The present invention relates to a novel approach to the use of gas bubble hydrophobic particle aggregates to give improved separation and recovery of valuable minerals from a wide range of ore types. A process for formation of gas bubble particle aggregates within a slurry and separating the formed aggregates from the slurry including using first and second flotation cells wherein the first and second cells operate with different levels of shear and including transfer of externally formed gas bubble hydrophobic particle aggregates to either or both of the first and second cells.