Cwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UKCwmorthin Slate Mine, north Wales, UK