Discharge characteristics of coarse polydisperse granular powders through a conical hopper are experimentally investigated. The average discharge rates of four different powder types are systematically measured for seven different diameters of hopper orifice under gravity flow conditions. Each powder type is a mixture of some subsizes (smaller than 3 mm) of same powder material. Effects of orifice diameter of hopper and size distribution of polydisperse powders on discharge characteristics are experimentally determined. The measured discharge data are compared with discharge values predicted by using modified forms of the well-known Beverloo correlation. The volume-moment-mean diameter, d(VM), and the 50% weight fraction diameter, d(50), cited in available literature are both checked to characterize the coarse polydisperse powders and used throughout the predictions. Comparisons implied that both d(VM) and d(50) diameters can be successfully used to characterize polydisperse test powders, and discharge rate predictions are in good agreement with experimental data, with mean deviations lower than +/- 4.04%.