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Minas-Rio is an Anglo American property, located in Brazil, which started its operation at the end of 2014. The Minas-Rio regrind circuit is currently the largest Vertimill™ installation in the world with sixteen Metso VTM-1500s installed in closed circuit with hydrocyclones. The grinding efficiency of this circuit was verified through a sampling campaign, and the results showed that the measured specific energy consumption was similar to the predicted specific energy consumption estimated at the engineering design stages of the project. Although essential for plant design, the specific energy consumption for a given product size is not sufficient to predict the performance of the circuit under different operating conditions. A more detailed model and simulations are required to predict performance under different operating conditions, so that the required product specifications can be achieved. A vertical stirred mill model, based on the Population Balance Model (PBM) technique, has recently been developed and validated using extensive data from pilot scale vertical stirred milling tests. This model is the subject of this investigation. Industrial scale data has been generated through a careful sampling campaign at the Minas-Rio plant, and used to further validate the model. PBM ore breakage parameters were obtained from the feed samples using simplified tests carried out in a laboratory scale conventional tubular ball mill and the results are discussed here. [ABSTRACT FROM AUTHOR]

The Minas-Rio Project is the biggest project from Anglo American in the world and considers Vertimill in the regrinding circuit to adequate the particle size distribution to feed slurry pipeline that will pump the ore from Conceição do Mato Dentro in Minas Gerais State to Acu Port in Rio de Janeiro State, Brazil. A Vertimill pilot test campaign was carried out at Metso's pilot plant facility located in York city, Pennsylvania State, USA, to provided information to sizing the industrial grinding circuit. The main objective of this work is proposing a way to simulate the industrial Vertimill using the population balance model, normally used to simulate ball mills. The simulations were based on the selection and breakage functions determined from the laboratory tests using a batch ball mill. The simulations were performed using a Vertimill model implemented in the ModsimTM plant-wide simulator. The results of simulations shows that was possible to simulate the pilot tests, with good accuracy, considering simple laboratory tests with small quantities of samples. [ABSTRACT FROM AUTHOR]

The mining industry is famous for many paradigms regarding different flowsheet designs and the use of new technologies and equipment. In this context, a question often performed to process engineers is: what grinding circuit is more efficient, the direct or the reverse? A precise answer could only be given by experimental data and simulations. Simulations were performed using ModSimTM software considering parameters obtained by batch mill tests of an iron ore sample. The simulations, preliminarily, indicated no significant differences between the two circuit configurations for the sample tested. Subsequently, tests were conducted on a pilot scale with detailed measurement of all the variables necessary for a correct interpretation of the differences between the direct and reverse circuits. The test results confirmed the prediction obtained by simulation. This work provides the basis to test other ores and to understanding better the real differences between grinding circuit configurations. Thus, it is expected that some myths of the mineral industry, with respect to flowsheet choices, are overcome. [ABSTRACT FROM AUTHOR]

The optimization of industrial grinding circuits has been successfully performed using mathematical models that describe the industrial scale data from breakage parameters determined in laboratory grinding tests. The test material studied here is a gold ore ground in a closed ball mill circuit with hydrocyclone classification. Several sampling campaigns were carried out aiming to produce mass balances and provide material for laboratory tests. The parameters determined in the laboratory tests were used to predict, by simulation, the circuit behavior with a low ball charge level and a balanced ball size distribution. [ABSTRACT FROM AUTHOR]

Over the years Vale S.A. has developed a methodology for scaling industrial comminution circuit that is being constantly improved and implemented in developing new routes and process optimization of circuits in operation. This work will be given a focus on the methodology of simplified balls mill Work Index (WI Anaconda) in performance prediction of Sossego Plant ball mill. The great advantage of this methodology is to reduce the time and weight to determine the energy consumption in ball mills, whose values can be used in studies of variability, geometallurgy and design and control of industrial grinding circuits. [ABSTRACT FROM AUTHOR]

Size control of particulate material is key in a mineral processing plant, allowing the downstream process equipment to separate the mineralogical components. Despite being extensively applied in millimetric particle size classification, recent advances in high frequency screens have allowed their application in grinding circuits, leading to production increases and better classification efficiency for the micrometric range. The development of models to simulate these systems is essential to allow estimating possible technological benefits in the plant performance. This study presents a review of models applied to screening processing, focusing on the wet classification of fine particles, and considering their applicability and limitations. The models review is combined with an assessment of their fitness to a high frequency screening trials database. Among the available alternatives, the model developed by Batterham et al. [1] presented the best fit to the dataset, but it has limited simulation capability. Mwale [2], in turn, was considered to offer the best compromise between fit to data and simulation readiness, since it does not demand a difficult sampling campaign and individualizes the process parameters from the model constants. However, a technology gap is still present, which would involve scale-up procedures from small-scale trials to industrial plants, since all the test work was developed using a real scale device. [Display omitted] [ABSTRACT FROM AUTHOR]

Microscope-based automated image analysis systems have been used to obtain data regarding mineral liberation. However, this kind of analysis leads to stereological bias due to the intrinsic two-dimensionality characteristic of the technique. Three-dimensional imaging techniques such as X-ray microtomography comes as an alternative method to measure liberation. We explored the potentiality of high-resolution X-ray microtomography to investigate the characteristics of liberation of a Brazilian bauxite. Grade distributions in 2D and 3D were correspondent when all possible cross-sections were considered in 2D. However, 2D surface exposure did not converge accurately to the 3D method due to the loss of 3D information. [ABSTRACT FROM AUTHOR]

A key factor in mineral concentration is mineral liberation. Scanning electron microscopebased (SEM-based) automated image analysis systems have been used to obtain information concerning liberation. One of the limitations of SEM-based techniques is the unavoidable loss of 3D information, leading to significant stereological errors. X-ray microtomography (μCT) emerges as an alternative that permits three-dimensional imaging and direct measurement of spatial characteristics of particles, eliminating stereological issues. We used high-resolution μCT and a microscope-based system to evaluate the characteristics of liberation of an iron ore waste. Grade and surface exposure have been overestimated by the 2D assessment. The stereological effect was more pronounced in surface exposure quantification. We found a linear relationship between (i) grade and surface exposure and (ii) particle size and surface exposure. A comparison of SEM-based and μCT techniques showed that a 3D technique is better for the purpose of particulate systems characterisation. [ABSTRACT FROM AUTHOR]

The Minas Rio project, owned by Anglo American, has HPGRs in open circuit operated as a tertiary/quaternary crushing stage. Currently this type of equipment is designed from HPGR tests on laboratory scale and pilot scale tests. This paper presents a methodology for simulating HPGR from piston-die tests on laboratory scale and a mathematical model developed in Hacettepe University in Turkey. The parameters determined from the results of the piston-die tests were used to validate the HPGR testing on pilot scale. Finally, the model was used to predict the particle size distribution in the HPGR product on industrial scale. [ABSTRACT FROM AUTHOR]

The main iron ore processing plants in Brazil operate through reverse cationic flotation. Many studies have been conducted in order to improve flotation efficiency by optimization process variables. The pneumatic flotation cell stands out due to the simplicity to and to the intense contact particle/bubble promoted by the pulp feeding system. In this study, laboratory scale and pilot were conducted using a sample of itabirite iron ore. The objectives are evaluating the performance of this device using low grade iron ore, and drawing a comparison with laboratory scale tests on conventional flotation cell. The results indicate the potential application of pneumatic flotation cell to the ore tested. Adjustments in the feed particle size and process optimizations can be performed on the concentrate, reaching Fe and SiO2 grades used by the industry. [ABSTRACT FROM AUTHOR]

Laboratory devices are key to modeling processes and allowing scale-up simulations to assess industrial scale performance. This study presents the development of a laboratory-scale high-frequency screen for continuous trials and initial modeling assessment using two different approaches. The models are assessed according to accuracy and precision for the data set considered. Additionally, the sensitivity of their parameters to changes in process conditions is analyzed for variations in solids concentration, feed rate and screen aperture. For both modeling accuracy and parameter sensitivity, Mwale et al. model presented better results, indicating a more suitable model for dataset description and process simulation. [Display omitted] • Lab scale device developed to reduce mass and complexity demanded. • Trials carried out varying solids concentration, feed rate and aperture. • Mwale et al. and Hatch&Mular models selected for trials' results analyses. • Mwale et al. presents better modeling quality and suitability for simulation. • Hatch&Mular shows acceptable trials' modeling, but simulation would be limited. [ABSTRACT FROM AUTHOR]