A water balance is a quantitative accounting framework that tracks all inputs and outputs of water within a mining operation or defined study area over a specified time period, ensuring that water is managed efficiently and that regulatory discharge limits, site water security, and environmental protection objectives are maintained. In its simplest form, the water balance equates water inputs — such as rainfall, groundwater inflows, and fresh water make-up supply — with water outputs — such as evaporation, process consumption, seepage losses, and managed discharges. In bauxite mining and alumina refining, water balances are essential for managing the large volumes of water used in ore washing, Bayer process digestion, evaporation, and red mud disposal. Gold mining operations use water balance modelling to determine the capacity requirements of tailings storage facilities, the risk of facility overflow during wet seasons, and the availability of water for processing during dry periods. Iron ore mine water balances must account for major inflows during the wet season and the risk of operational flooding in low-lying pit areas. Diamond mine water balances incorporate pit dewatering volumes, dense media separation plant water circuits, and evaporation losses from open water surfaces. Dynamic water balance models — often updated on a daily or weekly basis — are a cornerstone of modern mine water management planning.
