Alan Williams / Lake Cwmorthin looking south west showing spoil heaps and ruined cottages of the disused slate mine with pieces of slate covering the bed of the lake in the foreground near Blaenau Ffestiniog, North W...

Alan Williams / Looking east across Lake Cwmorthin showing the remains and spoil from the disused slate mine with Cnicht mountain covered in mist in the background, North Wales, UK, April 2018

Alan Williams / Reflections in Lake Cwmorthin showing pieces of slate from the slate mine below the surface near Blaenau Ffestiniog, North Wales, UK, April 2018.

Alan Williams / Cwmorthin slate mine showing the remains of terraced cottages for the families of the workers near Tanygrisiau and Blaenau Festiniog. North Wales, UK, February 2018.

Ashley Cooper / Slate quarries in Elterwater in the Langdale Valley, Lake District, England, UK, July.

Ashley Cooper / Slate quarries in Elterwater, Langdale Valley, Lake District, England, UK, July 2006.

Adrian Davies / Slate quarry, Delabole, Cornwall, England, UK. March, 2018.

Graham Eaton / Abandoned trolley in an adit at Cwmorthin Slate Mine, Tanygrisiau, Tanygrisiau, Gwynedd, Wales, UK, October 2016.

Graham Eaton / Abandoned mine buildings and slate waste with tree beside wall in foreground, Cwmorthin, Blaenau Ffestiniog, Wales, UK, October 2016.

Graham Eaton / Abandoned mine buildings and slate waste, Cwmorthin, Blaenau Ffestiniog, Wales, UK, October 2016.

Willem Kolvoort / Mine cart in flooded slate quarry on Belnahua island. Scotland. 1996

Willem Kolvoort / Mine cart in flooded slate quarry on Belnahua island. Scotland. 1996