Ogof Dydd Byraf

Ogof Dydd Byraf
Cavers climbing the side of Minera quarry to reach the entrance
Location	Wrexham County Borough, Wales
OS grid	SJ 2546 5201
Coordinates	53°03′37″N 3°06′49″W / 53.060163°N 3.113618°W / 53.060163; -3.113618
Length	750 metres (2,460 ft)
Elevation	340 metres (1,120 ft)
Discovery	1964
Geology	Limestone
Access	contact North Wales Caving Club
Translation	cave of the shortest day
Registry	Cambrian Cave Registry[1]

Ogof Dydd Byraf is a cave which extends under Esclusham Mountain in the north-east Wales from its entrance in the south face of the Minera Limeworks quarry. It was originally discovered and explored in 1964 by the Wrexham Caving Club, before it was merged into the North Wales Caving Club.^[2]

After a short series of mined passages there is a narrow 10 metre pitch into the main levels consisting of a series of well-decorated galleries. Some of the passages come very close to the cave Ogof Llyn Du whose access is blocked by a deep and difficult sump.

Over the years this cave had been under threat by the quarry operations,^[3] but it is now protected as an SSSI.^[4] and owned by North Wales Wildlife Trust^[5]

• Appleton, Peter (1989). "Limestones and Caves of North Wales". In Ford, Trevor D. (ed.). Limestones and Caves of Wales. Cambridge University Press. pp. 233–7. ISBN 0-521-32438-6.
• Waltham, A.C., Simms, M.J., Farrant, A.R., Goldie, H.S. (1997). Karst and Caves of Great Britain. Chapman & Hall, 2-6 Boundary Row, London SE1 8HN, UK. pp. 262–4. ISBN 0-412-78860-8.{{cite book}}: CS1 maint: multiple names: authors list (link)