Fabrica de Solvay
Salt deposit located nearly under whole Lorraine area belongs in France to the largest and richest as well. It´s reserves are estimated to 1000 milliards tonnnes.
The history of mining in Meurthe-et-Moselle goes down to first millenium BC and was technological unchanged until 1820, when the salt extraction method has been replaced by warm water injections.
Photography shows local "Fabrica de Solvay", still in use.
Pictures below shows several abandoned salines around.