L:70
V:

Twll Gwynt Oer, Cold Wind Hole


NGR: SN 85874 15958
368 m.asl

Powys , Northern Outcrop - Central (Penwyllt to Penderyn)
map using leaflet map:
Cave
Access In the dry valley behind the main Penwyllt Quarry. The entrance is marked by spoil.
Description Capped 10m shaft in a small shakehole leads to a miniature streamway. Upstream (north) reaches a boulder collapse after approx 30m. Downstream , the passage enters a constricted sump after a similar distance, which receives occasional (chemical) attention. The water flowing in this small cave appears in Cwmdwr Jama via the upstream choke.
History Brian Jopling, SWCC 1979/80
Hydrology Tests
Conservation SSSI: 0099 Ogof Ffynnon Ddu (Mixed)
Gallery

Brendan Marris
2008

Gary Evans
2020
Survey
SWCC Newsletter 93, 1981
References
BB 376/377, p.15 (1979) Twlll Gwynt Oer - A significant find in South Wales
CDG nl.52, p.29 (1979)
SWCC Newsletter 93, 1981
Catalogue of Speleological Sites...between...A4067...Pant Mawr Moor, Gary Evans (2021),p.79
Cambrian Cave Registry entry 348
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