The pit head gear of the upcast shaft at Cefn Coed Colliery in the Dulais Valley, which was at one time the world's deepest anthracite mine at 2,500 ft. Opened in 1928, it became known as the 'Slaughterhouse' as it was a notoriously dangerous place to work due to the presence of methane gas. The colliery closed in 1968, and part of its site has been preserved as a museum.