 metres |
| Third Pitch climb up | N/A | 4 metres (13 feet) | 10 metres |
| Fourth Pitch | 10 metres | 23 metres (75 feet) | 62 metres |
| Fourth Pitch lower drop | N/A | 7 metres (23 feet) | use upper lifeline |
| Fifth Pitch | 7 metres | 15 metres (49 feet) | 32 metres |
Even if rigged with perfect ladder lengths, made from the thinnest wire with wide rung spacing, and refusing to use traverse ropes, it would take a huge team of 16 people before their ropes and personal SRT gear weighed enough to equal the weight required for the ladders and lifelines. Once the lifelines get wet, they would be even worse. Real ladder lengths and traverse lines would make it closer to 20 people. For normal team sizes (under 16 people!), SRT is far more efficient in this cave, in terms of equipment weight.
Whilst every care has been taken in the compilation of this cave description, neither the author nor his fellow cavers can accept responsibility for loss or injury arising from any errors, omissions or inaccuracies in this cave description.
This description is subject to copyright. The copyright resides with the author and some other contributors. You are welcome to download, store, retransmit, print and distribute this document PROVIDED THAT (1) you do not do so for any form of reward, financial or otherwise, and (2) all references to the author are retained or otherwise clearly acknowledged. Any infringement of these conditions is an offence in the UK and also in most other countries.
©2025 MWJ