'The Columns' Ogof Ffynnon Ddu cave, South Wales, UK"The Nave" in Ogof Ffynnon Ddu cave, South Wales, UKRhosydd Slate QuarryRhosydd Slate QuarryRabbit Mine, Godstone, UKRabbit Mine, Godstone, UKCwmorthin Slate Mine, north Wales, UKWinch mechanism. Dinas Rock Silica Mine. South Wales, UKDinas Rock Silica Mine. the beginning of the flooded section. South Wales, UKA caver explores railway tracks. An incline on the right descends deeper into the Dinas Rock Mine.Dinas Rock Silica Mine. the beginning of the flooded section. South Wales, UKDinas Rock Silica Mine. Large chamber supported by rock pillars. South Wales, UKDinas Rock Silica Mine. the beginning of the flooded section. South Wales, UKCae Coch Sulphur Mine, Wales, UK"The Nave" in Ogof Ffynnon Ddu cave, South Wales, UKOgof Ffynnon Ddu cave, South Wales, UKOgof Ffynnon Ddu cave, South Wales, UKOgof Ffynnon Ddu cave, South Wales, UKOgof Ffynnon Ddu cave, South Wales, UKOgof Ffynnon Ddu cave, South Wales, UK