requires 13 trucks while only 12 trucks are necessary for the dispatching result using the integer
programming method. This further implies that the proposed truck dispatch approach results in a 15.65%
reduction of truck operating cost and a 21.76% improvement in truck use rate. This infers that the trucks'
traveling distance when empty is reduced as well as the overall operational cost.
Application to a heterogeneous fleet is also investigated. Two types of trucks, type 1 is the same as the
ones used in the homogeneous fleet experiment and the type 2 has a 192t capacity and an average speed
of 35km/h when loaded and 50km/h when empty. The average dumping speed of the latter is 2.4kt/h.
Results of the heterogeneous fleet dispatching shows that a further 19.56% reduction of operating cost
can be achieved in the case studied