Rhondda Cynon Taff
, Northern Outcrop - Central (Penwyllt to Penderyn)
map using leaflet map:
Sink
Cave
Access
On common land.
Description
A large postglacial depression, the sink of the Nant Sychbant.
Following the survey of the cave a dry entrance (this entry) was dug at the back of the shakehole.
History
Marked on 1840 tithe map of Penderyn. Water pumped to Penderyn until borehole at Lygad Cynon took over in 1945. Dug by BNSS. A small breakthrough was achieved by WSG in 1970, but ended in a massive choke beneath a 20m pitch, and was bloacked again by floods within a month. After floods blocked the lower parts again, a dig started in 2007 by Tony Donovan, Roy Fellows and Paul Quill broke into the cave near the sink in 2008.
Hydrology
After many unsuccessful tests, UBSS accidentally proved a connection to Llygad Cynon
WSG Bulletin Supplement 6, March 1973. Frank Bagueley, Water tracing [...contamination by fluorescein introduced by persons unknown into Ogof Fawr...two water boards affected likely to cost thousands of pounds...]
WSG Bulletin Vol.7, No.1
Brynmawr CC Jnl (1999) pp.18-23 Roy Morgan, Water tracing Penderyn Area
Descent 203, p.17 (2008), Ogof Fawr
Descent 205, p.13, Martyn Farr, New entrance for Ogof Fawr
Descent 206, p.18, Martyn Farr, Ogof Fawr update
Descent 208, p.19, Martyn Farr, Progress in Ogof Fawr
