Production capacity of a fully air-swept industrial scale two-compartment KHD Humboldt Wedag (R) cement ball mill was optimized with the aid of simulation. It was proposed to operate the mill as a single compartment by eliminating the pre-drying compartment. In this respect, grinding performance of the air-swept ball mill was evaluated and modelled as a perfectly mixed single tank using the perfect mixing ball mill modelling approach (Whiten, 1974). Static separator was modelled by efficiency curve model (Whiten, 1966). The empirical breakage function required in the estimation of average specific breakage rates was measured by drop-weight technique. The full scale model parameters were used to simulate the raw meal mill grinding circuit with the aid of JKSimMet Steady State Mineral Processing Simulator. Simulation results indicated 23% production capacity increase in cement throughput in case the predrying compartment was used in grinding. (C) 2015 Elsevier Ltd. All rights reserved.