What to do with mining waste? The example of red mud in the Mediterranean

A seminar will be held on December 14, 2021 at 11:00 am at the Observatoire Midi Pyrénées in Toulouse, presented by Stéphanie Jacquet (MIO-CEM) and Christophe Monnin (GET - Toulouse).

Since the 1960s, residues (red mud) from the extraction of aluminum from bauxites produced by the Gardanne plant (Bouches du Rhône) have been discharged into the Mediterranean in the Cassidaigne submarine canyon off Cassis. This sludge discharge was replaced in January 2016 by a clarified liquid effluent obtained by filtering the red sludge, with the solid part of the waste being stored on land. In 2019, a new process for neutralizing the liquid effluent has improved compliance with environmental standards. Recent studies of the chemical composition of the clarified effluent and the mineralogical composition of concretions and sediments collected from the discharge area inform the discussion of contaminant dispersion in the environment.

The case of the Gardanne alumina plant illustrates the general problem of waste management in the mining industry, amplified here by a highly urbanized geographical context and a very long history of industrial activity.