Distributed optimisation method for multi-resource constrained scheduling in coal supply chains

We consider an integrated planning and scheduling problem motivated by the coal supply chains in Australia. The problem considers production planning of several independent mines. The mines need trains to complete delivery of coal by the arrival of ships at the terminal. The trains, on the other hand, are in limited supply and therefore the mines need to share this common resource. For this problem, we present a mixed integer programming formulation which minimises total weighted earliness, tardiness and operational costs. We also present a distributed algorithm based on the Lagrangian relaxation, which incorporates the volume and Wedelin algorithms. The strength of our distributed algorithm is demonstrated by an extensive computational experiment on several randomly generated instances.