Caves of South Wales Dragon

Ogof Dwy Sir

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Ogof Dwy Sir also known as Quimps Quarry Cave is a short cave intersected by quarrying on Gilwern Hill. The cave is linear and is extremely dry throughout. The cave is undoubtably related to Ogof Draenen who's Northern extremities lie close to this cave.
Length 296m
Altitude 398m
Grid SO 24420 12876
The entrance was uncovered by quarrying. Graffiti on the walls point to this cave being visited over many years. In 1997 a dig at the end of the cave broke through into the Queen of Hearts Chamber, a large void below a gritstone roof, with a collapsed boulder floor.
The cave is best approached via the old tramroad that runs around the side of Gilwern Hill. The old tramroad meets the road beyond the Pwll Du Adventure Centre at the point that the track leads up to the radio mast. The tramroad passes Pwll Du Quarry before passing Quimps Quarry on the northern flank of the hill.
Clydach Gorge Google map showing the location of Ogof Dwy Sir and other caves in the area.
Location map - click marker to show entrance photo
No known access restrictions.
This linear cave is formed in very light coloured limestone and is exceptionally dry throughout it's length. A descent from the quarry down a slope of scree drops you into a 2m high passage which is followed through some areas of fractured rock to meet a short crawl before you can again walk. Unfortunately the walls of the main passage have been scratched with graffiti for virtually their whole length, which detracts from this fine piece of cave. The passage continues past some damaged flowstone at a corner on the left and then passes through sections where you need to traverse or follow lower level routes in the rift passage. Eventually the passage height lowers and a crawl in a mud floored tube is followed until this heads vertically upwards via a rope climb into the Wind Tunnel, an ascending mud tube. This breaks out into the Queen of Hearts Chamber that was discovered in 1997. This large chamber is a collapse feature, roofed with the overlying gritstone. The chamber floor is a slope of loose rocks and there are some areas of unstable boulders, so care needs to be taken. The upper and left hand sections of the chamber have the highest roof, while the lower right hand section is much lower and has a taped off section of mud flooring. Several digs lead off from the chamber, the most extensive is in the top left hand corner where a crawl leads to a small chamber with a hole in the floor that then leads under a fallen roof slab to enter a smaller lower chamber with to passages leading off, both too tight to follow.
No tackle is required.
Cambrian Cave Registry for Ogof Dwy Sir
Descent 140 Article on Ogof Dwy Sir Extensions
Caves of South Wales | Tim Stratford | ISBN: 1-871890-03-9 | Published by Cordee
The Caves of Clydach | Tony Oldham
There are some very loose boulders in Queen of Hearts Chamber.
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.