16/06/2026
⚒️ CEFN COED COLLIERY ⚒️
- Crynant, South Wales
Hidden deep within the Dulais Valley lie the remains of Cefn Coed Colliery, once one of the most remarkable and notorious coal mines in Wales.
Work on the colliery began in the early 1920s after several failed attempts to sink shafts through the incredibly hard Blue Pennant sandstone. Following major investment by the Amalgamated Anthracite Company, the mine finally succeeded in reaching the coal seams, and the first coal was raised in 1930. At the time, Cefn Coed was claimed to be the deepest anthracite mine in the world, reaching depths of almost half a mile underground.
The pit worked some of South Wales' highest-quality anthracite seams, including the Big Vein, Peacock, Dulais, White Four Feet and Nine Feet seams. During its peak years, more than 900 men were employed at the colliery, helping power homes, industry and exports across Britain and beyond. However, the extreme depth of the workings came at a cost. High temperatures, methane gas, and frequent roof falls made Cefn Coed one of the most dangerous pits in the coalfield. The mine gained the grim nickname
"The Slaughterhouse" due to the number of accidents suffered underground.
Following nationalisation in 1947, significant investment was made to keep the colliery operating, but the costs of maintaining such deep workings became increasingly uneconomical. Production declined throughout the 1950s and 1960s, and despite a major public campaign to save the pit, Cefn Coed eventually closed on 20 April 1968. Many miners transferred to nearby collieries or the adjacent Blaenant Drift Mine.
Today, the surviving headframes and buildings stand as a powerful reminder of South Wales' industrial heritage. Walking through the site, it's easy to imagine the thousands of miners who descended into the depths every day, facing conditions that few could comprehend. Nature may be reclaiming the colliery, but its history remains firmly embedded in the landscape.
Notable for being one of the deepest anthracite mines ever worked and earning the nickname "The Slaughterhouse" due to its hazardous conditions.
▪︎Opened: 1930
▪︎Closed: 20 April 1968
DID YOU HAVE FAMILY WHO WORKED HERE ??
📌Crynant, South Wales
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