At the entrance to the Souterroscope, we are greeted by a large, ivy-covered headframe that immediately evokes the site’s industrial and mining past.
We put on the obligatory hard hats and off we go! We have to follow the audioguide, whose narration is transmitted through different loudspeakers, which switch on and off to trace our path. We cross a small, rocky valley. In early spring, ferns reign supreme and wild hyacinths have bloomed. Here, the audioguide explains the geology of our planet, millions of years ago, and more specifically of Caumont l’Eventé, where these ancient clay deposits enabled the formation of slate deposits.
The sound signal indicates that we can now enter underground. The contrast between outside and inside is striking. It’s very cool and damp; in fact, temperatures never rise above 12 degrees, so we’d better bring a good coat. Our eyes gradually become accustomed to the half-light, and a gallery some thirty meters long opens up before us. We have to walk at the same pace as the lighting and sound. The smell of moss and humus tickles our nostrils, and the walls are constantly dripping water, even though it’s not raining outside.
We arrive at the first underground chamber, where we find a lake of astonishing blue and crystalline purity. The audio guide tells us that it’s three meters deep. Incredible! The bottom is so transparent you’d think you could touch it just by bending down. Further on, the path bends and we come to an open gallery. High, vegetation-covered rocks encircle a second, larger lake. This is the old mine entrance, through which workers used to descend and explore these once dry galleries, now submerged under fifteen meters of water. Today’s speleologists have yet to explore the full extent of this maze, dug out by sheer force of arms.
In another room, a film explains the hard work of these “Caumont blue gold” workers. Using picks and mallets, they had to extract large blocks of rock, which were then brought to the surface, where another team of workers was tasked with cutting them in the direction of the grain, finer and finer, to make slate. Accidents, though rare in this mine, were no less tragic.
