As the mining sector increasingly embraces the sustainability agenda, and implements thorough environmental reporting in support of its case for a continued social licence to operate', there is a need for ever-clearer metrics for key areas of impact. It is clear that natural waters are both the predominant pathway and main recipient of the environmental impacts of mining. A new approach to summarising the impacts of mining operations on water quantity and quality is proposed, adapted from an existing generic framework, which is increasingly used to quantify the water footprints' of cities and nations. This includes both direct water use and virtual water' use, implicit in goods and services used by the mine. In contrast to the existing formulation of water footprint', it is here argued that it makes hydrological sense to express the water footprints of mines in areal terms, as equivalent catchment areas. It is also important in the mining sector to capture systematic changes in the scale of impact, which can be anticipated and predictively quantified over the full life cycle. This includes the essentially infinite post-closure phase, during which remanent water consumption' occurs, either through physical water loss (eg by evaporation from pit lakes) or by ongoing contamination of sizeable flows of natural waters. Methods for assessing the water footprints of mines are now available, and the time is increasingly ripe for them to be applied in earnest in environmental reporting. An example application to a mine in a humid subtropical area of South America is presented. In that case, the mine site itself extended over 106 ha, whereas the maximum water footprint exceeded this by a factor of 27. Although the water footprint can be expected to decline by a factor of ten immediately after closure, sustained evaporation from pit lakes and tailings dams with water covers will gradually increase the remanent water consumption rate, such that the final post-closure water footprint remains about 25 per cent of that encountered during the peak of mining._x000D_
FORMAL CITATION:Younger, P L, 2006. The water footprint of mining operations in space and time - a new paradigm for sustainability assessments? in Proceedings Water in Mining 2006, pp 13-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).