where X is a matrix with entries ij x and Y is a matrix with elements ij y .
According to the solution X and Y , no truck was dispatched to shovel 5 and 6. The quality indicator
(iron ratio in the ore at ore dump sites) is maintained in specified range: 30.50\%, 30.49\% and 30.49\%
for ore dump site 1, 2 and 3 to be exact. Also, the prescribed transportation targets are met in the shift,
which can be verified by the quantity of ore/waste transported to each dump sites. Moreover, the
minimum truck number that should be used can be determined by (11) as [11.89]=12. The truck operating
cost using this dispatching result is 1122.80 units and the truck use rate (traveling distance when loaded
over traveling distance when empty) is 60.88%.
For comparison purpose, the same data set is used to solve the dispatch problem using fixed truck
assignment policy. The resulted truck operating cost is 1331.10 units and truck use rate is 50.00\% since
the trucks are assigned to fixed pairs of shovels and dump sites. Besides, using this fixed assignment