O preço atual do minério de ferro obrigou as empresas a reduzirem os custos operacionais na fase mina. O carregamento e transporte de materiais com utilização de escavadeiras e caminhões grande porte representam grande parcela do custo total, particularmente com pneus, diesel, manutenção e mão de obra. Metas de movimentação anual são divididas durante os meses e as condições climáticas podem influenciar na produtividade e desempenho dos equipamentos. O banco de dados da movimentação mensal está condicionado com a capacidade de cada caminhão. Cada frota possui o payload característico e este representa a capacidade de transporte, sendo o valor da massa transportada o único parâmetro extraído em cada ciclo, sem considerar o posicionamento do material sobre a caçamba dos equipamentos. Forças de cisalhamento e torção são aplicadas constantemente no chassi e pneus dos caminhões e, quando as cargas estão descentralizadas, potencializam estes eventos. O transporte de cargas descentralizadas agride os pneus diminuindo a vida útil causando danos como deslocamento da banda de rodagem e separação do flanco. Este trabalho teve como objetivo diminuir as ocorrências de cargas descentralizadas e os custos operacionais. Para incrementar o posicionamento do material sobre as caçambas, a telemetria foi a ferramenta utilizada. Análises de pressões de suspensões indicam o posicionamento das cargas e através desses valores foi criado um banco de dados. Este banco de dados pode indicar qual operador de carga precisa de reciclagem, contribuindo para a redução de cargas descentralizadas e custos, uma vez que cargas deste perfil sucateiam precocemente pneus e suspensões. O estudo foi realizado em Itabira, em uma mina de minério de ferro a céu aberto. A metodologia comprovou ser capaz diminuir as ocorrências de cargas descentralizadas assim como aumentar a vida útil de pneus. Uma possível economia foi apresentada para ano de 2014, período em que a média das horas trabalhadas de pneus ficou abaixo da meta aumentando os custos fase mina. / The actual iron ore price forces the companies to reduce costs in all production steps of the mining operation. Loading and hauling materials using shovel-truck system represents the highest mining costs, particularly tires, diesel, maintenance and workforce. Annual goals of materials movement are split by months were weather conditions can affect productivity and performance of the fleet. The data file of the monthly material movement is based on the scale of each truck. Every fleet has a payload and it represents the capacity of hauling, being the value of loading a unique input extracted in each duty cycle, without taking into account the position of the material over the truck’s dump. Shear forces and torsion are applied all time at the frames trucks and, when the truckloads are unbalanced, increases the forces over the frame and tires. Transport unbalanced truckloads into long distances attack the tires and decrease its end of life, causing damages like displacement of tread and flank separation. The objective of this study is to propose a methodology to decrease unbalanced truck loads reducing the mining costs. In this mission of incorporating a material position on the truck´s dump, the telemetry was taking into consideration. The analysis of the suspension pressures data values shows the truckloads positions and with this data was created a databank. This databank indicates that the operators need truck load training to reduce unbalanced loads and truck costs in the mining operation, since unbalanced loads leads to early tires and suspensions scrap. The case study was carried out at Itabira Iron Ore Mine Complex, Brazil. This methodology was able to reduce the number of unbalanced truck loads as well as the tires life was increased. An economic saving estimate is presented based on 2014 scrapped tires data bank, in this year the tires life cycle was underneath, burdening operational costs.

Methods for estimating productivity and costs, and dependent equipment selection process, have needed to be increasingly reliable. Estimated productivity and costs must be as accurate as possible in reflecting actual productivity and costs experienced by mining operations to accommodate the long-term trend for diminishing commodity prices, For loading and hauling equipment operating in open pit mines, some of the interrelated estimating criteria have been investigated for better understanding; and, consequently, more reliable estimates of production and costs, also more effective equipment selection process. Analysis recognizes many of the interrelated criteria as random variables that can most effectively be reviewed, analyzed and compared in terms of statistical mathematical parameters. Emphasized throughout is the need for management of the cyclical loading and hauling system using conventional shovels/excavators/loaders and mining trucks to sustain an acceptable “rhythm” for best practice productivity and most-competitive unit-production costs. Outcomes of the research include an understanding that variability of attributes needs to be contained within acceptable limits. Attributes investigated include truck payloads, bucket loads, loader cycle time, truck loading time and truck cycle time. Selection of “ultra-class” mining trucks (≥ 290 -tonne payload) and suitable loading equipment is for specialist mining applications only. Where local operating environment and cost factors favourably supplement diminishing cost-benefits of truck scale, ultra-class trucks may be justified. Bigger is not always better – only where bigger can be shown to be better by reasons in addition to the modest cost benefits of ultra-class equipment. Truck over-loading may, to a moderate degree, increase productivity, but only at increased unit cost. / From a unit-cost perspective it is better to under-load than overload mining trucks. Where unit production cost is more important than absolute productivity, under-trucking is favoured compared with over-trucking loading equipment. Bunching of mining trucks manifests as a queuing effect – a loss of effective truck hours. To offset the queuing effect, required productivity needs to be adjusted to anticipate “bunching inefficiency”. The “basic number of trucks” delivered by deterministic estimating must provide for bunching inefficiency before application of simulation applications or stochastic analysis is used to determine the necessary number of trucks in the fleet. In difficult digging conditions it is more important to retain truck operating rhythm than to focus on achieving target payload by indiscriminately adding loader passes. Where trucks are waiting to load, operational tempo should be restored by sacrificing one or more passes. Trucks should preferably be loaded by not more than the nominal (modal) number plus one pass. The research has: • Identified and investigated attributes that affect the dispersion of truck payloads, bucket loads, bucket-cycle time, loading time and truck-cycle time. • The outcomes of the research indicate a need to correlate drilling and blasting quality control and truck payload dispersion. Further research can be expected to determine the interrelationship between accuracy of drilling and blasting attributes including accuracy of hole location and direction. • Preliminary investigations indicate a relationship between drill-and-blast attributes through blasting quality control to bucket design, dimensions and shape; also discharge characteristics that affect bucket cycle time that needs further research.

O preço atual do minério de ferro obrigou as empresas a reduzirem os custos operacionais na fase mina. O carregamento e transporte de materiais com utilização de escavadeiras e caminhões grande porte representam grande parcela do custo total, particularmente com pneus, diesel, manutenção e mão de obra. Metas de movimentação anual são divididas durante os meses e as condições climáticas podem influenciar na produtividade e desempenho dos equipamentos. O banco de dados da movimentação mensal está condicionado com a capacidade de cada caminhão. Cada frota possui o payload característico e este representa a capacidade de transporte, sendo o valor da massa transportada o único parâmetro extraído em cada ciclo, sem considerar o posicionamento do material sobre a caçamba dos equipamentos. Forças de cisalhamento e torção são aplicadas constantemente no chassi e pneus dos caminhões e, quando as cargas estão descentralizadas, potencializam estes eventos. O transporte de cargas descentralizadas agride os pneus diminuindo a vida útil causando danos como deslocamento da banda de rodagem e separação do flanco. Este trabalho teve como objetivo diminuir as ocorrências de cargas descentralizadas e os custos operacionais. Para incrementar o posicionamento do material sobre as caçambas, a telemetria foi a ferramenta utilizada. Análises de pressões de suspensões indicam o posicionamento das cargas e através desses valores foi criado um banco de dados. Este banco de dados pode indicar qual operador de carga precisa de reciclagem, contribuindo para a redução de cargas descentralizadas e custos, uma vez que cargas deste perfil sucateiam precocemente pneus e suspensões. O estudo foi realizado em Itabira, em uma mina de minério de ferro a céu aberto. A metodologia comprovou ser capaz diminuir as ocorrências de cargas descentralizadas assim como aumentar a vida útil de pneus. Uma possível economia foi apresentada para ano de 2014, período em que a média das horas trabalhadas de pneus ficou abaixo da meta aumentando os custos fase mina. / The actual iron ore price forces the companies to reduce costs in all production steps of the mining operation. Loading and hauling materials using shovel-truck system represents the highest mining costs, particularly tires, diesel, maintenance and workforce. Annual goals of materials movement are split by months were weather conditions can affect productivity and performance of the fleet. The data file of the monthly material movement is based on the scale of each truck. Every fleet has a payload and it represents the capacity of hauling, being the value of loading a unique input extracted in each duty cycle, without taking into account the position of the material over the truck’s dump. Shear forces and torsion are applied all time at the frames trucks and, when the truckloads are unbalanced, increases the forces over the frame and tires. Transport unbalanced truckloads into long distances attack the tires and decrease its end of life, causing damages like displacement of tread and flank separation. The objective of this study is to propose a methodology to decrease unbalanced truck loads reducing the mining costs. In this mission of incorporating a material position on the truck´s dump, the telemetry was taking into consideration. The analysis of the suspension pressures data values shows the truckloads positions and with this data was created a databank. This databank indicates that the operators need truck load training to reduce unbalanced loads and truck costs in the mining operation, since unbalanced loads leads to early tires and suspensions scrap. The case study was carried out at Itabira Iron Ore Mine Complex, Brazil. This methodology was able to reduce the number of unbalanced truck loads as well as the tires life was increased. An economic saving estimate is presented based on 2014 scrapped tires data bank, in this year the tires life cycle was underneath, burdening operational costs.

O preço atual do minério de ferro obrigou as empresas a reduzirem os custos operacionais na fase mina. O carregamento e transporte de materiais com utilização de escavadeiras e caminhões grande porte representam grande parcela do custo total, particularmente com pneus, diesel, manutenção e mão de obra. Metas de movimentação anual são divididas durante os meses e as condições climáticas podem influenciar na produtividade e desempenho dos equipamentos. O banco de dados da movimentação mensal está condicionado com a capacidade de cada caminhão. Cada frota possui o payload característico e este representa a capacidade de transporte, sendo o valor da massa transportada o único parâmetro extraído em cada ciclo, sem considerar o posicionamento do material sobre a caçamba dos equipamentos. Forças de cisalhamento e torção são aplicadas constantemente no chassi e pneus dos caminhões e, quando as cargas estão descentralizadas, potencializam estes eventos. O transporte de cargas descentralizadas agride os pneus diminuindo a vida útil causando danos como deslocamento da banda de rodagem e separação do flanco. Este trabalho teve como objetivo diminuir as ocorrências de cargas descentralizadas e os custos operacionais. Para incrementar o posicionamento do material sobre as caçambas, a telemetria foi a ferramenta utilizada. Análises de pressões de suspensões indicam o posicionamento das cargas e através desses valores foi criado um banco de dados. Este banco de dados pode indicar qual operador de carga precisa de reciclagem, contribuindo para a redução de cargas descentralizadas e custos, uma vez que cargas deste perfil sucateiam precocemente pneus e suspensões. O estudo foi realizado em Itabira, em uma mina de minério de ferro a céu aberto. A metodologia comprovou ser capaz diminuir as ocorrências de cargas descentralizadas assim como aumentar a vida útil de pneus. Uma possível economia foi apresentada para ano de 2014, período em que a média das horas trabalhadas de pneus ficou abaixo da meta aumentando os custos fase mina. / The actual iron ore price forces the companies to reduce costs in all production steps of the mining operation. Loading and hauling materials using shovel-truck system represents the highest mining costs, particularly tires, diesel, maintenance and workforce. Annual goals of materials movement are split by months were weather conditions can affect productivity and performance of the fleet. The data file of the monthly material movement is based on the scale of each truck. Every fleet has a payload and it represents the capacity of hauling, being the value of loading a unique input extracted in each duty cycle, without taking into account the position of the material over the truck’s dump. Shear forces and torsion are applied all time at the frames trucks and, when the truckloads are unbalanced, increases the forces over the frame and tires. Transport unbalanced truckloads into long distances attack the tires and decrease its end of life, causing damages like displacement of tread and flank separation. The objective of this study is to propose a methodology to decrease unbalanced truck loads reducing the mining costs. In this mission of incorporating a material position on the truck´s dump, the telemetry was taking into consideration. The analysis of the suspension pressures data values shows the truckloads positions and with this data was created a databank. This databank indicates that the operators need truck load training to reduce unbalanced loads and truck costs in the mining operation, since unbalanced loads leads to early tires and suspensions scrap. The case study was carried out at Itabira Iron Ore Mine Complex, Brazil. This methodology was able to reduce the number of unbalanced truck loads as well as the tires life was increased. An economic saving estimate is presented based on 2014 scrapped tires data bank, in this year the tires life cycle was underneath, burdening operational costs.