Evaluation Of The New Truck Dispatching In The Mount Wright Mine

This paper describes an integrated procedure for the very short term production planning of an open pit and the execution of this plan: the truck dispatching. Integration of plan and dispatch means that the plan is realistic so that its objectives can be realized by the dispatch. This realism is obtained by supplying the plan optimization, which involves mixed integer programming, linear programming and non-linear programming, with experimental O.R. models of waiting and blending. The arrangement of these models in the computer programm has made it possible to obtain very short computing time for the planning in spite of the width of the optimisation. The dispatching of a truck is made by solving a classical assignment problem for each dispatch over a horizon of the expected*next 10-15 trucks to request dispatches. This deep-reaching dispatch procedure uses the continuously arriving information about trucks' positions and shovels situations and models by probability functions the expected waiting time of shovels and trucks. In this manner trucks and shovels are synchronized and last moments' opportunities for productivity gains can be obtained. The dispatch procedure takes .5 second on PDP11. This integrated planning and dispatch procedure gives high productivity while ensuring good blending. Results from the Mount Wright mine of the Quebec-Cartier Mining Co., where the integrated procedure has been installed on the existing computer equipment PDP11, are included.