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This article objectifies the implementation of a conveyor belt in an iron ore mine. The mine operational costs of the company Vale S.A. have a tendency to increase in coming years. This increase is related to the rising price of labor, fuel, tires, maintenance costs and large transport distances. Meanwhile, environmental impacts also need to be reduced. The case study of the Fabrica mine operated by VALE in the city of Congonhas, in Minas Gerais State of Brazil, was chosen aiming for a comparative study between the employment of big trucks and the deployment of conveyor belts. The decision for the best alternative would be made by an economic analysis of the incremental cash flow. After the economic evaluation of the project, economic and environmental gains were expected for the alternative of conveyor belt deployment.

The use of discrete event simulation optimisation methods is a tool commonly used as a decisionmaking support system in industrial problems, concerning management and resource allocation in order to maximise a set of values regarding costs, revenues and other enterprise interests. The present study has proposed and tested an optimisation algorithm developed on Python, with different wall clock time reduction strategies including parallelism, the Greedy Randomized Adaptive Search Procedure (GRASP) population-based metaheuristic, and ten machine learning methods. With the selected best machine learning method (Decision Trees Regressor) 6 optimisation scenarios were generated and then applied to an economic lot-size problem for a theoretical shop floor. The results showed improvements in the reduction of the processing time of 95.0 % comparing the serial GRASP with the parallel machine learning GRASP, obtaining a solution of 94.0 % of the best local optimum.

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In all mining projects, transportation costs influence net profit, justifying economic feasibility studies before transport fleet acquisition or replacement. These studies can provide the best loading and hauling equipment combination to meet production demands at lower costs by evaluating the alternatives available in the market. When there is more than one solution with similar costs and technical specifications, decision-making technics were considered to be used. Herein is presented the case of selecting hauling trucks used to transport run of mine (ROM) ore at a bauxite mining company, located in the State of Minas Gerais, Brazil, using the Multi-Criteria Decision Aid methodology (MCDA).

ResumoNesse trabalho são apresentados os principais mé-todos de lavra de rochas ornamentais usados atualmente em muitas pedreiras do Brasil e do exterior. Embora a tecnologia de corte e o beneficiamento sejam aspectos importantes relacionados à produção de rochas ornamentais, o objetivo desse trabalho é apenas descrever os métodos de lavra mais usados. Na ausência de normas técnicas brasileiras que estabeleçam uma classificação apropriada, foi utilizada a classificação mais usada na literatura e na indústria.Palavras-chave: lavra de rochas ornamentais, métodos de lavra, lavra a céu aberto. AbstractIn this study are reviewed the main dimensioned stones mining methods used at the quarries in Brazil and overseas. Although the stone cutting technology and the treatment are important points to be considered in the dimensioned stones production, the main objective of this study is only to describe the main mining methods.Still nowadays there are not Brazilian technical norms to classify the dimensioned stones mining methods used in the country. Therefore it was used the methods given in the literature and those used by the industry.