In the metals and mining industry, an ore-milling step followed by froth flotation is a very common processing route. It is also common that advanced controls of one form or another are installed on these units. It is less common for the advanced controllers to be combined in any formal way. This paper explores the way two typical model predictive control structures could be combined, and what are the benefits of doing so. Use is made of existing linear dynamic models of plants the authors have implemented model predictive control (MPC) on. The results show that the coordinated system can behave differently to the separate controllers, depending on the steady-state optimisation coefficients applied.