Mineral processing plants remain nowadays infamous for their low energy efficiency. Economic model predictive control (EMPC), by directly considering the energy costs, could possibly help reducing their footprint, but its environmental benefits are yet to be quantified. In an attempt to cast some light on this topic, this manuscript compares EMPC to advanced regulatory control (ARC) in scenarios with identical ore hardness disturbance sequences using the net value and the specific energy as metrics. The simulated circuit comprises a high-pressure grinding rolls (HPGR), a ball mill, and a flotation circuit. It is based on population balance modelling and is an extension of previous work. The ARC system consists of proportional-integral controllers maximizing the plant feed rate with override constraint handling. The results show that 1) The EMPC cost criterion must contain weights on the changes of the manipulable variables to ensure stability, 2) advanced regulatory control can generate the same economic performance as EMPC because the system's constraints define the economic optimum, and 3) the EMPC can minimize the specific energy by saturating the HPGR circuit circulating load with a hybrid criterion that penalizes power draw.