Tunnel Cave

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Tunnel Cave is located on the Black Mountain in the Swansea Valley, with the lower section of the cave forming Cathedral Showcave which is part of the Dan Yr Ogof showcaves complex. The cave is quite linear and characterised by long sections of high rift passage which are navigated by traversing in a roof tube in the top of the tall passages. This cave, having two entrances allows for an interesting through trip.
Length 2,135m
Altitude 386m
Grid SN 83694 16545 (Top Entrance)
Discovery of the cave was made through a small resurgence passage, that led to a boulder choke near the lower end of the cave. This was dug during 1953 and the break through into an impressive sized chamber was made on the day after the funeral of David Price. The large chamber that was entered was named Davy Price's Hall in his honour. A tunnel was driven from the surface to allow this chamber to be opened up as part of the Dan Yr Ogof showcaves complex, and is now open to view by the public. The cave was explored bottom up ending at the high passages in Cascade Aven. In 1963 a shaft was dug by the SWCC to intersect the top of this aven allowing passage from the top of the hill, through the cave and down to the showcave. The lower entrance - Cathedral Cave is part of the Dan Yr Ogof showcaves complex, while the upper entrance is located high on the mountain above and is best reached by following the mountain footpath from the showcaves.
Black Mountain East Google map showing the location of Tunnel Cave and other caves in the area Both entrances are best accessed from the Dan Yr Ogof Showcave complex. Please visit the ticket office if parking at the showcave and heading up onto the mountain from there.
Showcave entrance
An fan and airlock are located at the end of Davy Price's Hall and passage through this locked door has to be with the company of a Dan Yr Ogof Warden, see the DYOCAP website for details. Currently access is not possible through the airlock.
Top Entrance
The top of this shaft is locked and keys are held by SWCC (see Cambrian Caving Council for access) Beyond the Showcave is a predominantly a tall narrow rift with a reasonable gradient and progress is often made by traversing along ledges or in the tube in the roof of the passages. The upper end of the cave is a series of high chambers with impressive calcite slopes that lead to Cascade Aven where a shaft was dug down from the surface to intersect the cave. The route through the cave is described from this top entrance and through to the showcave.

Directly below the gated entrance a 12 m shaft breaks out into the side of Cascade Aven, a short traverse takes you out to a position where the final drop of 8m can be rigged from the in situ rawl bolts. You drop onto the top of a calcite slope, where a rope handline is fixed down the right hand wall to allow a safe descent to the start of a very exposed traverse. At the top of this calcite slope a low passage leads to the complex Cascade Aven extensions. A awkward 10m ladder pitch is encountered at the end of the crawl into the Courtyard. Back at the calcite slope a rope traverse line is in situ (cows tails recommended) to take to to the far side of this deep drop. Ahead from here is the Oasis, but the way on is down another steeply descending calcite slope that loops back below the traverse, a hand line assists this descent through the top section before it curves round to form a chamber at the bottom. Part way down this slope on the right is entry to Balcony Passage which has a few short routes off that all close down. At the bottom of the slope in Cascade Aven Chamber, a crawl ahead leads for a short distance to a 6m climb down into a chamber followed by another short climb down into a following chamber. A short section of passage then leads to the climb down into 15 Foot Pot Chamber. A slightly awkward climb up from the chamber leads into a sandy passage that continues to Wiggly Stal Passage. Below the climb up is a squeeze through boulders to Marble Arch passage that later connects with the main route at Marble Arch. Ahead the route is high level following the roof tube and continues some distance to Saddle Corner. At this point you can stay high and bear round to the left to reach the junction with Cross Passage, the upper link to the eastern section of the cave. At Saddle Corner going low and to the right leads to the 35 Foot Pot Series and the large Waterfall Chamber. Continuing ahead past Cross Passage leads to Cross Joint Passage which disgorges water from the aven at the end of it. Several climbs in the passage ahead lead to The Junction with East Passage to the left and the main route through the cave continues ahead. The going becomes a little easier with one or two climbs needed to progress until ahead the airlock door to the showcave is found. Only open one of the double airlock doors at once and ensure that the main door is locked once the party has passed.

Back at The Junction, East Passage is followed trending upwards to some crawls over calcite where the entry to Cross Passage can be found on the left, from this point East Passage descends to a junction. At the junction, the passage to the left ascends towards Steeple Aven while ahead the passage descends towards Xmas grotto. At two locations in this passage there is a choice of higher and lower routes, but all routes take you to the low mud covered passage that leads to Xmas Grotto. Here white calcite formations are encountered, many with mud deposits from flooding. The passage is taped across here and ends just past the formations. Back at the junction the ascending passage can be followed to Steeple Aven Passage and then following the right passage at Fork Junction leads to a climb up into The Tube a steeply ascending phreatic tube. Beyond this is the impressive and draughty Steeple Aven, this passage ends abruptly at a climb up into a small passage. This tight and awkward passage leads to Switchback Passage and then via a series of climbs and high level traverses to the Final Chamber. Returning from Steeple Aven a passage can be followed on the right which leads back to the second passage at Fork Junction. Pitch 1 12m ladder
Pitch 2 8m ladder
Courtyard Pitch 9m ladder
An SRT Topo rigging guide is available from the references below. Cambrian Cave Registry for Tunnel Cave Top Entrance
Cambrian Cave Registry for Cathedral Cave
Adrian Fawcett's South Wales SRT Topo Guide Including Tunnel Cave (PDF)
Adrian Fawcett's South Wales SRT Guide Home Page (MS Word)
Caves of South Wales | Tim Stratford | ISBN: 1-871890-03-9 | Published by Cordee
Selected Caves of Britain and Ireland | Des Marshall - Donald Rust | ISBN: 1-871890-43-8 | Cordee
Please ensure the airlock doors are properly closed when passing through from the Showcave. The photographs and information of this page has been provided to help cavers planning trips. Caving can be a dangerous activity, if you are interested in exploring caves please join a caving club so you can enjoy a safe introduction to this sport. Local caving clubs are listed on the links page or you can visit the 'New To Caving' website for more options.
If you feel that any of the information is incorrect or should be updated please contact us.