La Mine Bleue is a site where visitors go 126m below the surface to galleries in a mine called La Gâtelière. From the welcome building on the surface they travel with a guide on an original underground train used by quarrymen down a slope into the workings. Inside the mine, they walk around galleries cut into the solid rock to see how slate blocks were extracted and where waste was dumped. On the surface they see demonstrations of the processes of cutting slate blocks, splitting roofing slates and trimming them to shape. The mine opened in 1916, developed by the company Ardoisières Angevines de St Blaise. At this time, slate quarrying was at its peak in France and about 10 mines operated in the region. The mine closed in 1936 and then reopened as a visitor attraction in 1991. Visitors can take walking trails on the surface to see the further remains with the help of information boards.