Underground workings on 5 floors. Show Mine.**

Exploited a high quality band of Cambrian slate.

Opened in 1860s, but closed afer a few years, Re-opened at the end of the 19C with 17 men employed in 1898. Closed again during WW 1.

During 1930s, stone crushing machinery installed.

Opened to public as show caverns in 1960s.