, Blaenau Dolwyddelan, Conwy County, Wales,
I believe this to be a vent chimney for the Conwy Valley Rail Tunnel, in Snowdonia, North Wales. The Conwy Valley Railway Tunnel cuts through the mountain (Moel Dyrnogydd) on its way from Roman Bridge and Blaenau Dolwyddelan to Blaenau Ffestiniog. Much of the debris is waste from former slate quarrying.....