Mining Impacts on the Environment - Water Footprint Assessment of Copper Cathode and Copper Concentrate

Abstract

Water is the source of life and an essential resource for our global economy. It empowers agricultural and industrial production and development, and fosters the nature and ecosystems. With increasing water scarcity, growing population, climate change and extreme weather conditions, together with stricter water regulations, decline in ore grade and increasing controversy on water use between mining operations and local communities, effective governance of shared water resources and protecting water quality is an economic imperative and social responsibility for mining companies. Water Footprint Assessment (WFA) is a holistic methodological framework that allows integrated assessment for operational and supply-chain water use and the associated water footprint sustainability in different sectors at various spatial and temporal scales. This paper presents a WFA for two copper products – copper cathode and copper concentrate produced by Zijin Mining (China) based on the data from 2012 and 2013. The aim of this study is to evaluate the water consumption within the operations and supply chains, to understand the product sustainability and identify water footprint reduction targets to minimize its associated social and environmental impact on natural resources in the catchment. The two copper products were produced from two different processes, hence their different associated water footprints. Evaporation due to the vast area of heap leach pad is the main contribution to the blue water footprint (WF) for copper cathode whereas supply chain WF is negligible. The grey WF is found to be due to total copper concentration in the effluent discharge. This assessment goes beyond water footprint accounting stage and includes the environmental sustainability of the direct water footprint. Opportunities for efficiency improvement across the two processing plants and prevention strategies to reduce impacts on the environment are also discussed. The comprehensive approach makes the WFA unique from other water use assessments and shows its value in water sustainability strategy making.