It wasn't a slate quarry as such, but produced hone stones. Wyn's photos in the Melynllyn album says it all really. There isn't an inside as such- it's little more than an open cut on the hillside, with a couple of shallow openings. The mill is the most interesting part. When the working shut, the equipment was apparently moved to the Moel Siabod hone quarry and used there until the early 20th century. Having said all that, it's a fine walk up to the site.