Bottom of downcast shaft.

In 1872, work started on sinking the shafts of Harris's Navigation Colliery, eventually reaching depths of 593m (north shaft) and 695m (south shaft) by 1879, at the time the deepest in the south Wales coalfield. Production began shortly afterwards. By 1896 the mine was owned by the Ocean Coal Company and was known as Deep Navigation. The first pithead baths in Wales were opened, by Miss Davies of Llandinam, at Ocean Deep Navigation on 15 June 1916. The mine closed in 1991, since when the buildings have been demolished and the site cleared and landscaped.