An integral solution to the control problem has to deal with problems associated with instrumentation, process modelling, control strategies and control algorithms. The term ＇＇hierarchical＇＇ control is used here to mean the intelligent integration of available knowledge, control algorithms and logic rules of decision. The selection of information, algorithms and rules is based on the experimental and theoretical knowledge of the column flotation process. The software support was designed and implemented in object oriented computer programmes. This technique allowed the implementation of a combination of control techniques, algorithms and heuristics, in the form of a control strategy. This strategy has shown to fit well with processes exhibiting complex dynamic characteristics. The hierarchical control was developed and tested in a pilot and an industrial flotation column including the following general aspects: coordination of distributed conventional control loops, verification and diagnosis of sensors, on-line predictive estimation of operating variables and diagnosis of common operating problems.