The kinetics of the aggregation of colloidal particles was studied using a Discrete Element Method computer simulation. The simulation accounted for the effects of elastic contact forces, long range van der Waals forces and drag forces and considered the effect of including or excluding Brownian forces. The test sample consisted of 1000 silica particles with density 2200 kg/m3 and diameter 100 nm. Half the particles were assigned a Hamaker constant of 9×10-20 J and the remaining 500 had the Hamaker constant varied between 0 and 9×10-20 J. The rate of aggregation of these particles, with and without Brownian forces, was determined. The size distribution of the aggregates formed over time was measured. The results show that increasing the Hamaker constant increases the rate of aggregation of the particles.