Cwmorthin Quarry – photocatalystPublished July 2, 2016 at dimensions 870 × 519 in Cwmorthin Quarry. https://i0.wp.com/photocatalyst.uk/wp-content/uploads/2016/07/Cwmorthin-Quarry-1.jpg?fit=870%2C519&ssl=1 Cwmorthin Quarry – photocatalyst