Ogof Mynydd Llangynidr

Location
Grid Ref - SO 14500 15800 Altitude - 530m

Access
Open Access

Description
Length 82m

Warning - The whole entrance area is extremely loose. The entrance is located in the eastern bank of the shakehole. The millstone grit bedrock on this side is tilting and collapsing into the centre of the shakehole. The entrance is in a gap between two tilting blocks.

The cave is mostly in millstone grit with very little evidence of limestone. The entrance is a 3m deep, unsupported, dug shaft which drops into a very small chamber. At the base of the shaft is a squeeze into a small rift formed between and beneath large, loose blocks of bedrock. After 3m a low chamber, with an uncomfortably sharp boulder floor is entered.

''Immediately on the left, is a crawl leading back towards the small chamber at the bottom of the entrance shaft. On the far side of the low chamber, a short, tight crawl leads to a slightly higher chamber but there is no way on.''

Across the low chamber to the right, is a hole down through boulders that leads under the wall into a very small chamber. Running water can be heard here in wet conditions. On the far side a tight rift turns a sharp bend and a bouldery crawl leads into the main part on the cave.

The passage here is elliptical in cross section and it is tall enough to stand in the centre, where there is a smooth floor of collapsed bedding. To the right ends quickly, while to the left leads to a short lived narrowing of the passage. The passage enlarges once more and the floor becomes bouldery again.

''To the right, a passage leads to a 2.5m deep, blind pot and a low, crawling height passage under a fallen slab. There is a way on over the pot which connects into the main passage towards the end of the cave.''

In the main passage, the walls close in once more a climb up of 1.5m is negotiated. A few metres further on there is a small passage on the right which connects back to the passage with the blind pot. Ahead, the final chamber in the cave is entered.

The area around the entrance has a very good draft and a small stream sinks in the shakehole, near to the entrance, in wet conditions.

History
1968/69 - Discovered and explored by South Wales Caving Club. The entrance collapsed soon afterwards. 1993 - Reopened and extended by Morgannwg Caving Club. 1994 - Surveyed by Morgannwg Caving Club.