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Determination of critical state line(CSL)for silty-sandy iron ore tailings subjected to low-high confining pressures

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1684-1695页

作者： Nilo Cesar Consoli João Vítor de Azambuja Carvalho Alexia Cindy Wagner Hugo Carlos Scheuermann Filho Inácio Carvalho Pedro Pazzoto Cacciari João Paulo de Sousa Silva Civil Engineering Universidade Federal do Rio Grande do SulPorto AlegreRS90035-190Brazil Exploration and Mineral Projects-Mineral Development Centre VALE S.A.Santa LuziaMG33040-900Brazil Department of Civil Geological and Mining EngineeringPolytechnique MontrealQuebecH3C 3A7Canada

The disposal of filtered tailings in high dry stacks can induce particle breakage,changing the material's behaviour during the structure's lifetime.The grading changes influence material properties at the critical state,and this is not mature for intermediate artificial soils(tailings)in a broad range of confining pressures.In this paper,it aims to describe the behaviour of iron ore tailings in a spectrum of confining pressures broader than the reported in previous studies.A series of consolidated drained(CD)triaxial tests was carried out with confining pressures ranging from 0.075 MPa to 120 MPa.These results show that the amount of breakage plays an essential role in the response of iron ore tailings.The existence of curved critical state line(CSL)in both specific volume(ν)-logarithm of mean effective stress(p′)and deviatoric stress(q)-mean effective stress(p′)planes,and different responses in the deviatoric stress-axial strain-volumetric strain curves were verified.An inverse S-shaped equation was proposed to represent the silty-sandy tailings'behaviour up to high pressures onν-lnp′plane.The proposed equation provides a basis for enhancing constitutive models and considers the evolution of the grading up to severe loading conditions.The adjustment considered three regions with different responses associated with particle breakage at different pressure levels.

关键词： tailings Iron ore tailings dry stacking Silty-sandy material Critical state soil mechanics High confining pressures Particle breakage

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Geochemical and mineralogical characteristics of some gold mine tailings in the Eastern Desert of Egypt

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Frontiers of Earth Science 2022年第4期16卷 906-915页

作者： Mostafa REDWAN Geology Department Faculty of ScienceSohag UniversitySohag 82524Egypt

The adverse environmental effects of mine tailings disposal on the surrounding ecosystems are world-wide environmental problems.Due to environmental issues related to tailings discharged on land surface,detailed tailings characterization is a prerequisite for a long-term management solution.The tailings from four gold mines in Egypt,namely Fatira,El Sid,Barramiya,and Atud were investigated for their geochemical-mineralogical features and the effect of weathering behavior on the release of their heavy elements.The tailings samples were investigated by mineralogical(XRD and ESEM-EDS),physical(grain-size distribution)and geochemical(XRF)techniques.Most of the tailings have uniform silt-size with fine to very finesand and clay.Atud tailings have coarse to fine sands.High carbonate,predominantly calcite was found for the samples from Fatira and Atud,calcite-ankerite from El Sid and dolomite from Barramiya with little sulfide-content.High-mean of Cr(569287 mg/kg),Ni(89191 mg/kg)and Co(4221 mg/kg)values are coinciding with the ultramafic nature in Atud and Barramiya tailings.El Sid tailings have a high-mean concentration of Zn(1357 mg/kg)and Pb(1349 mg/kg).Barramiya tailings have a high-mean As concentration(2635 mg/kg).The Fatira tailings are characterized by high-mean values of Sr(444 mg/kg)and Cu(280 mg/kg)arising from auriferous mineralization.High Sr concentrations in Fatira tailings are mainly due to its adsorption to iron oxides.Pyrite oxidation is conceded along the cracks and/or the edges of the crystals in the El Sid,Barramiya and Atud tailings.The Threshold Effect Level(TEL)values indicated high contamination from heavy elements to the neighboring ecosystem.The tailings were deposited downstream into the small wadis.Wind and water erosion can dissolve efflorescent materials enriched in toxic elements like As,Zn,and Pb at tailings surface.The release of contaminants could be catastrophic for the environment without mine site rehabilitation strategies.

关键词： gold mine tailings geochemistry mineralogy Egypt

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Effect of temperature on the leaching of heavy metals from nickel mine tailings in the arctic area,Norway

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International Journal of Agricultural and Biological Engineering 2023年第2期16卷 152-158页

作者： Shuai Fu Jinmei Lu Ingar Walder Daishe Wu Department of Land Resources Management School of FinanceTaxation and Public AdministrationJiangxi University of Finance and EconomicsNanchang 330013China Department of Technology and Safety UiTThe Arctic University of NorwayN-9037 TromsøNorway Kjeoy Research and Education Center VestbygdNorway School of Materials and Chemical Engineering Pingxiang UniversityPingxiang 337000JiangxiChina

The leaching of heavy metals from tailings deposit due to the oxidation of sulphidic tailings and formation of acidic leachate is considered a high risk to the surrounding environment.Temperature plays an important role in the leaching of heavy metals from tailings in changing acid-based environment,especially in the Arctic area.To investigate how the temperature variation affected metal release from tailings in the Arctic area,a series of column leaching experiments was conducted under four temperature situations(5°C,10°C,14°C and 18°C).Physicochemical properties,Fe,Zn,Ni and Mn concentrations of leachates at each cycle were measured,and multivariate statistical analysis was applied to research the effect of temperature on heavy metals leaching from tailings in the Arctic area.The results showed that higher temperatures encouraged tailings to oxidation and sulfuration of and promoted heavy metal release from the tailings through precipitation and erosion.Ni,Zn and Mn have similar releasing resources from tailings and positive correlation in the leaching activity.Rising temperature accelerated Fe leaching;Fe leaching promoted leaching of the other metals,especially of Mn.Appropriately increase temperature will accelerate oxidization and sulfidization of the tailings,promote acid generation and increase TDS and,finally,promote the release of heavy metals.Climate change,with rising temperatures increasing the risk of heavy metals leaching from the tailings,should be given greater attention.Keeping tailings away from the appropriate temperature and in a higher alkalinity is a good method to control the leaching of heavy metals from tailings.

关键词： tailings heavy metals leaching temperature Norway

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Effect of the lenticles on moisture migration in capillary zone of tailings dam

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International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1036-1045页

作者： Di Liu Min-jie Lian Cai-wu Lu Wen Zhang College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Institute of Mining System Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Sinosteel Mining Co. Ltd.Beijing 100080China School of Resource Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Small-particle interlayers(lenticles)show some characteristic hydraulic properties and can affect the movement of unsaturated water.In this study,we developed a novel online capillary-water-absorption monitoring device and conducted three groups of comparison tests to simulate lenticle positions and thicknesses with respect to the capillary rise.The results show that the characteristic wetting front exhibits a fast rise in the early stage,a slow rise in the middle stage,and stability in the later stage.The motion of the capillary water in the lenticle is mainly transversal,with the upward curve being"flat,"and the longer is"flat,"the longer is the time needed for the water to move.The interlayer can form a capillary stagnation zone with moisture content close to saturation.The high interlayer may form a discontinuous corrugated capillary zone.Thus,when the wetting front reaches the"coarse-grain(lower)-fine-grain(upper)"interface,the"anti-capillary barrier effect"results in more moisture in the upper layer.Thus,when the wetting front of the capillary water reaches the"fine-grain(upper)-coarse-grain(lower)"interface,the"capillary barrier effect"causes the moisture content of the upper tailings to decreases sharply because of the horizontal movement of the water in the fine medium.It is clear that the presence of lenticles can retard the rise of capillary water by storing water.

关键词： tailings lenticle moisture migration capillary retarding effect microcosmic mechanism

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Mill tailings based composites as paste backfill in mines of U-bearing dolomitic limestone ore

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 310-322页

作者： Sandeep Panchal Debasis Deb T.Sreenivas Department of Mining Engineering Indian Institute of Technology Mineral Processing Division Bhabha Atomic Research Centre

This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of the physical, chemical and mineralogical properties. Time-dependent rheological behaviors and geotechnical properties of cemented paste backfill(CPB) are also determined. The studies show that the mill tailing has the potential to form paste and the CPB has adequate strength to provide support to mine pillars, roofs, and walls.

关键词： Mining engineering Uranium ore deposit tailings Cemented paste backfill(CPB) Rheology Compressive strength

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Synthesis and performance of Ca-α/β-SiAlON composites from tailings

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International Journal of Minerals,Metallurgy and Materials 2014年第5期21卷 515-522页

作者： Hong-shun Hao Yang Yang Fang Lian Wen-yuan Gao Gui-shan Liu Zhi-qiang Hu Institute of New Energy Materials Dalian Polytechnic University Liaoning Provincial Key Laboratory of New Materials and Material Modification Dalian Polytechnic University School of Materials Science and Engineering University of Science and Technology Beijing

Ca-α/β-SiAlON composites were prepared using Ca-α/β-SiAlON powder synthesized from gold ore tailings, which contained abundant Si and Al elements as the major raw materials together with minor additives, through a pressure-less sintering method. The influ- ences of sintering temperature on the phase composition and mierostrueture of the composites were analyzed. The scanning electron micros- copy images of the composites show the interlacing of grains with elongated columnar, short columnar and plate-like morphologies. The composites sintered at 1520℃ for 6 h have a flexural strength of 352 MPa, Vickers hardness of 11.2 GPa, and fracture toughness of 4.8 MPa·m1/2. The relative content of each phase in the products is I（Ca-α-SiAION）：I（β-SiAlON）：I（Fe3Si） = 23：74：3, where Ii stands for the dif- fraction peak intensity of phase i.

关键词： ceramic materials composite materials tailings mechanical properties microstructure sintering

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Experimental investigation and adaptive neural fuzzy inference system prediction of copper recovery from flotation tailings by acid leaching in a batch agitated tank

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 538-546页

作者： Jalil Pazhoohan Hossein Beiki Morteza EsfANDyari Department of Chemical Engineering Quchan University of Technology Department of chemical engineering University of Bojnord

The potential of copper recovery from flotation tailings was experimentally investigated using a laboratory-mixing tank. The experiments were performed with solid weight percentages of 30 wt%, 35 wt%, 40 wt% and 45 wt% in water. The measurements revealed that adding sulfuric acid all at once to the tank rapidly increased the efficiency of the leaching process, which was attributed to the rapid change in the acid concentration. The rate of iron dissolution from tailings was less than when the acid was added gradually. The sample with 40 wt% solid is recommended as an appropriate feed for the recovery of copper. The adaptive neural fuzzy system(ANFIS) was also used to predict the copper recovery from flotation tailings. The back-propagation algorithm and least squares method were applied for the training of ANFIS. The validation data was also applied to evaluate the performance of these models. Simulation results revealed that the testing results from these models were in good agreement with the experimental data.

关键词： flotation tailings leaching copper environments adaptive neural fuzzy inference system

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Applications of online monitoring technology for tailings dam on digital mine

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中国有色金属学会会刊：英文版 2011年第S3期21卷 604-609页

作者： YU Guang-ming1, SONG Chuan-wang1, ZOU Jing-bo1, WU Yan-xia1, PAN Yong-zhan1, LI Liang1, LI Ran1, WANG Pei-shou2, WANG Yan-lei2 1. School of Civil Engineering, Qingdao Technological University, Qingdao 266033, China 2. Hedong Goldmine, Zhaojin Mining Industry Company, Zhaoyuan 265400, China School of Civil Engineering Qingdao Technological University Qingdao 266033 China Hedong Goldmine Zhaojin Mining Industry Company Zhaoyuan 265400 China

Considering its structural features, geometric shapes, service mode, environmental media, mechanical behavior, etc, the special nature and complexity of tailings dam were summarized. The technical approach to safety management for tailings dam was proposed, which is the on-line automated monitoring and early warning information. The results show that a strong theoretical basis can be provided for security monitoring and security management of tailings dam. Online automated monitoring system for tailings dam has full implementation of the information. It is applied widely in Lingnan gold mine, Xiadian gold mine and Hedong gold mine in Zhaoyuan, Shandong Province, and achieves good effect.

关键词： digital mine tailings dam online monitoring security monitoring digitization

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A multiphysics-viscoplastic cap model for simulating blast response of cemented tailings backfill

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第3期9卷 169-182页

作者： Gongda Lu Mamadou Fall Liang Cui Civil Engineering Department University of Ottawa Ottawa ON Canada

Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill,an evolutive porous medium used in underground mine cavities,very few efforts have been made to improve the knowledge on its response under sudden dynamic loading during the curing process.In fact,there is a great need for such information given that cemented backfill structures are often subjected to blast loadings due to mine exploitations.In this study,a coupled thermo-hydro-mechanical-chemical(THMC)-viscoplastic cap model is developed to describe the behavior of cementing mine backfill material under blast loading.A THMC model for cemented backfill is adopted to evaluate its behavior and evolution of its properties in curing processes with coupled thermal,hydraulic,mechanical and chemical factors.Then,the model is coupled to a Perzyna type of viscoplastic model with a modified smooth surface cap envelope and a variable bulk modulus,in order to reasonably capture the nonlinear and rate-dependent behaviors of the cemented tailings backfill under blast loading.All of the parameters required for the variable-modulus viscoplastic cap model were obtained by applying the THMC model to reproducing evolution of cemented paste backfill(CPB)properties in the curing process.Thus,the behavior of hydrating cemented backfill under high-rate impacts can be evaluated under any curing time of concern.The validation results of the proposed model indicate a good agreement between the experimental and the simulated results.The authors believe that the proposed model will contribute to a better understanding of the performance of hydrating cemented backfill under blasting,and also to practical risk management of backfill structures associated with such a dynamic condition.

关键词： Thermo-hydro-mechanical-chemical (THMC) coupling Multiphysics processes tailings Paste backfill Cap model Blast

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Reconstructed rheometer for direct monitoring of dewatering performance and torque in tailings thickening process

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1430-1437页

作者： Yong Wang Ai-xiang Wu Zhu-en Ruan Zhi-hui Wang Zong-su Wei Gang-feng Yang Yi-ming Wang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China Section for Biological and Chemical Engineering Department of EngineeringAarhus UniversityHangøvej 2DK-8200Aarhus NDenmark

To further clarify the dewatering performance and torque evolution during the tailings thickening process,a self-made rake was connected to a rheometer to monitor the shear stress and torque.The dewatering performance of the total tailings was greatly improved to a solid mass fraction of 75.33%in 240 min.The dewatering process could be divided into three stages:the rapid torque growth period,damping torque growth period,and constant torque thickening zone.The machine restart was found to have a significant effect on the rake torque;it could result in rake blockage.Furthermore,the simultaneous evolution of the torque and solid mass fraction of thickened tailings was analyzed.A relationship between the torque and the solid mass fraction was established,which followed a power function.Both the experimental and theoretical results provide a reference for the deep cone thickener design and operation to enhance the dewatering performance.

关键词： tailings dewatering rake reconstructed rheometer torque monitoring

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