One of the most important challenges for mining engineers is to correctly analyze and generate short-term planning schedules, or simply month mining plan. The objective is to demonstrate how simulation and optimization models were combined, with simultaneous execution, in order to achieve a feasible, reliable and accurate solution for this problem. A tool based on Arena simulation software and Lingo was developed, tested and approved within VALE (former CVRD Brazil), with excellent results, presented in this paper.

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The rail network simulation models considering trains on closed loop may have many disturbances. These disturbances are caused by the railnet traffic, or queues at the load/unload stations, that changes the movement previously planned. The validation of these simulation models can be problematic because of these disturbances, and the search for the right validation procedure must count with a good train destination choosing process. The lack of studies about the validation of simulations applied to rail networks, considering the specific features of the closed loop trains and the disturbances, have leaded this thesis development, which proves that the development of algorithms that represent the movement process of the trains under sufficient detailing level, and the adoption of a correct destination choosing process, reaches the model validation. From the three options evaluated to represent this destination choosing procedure: random choosing between many loading points to one unloading point, or an internal model routine to do this same task, or an external optimization model called from the simulation model, was choosen the second option, because it validates the model and runs the simulation experiment faster. Once prepared the model with the destination choosing process selected, was possible to conduct experiments to measure the model sensitivity to the main parameters at the design of brazilian rail networks.

This paper describes a logistic study about an underground gold mine, belonging to AngloGold Ashanti, where four different layout options could be applied to the tunnels, and also different transportation strategies. Each evaluated layout had its own configuration for shaft and truck fleets. The study was made individually for each year of the mine operation life, determining the necessary transportation capacity to achieve the planned production for that year. Due to the very restrictive traffic options in the tunnels, a framework was developed to represent the tunnels and traffic rules in a discrete-event simulation model. The results pointed the scenario with the lowest necessary transportation capacity to achieve the planned production.Keywords: transportation capacity, simulation, ARENA. Resumo

A continuous and discrete system gets distinct approach from modelers, since both have very particular characteristics. Some simulation tools are specialized in one system or another, but the great majority focuses on discrete modeling. However, there are many hybrid systems where a continuous process interfaces with discrete. Despite being possible to model both systems with particular modeling tools, they have to be properly connected. An example of hybrid system is the ethanol production chain, where the transport of the raw material sugar cane has important interactions between the main components of the chain, where there is exchange of equipment, transport and interface of continuous systems with discrete, and vice versa. This study presents the algorithms and techniques used to model the logistics operations of the Alcohol/Sugar producer Raízen, developed using the SIMIO simulation tool.