| A computer model has been developed to simulate the truck and shovel operation of open pit mines. This model is able to simulate both fixed truck assignment and computerized truck dispatching with several dispatching options. Use of the FORTRAN based simulation language SLAM provides flexibility to accommodate particular requirements for a given mine. Stochastic simulation is used to reflect the random variation in duration of various activities. This gives a more realistic representation of the processes under study. Data were collected from an actual operating mine and suitable theoretical distributions were fitted to the time elements of the truck and shovel work cycle.;Validation of the model against production data from the operating mine showed good agreement with actual performance. This model was then used to study the possible impact of computerized truck dispatching on the productivity of the truck and shovel haulage system of this mine.;Simulation results indicate that under the conditions studied, computerized truck dispatching can effect a saving of at least one operating truck per shift, or 2-3% of the total truck fleet. The study also showed that computerized dispatching is more effective when shovels are undertrucked. When shovels are overtrucked, the addition of a shovel gives a greater increase in production than using computerized truck dispatching alone.;The model is particularly useful for evaluating alternatives in equipment acquisition, haulroad design, truck-shovel allocation and dispatching policies, providing data which will enable appropriate decisions to be made regarding the planning of new truck and shovel operations or the expansion of existing systems. |
