Fernandez-Iglesias, A, Corrêa de Araujo, A, Andrés, S, Xuan, W, Luiña, R & Álvarez, V 2013, 'Study of environmental feasibility of paste and thickened tailings by life-cycle assessment', in R Jewell, AB Fourie, J Caldwell & J Pimenta (eds), Paste 2013: Proceedings of the 16th International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 349-363, https://doi.org/10.36487/ACG_rep/1363_27_Fernandez-Iglesias
Paste and thickened tailings (P&TT) technology has important advantages not only from the safety point of view, but especially from the environmental point of view. The objective of this paper is to prove that this technology is a real sustainable alternative that can be evaluated using life-cycle analysis (LCA) methodology.
P&TT has emerged in recent years as an alternative for the treatment and disposal of mine waste. It involves thickening the tailings (a mix of process water and waste solids obtained after the process of separating the gangue of an ore) to a higher solid content, recovering the water, and recycling it back to the process. The volume of the final waste once it has been thickened is smaller and requires less storage capacity.
Conventional tailings disposal has some important disadvantages such as poor water recovery, high volume storage requirements, the need for containment structures like basins or dams (which can present stability and safety issues), and lower rehabilitation potential. Thickening technologies applied to tailings, in order to reach solid concentrations over 50%, are a real alternative to traditional disposal techniques. Scarcity of water and increasing demand for higher recycling rates can be partially solved, pollution and seepage problems are avoided, smaller containment facilities are required, and footprint is reduced due to smaller land needs, even allowing partial rehabilitation while the mine is still under operation.
Besides these important benefits, P&TT technologies require specific equipment and important energy consumption, with associated economic costs and environmental impacts. In order to evaluate them, a standardised tool should be used. This tool is the LCA, which allows calculating the potential environmental impact of an activity such as tailings thickening process during its whole lifecycle, quantifying the use of natural resources and the impacts on the evaluated system.
The International Organization for Standardization (ISO) defines LCA as a technique for assessing the potential environmental aspects and potential impacts associated with a product, process, or activity by compiling an inventory of relevant inputs and outputs, evaluating the potential environmental impacts associated with those inputs and outputs, and interpreting the results of the inventory and impact phases in relation to the objectives of the study.
The selection of LCA as an evaluation methodology for this study is due to the strong presence of this kind of tool in the environmental literature in the last several years. Its implementation has been fast, and several databases and software programs adequate for the inventory and impact assessment phases have been developed.
Bates, J., Dale, N. and Dolley, P. (2008) Environmental impacts of significant natural resource trade flows into the EU, Issue 6, AEA Energy and Environment, METROECONOMICA Economic and Environmental Consultants.
Böhm, J., Debreczeni, A., Faitli, J. and Gombkötö, I. (2005) Tailings management, Water management and the use of thickened tailings, Sustainable Improvement in safety of tailings facilities, TAILSAFE, University of Miskolc.
Classen, M., Althaus, H.J., Blaser, S., Doka, G., Jungbluth, N. and Tuchschmid, M. (2009) Life cycle inventories of metals, Final report Ecoinvent Data 2.1 (10), Swiss Centre for Life Cycle Inventories, Dübendorf, Switzerland.
Doka, G. (2008) Life cycle inventory data of mining waste: emissions from sulfidic tailings disposal, Doka Life Cycle Assessments, Zürich, Switzerland.
Durucan, S., Korre, A. and Munoz-Melendez, G. (2006) Mining life cycle modelling: A cradle-to-grave approach to environmental management in the minerals industry, Journal of Cleaner Production, Vol. 14, pp. 1057–1070.
Goedkoop, M., Effting, S. and Collignon, M. (2009) Anexo Eco-indicador’99, Método para evaluar el impacto ambiental a lo largo del Ciclo de Vida, Manual para diseñadores, PRé Consultants, IHOBE, Sociedad Pública Gestión Ambiental.
Gunson, A.J., Klein, B., Veiga, M. and Dunbar, S. (2011) Reducing mine water requirements, Journal of Cleaner Production, Vol. 21, pp. 71–82.
ILCD (2010) ILCD Handbook, International Reference Life Cycle Data System – General Guide for Life Cycle Assessment, JRC-ies European Commission (JRC) Institute for Environment and Sustainability (ies), First Edition 2010, EUR 24708 EN, Luxembourg, Publications Office of the European Union, ISBN 978-92-79-19092-6.
ISO (2006) UNE-EN ISO 14040:2006, Environmental management – Life cycle assessment, principles and framework, Asociacion Espanola de Normalizacion Publications.
Jolliet, O., Ruedi, M-W., Bare, J., Brent, A., Goedkoop, M., Heijungs, R., Itsubo, N., Peña, C., Pennington, D., Potting, J., Rebitzer, G., Stewart, M., Haes, H. and Weidema, B. (2004) The LCIA midpoint-damage framework of the UNEP/SETAC life cycle initiative, International Journal of Life Cycle Assessment, Vol. 9(6), pp. 394–404.
Kizil, M.S. and Muller, B. (2011) A numerical approach for prefeasibility analysis of tailings disposal options, in Proceedings 35th APCOM Symposium, E.Y. Baafi, R.J. Kininmonth, I. Porter (eds), Wollongong, Australia, 24–30 September, The Australasian Institute of Mining and Metallurgy, Carlton, Australia, pp. 455–463.
Kulczycka, J. (2008) LCA for minimisation of environmental impact of wastes from zinc and lead industry, Polish Academy of Sciences, Mineral and Energy Economy Research Institute, Poland.
Lesage, P., Reid, C., Margni, M., Aubertin, M. and Deschênes, L. (2008) Use of LCA in the mining industry and research challenges, CIRAIG, École Polytechnique de Montréal, Québec, Industrial NSERC Polytechnique-UQAT Chair, Environmental and Mine wastes Management, École Polytechnique de Montréal, Québec.
Moolman, P.L. and Vietti, A. (2012) Tailings disposal: An approach to optimise water and energy efficiency, in Proceedings Platinum 2012, 5th International Platinum Conference, Sun City, South Africa, 18–20 September, The Southern African Institute of Mining and Metallurgy.
Peck, P. (2007) Avoiding tailings dam failures: Good practice in prevention, PPT presentation, Workshop on the Safety of Tailings Management Facilities, Yerevan, Armenia, 12 November 2007, UNEP GRID Arendal and IIIEE at Lund University.
Reid, C., Bécaert, V., Aubertin, M., Rosenbaum, R.K. and Deschênes, L. (2008) Life cycle assessment of mine tailings management in Canada, Journal of Cleaner Production, Vol. 17, pp. 471–479.
Ripley, E.A., Redmann, R.E. and Crowder, A.A. (eds) (1995) Environmental effects of mining, 2nd edition, St. Lucie Press, United Kingdom, 188401576X, 36 p.
Stewart, M. and Petrie, J. (1999) Planning for waste management and disposal in minerals processing using life cycle assessment, Minerals and Energy: Raw Materials Report 14(4).
Toit, T. and Crozier, M. (2011) Khumani iron ore mine paste disposal and water recovery system, The Journal of The Southern African Institute of Mining and Metallurgy, Vol. 112, pp. 211–220.
Weir Minerals North America-Hazleton (2007) Centrifugal slurry pumps, Slurry equipment solutions.
Wennberg, T. (2010) Transporting highly concentrated slurries with centrifugal pumps: The thickened minerals tailings example, Department of Chemical Engineering and Geosciences Mineral Processing, Lulea University of Technology, Lulea, Sweden.
Wes Tech Engineering, Inc. (2011) Equipment: Item A, One (1) 40 m dia x 8 m sidewall hidensity paste thickener; Item B, One (1) 40 m dia anchor channel tank.
World Steel Association (2011) Life cycle assessment methodology report: Life cycle inventory study for steel products, World Steel Association, Brussels, 95 p.