2. Purpose of the PPRM

The various mining concessions granted in the past have given rise to numerous artificial underground cavities which, depending on their nature (shafts or galleries) and characteristics (depth, width), can present nuisances and risks for people and property following a process of ruin in the more or less long term.

These – phenomena, which can include settlements, collapses, landslides, the release of hazardous gases, radiation emissions, changes in groundwater and/or surface water flows, water pollution or other – problems, may persist long after the subsoil has been mined.

Events of this type occurred in Lorraine in the late 1990s, and were at the root of the public authorities' growing awareness of the post-mining situation.

That's why, from that time onwards, the State has taken steps to take these risks into...