Abstract: A method for optimizing an ore beneficiation flotation process through which a comminuted ore slurry, which includes a sulphide mineral, passes to produce a final flotation concentrate and a final flotation tail. The method comprises measuring oxygen demand in two or more locations in one or more of ore slurry, the final flotation concentrate and the final flotation tail, the locations being based on the potential for oxygen demand in the locations to be significantly different from each other, which would indicate that sulphide mineral particle oxidation can be manipulated. If sulphide mineral particle oxidation can be manipulated, flotation of the sulphide mineral is either promoted or suppressed (activated or deactivated) by manipulation of sulphide mineral particle oxidation depending on whether or not the sulphide mineral includes a valuable metal.