The entrainment of hydrophilic gangue particles in flotation is related to the amount of water reporting to the froth. It is well established that the amount of water reported to the froth is controlled by frother concentration. As it is shown in this paper, in the flotation systems in which emulsified oily collector is also used (e.g. coal flotation), solids recovery strongly depends on the collector dosages as also does the water recovery. While the tests carried out at low (1000 g/t) and high (8000 g/t) oil dosages show different effects of frother additions on water transfer rates to the froth, all the experimental points when water transfer rates are plotted versus solids transfer rates to the froth converge on one single curve. This suggests that the effect of both the frother and collector on water transfer rates is first of all determined by the transfer of solids to the froth, and thus by the effect of these two agents on the solids transfer to froth. (c) 2007 Elsevier B.V. All rights reserved.