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By V A. Chanturia, T N. Matveeva, V V. Getman, A Yu Karkeshkina

The development and application of new effective environmentally friendly reagents for the flotation of thin and ultrathin mineral components is an urgent task. The analysis of the nomenclature of chemicals, including flotation reagents and flocculants, showed that water-soluble polymers (WSP) might be used in flotation separation of fine grinding products containing non-ferrous and precious metals. Water-soluble polymers that are responsive to temperature changes are the most attractive as reagents during flotation. These are the thermo-responsive polymers or thermomorphic polymers. The presence of nitrogen and oxygen atoms in the polymer molecule contributes to the formation of a coordination bond with non-ferrous and precious metals. A research conducted at the ICEMR RAS within the framework of the scientific school of Academician of the Russian Academy of Sciences Chanturia helped to develop a method of flotation of finely ground mineral particles containing valuable components using modified thermomorphic polymers. The paper focuses on the experimental study of poly (vinyl caprolactam) (PVC) as a flotation reagent for gold recovery from finely ground mineral products. PVC is a ready-made water-soluble thermosensitive polymer that does not require complex synthesis. PVC has a high ability to form complexes in an aqueous environment when heated. According to experimental data, the polymer interacts with gold nanoparticles, contributing to the extraction of gold from fine mineral products and the tailings that makes it perspective as an additional flotation agent for the processing of gold-containing ores.

Aug 24, 2022

By Dr. Zach Agioutantis, Elliott Morgan

The explosives, mining, and heavy civil industries consistently battle the uncertainty that is associated with working with a heterogenous medium like rock in blasting. This has led to studies to increase fundamental understanding of material response under dynamic loading that is associated with blasting. This study looks at the dynamic strain associated with blasting the lab Split-Hopkinson Pressure Bar (SHPB) testing while also building off of previous studies with the goal of better understanding the dynamic forces that are enacted on a geologic body during a blast loading event. This is required in order to advance geologic blast response modeling. This is achieved through analyzing the stress and strain values for each specimen that are calculated from strain data collected with a SHPB. Based on this data, the dynamic material response characteristics are able to be determined. Tests were conducted on five Berea Sandstone specimens with a rough length to diameter ratio (L/D) of 1.0. The strain data from these tests were then used to create stress strain curves as well as charts depicting failure stress to both strain rate and failure particle velocities. The tests conducted returned similar results to previous tests results on Berea Sandstone while also showing a correlation between strain rate at failure and failure particle velocities. While further research is needed, there is evidence that SHPB test data could be used in conjunction with the MBF model. The MBF model states that the peak particle velocity (PPV) of blast vibrations can be correlated with deformation (strain) at a given point. With a further understanding of dynamic material response correlated to PPV measurements, further refinement could allow for better prediction of blast performance.

Jan 21, 2025

By José Flávio Viana, Alexandre Alvarenga Palmeira, Darlan Rodrigues Azevedo

O processo de dessulfuração do ferro gusa é uma etapa de grande importância para a fabricação do aço. Diante da necessidade cada vez mais exigente de aplicações nobres, dos aços, faz-se necessário o desenvolvimento e estudos buscando maior eficiência e custos operacionais otimizados para melhores resultados deste processo. O carbureto de cálcio é um insumo utilizado como matéria prima dos agentes dessulfurantes. Através do microscópio de varredura e o EDS, buscou-se estudar e entender o mecanismo de reação do carbureto de cálcio no processo de dessulfuração do ferro gusa líquido, sendo realizado o estudo no Laboratório de Ensaios e Análises em Materiais - LAMAT do SENAI de Itaúna – MG, em conjunto com o setor de pesquisa e desenvolvimento da Tecnosulfur S/A.

Oct 1, 2019

By João Henrique de Andrade Lima

Dentre os mecanismos de desgaste existentes o desgaste por abrasão é responsável por cerca de 50% de todo o desgaste gerado. Alinhado à busca do desenvolvimento de novos mercados para o aço inoxidável, foi desenvolvida uma metodologia, para a medição da taxa de desgaste abrasivo de diferentes aços. Uma politriz foi escolhida para o ensaio devido à possibilidade de controlar a força, tipo de abrasivo, vazão de água, tempo e velocidade de rotação do disco. Para o ensaio foram preparados corpos de prova do aço P410D com dimensões de 40x40mm. Os corpos de prova foram fixados em suportes de baquelite e este conjunto foi acoplado junto à politriz. Após a escolha dos parâmetros ideais para o teste foram realizados testes comparando a taxa de desgaste de diferentes tipos de aços permitindo ranqueá-los de acordo com sua resistência ao desgaste abrasivo.

Aug 17, 2017

By R. S. Wang, S. Z. Zhou, L. Wan, K. W. Zeng, Z. J. Sun, W. G. Wu, Z. B. Qian, X. R. Zhang, Z. K. Hu, Y. Yu

"In view of the present situation that the traditional environment friendly depressants for galena aren’t very effective in the separation of mixed concentrate including copper sulfide and lead sulfide, this research describes a new environment friendly depressant PD-1 and investigates its effects and mechanism in the separation of chalcopyrite and galena. This study is carried out through flotation tests, analysis of infrared spectra and absorption measurements. It is shown that when O-isopropyl-N-ethyl thionocarbamate (Z200) is used as collector, chalcopyrite and galena can be separated in the presence of PD-1 under appropriate conditions. Therefore, it can be concluded that PD-1 has an excellent depression ability and great selectivity for galena. Meanwhile, analysis of infrared spectra demonstrates that PD-1 can strongly absorb on the galena surface by chemical interaction with Pb2+, while it hardly absorbs on the chalcopyrite surface. In addition, the results of absorption measurements reveal that competitive adsorption occurs on the galena surface between PD-1 and Z200, PD-1 can block the absorption of Z200 on the galena surface. However, PD-1 has a little effect on the absorption of Z200 on the chalcopyrite surface under above conditions. What’s more, the hydrophilic groups of PD-1 molecules can make galena effectively depressed. The results of mechanism analysis are in accordance with those of flotation tests.INTRODUCTION In the processing of copper-lead sulfide ores, the process, copper increase and lead reduction (Zhang et al., 2017) after reagents removal of rough concentrate produced by mixed flotation of chalcopyrite and galena, is usually adopted. However, as a result of tight symbiosis and the similar flotability of chalcopyrite and galena, the separation is difficult (Hu and Feng, 2006). There are 3 kinds of depressants for galena in the separation of chalcopyrite and galena concentrate,including dichromate, sulfite and combined depressants of organic or inorganic reagents (Wei, 2012). As dichromate would cause serious environmental pollution, it is gradually banned to be used in industry (Xu et al., 2017; Lin et al., 2017). what’s more, due to the need of acidic slurry, using sulfite is not conductive to the maintenance of equipment and stable production(Wang, 1999). As for the combined depressants, they also have disadvantages of complex pharmaceutical system and no ideal separation effect (Wei and Sun, 2008). Therefore, the development of new safe and effective depressants for galena is a research focus for researchers in the minerals processing (Chen, 2000). In this paper, a new type of organic depressant PD-1 is applied to the copper-lead separation process of ""copper increase and lead reduction"" using Z200 as the collector. In addition, the performances and mechanism of its depression to galena are studied emphatically."

Jan 1, 2018

The tangible effects of leakage are presented graphically, and a technique for quantifying the leakage characteristics of a ventilation column using the æSolveÆ capabilities of a common spreadsheet is demonstrated. A case study of a working decline in Western Australia is used to demonstrate the potential for more realistic design of development ventilating systems, and for more cost effective management of the condition of the duct.

Jan 1, 2002

By W. Hawker, A. M. Ivana

"Pressure oxidation is used to liberate gold from refractory sulphide ore and concentrates with over fifteen autoclaves in operation. Despite the importance of pressure oxidation, the autoclave chemistry and chemical thermodynamics are not well established. For example, there is no consensus on aqueous iron speciation or stability of jarosite phases. Additionally, there remains questions about basic ferric sulphate formation and stability. In addition to a review of the current state of knowledge, a methodology to study the ferric precipitation reaction and relate the results to chemical thermodynamic predictions is presented which will be used to accurately define the phase boundaries of the iron precipitates in the future (hematite, jarosite and basic ferric sulphate).INTRODUCTION With declining availability of orebodies that respond to simple leaching conditions, pressure oxidation has become a prevalent technology to liberate gold locked in sulphide mineral matrices. Gold pressure oxidation was established 32 years ago, with McLaughlin being the first facility in 1985 (Thomas & Pearson, 2016). Pressure oxidation is carried out at elevated temperatures ranging from 180 to 240°C as shown in the summary of operations in Table 1 (Ruonala et al., 2016; Fleming, 2010).A considerable amount of research has been done to study iron solubility and precipitation under autoclave conditions (Tozawa & Sasaki, 1986; Umetsu et al., 1977; Sasaki et al., 1993; Fleuriault, 2016; Cheng & Demopoulos, 2004; Papangelakis et al., 1994; Yue et al., 2003). These reports provide a description of the process chemistry and iron behaviour in the autoclave. However, there remain questions about the type and stability of aqueous species and solid phases. This detailed information is required to build a robust chemical thermodynamic model of the system, allowing for equilibrium and kinetic reaction limitations to be discerned."

Jan 1, 2017

By Emre Turk, Suat Gullu, Candan Gokceoglu, Ahmet Sirri, Asli Can

In this study, the ground improvement application applied under the live railway bridge's approach embankments in Sivas, Türkiye was investigated as a case study. The soil profile is mainly composed of orangish conglomerate, clay, silty sandy clay, and under claystone, and mudstone units in the study area. As a soil improvement method, the Deep Soil Mixing (DSM) technique based on the principle of simultaneous mixing the ground while injecting with the water-cement mix, was selected. The application of DSM columns is designed to be 45 degrees horizontal, in order to reach the deepest point of the soft clay units for better improvement against settlement. The core samples were taken from the DSM columns and the compressive strength tests were performed in the laboratory. The results were higher than the minimum designed values. It means that inclined DSM columns were applied successfully, and the excessive settlement problem was solved.

Oct 1, 2022

By Fábio Arielo Guastala

Empilhadeiras são equipamentos essenciais na movimentação de cargas em praticamente qualquer ambiente industrial e devem receber atenção especial em caso de falhas, pois podem comprometer operações e colocar em risco a saúde e a segurança de colaboradores. Este trabalho apresenta uma análise de falha dos garfos de uma empilhadeira que romperam durante uma operação rotineira de levantamento de carga. Amostras dos garfos fraturados foram submetidas à análise química, análise macrográfica, micrografia óptica, análises de dureza e microdureza e ensaios de tração e impacto. Além disso, foram analisadas as tensões as quais os garfos estavam submetidos, considerando a carga levantada, a especificação do equipamento e análises de fadiga e de tenacidade à fratura. Dessa maneira foi possível identificar o material dos garfos, suas características e também de que maneira ocorreu a fratura, resultando em recomendações que possam prever e/ou evitar ocorrências desse tipo futuramente.

Aug 16, 2017

By Miguel Araújo Vasconcelos Filho, Ulisses Tetti

In order to determine the influence of the number of increments of the sinter sample on the variability of the chemical composition obtained in Sinter Plant production, a variographic study was carried out. It was performed with two series of samples. The first series was composed of 40 samples with a 6-second interval, with the objective of obtaining the so-called minimum practical error, resulting from the extraction processes of the sample of the conveyor belt and preparation and analysis in the laboratory and the second series composed of 60 samples with a range of 4 minutes, which points to the sample selection error. The results obtained showed that the minimization of the sample selection error occurs for increments spaced in 15 minutes, being in agreement with ISO 3082, but with significantly better results than those currently practiced for intervals between 1hour increments. It was then decided on the suitability of the sampler to allow hourly increments to be collected and on a second opportunity to install a sampling tower with primary and secondary samplers to collect increments every 15 minutes including sample size reduction.

Oct 1, 2019

By Renate Wellen, Olgun Guven, Mariane Y. T. Oide, Julyana Satana, Francisco Valenzuela-Díaz, Esperidiana Moura

Poly[(ethylene)-co-(vinylacetate)] (EVA) is a thermoplastic copolymer composed of randomly distributed polyethylene and polyvinyl acetate sequences within the molecular chain. EVA combines toughness with excellent flexibility, impact and puncture resistance. Because of these properties, this material is largely used for foam production as padding in equipment for various sports and as a shock absorber in sport’s shoes. This work aims to study the influence of clay reinforcement on the performance of recycled polymer foams. The blend containing recycled HDPE (high density polyethylene) and recycled EVA (70/30 wt%, respectively) reinforced with 2 wt%of clays were prepared by melt extrusion, using a twin-screw extruder to obtain the composites. The composites and foaming agent were fed into a special single screw extruder for foaming. The samples of HDPE/ EVA/Clay foams were characterized by tensile test, Field Emission Scanning Electron Microscopy (FE-SEM), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), density measurement and the correlation between the results was evaluated.

Mar 1, 2018

By B Morey, J Gordon, P Mackenzie

Mount Tom Price Mine is peerless amongst Rio Tinto iron ore resources around the world. It has provided Hamersley Iron with premium quality, high lump yield haematite ore over the last four decades. The Brockman type bedded ore, containing bands of haematite and shale of varying thicknesses has been traditionally bulk mined to either high-grade or low-grade based on alumina cut-off grades. As open pit mining has progressed deeper into the orebody approaching the keels of the megastructure, increased structural complexity, chemical and physical variations in the ore, unfavourable ore presentation and reduced blending options have become an issue for grade control and may have serious impacts on product stockpiles. The grade blocks and boundaries must be accurately defined according to geological contacts and where identified, selective mining may be applied. Therefore in-pit geological mapping is the definite and ultimate guide to achieve target grades and grade predictions. Under this scenario, it is absolutely vital that the mine geology team ensures this geological knowledge is passed onto the related departments including mining crews as well as to the short- and long-term planners.

Jan 1, 2002

By J. G. Stevens, S. W. Colley

"Selective separations of metals and ions in mineral extraction and refining are becoming more challenging as ore bodies become more complex and environmental pressures increase. The separation and containment of mercury produced in gold mining are a factor in the profitability and operability of mines. This paper will discuss the development and implementation of the Johnson Matthey HgFree selective mercury removal process. The process is designed to selectively recover co-leached mercury from either heap leach pregnant solutions at ambient temperature and low mercury concentrations, or electrowinning pregnant solutions at elevated temperature and high mercury concentration, without affecting gold or silver recovery. The process utilizes a highly selective adsorption-desorption step in which mercury is removed quantitatively by the HgFree adsorbent without adsorption of gold, silver or other metals present. Development of the original HgFree adsorbent has resulted in a process whereby mercury can be recovered as an inert salt and is never present as the free metal. The HgFree adsorbent can be regenerated and recycled in situ, and is capable of being reused multiple times. The overall process is compatible with existing gold mining and recovery practices and offers significant environmental and sustainability benefits, including reduction or elimination of the need to retort mercury with a subsequent reduction in potential mercury air emissions. Development of the HgFree adsorbent and process will be discussed along with a pilot operation at two operating mines.INTRODUCTIONMany gold ore bodies contain high concentrations of mercury which when extracted with cyanide, co-extract with the gold and other metals. This mercury is carried through the process with the gold, posing environmental and technical issues when it is separated from the doré. This paper describes a method to selectively adsorb mercury from the gold recovery circuit while it is in a soluble form, leaving gold to be processed as normal. The removal of mercury from the circuit eliminates the need for mercury retorting of doré and so reduces the potential environmental impact of fugitive emissions of elemental mercury."

Jan 1, 2016

By Kevin Azocar, Jim Hazzard

"Slope stability analysis is performed most commonly using limit equilibrium calculations or numerical models assuming a two-dimensional slice through an infinitely long slope surface. In areas such as open pit mining, where most slope surfaces are not planar, the importance of curvature becomes important due to the economic gains associated with creating a steeper slope. With advances in computing capabilities within the last decade, three-dimensional slope analysis can be performed within reasonable time frames. Some work has been done on the potential importance of curvature on slope stability, mainly assuming homogenous materials with a circular shear-failure mechanism. However, many open pit mines are excavated in jointed rock mass where a completely different set of failure mechanisms can be seen. Depending on the geometry and radius of the pit, the curved geometry may influence the factor of safety and failure behaviour compared to a two-dimensional slice.A series of numerical analyses were performed to investigate the effect of curvature on jointed rock slope stability compared to an equivalent two-dimensional slope analysis. By using discrete element method models, the influence of joint planes and interaction between distinct blocks can be seen. With a three-dimensional model, the effect of curvature can be combined with multiple joint sets at any orientation, which cannot be seen in a single slice. Numerous three-dimensional models are created, along with an equivalent unit-thick slice. The effect of curvature on a variety of different types of failure mechanisms is observed, and graphical relationships are created to quantify the difference between the three-dimensional factor of safety and the two-dimensional factor of safety based on the degree of curvature."

Jan 1, 2015

By S. Evans, J. Phillips-White, D. Morton

The partnership between Orica and MMG at the Dugald River Zinc mine in Australia has led to the first global field trials and deployment of Orica’s Subtek™ 4D™ (hereafter referred to as 4D) Bulk Systems underground bulk emulsion blasting technology. This technology offers advantages over conventional bulk explosives by extending the range of energy and length of explosive column that can be charged in underground production. 4D gives blast designers energy options between Relative Bulk Strength (RBS) 50 - 150, delivered uniformly along the entire column in most blasthole conditions along with the ability to instantaneously modify the energy within an individual blasthole. During Phases 1 – 3 of the project from October 2022 to January 2023, over 57 tonnes of the 4D Underground emulsion were loaded in 17 stopes. The primary objectives of this phase were to reduce hanging wall dilution and improve stope recovery. While drilling and other parameters remained unchanged, the energy selection was tailored for specific situations, guided by a revision to the site's drill and blast standard. The design used low energy (RBS 50 - 70) in holes adjacent to the hanging wall and high energy (RBS 130 - 150) where stope recovery had historically been challenging, such as at the toes of long downholes. Initial results of the project focused on five stopes selected for their similarity to those used for the baseline data set. Although the 4D data set was small, the post-blast scans indicated favourable results for recovery and dilution. This suggests that selecting and delivering bulk explosive with tailored energy levels can improve stope performance.

Jan 1, 2024

By Jim Finley, Adam Bedell, Eric Schrader

The CSO 52 Storage Tunnel and Pump Station project consists of 4,700 ft of hard rock tunnel, 2 intakes, and a 4 MGD wet pit pump station. During the geotechnical investigation, it was determined that the host geology contained abundant suldes. The purpose of this paper is to detail the investigation and subsequent determination that acid producing materials would affect the project during construction as well as long-term exposure of tunnel lining and permanent components during the operational life cycle of the tunnel and pump station. Details regarding the interaction between tunnel components and the acid producing material are also provided.

Jun 23, 2024

By T Walsh, S R. Mudnuru

The development of lithium-ion batteries, coupled with the global trend towards electrification of transportation, has led to a dramatic increase in the demand for lithium. The production of lithium from hard rock ores is increasing, and flotation has proved to be an effective means for the beneficiation of many pegmatitic lithium ores. Clariant Mining Solutions has developed a range of novel collectors for the flotation of spodumene and other lithium ores, and this paper presents examples of some of the most recent developments. Fatty acids are the typical collectors for lithium flotation, however the grade and recovery achieved with these collectors is often below the desired level. There are also some significant drawbacks associated with the use of fatty acid collectors, such as the formation of calcium soaps which give rise to filtration problems and the need for acid washing. Several FLOTINOR products have been developed as alternatives to fatty acids. These products offer equivalent or better metallurgical performance at significantly lower dosages than fatty acids. This offers benefits to the flotation circuit as well as potentially reducing the issues associated with downstream processing of the concentrate.

Aug 24, 2022

By Yong Pan, Purushotham Tukkaraja

Block caving is a preferred underground mining technique due to its high production rate and low operation cost. Before its final step into a mature caving system using gravity to break rock, drilling and blasting are required to form drawbells to connect the production level and undercut level and induce the initial caving propagation in undercut level. A large amount of toxic fume generated by blasting activities poses a big threat to people working in a confined environment and ventilation is assumed to be the most economical and efficient way to deal with this issue. Past research shows that it’s common to use traditional methods like using a formula or using numerical method (Computational Fluid Dynamic (CFD)) simulation to predict re-entry time after each blasting, but it fails to consider the percentage of toxic fume entrapped in muckpile, which could reach up to 70%. In this paper, CFD was used to investigate the blasting toxic fume characteristics under different entrapping percentages and under changing muck pile properties like broken rock size and porosity. It showed that CFD was a very useful method to study blasting fume in an underground mine and it took much longer time to dilute toxic fume into a safe level with higher entrapping percentage. The dilution time increased with a decrease of broken rock size and porosity.

By Carlos Virrueta

"El presente texto señala la importancia del comportamiento seguro en el sistema de riesgos aplicados al comportamiento de los trabajadores, salud y medio ambiente para así establecer los lineamientos yresponsabilidades requeridos para realizar el programa de Auditorías de Comportamiento Seguro, fortalecer el compromiso visible de liderazgo de los equipos de trabajo, así como crear y fortalecer en las personas el hábito de la prevención de los riesgos."

Oct 21, 2015

The mining of high-grade narrow vein deposits is a predominant field of activity in the precious metal sector. These types of deposits are located throughout the globe and have a significant presence in mining operations. The principle factor that has undermined the profitability and effectiveness of mining such ore zones is the substantial dilution that occurs when blasting with explosives during extraction. In order to minimise ore dilution, the thermal fragmentation mining method enables the operator to extract a narrow mineralised corridor, 30 cm to 1 m wide (according to the true width of the ore vein). By inserting a strong burner powered by diesel fuel and air into a pilot hole previously drilled directly into the vein, a thermal reaction occurs spalling the rock and enlarging the hole to 30 - 100 cm in diameter. This patented method produces highly concentrated ore, resulting in 400 - 500 per cent less dilution when compared to conventional mining methods. The mining method was conceived with the aim of mining ounces, not tonnes. This method of extraction, reduces the environmental impact of mining operations since much smaller quantities of rock are displaced, stockpiled, and treated using chemical agents. The fully mechanised equipment operated by a two-person team, maximises the effectiveness of skilled personnel, increases productivity, and reduces risks of injuries. Important economic benefits are generated for large- and small-scale mining operations alike. For large-scale operations, the mining method increases mining reserves, lowers the cost per ounce, and increases the total profitability of existing mine operations. The method also significantly lowers costs and risks of developing and mining small-scale deposits, requiring less investment capital, shortening the payback period, thus reducing the lending risk.  Combined with a small modular processing unit able to process between 100 - 300 tons per day, the method substantially lowers the financial break-even point for small-scale mining operations in a narrow vein environment. The company has been working with the technology at its Rocmec 1 mining site; results achieved and future developments are discussed.

Jan 1, 2008