An Optimisation Approach to Materials Handling in Surface Mines

In the surface mining industry the equipment selection problem involves choosing a fleet of trucks and loaders that have the capacity to move the materials speci ed in the mine plan. The optimisation problem is to select these fleets such that the overall cost of materials handling is minimised.


The scale of operations is such that although a single machine may cost several million dollars to purchase, the cost of operation outweighs this expense over several years.
This motivates the need for a purchase and salvage policy, so that the optimal equipment replacement cycle can be achieved.
Mining schedules often appear with multiple mining locations and dump-sites, where a dump-site can also represent a stockpile or a mill. Multiple periods must also be considered,  which adds to the complexity of determining the optimal replacement policy for equipment. Further, some mines begin with a pre-existing set of equipment, and the  subsequent fleet must be both compatible and satisfy the mill constraints.
We also need to consider the possibility of a heterogeneous fleet.
The equipment selection problem is cursed with a cascade of inter-dependent variables and parameters. For example, the cost of operating a piece of equipment depends on its  utilisation; the utilisation depends on the availability of the equipment; and the availability depends on the age of the equipment. We formally de ne the equipment selection problem in the Introduction (Chapter 1) and further discuss the complexities of the problem.
While numerous methods from Operations Research and Arti cial Intelligence have been applied to this problem, optimal multiple period solutions remain elusive.
 Also, pre-existing equipment and heterogeneous fleets have largely been ignored.

An Optimisation Approach to Materials Handling in Surface Mines

Christina Naomi Burt

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