Vehicle Routing Problem with Time Frames in Employee Transportation in the Mining Industry

This work aims to propose a mixed integer linear programming model for the problem of employee transportation in the mining industry. A set of workers needs to be embarked at different stops located on pre-established itineraries. These employees need transportation to a mine located in another municipality, whose geographical distribution is quite heterogeneous. As workers perform specific activities in the mine, time windows must be considered. Instances of related problems available in the literature were adapted. It was observed that the proposed formulation presented gaps of less than 1% in problems with up to 200 employees. Problems with more than 800 employees presented gaps of around 80%, indicating the need for approximate methods for solving large problems.