Browsing by Author "Martins, Aldrin Gustavo"

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    Lexicographic goal programming approach for a short-term mining planning problem.
    (2023) Martins, Aldrin Gustavo; Souza, Marcone Jamilson Freitas
    This article addresses a short-term mining planning problem. There are four objectives to be minimized: the deviations in grades and ore proportion in particle size ranges of the plant goals, the deviation in the waste mass to achieve the stripping rate, and the number of truck trips between mining fronts and discharges. The problem was solved through the lexicograph- ical goal programming (LGP) method, which generates solutions that can guarantee a more comprehensive analysis of the decision-making process. The LGP method was tested by using several scenarios of a Brazilian mining company. These scenarios differ in the number of excavators and the toler- ances concerning meeting the plants’ ore grades. In the results, the impact on the values of the other objectives is analysed of varying the number of excavators and the tolerances in the plants’ grade targets.
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    Short-term planning of a work shift for open-pit mines : a case study.
    (2023) Silva Júnior, Ademar Lopes da; Martins, Aldrin Gustavo; Pantuza Júnior, Guido; Cota, Luciano Perdigão; Souza, Marcone Jamilson Freitas
    This work deals with the short-term planning problem of a work shift for open-pit mines. The problem involves ore and waste fronts, shovels, heterogeneous truck fleets, and discharge points. The allocation of trucks is dynamic to allow multiple routes to be assigned to each truck. The problem consists of deciding which fronts must be mined and establishing the number of trucks, their routes, and the amount of material transported by them to each discharge point, satisfying a stripping ratio at the desired level. The objectives are to minimize the deviations from the targets for production, chemical grade, and particle size range of each control parameter at each plant and reduce the number of trucks needed for the process. To solve the problem, we developed a mixed-integer linear goal program- ming model and tested it using real data from an iron ore mine. The results showed that the proposed approach supports decision-makers in the sizing and allocation of truck fleets and in meeting the production and control parameter targets required by the ore processing plants according to the daily scenario, such as low availability of shovels and trucks, flexibility in ore quality, and need for increased production.
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    Simulação das operações de lavra da mina de Brucutu utilizando um modelo de programação linear para alocar os equipamentos de carga.
    (Programa de Pós-Graduação em Engenharia Mineral. Departamento de Engenharia de Minas, Universidade Federal de Ouro Preto., 2013) Martins, Aldrin Gustavo; Curi, Adilson
    Este trabalho abrange a simulação das operações de lavra da mina de Brucutu. Um modelo de simulação e um modelo de programação linear inteira mista são apresentados. São abordadas as frotas de operação: perfuratrizes, caminhões, carregadeiras e escavadeiras, além das frentes de lavra, depósitos de minério, pilhas de estéril e britadores. O modelo matemático é responsável por alocar os equipamentos de carga nas frentes, informar a quantidade de viagens que cada frota de caminhão deve realizar, respeitando as restrições referente à qualidade, granulometria e massa mínima desejada para cada ponto de descarga. O modelo de simulação interage com o modelo matemático e executa o resultado deste último. Informações sobre as atividades dos equipamentos, como curvas probabilísticas para atividades externas e tabelas sobre as atividades internas são inseridas no simulador fazendo com que esse abranja a maior quantidade de informações analisadas na fase de lavra. Ao final são apresentados e analisados os resultados da aplicação dos modelos no período de fevereiro e dezembro de 2012.