Puits de Saint-Saulve, Valenciennes

The Compagnie des mines de Marly was a mining company that exploited coal in the Nord-Pas-de-Calais mining basin, at Saint-Saulve. Unlike the other companies, the one in Marly did not have continuity. The concession went from short periods of exploitation to long periods of abandonment. Strong water inflows flooded the workings of three pits, which were then abandoned and became swallows. For the others, the period of exploitation is very short, less than ten years. Some pits are reused decades after their closure.