Kinetics of semi-batch flotation behavior of a gold ore from North-Western Quebec, Canada was investigated with respect to fineness of grind (P-80). The gold was mostly associated with pyrite in native form as inclusions and was also in contact with pyrite along the boundaries of non-sulphide gangue. Gold recoveries were found to increase from 91.8% to 95.8% as the particles size decreased from an F-80 of 205 mu m to 53 mu m. Data treatment according to the graphical method of kinetic analysis indicated a much better fit to second order kinetics for both gold and pyrite with correlation coefficients higher than 0.998 compared to first order kinetics with correlation coefficients of less than 0.95. Variation and implication of flotation rate constants are discussed with respect to chemical conditions and particle size. (C) 2010 Elsevier B.V. All rights reserved.