Ogof Ffynnon Ddu

OFD was discovered in 1946 through digging by Peter Harvey and Ian Nixon, members of the newly formed South Wales Caving Club. Exploration beyond the Boulder Chamber in 1957 revealed passages as far as the Dip Sump. Major extensions were discovered in 1967 through to Cwm Dŵr, which is now known as OFD2. The system is famous for its intricate maze-like structure and its impressive main stream passage. The cave has seen many minor incidents resulting from people getting lost or tired, or surprised by flooding, and various accidents such as falls which are handled by volunteer cave rescue teams who are alerted by the police. More prolonged rescues have included: In 1951, before cave rescue was…

With a depth of 274 m and a length of at least 50 km, it is the deepest cave in the UK and the second-longest in Wales. The passages and chambers of Ogof Ffynnon Ddu weave a tortuous path beneath the east side of the Tawe Valley. The stream passage cuts through black limestone producing waterfalls, rapids, deep potholes and scalloped walls. The system is divided into three parts: the lowermost (western) section is referred to as Ogof Ffynnon Ddu I (or simply OFD I), the central section as Ogof Ffynnon Ddu II (or OFD II) and the uppermost (eastern) section as Ogof Ffynnon Ddu III (or OFD III). A variety of specialised wildlife has developed underground including cave shrimps and the pale…