cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.8324405.v1
title: Developing a stepwise approach to simulate a hammer mill through the Whiten model - the adherence for a gold ore

description: Abstract Comminution represents a large portion of the capital and operating cost of a mineral processing plant. In 1983, Cohen estimated that comminution processes could account for 30% to 50% of the power consumption of the mill, and typically represents 50% of the operating costs of a mine. Therefore, its optimization is directly related to reduction of these operating costs. Among the crushing equipment, the hammer mill is one which is dedicated to operations that aim for a high reduction ratio with the controlled generation of fines. This crusher is recommended for friable and low abrasive ores presenting a high productive capacity. This study aims to develop a stepwise approach that allows the use of the classical crusher model (Whiten-Andersen) in modeling and simulation of circuits containing a hammer mill, simulating the resulting product according to variation of rotation speed within the equipment. The existing model for crushers developed by Whiten-Andersen considers the Perfect Mixing Model, which represents crushing through equations related to selection and breakage functions, that provide an equilibrium condition. This study aims to develop a stepwise approach that allows the use of the classical crusher model in modeling and simulation of circuits containing a hammer mill, by simulating the effect that the variation of rotation speed within the equipment implies in the generated product. The comparisons between the experimental and simulated data indicated that the model fits the data for both, P80 values and percentage passing in 19.1 mm sieve. The model created was validated based on specific experimental campaign.
DOI: 10.6084/m9.figshare.9870623
title: Load equivalency factors for off-road trucks

description: Abstract This article addresses an analysis of the Load Equivalency Factor (LEF) for off-road trucks. A new LEF curve for single axles with dual wheels covering trucks from 6.0 to 151.42 tons per axle is proposed, converting various magnitudes of damage from wheel loads to damage caused by the standard axle load of 8.2 tons. Then, this damage ratio was raised to the exponent proposed by Pereira (1992), and LEF for the considered loads was obtained. In the determination of LEF from the structural response of the subgrade, it was confirmed that LEF values did not suffer significant variations with the various parameters adopted, encompassing variations in the axle loads between 6 and 151.42 tons, tire pressures of 80.0, 100.0 and 120.0 psi, as well as five different pavement structures. In the study, LEF remained stable even in pavement structures with low and high axle capacities. In order to validate the results, the resulting factors were then compared with those proposed by DNIT (2006), displaying a coefficient of determination of 0.99. The conclusion is that pavements for off-roads trucks can be designed using the procedure recommended by DNIT (2006) for flexible pavement, without extrapolation of the respective LEF curve.
DOI: 10.6084/m9.figshare.9870623.v1
title: Load equivalency factors for off-road trucks

description: Abstract This article addresses an analysis of the Load Equivalency Factor (LEF) for off-road trucks. A new LEF curve for single axles with dual wheels covering trucks from 6.0 to 151.42 tons per axle is proposed, converting various magnitudes of damage from wheel loads to damage caused by the standard axle load of 8.2 tons. Then, this damage ratio was raised to the exponent proposed by Pereira (1992), and LEF for the considered loads was obtained. In the determination of LEF from the structural response of the subgrade, it was confirmed that LEF values did not suffer significant variations with the various parameters adopted, encompassing variations in the axle loads between 6 and 151.42 tons, tire pressures of 80.0, 100.0 and 120.0 psi, as well as five different pavement structures. In the study, LEF remained stable even in pavement structures with low and high axle capacities. In order to validate the results, the resulting factors were then compared with those proposed by DNIT (2006), displaying a coefficient of determination of 0.99. The conclusion is that pavements for off-roads trucks can be designed using the procedure recommended by DNIT (2006) for flexible pavement, without extrapolation of the respective LEF curve.
DOI: 10.6084/m9.figshare.9871133
title: Experimental analysis of built-up cold-formed steel lipped channel stub column

description: Abstract This article reports the results of experimental tests conducted on built-up cold-formed steel (CFS) stub columns, composed of double lipped channel members connected with self-drilling screws, which will be applied as the chord members of laced columns. These experiments aim to quantify the effect of four distinct web fastener layouts on the composite action, including the ultimate strength, buckling modes and collapse mechanism for built-up CFS members. The tested stub columns are of 480mm length, double 88x86x40x42x12mm lipped channel cross-section and 0.8mm thickness. The built-up CFS lipped channel members were analyzed with help of the Generalized Beam Theory in order to identify their buckling loads and modes. The Direct Strength Method (DSM) was adopted to obtain the analytical strength of the built-up members, to be compared with the experimental results. The axially compressed built-up members displayed local and distortional buckling, negligible composite behavior and minor effect of number and distribution of the screws. The results indicate (i) inefficient behavior of the self-drilling screws for composite condition purposes and (ii) the DSM rules for non-composite CFS are able to estimate the ultimate strength of this type of built-up lipped channel section.
DOI: 10.6084/m9.figshare.9871133.v1
title: Experimental analysis of built-up cold-formed steel lipped channel stub column

description: Abstract This article reports the results of experimental tests conducted on built-up cold-formed steel (CFS) stub columns, composed of double lipped channel members connected with self-drilling screws, which will be applied as the chord members of laced columns. These experiments aim to quantify the effect of four distinct web fastener layouts on the composite action, including the ultimate strength, buckling modes and collapse mechanism for built-up CFS members. The tested stub columns are of 480mm length, double 88x86x40x42x12mm lipped channel cross-section and 0.8mm thickness. The built-up CFS lipped channel members were analyzed with help of the Generalized Beam Theory in order to identify their buckling loads and modes. The Direct Strength Method (DSM) was adopted to obtain the analytical strength of the built-up members, to be compared with the experimental results. The axially compressed built-up members displayed local and distortional buckling, negligible composite behavior and minor effect of number and distribution of the screws. The results indicate (i) inefficient behavior of the self-drilling screws for composite condition purposes and (ii) the DSM rules for non-composite CFS are able to estimate the ultimate strength of this type of built-up lipped channel section.
DOI: 10.6084/m9.figshare.9871394.v1
title: Application of the fundamental parameter method to the assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF

description: Abstract Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) is a suitable technique for the characterization of contaminated mining sites, providing a quick and reliable screening for areas of significant contamination. This study established and validated a non-destructive methodology for quantitative simultaneous determination of major and minor constituents in soil and sediments by WDXRF, which was further applied to quantify soil and sediment samples from Osamu Utsumi uranium mine (Caldas, Minas Gerais, Brazil). Elements such as Ce, La, Nd, Mn and U were found in more concentrated levels in the calcium diuranate deposit (DUCA), whereas Fe and Al were found at higher levels in the soil samples corresponding to sites where accentuated leaching processes have occurred. Comparatively, the levels of U and rare-earth elements were found in significantly higher levels in the sediments retrieved from the mine’s pit as a result of acid mine drainage. These findings are believed to be useful as an initial environmental assessment for the decommissioning process of the mine.
DOI: 10.6084/m9.figshare.9871394
title: Application of the fundamental parameter method to the assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF

description: Abstract Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) is a suitable technique for the characterization of contaminated mining sites, providing a quick and reliable screening for areas of significant contamination. This study established and validated a non-destructive methodology for quantitative simultaneous determination of major and minor constituents in soil and sediments by WDXRF, which was further applied to quantify soil and sediment samples from Osamu Utsumi uranium mine (Caldas, Minas Gerais, Brazil). Elements such as Ce, La, Nd, Mn and U were found in more concentrated levels in the calcium diuranate deposit (DUCA), whereas Fe and Al were found at higher levels in the soil samples corresponding to sites where accentuated leaching processes have occurred. Comparatively, the levels of U and rare-earth elements were found in significantly higher levels in the sediments retrieved from the mine’s pit as a result of acid mine drainage. These findings are believed to be useful as an initial environmental assessment for the decommissioning process of the mine.
DOI: 10.6084/m9.figshare.9870971
title: Direct sequencing of blocks in stochastic models with multi-mines and multi-destinations

description: Abstract Mining Scheduling is the one that maximizes profit from mining over time. By means of computational methods, the deposit is discretized in blocks and algorithms are used to consummate this objective. The methods that are widely known nowadays for mining scheduling optimization of a discrete block model were based on graph theory, and among those most used by the mining industry is a solution found by Lerchs and Grossmann (1965) which, together with other methods, was consolidated as the process of traditional mining planning. For both supply and multi-destination models, there is a limitation of the current methodology, since it consists of the optimization of each mine separately which may not be a global optimization solution. This article proposes an optimization of the benefit in a stochastic model through the DBS (Direct Block Scheduling) for a copper mining complex with two mines, a pre-existing copper stockpile and two treatment streams, comparing several scenarios and analyzing the best alternative for the proposed problem.
DOI: 10.6084/m9.figshare.9870971.v1
title: Direct sequencing of blocks in stochastic models with multi-mines and multi-destinations

description: Abstract Mining Scheduling is the one that maximizes profit from mining over time. By means of computational methods, the deposit is discretized in blocks and algorithms are used to consummate this objective. The methods that are widely known nowadays for mining scheduling optimization of a discrete block model were based on graph theory, and among those most used by the mining industry is a solution found by Lerchs and Grossmann (1965) which, together with other methods, was consolidated as the process of traditional mining planning. For both supply and multi-destination models, there is a limitation of the current methodology, since it consists of the optimization of each mine separately which may not be a global optimization solution. This article proposes an optimization of the benefit in a stochastic model through the DBS (Direct Block Scheduling) for a copper mining complex with two mines, a pre-existing copper stockpile and two treatment streams, comparing several scenarios and analyzing the best alternative for the proposed problem.
DOI: 10.6084/m9.figshare.11452347
title: Composite floor system with CFS trussed beams, concrete slab and innovative shear connectors

description: Abstract Steel and concrete floor systems are widely applied for buildings and provide excellent structural response, optimized material consumption, reduced beam height, and improved bending strength and stiffness capacity. In recent years, many experimental investigations concerned with new alternatives addressed to efficient interaction between steel and concrete structures have been reported. In this context, the present study aims at investigating the behavior of a structural composite floor system composed of light cold-formed steel trusses and a partially pre-cast concrete slab, as well as developing an innovative solution for shear connectors. The referred to shear connector consists of Thin-Walled Perfobond (TWP) ribs, composed of 1.25mm thick cold-formed plates crossed by 4.2 mm reinforcing steel bars and connected to the truss chord by self-drilling screws. Preliminary results, based on experimental full-scale testing, indicate that the performance of the composite truss is adequate in terms of ultimate load and deformation capacity. Additionally, the investigation showed that traditional analytical solution is in good agreement with experimental results.
DOI: 10.6084/m9.figshare.11452347.v1
title: Composite floor system with CFS trussed beams, concrete slab and innovative shear connectors

description: Abstract Steel and concrete floor systems are widely applied for buildings and provide excellent structural response, optimized material consumption, reduced beam height, and improved bending strength and stiffness capacity. In recent years, many experimental investigations concerned with new alternatives addressed to efficient interaction between steel and concrete structures have been reported. In this context, the present study aims at investigating the behavior of a structural composite floor system composed of light cold-formed steel trusses and a partially pre-cast concrete slab, as well as developing an innovative solution for shear connectors. The referred to shear connector consists of Thin-Walled Perfobond (TWP) ribs, composed of 1.25mm thick cold-formed plates crossed by 4.2 mm reinforcing steel bars and connected to the truss chord by self-drilling screws. Preliminary results, based on experimental full-scale testing, indicate that the performance of the composite truss is adequate in terms of ultimate load and deformation capacity. Additionally, the investigation showed that traditional analytical solution is in good agreement with experimental results.
DOI: 10.6084/m9.figshare.11452914
title: Optimization of shells modeled using NURBS subjected to a dynamic loading condition

description: Abstract This study presents an optimization method for the thickness of shell elements subjected to dynamic loads. Structural analyses were carried out using the finite element method. The analyzed domains were modeled using NURBS, and meshes were generated using a transformation of the parametric domain into the geometric domain via a geometric function. The shell element considered is a combination of a CST membrane element and a DKT plate element, forming an element with 15 degrees of freedom. The Newmark method with constant acceleration was applied to solve the equation of motion. The optimization approach was considered in two different ways: with uniform and variable thickness throughout the shell element. Due to the nonlinear constraints of the problem, the Sequential Quadratic Programming (SQP) method was employed. SQP routines are available in MATLAB, in which this study was performed. Useful examples were detailed in this study to demonstrate the applicability of the optimization method to real structures, such as the Igrejinha da Pampulha, a church located in Belo Horizonte, Brazil, whose modeling was performed.
DOI: 10.6084/m9.figshare.11452914.v1
title: Optimization of shells modeled using NURBS subjected to a dynamic loading condition

description: Abstract This study presents an optimization method for the thickness of shell elements subjected to dynamic loads. Structural analyses were carried out using the finite element method. The analyzed domains were modeled using NURBS, and meshes were generated using a transformation of the parametric domain into the geometric domain via a geometric function. The shell element considered is a combination of a CST membrane element and a DKT plate element, forming an element with 15 degrees of freedom. The Newmark method with constant acceleration was applied to solve the equation of motion. The optimization approach was considered in two different ways: with uniform and variable thickness throughout the shell element. Due to the nonlinear constraints of the problem, the Sequential Quadratic Programming (SQP) method was employed. SQP routines are available in MATLAB, in which this study was performed. Useful examples were detailed in this study to demonstrate the applicability of the optimization method to real structures, such as the Igrejinha da Pampulha, a church located in Belo Horizonte, Brazil, whose modeling was performed.
DOI: 10.6084/m9.figshare.11452557
title: Diamonds from the Santo Antônio River (Delfinópolis, Minas Gerais): probable relationship with the Canastra-3 Kimberlite

description: Abstract The study identifies the Canastra-3 Kimberlite magnetic anomaly as the likely primary source of the alluvial diamonds recovered by "garimpeiros" in the Santo Antônio River basin (Delfinópolis, southwestern Minas Gerais). This conclusion is based on cumulative geophysical, hydrographic, metallogenical and mineral geochemistry evidences. The study area is located within fertile ground in the border of the São Francisco craton, close to other diamond primary sources and secondary deposits. This kimberlitic target is the only known in the Santo Antônio River basin. In addition, the known mineralized gravels of this river, worked in the past by "garimpeiros", have evidence of a short transport (angular pebbles and blocks), further evidence of a nearby source. The original data collected in the "Minas Gerais Aerogeophysical Survey Program" was processed and analyzed with the Euler Deconvolution method, implemented in software Oasis Montaj. With the exception of the Canastra-3 body anomaly, all others in the study were classified as non-kimberlitic. Recent sampling work on the weathered top of the Canastra-3 Kimberlite recovered indicator minerals, notably a high proportion of pyrope garnets of the G-10 type, which is unusual among the kimberlites of the region.
DOI: 10.6084/m9.figshare.11452557.v1
title: Diamonds from the Santo Antônio River (Delfinópolis, Minas Gerais): probable relationship with the Canastra-3 Kimberlite

description: Abstract The study identifies the Canastra-3 Kimberlite magnetic anomaly as the likely primary source of the alluvial diamonds recovered by "garimpeiros" in the Santo Antônio River basin (Delfinópolis, southwestern Minas Gerais). This conclusion is based on cumulative geophysical, hydrographic, metallogenical and mineral geochemistry evidences. The study area is located within fertile ground in the border of the São Francisco craton, close to other diamond primary sources and secondary deposits. This kimberlitic target is the only known in the Santo Antônio River basin. In addition, the known mineralized gravels of this river, worked in the past by "garimpeiros", have evidence of a short transport (angular pebbles and blocks), further evidence of a nearby source. The original data collected in the "Minas Gerais Aerogeophysical Survey Program" was processed and analyzed with the Euler Deconvolution method, implemented in software Oasis Montaj. With the exception of the Canastra-3 body anomaly, all others in the study were classified as non-kimberlitic. Recent sampling work on the weathered top of the Canastra-3 Kimberlite recovered indicator minerals, notably a high proportion of pyrope garnets of the G-10 type, which is unusual among the kimberlites of the region.
DOI: 10.6084/m9.figshare.11452275
title: The Tatuí Formation as a source of raw material in the ceramic pole of Santa Gertrudes (SP)

description: Abstract The importance of the Santa Gertrudes Ceramic Complex (SGCC) in the ceramic market is directly associated with the high quality of the Corumbataí Formation clays used in the manufacture of its products. Although the volumetric capacity of the Corumbataí Formation is able to meet the SGCC demand for the coming years, its industries are always in search of alternative sources for raw material, among these sources is the Tatuí Formation. In order to determine if the sediments coming from the Tatuí Formation have the potential to be used in the ceramist industry, geochemical, mineralogical and physical characterization tests were carried out on samples obtained from two different profiles. The analyses showed a sequence of fine sandstones rich in SiO2 and Al2O3, with a mineralogy composed of quartz, potassium feldspar / plagioclase (albite), filosilicates and iron oxides in secondary proportions. The ceramic tests, in turn, presented heterogeneous results for the specimens submitted to burning at 1150 º C, but in general, the material coming from the Tatuí Formation has a promising potential within the field of ceramic manufacturing.
DOI: 10.6084/m9.figshare.11452275.v1
title: The Tatuí Formation as a source of raw material in the ceramic pole of Santa Gertrudes (SP)

description: Abstract The importance of the Santa Gertrudes Ceramic Complex (SGCC) in the ceramic market is directly associated with the high quality of the Corumbataí Formation clays used in the manufacture of its products. Although the volumetric capacity of the Corumbataí Formation is able to meet the SGCC demand for the coming years, its industries are always in search of alternative sources for raw material, among these sources is the Tatuí Formation. In order to determine if the sediments coming from the Tatuí Formation have the potential to be used in the ceramist industry, geochemical, mineralogical and physical characterization tests were carried out on samples obtained from two different profiles. The analyses showed a sequence of fine sandstones rich in SiO2 and Al2O3, with a mineralogy composed of quartz, potassium feldspar / plagioclase (albite), filosilicates and iron oxides in secondary proportions. The ceramic tests, in turn, presented heterogeneous results for the specimens submitted to burning at 1150 º C, but in general, the material coming from the Tatuí Formation has a promising potential within the field of ceramic manufacturing.