High up on the moors above Trefil village, a small stream sinks into an opening in the overlying Gritstone. It was here that a group of Brynmawr diggers started a project that grew into epic proportions. Over many years, they strove to open a way into the uncharted depths below. Hard toil and many near misses resulted in the legend that has become Crescent Cave.
Well okay, it's a legend within Brynmawr Caving Club at least. But there was a lot of bloody hard work as well as some broken fingers and a split head. Also part of Brynmawr Caving Club folklore is the collapse that managed to trap most of Brynmawr Caving Club (and Gwent Cave Rescue Team) on the wrong side.
"The Caves of South Wales" puts Crescent Cave under the Lesser Caves and Sites of Speleological Interest list at the end of the Central Northern Outcrop section. When the initial survey was completed though, it had a length of 500m, with a depth of 70m. This is longer than all but three of the other caves in this section and so by rights, should now be elevated into the next division with the others of the Central Northern Outcrop. The potential here though is tremendous, with a positive dye trace to the substantial stream of Siôn Sieffre some 160m lower and very little known cave in the area of any great size. It seems to indicate a substantial vadose system waiting to be discovered. If only it was a bit easier to get to.
Phil Jayne published a short account of the exporation in BCC's 1997 journal, "Crescent Cave: An Undertaking Symbolic of Man's Struggle Against the Forces of Reality"
Mark
"Tarquin" Wilton-Jones has produced a detailed
description of the cave
which he has kindly allowed me to "lift" and include
here.