In this abstract, I will present the application of a probability-based simulation to a copper plant in Kazakhstan (the client). This will be of interest to mineral processors whose focus is the optimisation of the performance of mineral processing plants using a logical and elegant approach. There are various approaches to simulate the performance of a mineral processing plant using plant survey data. A common approach is to construct unit models which are then combined by using a flow sheet visualisation framework. Conventional unit-based modelling is generally based on semiphenomenological models. An alternative unit modelling approach is to use probabilistic models. These models are based on a relatively new mathematical approach called information theory (popularised in the 1960s). In this context, information theory means the mathematical interpretation of available information. There are advantages of the two alternative approaches (conventional and information theory), and ideally, they would be used synergistically.