Use of acid mine drainage treatment sludge by combination with a natural soil as an oxygen barrier cover for mine waste reclamation: Laboratory column tests and intermediate scale field tests. (June 2017)

• Record Type: Journal Article
• Authors: Demers, Isabelle; Mbonimpa, Mamert; Benzaazoua, Mostafa; Bouda, Médard; Awoh, Sylvette; Lortie, Sylvain; Gagnon, Mario
• Is Part Of: Minerals engineering. Volume 107(2017)
• Page Start: 43
• Page End: 52
• Publication Date: 2017-06
• Subjects: Acid mine drainage -- Sludge -- Soil covers -- Mine site reclamation -- Oxygen barrier -- Column tests -- Intermediate field tests; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2016.11.017
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: Sludge-soil mixtures were tested as an oxygen barrier over acid-generating mine waste. The mixture cover enabled to respect the effluent regulation criteria. Sludge dissolution is not an issue when the system remains at neutral pH. A sand-gravel layer over the mixture helps to reduce evaporation and cracking. Abstract: Acid mine drainage (AMD) is often treated using active lime treatment, which generates a significant amount of sludge that contains mainly metal hydroxide precipitates, calcium sulfate, and unreacted lime. Previous work showed that sludge may have interesting geotechnical and geochemical properties to be used, in combination with a silty soil, as a part of covers (oxygen barriers) to prevent AMD generation from waste rock and tailings impoundments. The reuse of sludge can reduce the volume of natural soil required for site reclamation. Mixtures of sludge and a natural silty soil were tested in the laboratory (for over 500 days) and in field experiments (4 years) as an oxygen barrier cover placed over acid-generating tailings and waste rock. Data from the testwork include monitoring of leachate geochemical parameters (e.g. pH, conductivity, metal and sulfate content) and hydrogeological parameters (water content, suction, effluent flowrate). Results indicate that soil-sludge mixture is an efficient oxygen barrier.