The mean diameter of the distribution has been correlated to the mechanical input power, volume phase fraction and gold concentration in chloroauric acid/DBC system in a horizontal single stage mixer-settler in the frame of the classical Hinze-Kolmogorov theory. Sauter mean diameter (D-32) shows a decrease of 45% by increasing impeller speed. In contrast, holdup leads to larger drop size. The D-32 increasing rate diminishes about 50% for a system containing 200 ppm gold concentration in aqueous phase with respect to the system with 100 ppm Au. Overall, empirical correlations for drop size at the different conditions are obtained, and a modified correlation for D-32 is presented. The results reveal that D-32 depends on the impeller speed with a power low function, and on gold by a linear function as well. The correlation is found to be D-32/D=(-0.709C(Au)+0.823)(1+2.022 phi)W-e(-0.865). The calculated average absolute relative deviation is found to be less than 4.5%, showing good conformity to experimental data.