Water efficiency in mining is a measure of how effectively water is used to achieve operational objectives — such as ore processing, dust suppression, or reagent preparation — relative to the volume of water consumed. A more water-efficient operation achieves the same or greater output using less water, thereby reducing costs, environmental impact, and vulnerability to water scarcity. Water efficiency is typically quantified as a ratio of production output to water consumed, such as megalitres of water per tonne of ore processed or per kilogram of gold produced. In bauxite mining and alumina refining, water efficiency improvements focus on reducing evaporative losses from red mud ponds, recovering water from tailings, and optimising ore washing circuits. In gold mining, water efficiency is enhanced through high-rate thickeners that return process water rapidly to the circuit, reducing the need for freshwater make-up. Dry grinding technologies and filtered tailings systems represent frontier innovations in gold mine water efficiency. Iron ore operations improve water efficiency through paste tailings, which reduce the water content of disposed tailings and increase the volume of water returned to the process circuit. Diamond processing operations enhance water efficiency by installing closed water circuits with multiple re-use stages before discharge or evaporation. Water efficiency targets are embedded in sustainability reporting frameworks, including GRI Standards and the Mining Association of Canada's Towards Sustainable Mining protocols.
