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Abstract(s)
Atualmente, face ao constante aumento do custo das matérias-primas (seja o preço do aço, do explosivo, ou do próprio combustível), as pedreiras sentem a necessidade de aumentar o seu preçário, mas tentando sempre manter a sua competitividade quando comparadas com as restantes empresas do setor. Seguindo esta visão estratégica, a Nicolau de Macedo, S.A., realizou um investimento avultado num novo sistema híbrido, composto por sistemas de transporte contínuo e descontínuo. Este novo método de transporte permitirá, na ótica da pedreira, reduzir substancialmente os gastos inerentes ao processo de transporte do material desde a frente de desmonte até aos pré-stocks que, posteriormente, irão alimentar as respetivas centrais de britagem. Assim, a presente tese tem como propósito estudar a solução adotada pela pedreira da Nicolau de Macedo, analisando os diferentes fatores que influenciam os sistemas de transporte do material (tais como a geometria do diagrama de fogo ou a capacidade dos equipamentos de transporte) e qual a melhor frota para alimentar a mesma. Analisando os diferentes cenários, verifica-se que, embora duas das frotas apresentem custos inferiores, uma terceira frota é a mais indicada, uma vez que é a que permite efetuar a menor alimentação possível do britador primário, garantindo assim a preservação dos equipamentos seguintes.
Due to the constant increase in the cost of raw materials (whether the price of steel, explosives, or the fuel itself), quarries need to increase their prices, but always try to maintain their competitiveness compared to other companies in the sector. Following this strategic vision, Nicolau de Macedo, S.A., made a large investment in a new hybrid system composed of continuous and discontinuous transport systems. This new transportation method will allow, from the quarry's perspective, to reduce the costs inherent in transporting the material from the blasting front to the pre-stocks that will later feed the respective crushing plants. Therefore, the purpose of this thesis is to study the solution adopted by the Nicolau de Macedo quarry, analysing the varied factors that influence the material transportation systems (such as the geometry of the firing diagram or the capacity of the transportation equipment) and which is the best fleet to feed it. This way, it was possible to verify that, although two of the fleets present lower costs, a third fleet is the most suitable one since it is the one that allows the least possible feeding of the primary crusher, thus ensuring the preservation of the following equipment.
Due to the constant increase in the cost of raw materials (whether the price of steel, explosives, or the fuel itself), quarries need to increase their prices, but always try to maintain their competitiveness compared to other companies in the sector. Following this strategic vision, Nicolau de Macedo, S.A., made a large investment in a new hybrid system composed of continuous and discontinuous transport systems. This new transportation method will allow, from the quarry's perspective, to reduce the costs inherent in transporting the material from the blasting front to the pre-stocks that will later feed the respective crushing plants. Therefore, the purpose of this thesis is to study the solution adopted by the Nicolau de Macedo quarry, analysing the varied factors that influence the material transportation systems (such as the geometry of the firing diagram or the capacity of the transportation equipment) and which is the best fleet to feed it. This way, it was possible to verify that, although two of the fleets present lower costs, a third fleet is the most suitable one since it is the one that allows the least possible feeding of the primary crusher, thus ensuring the preservation of the following equipment.
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Keywords
Sistemas de carga e transporte Tempos de ciclo Frotas Geometria do diagrama de fogo Hauling and loading systems Cycle times Fleet Fire diagram geometry