Authors: Torgersrud, O; Breedveld, GD; Okkenhaug, G; Malme, B; Cataldi, P

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DOI https://doi.org/10.36487/ACG_rep/1915_08_Torgersrud

Cite As:
Torgersrud, O, Breedveld, GD, Okkenhaug, G, Malme, B & Cataldi, P 2019, 'Challenges for the closure and natural rehabilitation of bauxite residue disposal sites', in AB Fourie & M Tibbett (eds), Proceedings of the 13th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 89-94, https://doi.org/10.36487/ACG_rep/1915_08_Torgersrud

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Abstract:
In the Bayer process, bauxite ore is digested with NaOH at high temperature and pressure, which results in the production of alumina and the recrystallisation of various residual minerals ending up in a bauxite residue. The main minerals in this residue, which is commonly referred to as ‘red mud’, are iron and aluminium oxides (goethite, hematite, gibbsite and boehmite), Na- and Ca-aluminosilicate phases (e.g. sodalite and cancrinite) and titanium oxide. The main challenges facing the natural rehabilitation (direct revegetation) of bauxite residues are related to inherent physicochemical properties of the bauxite residue, in particular alkalinity, salinity, sodicity and low hydraulic conductivity. Physical restrictions to growth of vegetation in bauxite residue material include low hydraulic conductivity (low transport of water), poor drainage (water logging) and restricted root growth. Additionally, in dry periods, capillary rise of water and dissolved salts can occur, salts may accumulate at the cap surface, and drying cracks will occur. Pilot studies have been initiated to compare different closure solutions that take into consideration the physical, chemical and biological limitations of bauxite residues. Methods include the use of different liners, geomembranes, drainage systems and topsoil covers. Gypsum amendment and the addition of organic matter are studied as potential natural rehabilitation methods that can limit the use of pristine soil in the construction of the top cover. The study is part of the Norwegian Geotechnical Institute’s research program on sustainable mine tailings, which comprises studies on material properties, modelling and prediction of physical and chemical stability, remote sensing for long-term monitoring and risk-informed decision-making.

Keywords: bauxite residue, disposal, closure, capping

References:
Bray, AW, Stewart, DI, Courtney, R, Rout, SP, Humphreys, PN, Mayes, WM & Burke, IT 2018, ‘Sustained bauxite residue rehabilitation with gypsum and organic matter 16 years after initial treatment’, Environmental Science and Technology, vol. 52, pp. 152−161.
Di Carlo, E & Courtney, R 2018, ‘Bioassays for assessing bauxite residue rehabilitation strategies’, Fourth Interim Report, Rio Tinto, University of Limerick, World Aluminium.
Jones, BEH & Haynes, RJ 2011, ‘Bauxite processing residue: a critical review of its formation, properties, storage, and revegetation’, Critical Reviews in Environmental Science and Technology, vol. 41, pp. 271–315.
McMahon, K 2017, ‘Bauxite residue disposal area rehabilitation’, Proceedings of 35th International ICSOBA Conference, The International Committee for Study of Bauxite, Alumina & Aluminium, Quebec.
Power, G, Grafe, M & Klauber, C 2009, Review of Current Bauxite Residue Management, Disposal and Storage: Practices, Engineering and Science, CSIRO Document DMR-3609, Commonwealth Scientific and Industrial Research Organisation, Canberra.
Santini, T & Fey, MV 2018, ‘From tailings to soil: long-term effects of amendments on progress and trajectory of soil formation and in situ remediation in bauxite residue’, Journal of Soil and Sediments, vol. 18, pp. 1935–1949.
Stevenson, FJ 1994, Humus Chemistry: Genesis, Composition, Reactions, 2nd edn, Wiley, New York.




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