In the present investigation the relationship between collection zone rate constant (kappa(c)) and gas dispersion parameters, viz. bubble size (d(b)), superficial gas velocity (J(g)), gas hold-up (epsilon(g)) and bubble surface area flux (S(b)) was evaluated. Experiments were conducted in an industrial (4 m in diameter and 12 m high) and a pilot (0.1 m in diameter and 4 m high) flotation column in rougher circuit at Miduk copper concentrator in Iran. Gas hold-up was measured using pressure difference technique and mean bubble sizes were estimated from a drift flux analysis. It was found that the collection zone rate constant was not correlated with d(b) and J(g) solely but was linearly dependent on epsilon(g) and S(b) for the range of interest. Collection efficiency (Ek) and floatability factor (P) in the industrial columns were quantified (E(k) = 3.1%: P = 7.7 x 10(-3)). The influence of operating parameters comprising superficial gas velocity, slurry solids% and frother dosage/type on S(b) and flotation kinetics was discussed. Analysis of available industrial data suggested that S(b) and epsilon(g) were related by S(b) = 4.46 epsilon(g) over the range 30 < S(b) < 60 s(-1) and 7% < epsilon(g) < 14%. (C) 2008 Elsevier Ltd. All rights reserved.