Search

The increasing demand for precise and dependable models has led to the development of both sensors and statistical algorithms. However, numerous studies have demonstrated that model performance is highly dependent on a range of environmental factors, such as spatio-temporal fluctuations of moisture, sensor type, sample variability, preprocessing methods, and model selection. These factors can impact prediction results, leading to erroneous comparisons across lab, field, or imaging models. Samples for this study were collected from a tailing settling basin of a porphyry copper deposit near Erdenet, Mongolia. The database contains lab and field spectra and hyperspectral imagery from a HySpex imaging sensor. In this study we propose a workflow that includes a simulation that yields an appropriate regression threshold while addressing data-driven uncertainty. The workflow consists of two regression models and five classification models at different scales for quantitative geochemical, mineralogical, and textural prediction of tailing samples. Each model is compared to the acquisition space's performance potential. Acceptable R2 values for regression models are 0.58 for laboratory, 0.40 for field, and 0.31 for hyperspectral airborne data. Results of this study are not limited to tailing samples but can be applied on other fields of research such as geology, pedology or agriculture. [ABSTRACT FROM AUTHOR]

Complexant-montmorillonite nanocomposites were successfully prepared through the intercalation of the complexants cysteamine hydrochloride (CSH), 1,6-diaminlhexane (DA), tetraethylenepentamine (TEPA) with different functional group and molecular weight in this work. More importantly, it was proved that the heavy metal stabilization property of montmorillonite improved significantly after intercalation of complexants through characterization by XRD and SEM-EDS. Here, the complexant-montmorillonite nanocomposites exhibited strong pH buffering effects. The Zn stabilization rate was prone to 100% by adding DA or TEPA modified montmorillonite (DA-Mt or TEPA-Mt) into the tailings, and the releasing rate of As and Mn from tailings also decreased greatly. Generally, the Zn, Pb, Mn and As stabilization effects of both TEPA-Mt and DA-Mt were much better than that of CSH modified montmorillonite, which suggested that the heavy metal complexing abilities of complexant-montmorillonite nanocomposites highly depended on the functional group and molecular weight of the complexants. In this study, electrostatic adsorption, physical adsorption, ion exchange and complexation worked together and produced good heavy metal stabilization effect. Our findings could provide an important reference for the synthesis of efficient stabilization nanomaterials.

Coal spoil-heaps cause man-made pressure on the environment of the coal mining area. Coal mining, and in recent years the mass closure of mines has been accompanied by a negative impact on natural objects and engineering structures - the basements of houses and buildings are flooded, walls and wooden fences rot, crops, trees and bushes are destroyed. Reclamation is carried out on spoil-heaps of coal mines to reduce man-made pressure. However, in the process of rock dumping on the spoil-heaps a neorelief begins to emerge causing the vegetation development. The emergence of vegetation groups is a positive phenomenon, as phytomass decomposition promotes the formation of humus. The development of vegetation on the surface of coal spoil-heaps is called vegetative reclamation or phytomelioration. Efficiency of vegetative reclamation is calculated in points and is an indicator of the suitability of a particular man-made object for natural overgrowth. The aim of the work is to establish the features of spatial arrangement of plants in populations on the surface of coal spoil-heaps. It is established that on the coal spoil-heaps, as well as in natural conditions, vegetation tends to aggregate, thus forming phytogenic fields. It should be noted that at different stages of successions, phytogenic fields are formed in different ways. Monocentric phytogenic field arises on the waste heaps during the syngenetic stage of succession. The initial endecogenetic stage of succession provides the formation of phytogenic fields of two types. The first type is the initial polycentric phytogenic field. It is characterized by the ability to combine several individuals of the same species. The second type is a mature polycentric phytogenic field. It is characterized by higher resistance, and plant community is already able to convert geoprocesses. The mature endoecogenic stage of succession is characterized by the development and expansion of tree species, and the phytogenic field is acentric and global. This kind of phytogenic fields is found on tailings with artificial vegetative reclamation.

Mining and disposal of mining wastes are notable human activities that have resulted in substantial environmental and human health deterioration. The objectives of this study were to evaluate the level of pollution, potential ecological and human health risks associated with gold mining activities in Ife-Ijesha land, Osun State, Southwestern Nigeria. For this purpose, soil and tailing samples were collected and analyzed for six metals using the atomic absorption spectroscopic technique. The contamination status, potential ecological and human health risks were evaluated using different pollution indices. The mean concentrations (in μg/g) of Fe, Cd, Cu, Cr, Pb, Ni, and Zn in soil and tailing were 196.78, 0.36, 3.78, 65.74, 6.12, 19.56, 10.78 and 241.30, 0.53, 4.30, 76.63, 11.07, 23.50, 24.6, respectively. The geo-accumulation index (Igeo) and contamination factor (Cf) suggested that Cr and Cd may pose an ecological risk. The potential ecological risk index (PERI) indicated a moderate risk level for both soil, and tailings with Cd contributing considerably. The hazard index (HI) indicated no significant non-carcinogenic risks (HI < 1). Additionally, Pb, Cd, and Cr had lifetime cancer rates that were in accordance with the acceptable limit. [ABSTRACT FROM AUTHOR]

BACKGROUND: The food security problem caused by heavy metal pollution in farmland soil has attracted widespread attention. Objective pollution investigation and evaluation work is of great significance for the later pollution prevention and safe utilization of soil. OBJECTIVES: To fully understand the heavy metal contamination condition, ecological risk and human health risk of soil and rice in the farmland around the copper-lead-zinc tailing pond in Western Hubei Province. METHODS: 50 sites of topsoil and rice were investigated systematically. ICP-MS, ICP-OES and AFS were used to determine the contents of eight heavy metals (As, Cd, Cu, Pb, Zn, Hg, Ni, Cr), as well as the pH value of the soil. The potential ecological risk index method and human health risk assessment model were used to evaluate the potential ecological risk and health risk of soil and rice. RESULTS: The results indicate that: (1) The contents of As, Cd, Cu, Pb and Zn in the soil exceed the standard, with the maximum exceedance rate of Cd being 20%. Only Cd in rice exceeds the standard with the exceedance rate of 14%. (2) Correlation analysis shows that soil heavy metals have the same pollution source, and leachate leakage is a possible source of pollution. There is a positive correlation between the heavy metals in rice and the surface soil, with the strongest correlation for Cd, which may be related to the strong absorption capacity of rice for soil Cd. (3) The evaluation results of potential ecological risk index show that Cd, Pb, Zn and Cu are significantly enriched in the soil, with the Cd enrichment coefficient of 4. 41. The overall ecological risk is moderate, with 6% of the sites having very strong potential ecological risk. (4) The results of the health risk assessment indicate that the total and non-total carcinogenic risks are greater than the acceptable level at almost all sites. There is an overall risk of heavy metal carcinogenicity in the soil, with As and Cd being the major contributors. The total non - carcinogenic risk for rice at almost all sites in the study area is greater than the acceptable level, with Cd being the largest contributor. The total non-carcinogenic risk for rice at all sites is within the acceptable level. CONCLUSIONS: The soil and rice in the vicinity of the tailings pond have been contaminated by heavy metals, posing a certain ecological risk, and the risks to the health of the local population should be taken into account. [ABSTRACT FROM AUTHOR]

A tailing gluing method based on microbial induced calcium carbonate precipitation(MICP)technology was presented. Facultative anaerobic bacteria was used to glue tailing in sealed curing conditions, aiming to solve the problem that aerobic bacteria cannot be used in anoxia or anaerobic environment. The control variable method was used to explore the influencing factors of facultative anaerobic bacteria MICP technology in glue tailing test, in which four influencing factors were studied, namely the concentration of bacteria solution, the concentration of cementing solution, the particle size of tailing and the curing temperature. The results show that when the OD600 of the bacterial liquid is 1, and the concentration of acetate ion in the cementing solution is 0.6mol/L, the tailings is a mixture of tailings with various particle sizes, and when the curing temperature is 30℃, the cementing effect is best. It is found that the MICP technology of facultative anaerobic bacteria can effectively cementing tailings, which provides a solution for replacing cement by tailings cementing material. [ABSTRACT FROM AUTHOR]

Mining resources have played a leading role in the development of humanity, and the demand for these raw materials is expected to increase in the foreseeable future. In addition, new technologies also require the extraction of new critical materials. These trends pose various challenges as there is a limited supply of natural resources, and standard mining and mineral processing practices are associated with significant environmental impacts, such as waste generation, energy and water consumption, and CO2 emissions. The circular economy (CE) has recently gained attention as a model to address such a complex scenario. This work analyzes the current efforts toward the application of CE in mineral processing. Although advances have been made, this review shows that the most significant material flows and environmental impacts occur near the production sites, which currently limits the closure of loops. Besides, mining industries are conservative regarding the adoption of new technologies or processing strategies, which is another hindrance to the implementation of the CE. Thus, and with few exceptions, while some sectors are already facing advanced stages of CE (namely, CE 3.0), the mineral processing field struggles to advance from the basic CE requirements (i.e, CE 1.0 to CE 2.0). [ABSTRACT FROM AUTHOR]

This study aimed to find optimal models in a comparative framework to estimate the recovery and grade of barite concentrate obtained from the rougher flotation of the barite tailings. Therefore, firstly, the effect of four operating parameters (flotation time, pH, collector dosage, and depressant dosage) on the rougher flotation of the barite tailings containing 37.23% BaSO4 was experimentally investigated. Secondly, two models called the multivariable linear regression (MLR) and the artificial neural network (ANN) were used for the estimation of the recovery and grade of the barite concentrate for the rougher flotation optimization. The R² values found from the MLR and ANN models were 0.828 and 0.995 for the concentrate recovery, and 0.977 and 0.960 for the barite concentrate grade, respectively. In the comparison of the models determined, it was found that the ANN model expressed quite well than the MLR models, especially for the recovery of the rougher concentrate. [ABSTRACT FROM AUTHOR]

In India, the tailings of iron ore beneficiation are dumped in slime ponds, which is a major environmental concern. In the present study, a new beneficiation circuit was designed to recover the valuable minerals from the tailing effectively. The present study involves the characterization of three different samples using chemical, particle size, optical microscopy, and Electron probe micro-analyzer analysis. The characterization study has resulted in the analysis of the various mineralogy components present in the samples. The newly designed beneficiation circuit involves iron ore tailing processing in different stages, i.e., de-sliming and gravity separation, followed by magnetic separation. Further, the results of the conventional process, i.e., de-sliming followed by flotation using dual extraction column flotation cell, have been compared with the results of the newly designed beneficiation circuit. Results showed that the newly designed circuit has improved iron recovery, which is suitable for pellet feed. Additionally, the developed beneficiation circuit is easy to handle and environmentally friendly as the process does not require any chemical reagents. [ABSTRACT FROM AUTHOR]

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the Philippines, legacy mines and active mine wastes pose potential threats since these may contain elevated concentrations of potentially toxic elements (PTEs) and high natural radioactivity. In this study, legacy mine wastes from the Philippine Iron Mine (PIM), Barlo Mine (BM), and Rapu-Rapu Mine (RRM) and active mine tailing from Padcal Mine (PM) were analyzed to determine the concentrations of fifteen (15) PTEs and the activity concentrations of natural radionuclides. Several quantitative risk indicators and radiological health risk parameters were utilized to determine the potential effects of these mine wastes to the natural environment and to human health. Legacy mine wastes have higher contents of PTEs and are more polluted by PTEs than PM tailing. Both enrichment factor (EF) and geoaccumulation index (Igeo) values suggest that legacy mine wastes are strongly polluted by As, Cd, Cu, and Mo. BM and RM wastes are also polluted by Pb, Sb, and Zn; PIM waste is polluted by Ni and V; and BM waste is polluted by Tl. Padcal mine tailing is only moderately polluted by Cu and Mo. The natural radionuclide activity concentrations of legacy and active mine wastes are below the global background values and the radiological hazard indices are also all lower than their permissible limits, except for 40K, 238U, and absorbed gamma dose rate in PIM due to a geogenic source. Unlike the PTEs, radioactivity in the legacy and active mine wastes are not enhanced by mining activities and is not a significant risk factor to human health. [ABSTRACT FROM AUTHOR]

The developed karst caves may become the seepage channels of heavy metal to the soil and underground water in Southwest China. Therefore, it is necessary to apply effective seepage treatments to the base of heavy metal tailing reservoirs. This paper addressed the high-pressure rotary jet technology and slurry systems used in the seepage treatment of the deep tailing sand of the Shenxiandong tailing pond located in Southwest China. In this study, the factors of fluidity, initial and final setting times, compressive strength, and permeability coefficient of the slurry were conducted. The mechanism analysis was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and inductively coupled plasma-mass spectrometry (ICP-MS). Three different types of slurry systems were proposed, and the permeability coefficients of the solidification body following 28 days of curing were less than 1 × 10−7 cm/s. The concentrations of Pb and Zn in the slurry system containing bentonite were reduced by 26.2% and 45.7%, respectively. In the presence of slaked lime and fly ash, the concentrations of Pb and Zn could be reduced by 26.8% and 30%, respectively. A total of 2142 high-pressure rotary jet piles were completed by the high-pressure rotary jet method in the field trial. The diffusion radius of these piles was over 1 m. Following 28 days of curing, the solidification body’s compressive strength was 7.45 MPa and the permeability coefficient was 6.27 × 10−8 cm/s. Both the laboratory and on-site trials showed that this method produced a good pollution barrier effect, which could prevent the diffusion of heavy metal into the adjacent underground water through the karst caves. It is also an effective way of engineering technology concerning heavy metal pollution control that occurs in tailing ponds.

Mining activities offer clear economic benefits for mineral-rich countries. However, mining operations can produce several environmental impacts. Many of these are associated with generating and managing mining waste known as tailings, which are typically stored in surface facilities. Windblown dust emissions from tailing deposits can cause severe damage to local ecosystems and adverse health effects for the surrounding population. Microbially induced calcite precipitation (MICP) can be used for the superficial biocementation of tailings, thereby preventing such emissions. This research studied the capacity of MICP for the biocementation of tailings. The effect of applying different doses of biocementation reagents and two different methods for their application were evaluated. Results show that a relevant increase in surface strength can be achieved, especially if reagents are mechanically mixed with the tailings to induce a more homogeneous distribution of precipitates. Micrographical and mineralogical analysis by SEM, FTIR and XRD analysis showed the precipitation of calcium in the form of anorthite, calcite or vaterite. Overall results indicate that calcite precipitation can be induced in tailing by microorganisms with urease activity, providing a potential technique for the biocementation of this material.

The technological mineralogical characteristics of cesium-containing minerals in tailings were examined by means of chemical analysis, the energy spectrum analysis method, and MLA (mineral liberation analyzer) to determine the element content, phase analysis, associated mineral components, degree of liberation, particle size, etc. The results showed that the samples mainly contained spodumene, quartz, feldspar, mica, and other minerals. Pollucite was the main cesium-containing mineral in the sample, which had a cesium oxide content that was as high as 34.58%. The mineral content of pollucite in the sample was relatively low—only 1.23%. The pollucite monomer content and the amount of rich intergrowth was 85.25%, and the metal distribution of cesium in the +0.074 mm sample was as high as 87.06%. Spodumene was the main mineral associated with pollucite. The beneficiation evaluation of this tailing sample was conducted using a combined process that integrated desliming, magnetic separation, and froth flotation, and a pollucite concentrate containing 4.45% Cs2O was obtained with a 63.71 recovery rate. This indicates that little pollucite was removed by means of desliming and magnetic separation before froth flotation recovery, but during the froth flotation stage in spodumene and feldspar, a large pollucite loss was observed. Therefore, to improve pollucite recovery, a pollucite-specific adsorption reagent should be synthesized. [ABSTRACT FROM AUTHOR]

Instead of environmental hazard, tailing might contain resources which could be reworked with the development of mining and separation technologies. Tailing dumps and waste ponds which associated with the long period of tin mining are easily found in Singkep Island. The waste should be processed to recover and purify precious metals within, and to reduce environmental degradation. REE-bearing minerals identification in tin tailing based on trace and rare earth element abundances is the aim of this study. Concise mineral beneficiation is illustrated for any further re-work strategy. The tailings collected from four locations in Singkep were analyzed for their trace and rare earth element compositions using ICP-MS at The Centre for Geological Survey. REE content in concentrates was upgraded at the range of 9 to 94 folds of the corresponding wastes. Monazite-(Ce), xenotime, and zircon are the REE-bearing minerals of the studied samples according to the elemental composition. Gravity, flotation, magnetic, and electrostatic methods would be applicable to separate the REE-bearing minerals from the tailing. [ABSTRACT FROM AUTHOR]

Potentially toxic metals and metalloids present in mining residues can affect ecosystems, particularly plant growth and development. In this study we evaluated heavy metal (Fe, Zn, Cu, Cd, Pb) and As contents in maize (Zea mays L) plants grown in soils collected near (40 m), at intermediate (400 m) and remote (3000 m) distances from mine tailings near Taxco City, Mexico. Soils sampled near and at intermediate sites from the tailings contained high levels of heavy metals which were 3- to 55-fold higher compared to the control samples. Heavy metal and As content in plants reflected the soil contamination being the greatest for most studied elements in root samples followed by stems, leaves, and kernels. Though plants were capable of completing their life cycle and producing the seeds, high bioaccumulation levels had a strong impact negatively on plant development. Abnormalities in the organs like malformations in reproductive structures (tassel and ear), reduction in the phytomer number and the plant height were present. Microscopic studies and morphometric analyses suggest that strongly affected plant growth result from negative and synergistic action of heavy metals and As in soils on cell growth and cell production. This study showed that maize grown near mine tailings accumulated high levels of heavy metals and As which decrease significantly plant yield and could be dangerous if it is consumed by animals and humans. [ABSTRACT FROM AUTHOR]

Tailing dams and waste dumps formed by the accumulation of mine wastes are usually at long-term unsaturated state under evaporation and consolidated drainage conditions. Soil-water retention relation is one of the key constitutive relations to analyze the seepage processes in tailing dams and waste dumps. In this study, typical coarse- and fine-grained tailings from a metallurgical mine were chosen to study the soil-water retention characteristics of the tailing samples. To begin with, the relationship between volumetric water content and suction of the tailing samples was experimentally measured, and typical soil-water characteristic curves (SWCCs) (i.e., Gardner, van Genuchten and Fredlund–Xing curves) were applied to fit the experimental data. After that, four empirical models to estimate the parameters in SWCCs (i.e., Aubertin-1998 model, Aubertin-2003 model, Vanapalli-2005 model and Chin-2010 model) were tested, and the Vanapalli-2005 model was the best-fit model for the tailing samples. Furthermore, this study proposes a generalized emergency risk assessment soil-water retention characteristics model for tailing dams and waste dumps, and a framework for the quick estimation of parameters in the SWCC is proposed as well. The recommended soil-water retention characteristics model and the related parameters can be used to predict water levels in tailing dams and waste dumps, which are very helpful for emergency risk assessment under rainstorm or flooding conditions. HIGHLIGHTS This study is the first study to prove the feasibility of using the Vanapalli-2005 model to estimate parameters in soil-water characteristic curves (SWCCSs) for mine wastes.; This study proposes a framework for the fast determination of SWCCs for mine wastes, which can be used to predict water levels in mine wastes.; The framework is helpful for the emergency risk assessment of mine wastes under rainstorm and flooding conditions.;

[Display omitted] • Detection of ion-unexchangeable REEs mainly in Fe-enrichments. • Bioleaching of ion-unexchangeable REEs from IREO or tailings. • Leaching mechanism involved proton-mediated dissolution and REEs complexation. • Bioleaching yield for ion-unexchangeable REEs reached 31.4 wt%. Ion-adsorption type rare earth ores (IREO) in China serve as the primary source of medium and heavy rare earth globally. With the rapidly growing demand for rare earth elements (REEs) and the dwindling supply of premium IREO, enhancing the recovery of REEs, especially the ion-unexchangeable REEs with ultra-low content and ambiguous speciation from IREO or its tailing, has become a critical trend and challenge. This study identified the occurrences of ion-unexchangeable REEs, primarily detected in Fe-enriched minerals, xenotime, and monazite of IREO using TESCAN integrated mineral analyzer (TIMA) and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) analysis. To extract these elusive REEs, a bioleaching technique utilizing Aspergillus niger (A. niger) metabolites was proposed, achieving a leaching yield of 31.4 wt%. Complementary sequential chemical extraction methods (SCEM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations further elucidate the underlying mechanism, involving the carboxylic acid produced by the metabolic process of microbes that dissolves goethite by disrupting Fe O bonds and liberating REEs, which complexed with carboxylate (R COO), to promote further dissolution. This work offers insight into enhancing the recovery of ion-unexchangeable REEs from IREO or its tailing, paving the way for sustainable and efficient rare earth mining practices. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coal spoil-heaps cause man-made pressure on the environment of the coal mining area. Coal mining, and in recent years the mass closure of mines, have been accompanied by a negative impact on natural objects and engineering structures; the basements of houses and buildings are flooded, walls and wooden fences rot, crops, trees and bushes are destroyed. Reclamation is carried out on spoil-heaps of coal mines to reduce the man-made pressure. However, in the process of rock dumping on the spoil-heaps,a neorelief begins to emerge causing the vegetation development. The emergence of vegetation groups is a positive phenomenon, as phytomass decomposition promotes the formation of humus. The development of vegetation on the surface of coal spoil-heaps is called vegetative reclamation or phytomelioration. The efficiency of vegetative reclamation is calculated in points and is an indicator of the suitability of a particular man-made object for natural overgrowth. The aim of the work was to establish the features of spatial arrangement of plants in populations on the surface of coal spoil-heaps. It was established that on the coal spoil-heaps, as well as under natural conditions, vegetation tends to aggregate, thus forming phytogenic fields. It should be noted that at different stages of successions, phytogenic fields are formed in different ways. A monocentric phytogenic field arises on the waste heaps during the syngenetic stage of succession. The initial endecogenetic stage of succession provides the formation of phytogenic fields of two types. The first type is the initial polycentric phytogenic field. It is characterized by the ability to combine several individuals of the same species. The second type is a mature polycentric phytogenic field. It is characterized by higher resistance, and plant community is already able to convert geoprocesses. The mature endoecogenic stage of succession is characterized by the development and expansion of tree species, and the phytogenic field is acentric and global. This kind of phytogenic fields is found on tailings with artificial vegetative reclamation. [ABSTRACT FROM AUTHOR]

BACKGROUND The Sr and Nd isotopic compositions of a sample depend on its initial isotopic ratios, the ratios between the parent nuclide and daughter product, and the decay time. Due to their significance for the tracing of reservoirs, they were widely applied in the geological studies. Traditional cation resin was applied to purify Sr and Nd for isotope analysis, which involved the organic reagent and pH adjustment. The complex chemical procedure was time-consuming. In recent years, the appearance of special resins has made it easy to separate these elements. However, due to the influence of sulfates and other factors, the use of special resins is limited. OBJECTIVES To shorten the chemical purification time of Sr and Nd, and to avoid the damage of sulfate ions on the Sr and REE specific resins, we proposed a new chemical purification method, where multiple columns were utilized. METHODS The method combines cationic resin and special resin to realize the rapid separation of Sr and Nd and can extend the using time of special resin. The experiment uses cationic resin, Sr special resin and LN rare earth special resin to analyze the basalt standard BCR-2. RESULTS The recoveries of Sr and Nd with this method were larger than 90%. The 87Sr/86Sr and 143Nd/144Nd isotope ratios were 0.705016±0.000016 (n=36, 1SD) and 0.512624±0.000012 (n=39, 1SD), respectively, which were in coincidence with the values previously reported by TIMS method within the analytical error. The complied 87Sr/86Sr and 143Nd/144Nd isotope ratios obtained TIMS were 0.705000-0.705023 and 0.512630-0.512650, respectively. The 85Rb/86Sr and 147Sm/144Nd rations of the purified Sr and Nd solution were less than 0.01 and 0.001, respectively. CONCLUSIONS The proposed chemical purification procedure can efficiently separate Rb, Sr, Sm and Nd, and realize the accurate analysis of Sr and Nd isotopes.

Hydrogeological survey of wider Majdanpek mining area in the Carpathian mountain arch of eastern Serbia, including open mine pits, tailings sites, and major karstic springs and caves has been undertaken in order to estimate environmental conditions in groundwater body (GWB) “Krš–sever”, groundwater quality, and to investigate causes of their earlier indicated poor chemical status. Bearing in mind that Majdanpek copper mine field is directly bordering the karst aquifer and delineated GWB “Krš–sever”, the two karst springs namely Valja Fundata and Kaludjerica were in situmeasured and sampled in high and low-water periods (spring 2019, late autumn 2019 and spring 2020). Sampling and analysis of groundwater were carried out under the frame of project “Operational Monitoring of Groundwater of the Republic of Serbia”, established by the Ministry of Environmental Protection of Serbia. The field measurements of unstable chemical components and physical properties as well as laboratory analyses confirmed very poor and even hazardous water quality of both surveyed springs Valja Fundata and Kaludjerica. Registered concentrations of some ions, such as Fe2+, Mn2+, Ca2+, SO4 2–are high above maximal permitted level for potable water in Serbia. High turbidity rate also confirms impact of colloidal suspensions from the tailing which is located in karstic blind valley. Leakage of mine water passes through joints, open cavities and even large cave system Valja Fundata. Results of undertaken survey confirm that low-water period results with worse water quality and much higher concentration of hazardous substances than that characterized high-water season when infiltrated rainy water and/or melted snow dilute tailing’s wastewater. Strict application of environmental protection measures and de - sign/construction of the smaller water treatment facility at both surveyed springs should possibly mitigate the impacts of mining activities to karst groundwater and dependant ecosystem.

There has been a growing environmental and economic concern about the final destination of industrial waste. This paper aims to evaluate the effect of incorporating iron ore tailing and steel slag on red ceramic bricks. The procedure for producing the fired bricks includes forming the bricks by compressing them into a mold under a specified pressure, and calcination (950 oC). In this study, the influence of high substitution (50%) of clay with IOT and BOF slag are investigated using flexural strength and scanning electron microscope (SEM). To the clay mass different proportions of residues were added, being: 25% of slag and 25% of tailing in T25.I25; 50% slag and 0% tailing at T50.I0; 0% slag and 50% tailing at T0.I50; 35% slag and 15% tailing in T35.I15; and, 15% of slag and 35% of tailing in T15.I35. Results show that IOT and BOF slag can be used together to produce fired clay brick with high level substitution, however some adjustments are required depending on the final application. This study contributes to the valorization of the waste, contributing to the planning and management of waste based on sustainability principles and aiming at reducing greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The plant root-associated microbiomes, including both the rhizosphere and the root endosphere microbial community, are considered as a critical extension of the plant genome. Comparing to the well-studied rhizosphere microbiome, the understanding of the root endophytic microbiome is still in its infancy. Miscanthus sinensis is a pioneering plant that could thrive on metal contaminated lands and holds the potential for phytoremediation applications. Characterizing its root-associated microbiome, especially the root endophytic microbiome, could provide pivotal knowledge for phytoremediation of mine tailings. In the current study, M. sinensis residing in two Pb/Zn tailings and one uncontaminated site were collected. The results demonstrated that the metal contaminant fractions exposed strong impacts on the microbial community structures. Their influences on the microbial community, however, gradually decreases from the bulk soil through the rhizosphere soil and finally to the endosphere, which resulting in distinct root endophytic microbial community structures compared to both the bulk and rhizosphere soil. Diverse members affiliated with the order Rhizobiales was identified as the core microbiome residing in the root of M. sinensis. In addition, enrichment of plant-growth promoting functions within the root endosphere were predicted, suggesting the root endophytes may provide critical services to the host plant. The current study provides new insights into taxonomy and potential functions of the root-associated microbiomes of the pioneer plant, M. sinensis , which may facilitate future phytoremediation practices. [Display omitted] [ABSTRACT FROM AUTHOR]

Nowadays, casted multicrystalline silicon is the most important material in photovoltaic industry. In order to reduce the cost of silicon ingots, the recycle of silicon ingot tailings is explored. In this paper, the secondary utilization of silicon block tailings with a thickness of 25 mm, matched with process of diamond wire saw machine was studied. The comparative analysis on technical parameters of bottom red zone and wafers generated by virgin crushed polycrystalline silicon feedstock and secondary utilized tailings was discussed. The result shows that recycle of tailing seeds is feasible. The above-mentioned tailings of diamond wire saw ingots shall be with a thickness of 25 mm. The bottom red zone of area paved by tailings is 2 mm longer than that in area paved by virgin crushed polycrystalline silicon feedstock. But the difference of cell conversion efficiency is negligible, 0.01% lower. Consequently, it is feasible to recycle high-efficiency multicrystalline ingots tailings, which push forward further cost reduction of high-efficiency multicrystalline ingots. [ABSTRACT FROM AUTHOR]

There are only a few pilot schemes, especially among scientific studies carried out to solve numerous environmental and ecological problems created by water during tailing storage on the surface. It is extremely important to establish precautions that can be taken, especially in the tailing storage process by examining the physical, chemical, mineralogical, and geotechnical changes that develop due to the effect of moisture in the tailing and surface water. In this study, 2 different pilot-scale designs of storage with no additions (reference) and with binder additions (cement and fly ash) to some layers were observed in field conditions for about 1 year to determine the effects of seasonal changes on paste material. The results of the measurements revealed that the water content of the reference design was ~ 10% higher than that of the design with cement addition at the substrates that provide stability and sudden temperature changes at the top layer of the reference design was found to be ~ 35 °C. Maximum sudden temperature changes in layers with cement addition and layers with cement and fly ash addition were observed to be ~ 15 °C. As a result, the use of cement has made the material more resistant to external factors. However, the study also revealed that fly ash could be used instead of cement with a substitute rate of 50% to reduce the cost for long-term storage in terms of industrial applications. [ABSTRACT FROM AUTHOR]

• Peak detection algorithm tailored to micro-scale gas chromatographs. • Peaks detected using tailored filters based on retention time and peak width. • Peak overlap and asymmetry detected by features in continuous wavelet coefficient. • Positive and negative peaks processed using results from detectors in series. Peak detection for chromatograms, including the detection of peak retention times, peak start locations, and peak end locations, is an important processing step for extracting peak information that is used for chemical recognition. Compared to benchtop gas chromatographs, the chromatograms generated by microscale gas chromatographs (µGCs) often contain higher noise levels, peak overlap, peak asymmetry, and both positive and negative chromatographic peaks, increasing the challenges for peak detection. This paper reports an automatic peak detection algorithm based on continuous wavelet transform (CWT) for chromatograms generated by multi-detector µGCs. The relationship between chemical retention time and peak width is leveraged to differentiate chromatographic peaks from noise and baseline drift. Special features in the CWT coefficients are leveraged to detect peak overlap and asymmetry. For certain detectors that may generate positive and negative chromatographic peaks, the peaks cannot be independently detected reliably, but the peak information can be well extracted using peak information generated by other in-line single-polarity detectors. The implemented algorithm provided a true positive rate of 97.2 % and false discovery rate of 7.8 % for chromatograms generated by a µGC with three integrated detectors, two capacitive and one photoionization. The chromatograms included complex scenarios with positive and negative chromatographic peaks, up to five consecutive overlapping peaks, peak asymmetry factor up to 24, and signal-to-noise ratios spanning 9-2800. [ABSTRACT FROM AUTHOR]

Mercury containing tailing waste from public gold mines in Indonesia is generally deposited on soil without treatment. This research aimed to determine the amount and composition of mercury species in the tailing, and to test the effect of sulfur and sulfide to mercury stabilization. Samples were collected from a tailing pile at different depths in a public gold mine in Kulon Progo, Indonesia. The samples were characterized according to mercury concentrations and Toxicity Characteristic Leaching Procedure (TCLP test). Mercury speciation was carried out using nitrogen gas flow into tailing samples, which were placed in three test tubes. The released mercuric species was entrapped in KCl and KMnO4 solutions. Mercury stabilization was done using sulfur and sodium sulfide. TCLP test was performed to the stabilization products. Mercury concentrations were measured using a mercury analyzer. The results showed that mercury in the tailings were dominated by elemental Hgo, of which concentrations in the tailing piles of 30, 60, and 90 cm depths were 74.7%, 71.6%, and 76.5% respectively. Those of ionic Hg2+ form were 25.3%, 28.4%, and 23.5%, respectively. Additions of sulfur powder and sodium sulfide solution produced stable black-colored mercury sulfide. When compared to sulfide, sulfur was more recommended for stabilizing mercury in the tailing waste. Keywords: mercury; gold mine, speciation, sulfide, sulfur, tailing

Remotely Aircrafts (RA), popularly known as Drones, are capable tools to generate highly accurate remote sensing products with a great potential perspective for use in the Environmental Audit process, performing previously exclusive tasks of manned aircrafts. However, because it is a relatively recent technology, it is justified the need to consider the applicability of its use in environmental studies. The purpose of this article is to evaluate the potentialities and applications of Drones in the Environmental Audit process, as well is present a methodology for data acquisition and identification of environmental impacts, listing the conformities and nonconformities of the audited enterprise, giving subsidy for an effective planning of actions to minimize impacts. Orthomosaics generated by the Drone in this studied case was used to carry out a compliance audit, based on the applicable legislation and regulations, being a fundamental tool to verify the real situation of the mining company through the legislation in force in the country, giving support to the implementation of corrective actions of detected nonconformities. In view of the obtained results it was possible to conclude that Drone presented promising quickly and low cost data, proving to be an important tool in environmental audits, providing necessary information to carry out an effective planning and implementation of corrective actions of detected non-adjustments, considering the principle of reparability of environmental damage, which obliges the polluter and the predator to recover and/or indemnify the damages caused.

The technological mineralogical characteristics of cesium-containing minerals in tailings were examined by means of chemical analysis, the energy spectrum analysis method, and MLA (mineral liberation analyzer) to determine the element content, phase analysis, associated mineral components, degree of liberation, particle size, etc. The results showed that the samples mainly contained spodumene, quartz, feldspar, mica, and other minerals. Pollucite was the main cesium-containing mineral in the sample, which had a cesium oxide content that was as high as 34.58%. The mineral content of pollucite in the sample was relatively low—only 1.23%. The pollucite monomer content and the amount of rich intergrowth was 85.25%, and the metal distribution of cesium in the +0.074 mm sample was as high as 87.06%. Spodumene was the main mineral associated with pollucite. The beneficiation evaluation of this tailing sample was conducted using a combined process that integrated desliming, magnetic separation, and froth flotation, and a pollucite concentrate containing 4.45% Cs2O was obtained with a 63.71 recovery rate. This indicates that little pollucite was removed by means of desliming and magnetic separation before froth flotation recovery, but during the froth flotation stage in spodumene and feldspar, a large pollucite loss was observed. Therefore, to improve pollucite recovery, a pollucite-specific adsorption reagent should be synthesized.

Even after being abandoned for many years, a large number of weathered crust elution-deposited rare earth (WCED-RE) tailings continue to release ammonia nitrogen (AN) pollution into their surrounding environments. However, the influences of particle size distribution and clay minerals on AN pollution caused by these tailings have been insufficiently studied, and its causes are poorly understood. In this study, soil samples at different depths (5, 7, 9, 11 and 14 m) were collected from a rare earth tailing in Ganzhou City, Jiangxi Province, China. Particles were screened by size into six groups (2–1, 1–0.5, 0.5–0.25, 0.25–0.1, 0.1–0.075 and < 0.075 mm), and AN forms were extracted. The results showed that as soil particle size decreases, both soil specific surface area and clay content increase, leading to stronger AN enrichment ability. With increased sampling depth, the distribution of clay across the six particle fractions became more uniform, such that the accumulation of AN in soil with fine particle size was less obvious. Clay minerals with different capacities for AN enrichment vary with sampling depth. This variation is responsible for the profile of AN distribution in the mine, where AN first increases and then decreases as vertical depth is increased. Although AN content was highest at 11 m, water soluble AN content was higher in the upper part of the completely weathered layer (5 and 7 m), which poses a higher environmental risk. This study provides significant information to deepen our understanding of the distribution characteristics of AN and its main influencing factors, as well as a foundation for the prevention and remediation of nitrogen pollution from WCED-RE tailings.

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tailings are waste generated from the processing of gold ore. The tailings in Kertajaya Village, Sukabumi are generally dumped into a pond or garden which is then used by the community to grow crops. The characteristics of the tailings, which contain low organic matter, microorganism activity, CEC and essential nutrients, make it necessary to improve their condition. This study aimed to determine the effect of adding top soil and compost to the tailings on the growth of sweet potatoes in the vegetative phase. This experiment used a factorial randomized block design with two factors, namely a top soil-tailing ratio of 3 levels (70: 30% w/w; 50: 50% w/w; and 30: 70% w/w) and a compost dose of 4. level (without compost (control); 10 t ha-1; 20 t ha-1; and 30 t ha-1) with 3 replications. The results showed that the combination of the addition of top soil ratios and the dose of compost to the tailings had no effect on the addition of tendrils length, tendril diameter and number of sweet potato branches during the vegetative phase. The addition of 70% top soil independently on the tailings had an effect on the highest increase in tendril length, tendril diameter and number of branches of sweet potato. Meanwhile, the application of compost dosage of 30 t ha-1 had the highest effect on the number of branches   of sweet potato.

Mining extractive companies have extended their operations to other realms, such as the management of media. Thus, from a space of physical intervention, they start to conquer a space of symbolic representation, creating a gap between local communities' perceptions of the mining process and the perception that is spread through media outlets about the operations in the territories. In Chile, this perception is complicated by the participation of the mining industry in media ownership and the overall concentration of media. Through critical ethnographic fieldwork, analysis of national and local community media examples, this article explores an ongoing socio-environmental conflict in the Choapa Valley where the copper mine Los Pelambres operates. It does it by first discussing how the mining industry pursues narratives of extractivism in the Chilean media and then discussing how local communities defy this narrative by creating their description of the territory through local media outlets. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Sr and Nd isotopic compositions of a sample depend on its initial isotopic ratios, the ratios between the parent nuclide and daughter product, and the decay time. Due to their significance for the tracing of reservoirs, they were widely applied in the geological studies. Traditional cation resin was applied to purify Sr and Nd for isotope analysis, which involved the organic reagent and pH adjustment. The complex chemical procedure was time-consuming. In recent years, the appearance of special resins has made it easy to separate these elements. However, due to the influence of sulfates and other factors, the use of special resins is limited. OBJECTIVES: To shorten the chemical purification time of Sr and Nd, and to avoid the damage of sulfate ions on the Sr and REE specific resins, we proposed a new chemical purification method, where multiple columns were utilized. METHODS: The method combines cationic resin and special resin to realize the rapid separation of Sr and Nd and can extend the using time of special resin. The experiment uses cationic resin, Sr special resin and LN rare earth special resin to analyze the basalt standard BCR-2. RESULTS: The recoveries of Sr and Nd with this method are larger than 90%. The 87Sr/86Sr and 143Nd/144Nd isotope ratios were 0.705016±0.000016 (n=36, 1SD) and 0.512623±0.000008 (n=39, 1SD), respectively, which are in coincident with the values previously reported by TIMS method within the analytical error. The complied 87Sr/86Sr and 143Nd/144Nd isotope ratios obtained TIMS are 0.705000-0.705023 and 0.512630-0.512650, respectively. The 85Rb/86Sr and 147Sm/144Nd rations of the purified Sr and Nd solution are less than 0.01 and 0.001, respectively. CONCLUSIONS: The proposed chemical purification procedure can efficiently separate Rb, Sr, Sm and Nd, and realize the accurate analysis of Sr and Nd isotopes. [ABSTRACT FROM AUTHOR]

In this study, the concentration of chromite minerals by amine flotation of a chromite tailing (slime) with content 23.84% Cr2O3 from Yeşilova-Burdur (Turkey) was investigated. In experimental studies, firstly, some operating parameters of the rougher flotation observed for a low-grade chromite tailing were investigated. Secondly, multiple linear regression (MLR) analyses were performed to determine the effects of some operating parameters on the performance of the rougher amine flotation. From the experimental results, multiple linear regression equations were developed to predict the recovery and grade of the chromite concentrate, and the regression coefficients between experimental and predicted values were found to be quite good (R² values of 0.772 and 0.917, respectively). Additionally, it was found that the conditioning time and low pH value using H2SO4 showed an important effect on the recovery and the grade of the chromite concentrate. [ABSTRACT FROM AUTHOR]

During the geological prospecting works conducted in 2013 on Bangka Island (Indonesia), high monazite content was identified in the wastes produced during processing of cassiterite deposits. Monazite, among 250 known minerals containing REE, is one of the most important minerals as primary source of REE. The monazite content in this waste is up to 90.60%. The phase composition of the investigated tailing proves that the sources of minerals accompanying the placer sediments tin mineralization are granitoids. The tailing is composed of numerous ore minerals, including monazite, xenotime, zircon, cassiterite, malayaite, struverite, aeschynite-(Y), ilmenite, rutile, pseudorutile and anatase. Monazite grains belong to the group of cerium monazite. Its grains are characterized by high content of Ce2O3 27.12-33.50 w t.%, La2O3 up to 15.46 w t.%, Nd2O3 up to 12.87%. The total REE 2O3 + Y content ranges from 58.18 to 65.90 wt.%. Monazite grains observations (SEM-BSE) revealed the presence of porous zones filled with fine phases of minerals with U and Th content. The radiation intensity of 232Th is ATh = 340 ± 10 Bq and 238AU = 114 ± 2 Bq. High content of monazite and other REE minerals indicates that tailing is a very rich, potential source of REE s, although the presence of radioactive elements at the moment is a technological obstacle in their processing and use. The utilization of monazite bearing waste in the Indonesian Islands can be an important factor for development and economic activation of this region and an example of the good practice of circular economy rules. [ABSTRACT FROM AUTHOR]