Unprecedented expansion of coal mining in Australia is occurring within the context of a severe ongoing drought. This has induced more companies to adopt improved water management strategies, such as water reuse. A direct consequence of this is an increase in the salt concentration of the water, which affects in turn the efficiency of the coal preparation processes, the quality of the coal product, and the level of required equipment maintenance. There are three strategies that can be adopted with respect to salt management: accept the elevated salt concentrations and increase spending on equipment maintenance; remove the salt by desalination; and dilute the salt by importing more water. A tool is required to predict the salt concentrations arising from water reuse and to simulate the impact of potential management strategies. This paper presents a systems approach to the modelling of coupled mine site water and salt balances to assist with understanding the implications of implementing desalination or dilution and with assessing the costs and benefits of each option.