In flotation separation, the sliding of particles over bubble surfaces may result in bubble-particle attachment interactions. This technical note investigates the influence of pulp pH, collector dosage and particle size of pyrite on the sliding interactions and proposes a model that can predict the sliding time under a wide range of conditions. The results showed that the increase in particle size resulted in higher sliding times probably due to longer time for the displacement of the liquid film on the surface of larger particles. A similar trend was also observed with an increase in pulp pH possibly due to the partial oxidation of pyrite surfaces at higher pulp pH. By contrast, the increase in collector dosage reduced the sliding times due to higher adsorption of collector molecules on pyrite surfaces. The sliding times were correlated with pulp pH, collector dosage and particle diameter. The proposed correlation was highly non-linear and can be used to successfully predict the sliding times under a wide range of conditions.