Comparing the environmental sustainability of two gold production methods using integrated Emergy and Life Cycle Assessment. (December 2019)

• Record Type: Journal Article
• Authors: Cano Londoño, Natalia A.; Velásquez, Héctor I.; McIntyre, Neil
• Is Part Of: Ecological indicators. Volume 107(2019)
• Publication Date: 2019-12
• Subjects: Emergy accounting -- Life cycle assessment -- Alluvial mining -- Open-pit mining -- Sustainability; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2019.105600
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: Critical assessment of the applicability of emergy accounting to alternative gold mining methods. Mines exhibit low apparent sustainability because of emergy demands of non-renewable resources. A new method of integrating emissions into emergy worsens the apparent sustainability of the mines. Abstract: Emergy analysis and combined emergy and Life Cycle Assessment (EM-LCA) were used to evaluate the sustainability of an open-pit gold mine and an alluvial gold mine in Colombia. The emergy is the work done to support the gold production separated into renewable and non-renewable energy, and also into those associated directly with the mining and those due to imported resources. The EM-LCA is a new extension of emergy that incorporates the work done by the environment to assimilate airborne and waterborne pollutants. Emergy Sustainability Index values <1 indicate an unsustainable practice, those between 1 and 5 indicate a sustainable contribution in the medium term but not necessarily in the long term, and those >5 can be considered sustainable. The open-pit and alluvial mines were found to have Emergy Sustainability Index values of 0.02 and 0.04 respectively using emergy accounting, and 0.002 and 0.035 using EM-LCA. The low values from the emergy analysis are mainly due to the large amount of imported resources required by the gold production. The open-pit mine uses a more highly industrialized process and hence relies more on imported resources and less on renewable resources. Open-pit mining also generates more emissions hence its comparatively low EM-LCA rating. The results demonstrate the need to implement management policies that encourage a higher dependence on renewable resources and to reduce reliance on imported resources, as well the need for technologies that lower emissions. It is also concluded that the novel EM-LCA approach has the potential to extend emergy analysis to incorporate emissions. The study also highlights the limitations of emergy accounting for coherent assessment of mining projects.