DEMIN - Departamento de Engenharia de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/510
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Resultados da Pesquisa
Item Development of a low-cost device for monitoring ventilation parameters (temperature, humidity and pressure) in underground environments to increase operational safety using IoT.(2022) Santos, Rita de Cássia Pedrosa; Silva, José Margarida da; Albergaria Junior, Walter; Pinto, Cláudio Lúcio Lopes; Oliveira, Michel Melo; Mazzinghy, Douglas BatistaThe important role of ventilation in underground mines is to ensure safety and adequate environmental conditions in all accessible areas of a mine. This research aims to develop lowcost solutions for monitoring ventilation parameters in underground mines using the Internet of Things (IoT). A comparison between standard measuring equipment and a new low-cost wearable monitoring device prototype was performed, and the variables measured in an underground mine were pressure, temperature, and relative humidity. The results in all surveys indicate that the wearable monitoring device prototype can properly be used for continuous monitoring of the underground environment. The standard measurement devices for underground mines should continuously be used by mining companies as requested by local legislation. The low-cost wearable monitoring device developed should be viewed as a redundant measurement device for operators’ safety. The constant innovations in technology can support mining operators in anticipating problems, improving productivity, ensuring safety, and meeting standards at low investments.Item Diagnosis of the production cycle in the small shaft sinking.(2022) Luz, José Aurélio Medeiros da; Silva, José Margarida da; Neuppmann, Pedro HenriqueShaft sinking is a classic activity in underground mines. In shafts with small cross-section or in mines with low mechanization indices it is common to use hand pneumatic drills and blasting by explosive gelatin in cartridges, employing natural draft or flexible ducts with axial fans for gases and fumes exhaustion, muck removal by hand shoveling into hoistable dumping buckets. System of this type has been studied here, consisting of a rectangular cross- section shaft (3.7 m x 2.0 m), with final depth of 94 m, excavated in order to obtain samples for a pilot-scale mineral processing testwork, before the open pit mine’s industrial startup. The shaft had a concrete collar and its walls were supported by wooden sets spaced 1.5 m and 25 mm thick wooden planks as liners. This shaft has been excavated in schist rocks belonging to the metamorphosed hydrothermal deposit of copper and gold located in Chapada (municipality of Mara Rosa, Brazil). Daily production worksheets covering one month campaign were statistically analyzed, encompassing the entire cycle of mining operations, namely drilling, charging and blasting, fumes exhaustion, mucking, wall and face trimming and scaling, and assemblage of support system. Operation downtimes were also quantified. Statistical analysis of productivity indices allowed the detection of critical points of the operation and the establishment reference for similar mining operations.Item Strategies used to control the costs of underground ventilation in some Brazilian mines.(2020) Costa, Leandro de Vilhena; Silva, José Margarida daIn an underground mine, the ventilation is responsible for 25% to 50% of its electrical energy consumption. In countries such as South Africa, United States and Canada researchers have started to achieve a significant reduction in energy consumption without neglecting aspects of the quantity and quality of air required for the best performance of the system, in compliance with safety standards and worker comfort. In Brazil, on demand this ventilation application began in 2013 at the Ipueira mine (Bahia, controlled by Ferbasa company), and was soon after applied by the Cuiabá, Córrego do Sitio I and Lamego mines; all three mines administered by Anglo Gold Ashanti. Each mine adopted frequency inverters for the main ventilation, whereby the fan rotation is adjusted according to demand and speed drivers. This measure resulted in the saving of thousands of reais, since the flow is proportional to the velocity, the pressure is proportional to the square of the velocity, and the power is proportional to the cubed velocity. Therefore, a reduction of 20% in the flow will save about 50% of the energy required. The Cuiabá mine presents the most modern and automated system in the country. The fans are controlled and monitored through a control room. In addition, sensors scattered in the mine, control the required flow rate. The Lamego mine has a similar but simpler system. This article proposes to discuss the application and improvement of the process of ventilation on demand in Brazilian mines where this system is applied.Item Cost-saving electrical energy consumption in underground ventilation by the use of ventilation on demand.(2020) Costa, Leandro de Vilhena; Silva, José Margarida daElectricity is one of the biggest expenses associated with underground mining and ventilation often accounts for 50% of the total electricity use. Ventilation on demand is not widely used in Brazil, but the Ipueira, Cuiaba, and Corrego do Sitio I mines reported savings of 26%, 30%, and 21%, respectively, following its application. Frequency inverters are used to control the rotation of the main fans during shift changes. The Cuiaba mine has a control room and fans are monitored online using wireless scattered sensors. Data from field studies were compared to other foreign mines. The results showed that the application of this technique, even in an experimental way, can reduce electricity consumption significantly. Despite the energy savings that can be achieved by providing air only when/where it is needed, the costs of automation, software, and infrastructure mean that it is not practical to apply this technique at a more advanced level.Item Avaliação dos danos causados pelo desmonte com explosivos no contorno de galerias subterrâneas a partir de um modelo baseado em medidas de velocidade de partícula.(2006) Silva, João Carlos Ribeiro Monteiro da; Silva, Valdir Costa eA ação das ondas de choque de detonações realizadas para a abertura de galerias subterrâneas induz danos ao maciço rochoso remanescente. Esse trabalho tem por objetivo avaliar a extensão desses danos, aplicando uma metodologia baseada no modelo de Holmberg e Persson, ao caso da mina subterrânea de Agalmatolito da LAMIL em Pará de Minas, MG. A partir de medidas de velocidade de partícula e das velocidades de propagação da onda primária, determinaram-se limites de vibração, acima dos quais são esperados danos. Utilizando a equação de atenuação das vibrações no campo próximo, desenvolvida para o local, calcularam-se os raios de duas zonas de dano em torno de duas classes de maciço: 0,24 m (raio de dano crítico) e 1,64 m (raio de dano mínimo) para o Metariolito; e 1,29 m e 1,59 m, respectivamente, para o Agalmatolito. Confrontando-se os resultados obtidos com aqueles constantes na literatura, verificou-se consistência com os valores encontrados para rochas semelhantes. Uma comparação da posição efetiva da superfície escavada com aquela prevista pelo modelo apresentou um erro de estimativa médio de 0,06 m.