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The drain pipe wrapped in steel wire mesh serves a dual purpose of drainage and reinforcement in tailings pond projects. The self-filtering layer that develops upstream of the steel wire mesh influences the reinforcement characteristics of the drainage pipe. This study first conducts interfacial shearing experiments to explore the impact of the self-filtering layer on the shearing properties between tailings and the steel wire mesh. An exponential interface constitutive model is then proposed to delineate the shear stress–displacement relationship. Finally, through finite element simulations, the study assesses the effect of the self-filtering layer on the load-bearing behavior of the drain pipe, considering the interactive dynamics between the tailings and the steel wire mesh. The results reveal that the interfacial shear strength, across varying median particle sizes of the self-filtering layer, adheres to Mohr–Coulomb strength theory. Specifically, as the median particle size of the self-filtering layer increases, interfacial cohesion diminishes while the friction coefficient rises. The initial shear stiffness demonstrates a linear increase with the median particle size. With the presence of the self-filtering layer, the pull-out resistance of the drainage pipe can be enhanced by up to 26%. Moreover, the self-filtering layer significantly affects the distribution of negative skin friction. This research enhances the safety assessment of tailings ponds by providing crucial insights and solutions, emphasizing the influence of the self-filtering layer on the bearing behavior of the drain pipe. [ABSTRACT FROM AUTHOR]

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The present study aims to investigate the environmental geochemistry of potentially toxic elements (PTEs) in tailing samples of the Ahangaran Pb-Zn mine, located 95 km southeast of Hamadan. For this purpose, physico-chemical properties of 14 tailing samples, mineralogy and the concentration of PTEs were studied. The values of pH, carbonate content, and cation exchange capacity (CEC) ranged between 7.7-9.4, 50.5-64.5 %, and 27.3-35.1 meq/100g, respectively. The main clay mineral detected in the studied samples was montmorillonite; quartz and siderite were the most frequent mineral phases in the samples. The tailing samples, based on the total concentration of potentially toxic elements and the calculation of environmental indices, were enriched in Pb, Zn, Cd, As and Ag, and were of high ecological risk. Human Health Risk Assessment (HHRA) revealed that the hazard quotient of PTEs was much higher for children than adults. The highest values of non-carcinogenic risks via ingestion, dermal contact and inhalation were obtained for As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children, and the ingestion of Cd for adults are associated with probable carcinogenic risks. Based on the obtained results, disposed tailings around the Ahangaran mine can be considered a potential source to pollute the groundwater resources and agricultural soils. Therefore, appropriate environmental management of waste disposal as well as taking remediation actions deem necessary. Introduction During the last decades, extensive anthropogenic activities around the world enhanced the input of PTEs into different compartments of the environment. Mining, processing, and smelting of sulfidic ores are considered the most important source of PTEs in the environment. The waste materials produced during the ore processing (i.e. tailings) have been classified as threatening hazardous wastes that need specific environmental management and treatment (Banerjee et al., 2023). Ahangaran mine located 95 km SE Hamadan is a large Pb-Zn producer wherein the ore mineral is processed by flotation, and the produced tailings are dumped in tailing ponds around the mine. The present study aims to investigate the concentration and environmental geochemistry of PTEs in mine tailings and to assess the human health risk imposed by PTEs through the standard method of USEPA (1989). Materials and methods Sampling, sample preparation and analyses 14 surface composite tailings samples were collected from the tailing ponds (0-30 cm) by a stainless steel trowel. The samples were dried at room temperature. pH, carbonate content, and cation exchange capacity (CEC) of the samples were determined in particles < 0.15 mm. To determine the total concentration of major and trace elements, 1gr of tailings passed through a 230 mesh sieve (63 μm) was digested by a mixture of hot concentrated acids (HF + HClO4 + HCl + HNO3) in the open system ( Jeffery and Hutchinson, 1981). The concentrations of major and trace elements in the digested solutions were measured by an ICP-OES instrument. pH was determined using the standard method of the USEPA test method (USEPA,1989). The carbonate content was measured by titration method, and CEC was determined based on the USEPA standard method (USEPA,1989). X-Ray Diffraction (XRD) method was used to investigate the mineralogy of the samples. Results and discussion The physico-chemical properties of tailing samples pH of the tailing samples varies between 7.7 and 9.4. The neutral to alkaline nature of the samples may enhance the bioavailability of metalloids such as As and Sb. The average amount of carbonate content in the samples is 55.9%, which is in accordance with the alkaline pH of the studied samples. Based on the Metson classification (Metson, 1956), the samples are classified as high CEC. XRD analysis of the samples shows that the predominant clay mineral in the studied samples is montmorillonite, which explains the high CEC values of the studied samples. Concentrations of major and trace elements in tailing samples The average concentration of elements (mg/kg) in the studied samples decreases in the following order: Fe > Mn > Pb > Al > Zn > Cu > Sb > Ni > Th > As > Co > V > Cr > Cd > Ag > Sc The average concentrations of PTEs in the tailings samples are much higher than their respective values in the mean crust composition; therefore, the tailings of the Ahangaran mine may enhance the concentration of PTEs in soils, cultivated crops, and groundwater of the adjacent area. In order to assess the level of contamination, the geoaccumulation index (Igeo) was calculated as follows: Igeo= log 2 [(Cn)⁄1.5(Bn)] where Cn and Bn are the target element’s concentration in the study sample and the reference material (mean crust composition), respectively. According to the classification of the geoaccumulation index, the studied samples are very highly polluted in Pb, Sb and Ag. The enrichment factor (EF) is calculated using the normalized ratio of target element (x) in the study sample to the respective value in the reference (background) material: EF = RE refers to the concentration of a normalizing element (Sc). The mean crust composition was considered the background sample. On the basis of the obtained results, the studied samples are characterized as extremely high enriched in Pb, Sb, Ag, Mn, Zn, Cd, As, very high enriched in Th and Cu, significantly enriched in Fe, Co, Mo, and moderately enriched in Ni, Cr, and V. Hakanson (1980) defined the Potential Ecological Risk Index (PERI) as follows: where Ei and Ti are the ecological risk index and biological toxicity factor, respectively. The obtained PERI values of all tailing samples are much higher than 600; thus the ecological risk imposed by tailings is very high and suitable measures should be taken to reduce the pollution level in the study area. To assess the human health risk imposed by high levels of PTEs in the tailing samples, the average daily dose (ADD, mg/kg/day) of each element through ingestion, inhalation, and dermal contact routes as was calculated: ADDinh = The Hazard Quotient (HQ) of each pathway was obtained to assess the non-carcinogenic risk of each target element (USEPA, 1989): Where RfDi is the reference dose (mg/kg/day). While HQ≤1 indicates that there is no non- carcinogenic risk, HQ> 1 shows that non-carcinogenic risks are probable through a certain exposure route. Hazard index (HI) is also an indicator of probable non-carcinogenic health risks: n refers to the number of the studied elements. If the value of HI is ≤1, there is no adverse health effects. HI> 1 indicates likely adverse health effects. Human health risk assessment shows that the HQ values of target elements is higher in children than in adults. The highest non-carcinogenic risk for digestion, inhalation and dermal contact is related to As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children and ingestion of Cd for adults is associated with probable carcinogenic risks. Conclusion Based on the total concentration of PTEs in the samples and the values of geochemical indices, the studied tailings are highly polluted with Pb, Sb, Mn, Zn, Cu, As, Cd, and Ag. Human health risk assessment shows that ingestion is the most important route for element’s exposure, and children are at higher risks. The highest values of non-carcinogenic risks through ingestion, inhalation and dermal contact pathways were obtained for As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children, and the ingestion of Cd for adults are associated with probable carcinogenic risks.

This study aims to contribute to the characterization of Katangese Copperbelt's (DR Congo) mining wastes and soils polluted with trace metals, using pollution indices and direct concentration measurements. This study also evaluated the use of these indices in assessing the success of remediation projects. Data from previous studies and samples collected from six types of discharge and one polluted soil were used to address the first objective. Soil and plant samples were collected at Kipushi and Penga Penga for the second objective. The results reveal very high concentrations of As, Cd, Co, Cu, Mn, Pb, and Zn in all mine tailings and polluted soils, compared with local references. The degree of contamination (DC) values (from 72 to 5440) and potential ecological risk (RI) values (from 549 to 162,091) indicate very high-risk situations associated with polluted discharges and soils. Regarding revegetation trials, the results show lower concentrations and RIs in tree rhizospheres compared with unamended areas at both sites. However, trace metal concentrations are higher in tree rhizospheres compared with local references, and RI values are in the considerable risk range for Penga Penga (RI = 533) and in the very high range (>1500) for Kipushi. Bioconcentration factor values are below 1, indicating low accumulation in roots, wood, and leaves, and low risk of contamination of the trophic chain. In this context, it seems that the pollution indices used are suitable for characterizing pollution and prioritization for remediation. However, there seems unsuitable for assessing the effectiveness of phytotechnology processes based on metal stabilization. Direct plant performance measurements combined with direct measurements of metals in substrates and plants to assess transfer and efficiency are more appropriate. [ABSTRACT FROM AUTHOR]

The increase of water content in tailings is the key cause of various diseases. In order to study the microscopical mechanism of tailings capillary water transport, an online monitoring capillary water rise test system was developed by itself, which mainly includes distortionless high definition digital microscope, 3-D mobile microscopic observation frame, CAMERA/VIEW PLAY CAP wireless acquisition system and computer. The system is used to carry out the dynamic real-time observation experiment of the capillary water rising process of tailings, analyze the movement trajectory and migration characteristics of the capillary water, and clarify the evolution law of the unsaturated tailings micro-structure under the hydraulic path. The results show that: There is a power exponential relationship between the rising height of capillary water and time, and the rising process can be divided into pure inertia stage, viscosity-inertia stage and pure viscosity stage. Capillary absorption is a process of non-uniform water absorption, the water content of the capillary zone decreases with the increase of the height, and its relationship curve shows an inverse “S” shape, the water content varies from 4.15% to 21.3%. Capillary water migration is a dynamic process in both vertical and lateral directions and the most obvious change in the microscopic structure of tailings is the occurrence of water in pores, with the change of the saturation from low to high, the occurrence shows the shape of pendulum, ring cord, capillary and serous liquid bridge. The capillarity of tailings follows the order of macropores, mesopores and micropores to absorb water, most of which occurs in mesopores, the mechanism of ‘in the macropores and mesopores, capillary water increased preferentially’ in tailings granular materials is proposed. The research results revealed the internal correlation mechanism of macro and micro capillary mechanics of tailings, clarified the evolution model of the micro-structure of tailings during the rise of capillary water, and further clarified the reasons for the macroscopic damage phenomenon of granular materials caused by the development process of tailings particle drying to humidification. [ABSTRACT FROM AUTHOR]

Iron concentration tailings contain many valuable minerals, including apatite, which is not currently being recovered despite its use to make fertilizers and chemicals. This article proposes a flotation circuit to recover apatite from tailings generated by mining in Chile, based on laboratory tests and using the "Split Factor" method. The iron tailings were characterized by granulometry, chemical and mineralogical analyses, zeta potential, and contact angle. The effect of the collector, frother, and dispersant dose, along with the number of flotation stages, on both the grade and recovery of P2O5 were studied. The results indicate that it is possible to produce concentrates with a P2O5 grade of 29.1% and 89.6% recovery in a flotation circuit that includes the rougher–scavenger–cleaner stages. To obtain these results, it is only necessary to condition the iron tailings with 400 gt−1 of Atrac-2600, 400 gt−1 of sodium silicate, 10 min of conditioning time, pH adjustment to 10, and a time for the rougher, cleaner, and scavenger stages set at 10, 7.6, and 6.8 min, respectively. A chemical interaction is suggested, where the collector is specifically adsorbed onto the apatite surface. [ABSTRACT FROM AUTHOR]

In order to alleviate the ecological pressure caused by rare earth tailings, this study focuses on the application of ion-adsorbed rare earth tailings in the preparation of functional pigments. By using mechanical grinding and high-temperature calcination, 33 new functionalized red pigments were successfully prepared by doping iron and lanthanum elements. X-ray diffraction (XRD), scanning electron microscopy (SEM), CIE 1976 color space system, and ultraviolet–visible–near-infrared spectrophotometer were used for characterization. The synthesized pigment exhibits a rich color range from light yellow to reddish brown. Compared with commercially available iron red pigments, it exhibits significantly enhanced near-infrared reflectance, excellent acid and alkali resistance, and strong thermal stability up to 900 °C. It is worth noting that pigment P-1-2-1 achieved the best red value (L* = 43.73, a* = +24.07, b* = +15.65) with a maximum near-infrared reflectance of 91 %. Therefore, the utilization of rare earth tailings as raw materials for the preparation of functional pigments has significant effects. This study provides valuable insights for the development of eco-friendly pigments, which not only helps alleviate the urban heat island effect but also promotes the sustainable utilization of rare earth tailing resources, contributing to the achievement of carbon neutrality goals. [ABSTRACT FROM AUTHOR]

The Tansrift mine is an open-pit exploitation mine that mines copper substances. It is located on the southwestern flank of the Beni Mellal Atlas, 9 km Northeast of Ouaouizaght village. The mining activity delivered about 650 000 t of 1.5% Cu, with an estimated reserve of 1 Mt to 1.32% Cu. In this study, seven hazardous heavy metals (Cd, Cr, Cu, Pb, Zn, Fe, and Ni) have been studied in the tailing and exploitation of the Tansrift mining district. The geochemical analysis contents of the metals were measured in the samples collected from this area. In addition, the pollution indexes, including the geo-accumulation index, the enrichment factor, the contamination factor, and the pollution load index, were used to assess pollution levels caused by those heavy metals. The Igeo index revealed a high to extreme copper contamination with a value above 4. As for the contamination factor, extreme and moderate contamination is shown by the copper and chrome in the totality of the exploitation and tailing areas. Moreover, the pollution load index shows very high pollution in all samples. The climatic conditions are also affecting the pollution of the atmosphere by contaminated dust and the water table and watershed by the contamination from the tailings and mineralized structures. [ABSTRACT FROM AUTHOR]

The community in Central Bangka Regency carried out an increase in illegal mining in 2021, which could potentially threaten the loss of strategic natural resources. Rocking table miners in Central Bangka Regency produce zircon sand, tin sand, monazite, ilmenite, and tailings, which are potential natural resources containing rare earth metal elements. This research aims to analyze the radioactive content of the minerals zircon sand, tin sand, monazite, ilmenite, and tailings as a threat to human health. The research showed that monazite samples from all villages still had a lot of rare earth metals in them, like yttrium (Y), lanthanum (La), cerium (Ce), samarium (Sm), neodymium (Nd), and gadolinium (Gd). The test results showed that monazite had the highest average concentrations of Rare Earth Elements (REEs), with values of 10.27±3% for La, 12.15±3% for Ce, 24.40±3% for Sm, 7.37±3% for Nd, and 0.69±3% for Gd. For tin samples, the average (Ce) was 2.79±3%, zircon samples had an average (Ce) of 4.33±3%, and (Nd) 1.04±3%. In the ilmenite samples, the average value (Y) was 6.64 ± 3%. Monazite has the most rare earth metal elements, but it has a very low selling price. Monazite plays a crucial role in safeguarding and preventing the loss of strategic natural resources and health threats. It provides policy advice to related institutions through various roles and functions, including investigation, early prevention, and forecasting of these threats.

The use of local bacteria is preferred in bioleaching as an environmental-friendly alternative technology in gold mining. In a preliminary study, rhizobacteria were isolated and cultured from three types of hyperaccumulator vegetation from the Ratatotok gold mine, Indonesia, namely Pteris vittata L., Syzygium aromaticum L., and Swietenia mahagoni Jacq. These rhizobacteria still need to be characterised and identified. This study is aimed to cover bacterial phenotypic characterisation, assessment of bacteria resistance to tailing, and identification of bacterial strains the exhibit the highest resistance to tailings. The assessment was carried out across a spectrum of tailing concentrations, selecting the three most robust strains for molecular identification. The process involved genotypic characterisation to determine the species name by analysing the 16S rRNA gene. The results reveal that the phenotypic characteristics of the bacteria isolates vary, but all of them are the indole acetic acid (IAA) hormone producers. The highest IAA producer is the isolate from the rhizosphere of S. aromaticum. Based on the genotypic characterisation test, three most resistant isolates to tailing stress are the following strains Pseudomonas aeruginosa (RTKP1) and Stenotrophomonas geniculata (RTKP2), both from the rhizosphere of P. vittata; as well as Bacillus cereus (RTKS) from the rhizosphere of S. aromaticum. These three strains need to be further tested for their bioleaching capability to recover gold from tailings. Additionally, this study recommends that gold recovery using biological agents can combine the role of hyperaccumulator plants in phytomining and rhizobacteria in bioleaching.

The Tansrift mine is an open-pit exploitation mine that mines copper substances. It is located on the SW flank of the Beni Mellal Atlas, 9 km Northeast of Ouaouizaght village. The mining activity delivered about 650 000 t of 1.5% Cu, with an estimated reserve of 1 Mt to 1.32% Cu. In this study, seven hazardous heavy metals (Cd, Cr, Cu, Pb, Zn, Fe, and Ni) have been studied in the tailing and exploitation of the mining district of Tansrift. The geochemical analysis contents of the metals were measured in the samples collected from this area. In addition, the pollution indexes, including the geo-accumulation index, the enrichment factor, the contamination factor, and the pollution load index, were used to assess pollution levels caused by those heavy metals. The Igeo index revealed a high to extreme copper contamination with a value above 4. As for the contamination factor, extreme and moderate contamination is shown by the copper and chrome in the totality of the exploitation and tailing areas. Moreover, the pollution load index shows very high pollution in all samples. The climatic conditions are also affecting the pollution of the atmosphere by contaminated dust and the water table and watershed by the contamination from the tailings and mineralized structures.

Tailing land reclamation aims to improve the environment so that the tailing areas become productive for crop cultivation. The research was carried out in the tailings area of Mile 21.5 Timika from March to September 2022. The research aimed to study the dosage levels of Pistia stratiotes composts as an ameliorant to support the growth and yield of chili cultivated in the fresh tailings area. This study was laid out in a randomized block design with the Pistia stratiotes compost as a treatment, which consisted of PS1 = 1 kg/plant, PS2 = 2 kg/plant, PS3 = 3 kg/plant, and PS4 = 4 kg/plant in 6 replications. Based on the results, there was a significant effect of Pistia stratiotes compost on the growth and yields of chili. PS4 treatment produced the highest growth (plant height and leaf number) and highest yields (fruit number/plant, fruit weight/plant, fruit weight/plot, fruit weight/ha), while PS1 produced the lowest growth and yields. Chili produced 4.19 t/ha by PS4, indicating a high yield potential when tailings turned into a more stable growth media over time. There was a significant correlation between plant height and leaf number with the fruit weight. This shows that the vegetative growth component is closely related to increased chili yields. The high heritability value indicates the genetic factor influenced the growth and yields of chili more than the environmental factors. The metal contents in the chili fruit tissue are below the threshold level. The findings of this study emphasized the appropriate reclamation approaches using Pistia stratiotes compost as an ameliorant, which effectively improves the quality of tailing as growing media to maximize chili yields.

Currently, more attention is focused on the durability of microbial mineralization solidification of sandy soil in high-temperature environments to enhance the unconfined compressive strength (UCS), while with less emphasis on the immobilization effect on heavy metals. Lead (Pb)-zinc(Zn) mining tailings (LZMT) has the characteristics of loose soil and the release of heavy metal pollutants. This experiment, based on the microbial mineralization curing technology, using LZMT as raw materials to conduct microbial mineralization solidification experiments, and the effect of temperature on the microbial mineralization curing of LZMT was evaluated by using the UCS and the fixation rate of heavy metal ions as the key indexes. Combined with fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), we revealed the mechanism of temperature affecting microbial mineralization solidification of LZMT. The results showed that during microbial mineralization solidification of LZMT, Sporosarcina pasteurii mainly removed heavy metal ions through electrostatic attraction and precipitation reactions. Temperature had almost no impact on heavy metal ions fixation rate in microbial mineralization solidification LZMT. The impact of temperature on UCS of microbial mineralization solidifying LZMT specimens showed an initial increase then decrease trend. The UCS was maximum at 125°C, reaching 1.53 MPa, which was 47 % higher than the UCS at 50°C. This study is instructive for the application of LZMT in the field of building materials.

The Yoon–Nelson model serves as a widely used tool for describing the breakthrough behavior of organic micropollutants within fixed bed adsorbers. This study aims to augment its modeling efficacy through two proposed refinements found in the literature: a logarithmic transformation and the incorporation of steric hindrance effects. We systematically evaluated the original Yoon–Nelson model alongside the modified versions, using breakthrough data associated with micropollutant adsorption on solid materials. Three distinct cases were scrutinized: (1) caffeine adsorption on activated carbon; (2) tetracycline adsorption on hierarchical porous carbon; and (3) diclofenac adsorption on organoclay. While all three models demonstrated comparable performance with highly symmetric breakthrough data in case 1, their efficacy diverged significantly when confronted with strongly asymmetric breakthrough data in cases 2 and 3. The original Yoon–Nelson model and the logarithmically modified version fell short in accurately representing these intricate breakthrough curves. In contrast, the version incorporating steric hindrance effects showcased substantial accuracy, outperforming other models in capturing the complexities of asymmetric breakthrough data. This advancement markedly enhances the modeling accuracy and versatility of the Yoon–Nelson model, particularly in assessing the dynamic behavior of organic micropollutants within fixed bed adsorbers. [ABSTRACT FROM AUTHOR]

Column adsorption studies frequently adopt classical breakthrough curve models such as semi-mechanistic Bohart-Adams and Thomas models. They are logistic functions which simulate symmetrically sigmoidal curves centrosymmetric at 50% breakthrough; consequently, they fail and estimate erroneous results when dealing with asymmetric breakthrough curves. This work analyses and compares the trend of how log-modified, fractal-like modified, and probability distribution function models simulate asymmetric breakthrough curves with varied extents of tailing. We generated the asymmetric breakthrough curves by varying the bed depth: 6 mm, 9 mm, and 12 mm on a glass microcolumn of 100 mm length and 5.5 mm inner diameter at a fixed flow rate of 1 mL/min using 10 mg/L bisphenol-A as adsorbate and polyaniline as adsorbent. The asymmetrical curves were a consequence of polyaniline's low specific surface area of 6.96 m²/g, heterogeneous particle size distribution, slow intraparticle and surface diffusion. The log-Bohart-Adams and fractal-like Bohart-Adams models perfectly fit the curves regardless of symmetry although log-Bohart-Adams performed subpar with increased tailing. The fractal-like Bohart-Adams model accurately estimated the breakthrough times of 13 min, 26 min, and 90 min for the 6 mm, 9 mm, and 12 mm bed depths with a critical bed depth of 5.65 mm. The normal and Gompertz probability distribution functions were unable to adapt to asymmetry of the curves owing to their fixed inflection points at c / c c = 0.5 and 0.37 respectively. Although the Weibull, log-normal, and log-Gompertz functions have floating inflection points, only log-Gompertz function had a satisfactory fit (R adj 2 > 0.98) regardless of symmetry. [Display omitted] • Modifying simplistic models using log and fractal-like components leads to more accurate fits when dealing with asymmetry. • Unlike the fractal-like models, log-modified models underperform as the extent of tailing increases. • Log-Bohart-Adams model shares numerical similarities with the modified dose-response model. • Only log-Gompertz function had a satisfactory fit regardless of symmetry. • A smaller point of inflection shows goodness-of-fit of probability distribution functions for inter-model comparison only. [ABSTRACT FROM AUTHOR]

It has been proposed that transient and reversible phenotypic changes could modify the response of bacteria to germicidal radiation, eventually leading to tailing in the survival curves. If this were the case, changes in susceptibility to radiation would reflect variations in gene expression and should only occur in cells in which gene expression is active. To obtain experimental evidence supporting the involvement of phenotypic changes in the origin of tailing, we studied changes in the susceptibility to radiation of cells able to survive high fluences, using split irradiations. Stationary phase cells of Enterobacter cloacae and Deinococcus radiodurans, in which gene expression is active, and spores of Bacillus subtilis, which are dormant cells without active gene expression, were used as microbial models. While cells of E. cloacae and D. radiodurans became susceptible after surviving exposures to high fluences, tolerant spores exhibited unchanged response to radiation. The results can be interpreted assuming that noise in gene expression modifies bacterial susceptibility to radiation, and tailing is the result of intrinsic phenomena of bacterial physiology rather than a technical artifact. For either theoretical or practical purposes, deviations from simple exponential decay kinetics should be considered in estimations of the effects of germicidal radiation at high fluences. [ABSTRACT FROM AUTHOR]

The use of local bacteria is preferred in bioleaching as an environmental-friendly alternative technology in gold mining. In a preliminary study, rhizobacteria were isolated and cultured from three types of hyperaccumulator vegetation from the Ratatotok gold mine, Indonesia, namely Pteris vittata L., Syzygium aromaticum L., and Swietenia mahagoni Jacq. These rhizobacteria still need to be characterised and identified. This study is aimed to cover bacterial phenotypic characterisation, assessment of bacteria resistance to tailing, and identification of bacterial strains the exhibit the highest resistance to tailings. The assessment was carried out across a spectrum of tailing concentrations, selecting the three most robust strains for molecular identification. The process involved genotypic characterisation to determine the species name by analysing the 16S rRNA gene. The results reveal that the phenotypic characteristics of the bacteria isolates vary, but all of them are the indole acetic acid (IAA) hormone producers. The highest IAA producer is the isolate from the rhizosphere of S. aromaticum. Based on the genotypic characterisation test, three most resistant isolates to tailing stress are the following strains Pseudomonas aeruginosa (RTKP1) and Stenotrophomonas geniculata (RTKP2), both from the rhizosphere of P. vittata; as well as Bacillus cereus (RTKS) from the rhizosphere of S. aromaticum. These three strains need to be further tested for their bioleaching capability to recover gold from tailings. Additionally, this study recommends that gold recovery using biological agents can combine the role of hyperaccumulator plants in phytomining and rhizobacteria in bioleaching. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the environmental geochemistry of potentially toxic elements (PTEs) in tailing samples of the Ahangaran Pb-Zn mine, located 95 km southeast of Hamadan. For this purpose, physico-chemical profaties of 14 tailing samples, mineralogy and the concentration of PTEs were studied. The values of pH, carbonate content, and cation exchange capacity (CEC) ranged between 7.7-9.4, 50.5-64.5 %, and 27.3-35.1 meq/100g, respectively. The main clay mineral detected in the studied samples was montmorillonite; quartz and siderite were the most frequent mineral phases in the samples. The tailing samples, based on the total concentration of potentially toxic elements and the calculation of environmental indices, were enriched in Pb, Zn, Cd, As and Ag, and were of high ecological risk. Human Health Risk Assessment (HHRA) revealed that the hazard quotient of PTEs was much higher for children than adults. The highest values of non-carcinogenic risks via ingestion, dermal contact and inhalation were obtained for As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children, and the ingestion of Cd for adults are associated with probable carcinogenic risks. Based on the obtained results, disposed tailings around the Ahangaran mine can be considered a potential source to pollute the groundwater resources and agricultural soils. Therefore, appropriate environmental management of waste disposal as well as taking remediation actions deem necessary. IntroductionDuring the last decades, extensive anthropogenic activities around the world enhanced the input of PTEs into different compartments of the environment. Mining, processing, and smelting of sulfidic ores are considered the most important source of PTEs in the environment. The waste materials produced during the ore processing (i.e. tailings) have been classified as threatening hazardous wastes that need specific environmental management and treatment (Banerjee et al., 2023). Ahangaran mine located 95 km SE Hamadan is a large Pb-Zn producer wherein the ore mineral is processed by flotation, and the produced tailings are dumped in tailing ponds around the mine. The present study aims to investigate the concentration and environmental geochemistry of PTEs in mine tailings and to assess the human health risk imposed by PTEs through the standard method of USEPA (1989).  Materials and methodsSampling, sample preparation and analyses 14 surface composite tailings samples were collected from the tailing ponds (0-30 cm) by a stainless steel trowel. The samples were dried at room temfaature. pH, carbonate content, and cation exchange capacity (CEC) of the samples were determined in particles < 0.15 mm. To determine the total concentration of major and trace elements, 1gr of tailings passed through a 230 mesh sieve (63 μm) was digested by a mixture of hot concentrated acids (HF + HClO4 + HCl + HNO3) in the open system (Jeffery and Hutchinson, 1981). The concentrations of major and trace elements in the digested solutions were measured by an ICP-OES instrument.pH was determined using the standard method of the USEPA test method (USEPA,1989). The carbonate content was measured by titration method, and CEC was determined based on the USEPA standard method (USEPA,1989). X-Ray Diffraction (XRD) method was used to investigate the mineralogy of the samples. Results and discussionThe physico-chemical profaties of tailing samplespH of the tailing samples varies between 7.7 and 9.4. The neutral to alkaline nature of the samples may enhance the bioavailability of metalloids such as As and Sb. The average amount of carbonate content in the samples is 55.9%, which is in accordance with the alkaline pH of the studied samples. Based on the Metson classification (Metson, 1956), the samples are classified as high CEC. XRD analysis of the samples shows that the predominant clay mineral in the studied samples is montmorillonite, which explains the high CEC values of the studied samples. Concentrations of major and trace elements in tailing samplesThe average concentration of elements (mg/kg) in the studied samples decreases in the following order:Fe > Mn > Pb > Al > Zn > Cu > Sb > Ni > Th > As > Co > V > Cr > Cd > Ag > ScThe average concentrations of PTEs in the tailings samples are much higher than their respective values in the mean crust composition; therefore, the tailings of the Ahangaran mine may enhance the concentration of PTEs in soils, cultivated crops, and groundwater of the adjacent area. In order to assess the level of contamination, the geoaccumulation index (Igeo) was calculated as follows: Igeo= log 2 [(Cn)⁄1.5(Bn)]where Cn and Bn are the target element's concentration in the study sample and the reference material (mean crust composition), respectively. According to the classification of the geoaccumulation index, the studied samples are very highly polluted in Pb, Sb and Ag. The enrichment factor (EF) is calculated using the normalized ratio of target element (x) in the study sample to the respective value in the reference (background) material:EF = RE refers to the concentration of a normalizing element (Sc). The mean crust composition was considered the background sample. On the basis of the obtained results, the studied samples are characterized as extremely high enriched in Pb, Sb, Ag, Mn, Zn, Cd, As, very high enriched in Th and Cu, significantly enriched in Fe, Co, Mo, and moderately enriched in Ni, Cr, and V. Hakanson (1980) defined the Potential Ecological Risk Index (PERI) as follows:where Ei and Ti are the ecological risk index and biological toxicity factor, respectively. The obtained PERI values of all tailing samples are much higher than 600; thus the ecological risk imposed by tailings is very high and suitable measures should be taken to reduce the pollution level in the study area.To assess the human health risk imposed by high levels of PTEs in the tailing samples, the average daily dose (ADD, mg/kg/day) of each element through ingestion, inhalation, and dermal contact routes as was calculated:ADDinh =  The Hazard Quotient (HQ) of each pathway was obtained to assess the non-carcinogenic risk of each target element (USEPA, 1989): Where RfDi is the reference dose (mg/kg/day). While HQ≤1 indicates that there is no non- carcinogenic risk, HQ> 1 shows that non-carcinogenic risks are probable through a certain exposure route. Hazard index (HI) is also an indicator of probable non-carcinogenic health risks:n refers to the number of the studied elements. If the value of HI is ≤1, there is no adverse health effects. HI> 1 indicates likely adverse health effects. Human health risk assessment shows that the HQ values of target elements is higher in children than in adults. The highest non-carcinogenic risk for digestion, inhalation and dermal contact is related to As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children and ingestion of Cd for adults is associated with probable carcinogenic risks. ConclusionBased on the total concentration of PTEs in the samples and the values of geochemical indices, the studied tailings are highly polluted with Pb, Sb, Mn, Zn, Cu, As, Cd, and Ag. Human health risk assessment shows that ingestion is the most important route for element's exposure, and children are at higher risks. The highest values of non-carcinogenic risks through ingestion, inhalation and dermal contact pathways were obtained for As, Mn, and Cd, respectively. The ingestion of As, Cd, and Cr for children, and the ingestion of Cd for adults are associated with probable carcinogenic risks.  AcknowledgmentThe authors gratefully acknowledge the financial support of the Research Office of the Shahrood University of Technology. [ABSTRACT FROM AUTHOR]

Tailing land reclamation aims to improve the environment so that the tailing areas become productive for crop cultivation. The research was carried out in the tailings area of Mile 21.5 Timika from March to September 2022. The research aimed to study the dosage levels of Pistia stratiotes composts as an ameliorant to support the growth and yield of chili cultivated in the fresh tailings area. This study was laid out in a randomized block design with the Pistia stratiotes compost as a treatment, which consisted of PS1 = 1 kg/plant, PS2 = 2 kg/plant, PS3 = 3 kg/plant, and PS4 = 4 kg/plant in 6 replications. Based on the results, there was a significant effect of Pistia stratiotes compost on the growth and yields of chili. PS4 treatment produced the highest growth (plant height and leaf number) and highest yields (fruit number/plant, fruit weight/plant, fruit weight/plot, fruit weight/ha), while PS1 produced the lowest growth and yields. Chili produced 4.19 t/ha by PS4, indicating a high yield potential when tailings turned into a more stable growth media over time. There was a significant correlation between plant height and leaf number with the fruit weight. This shows that the vegetative growth component is closely related to increased chili yields. The high heritability value indicates the genetic factor influenced the growth and yields of chili more than the environmental factors. The metal contents in the chili fruit tissue are below the threshold level. The findings of this study emphasized the appropriate reclamation approaches using Pistia stratiotes compost as an ameliorant, which effectively improves the quality of tailing as growing media to maximize chili yields. [ABSTRACT FROM AUTHOR]

Tailing post-tin mining land has a sandy textured and loose structure. Those physical properties can affect the efficiency of fertilization and cause inefficiency of nutrient absorption in plants. That issue can be corrected by the application of organic material such as cow manure compost which has the potential for plant cultivation, especially for “porang” (Amorphaphillus oncophyllus Prain). This study aimed to examine the cultivation of porang plants in post-tin mining tailings by applying cow manure compost and to determine the best dose of cow manure compost for porang cultivation in artificial ex-tin mining land. This study used a single-group randomized design method with the treatment factor being the dose of cow manure compost consisting of five dose levels (5 t ha-1, 10 t ha-1, 15 t ha-1, 20 t ha-1, and 25 t ha-1). Each treatment level was replicated with five replications, and each replication consisted of five populations so the total population was 125 plants. The results showed that the application of various doses of cow manure compost to artificial post-tin mining land affected the growth and yield of porang plants. The treatment of cow manure compost at a dose of 25 t ha-1 gave the best growth and yield of porang plants. Heavy metal (Pb) analysis on porang tubers showed that all doses of cow manure compost had a Pb content value of

The drain pipe wrapped in steel wire mesh serves a dual purpose of drainage and reinforcement in tailings pond projects. The self-filtering layer that develops upstream of the steel wire mesh influences the reinforcement characteristics of the drainage pipe. This study first conducts interfacial shearing experiments to explore the impact of the self-filtering layer on the shearing properties between tailings and the steel wire mesh. An exponential interface constitutive model is then proposed to delineate the shear stress–displacement relationship. Finally, through finite element simulations, the study assesses the effect of the self-filtering layer on the load-bearing behavior of the drain pipe, considering the interactive dynamics between the tailings and the steel wire mesh. The results reveal that the interfacial shear strength, across varying median particle sizes of the self-filtering layer, adheres to Mohr–Coulomb strength theory. Specifically, as the median particle size of the self-filtering layer increases, interfacial cohesion diminishes while the friction coefficient rises. The initial shear stiffness demonstrates a linear increase with the median particle size. With the presence of the self-filtering layer, the pull-out resistance of the drainage pipe can be enhanced by up to 26%. Moreover, the self-filtering layer significantly affects the distribution of negative skin friction. This research enhances the safety assessment of tailings ponds by providing crucial insights and solutions, emphasizing the influence of the self-filtering layer on the bearing behavior of the drain pipe.

This article deals with the use of ash from biomass burning for the remediation of thermally active dump in Heřmanice, Czech Republic. Nowadays, various chemical, physical, or biological methods of remediation are used for the remediation of dumps. The authors discuss the complex use of ash from biomass as a possibility for biological remediation of the Heřmanice dump. The main advantage of obtaining ash when burning biomass is primarily the fact that it is a renewable energy source, which produces electricity and large amounts of ash, which can be used, for example, for the remediation of the Heřmanice dump. Tailings are characterized by their acidity, while fly ash is characterized by high alkalinity. This study deals with which ratio (tailings:ash) would achieve the necessary neutral values in order to prevent the release of heavy metals into the surroundings of the Heřmanice dump. The value of the active soil reaction (pH/H2O), the value of the exchange soil reaction (pH/CaCl2), the value of hydrolytic acidity (Ha), together with the value of soluble salts in the tailings, i.e., electrical conductivity, were also studied. Based on the obtained results, it can be concluded that the addition of biomass combustion ash had a positive effect on the pH value of the tailings. Based on this fact, Al3+ is excreted more slowly into the environment. A higher content of aluminum is toxic to plants, while in a smaller amount, its content is necessary and at the same time an important factor in the process of plant growth. The mixing of alkaline ash with unburned surface tailings from the thermally active Heřmanice dump significantly influenced its acidity, which had a positive effect on increasing the active and exchange acidity. [ABSTRACT FROM AUTHOR]

Modern mining and metal ore smelting produce vast tailings, increasing heavy metal pollution. The study of heavy metal occurrence forms is a promising way to remediate contaminated tailings while minimizing environmental damage. However, laboratory measurements of heavy metal occurrence forms are complex and time-consuming, so a fast and accurate identification method is urgently needed. This study used gradient boosting regression tree (GBRT) approaches to predict heavy metal occurrence forms in tailings, with tailings mineralogy information and heavy metal properties as input variables and the percentages of seven occurrence forms as output variables. The optimum GBRT model achieved excellent performance, with R values greater than 0.92 recorded on the testing set for all seven occurrence forms. The feature importance analysis showed that electronegativity was the most critical variable across all occurrence forms, with an average feature importance of 0.442, followed closely by atomic number, which had an average feature importance of 0.211. Overall, this study proposes a reliable and efficient GBRT prediction model for heavy metal occurrence forms, providing new insights into the effects of tailings mineralogy on heavy metal occurrence forms. This approach can be applied to contamination analysis and the safe and efficient use of heavy metals. [ABSTRACT FROM AUTHOR]

Copyright of IGKOJEI Jurnal Pengabdian Masyarakat is the property of Fakultas Peternakan Universitas Papua 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.)

Tailing post-tin mining land has a sandy textured and loose structure. Those physical properties can affect the efficiency of fertilization and cause inefficiency of nutrient absorption in plants. That issue can be corrected by the application of organic material such as cow manure compost which has the potential for plant cultivation, especially for porang (Amorphaphillus oncophyllus Prain). This study aimed to examine the cultivation of porang plants in post-tin mining tailings by applying cow manure compost and to determine the best dose of cow manure compost for porang cultivation in artificial ex-tin mining land. This study used a single-group randomized design method with the treatment factor being the dose of cow manure compost consisting of five dose levels (5 t ha-1, 10 t ha-1, 15 t ha-1, 20 t ha-1, and 25 t ha-1). Each treatment level was replicated with five replications, and each replication consisted of five populations so the total population was 125 plants. The results showed that the application of various doses of cow manure compost to artificial post-tin mining land affected the growth and yield of porang plants. The treatment of cow manure compost at a dose of 25 t ha-1 gave the best growth and yield of porang plants. Heavy metal (Pb) analysis on porang tubers showed that all doses of cow manure compost had a Pb content value of <0.059%, which means that cow manure compost can reduce heavy metal uptake in porang tubers. Porang planted in artificial post-tin mining land is safe for consumption because lead (Pb) content was below the threshold of Indonesia National Standard (SNI) for food. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is commonly utilized in artisanal gold mining on Buru Island; the Hg-contaminated tailing possibly contaminates the agricultural land nearby. In general, tailings contain very low organic carbon and plant nutrients but are high in mercury and have extreme soil acidity. The objective of this study was to observe the growth of various legume cover crops (LCC) and the change of Hg in tailing inoculated with Azotobacter-Trichoderma. The field trial was conducted on Buru Island of Maluku by using a split-plot design with three replications. The main plot was LCC species, composed of Centrosema pubescens (CP), Mucuna sp. (MC), and Crotalaria sp. (CR); the subplots were microbial inoculants composed of two formulations of Azotobacter-Trochoderma inoculants. The results showed that the Mucuna sp. and consortia Azotobacter-Trichoderma (2:1) had the highest survival rate in the tailings and Hg uptake by 8.83 mg kg-1 per plant. Consortia Azotobacter-Trichoderma inoculant with the composition of 2:1 (v:v) was able to increase soil pH, total bacterial population, LCC biomass, and Hg uptake by LCC plants. The highest Hg removal effectivity was observed in the plot treated with Crotalaria sp. and in a plot with Azotobacter-Trichoderma (2:1), which was 34.0% and 33.6%, respectively.

Artisanal and small-scale gold is known to be sources of mercury pollution. This mercury contamination occurs when gold is isolated by the amalgamation method, contamination occurs. Mercury pollution in small-scale artisanal gold mining in the Kulon Progo area of Yogyakarta, the lowest tailing content was 164.49 mg kg-1, and the highest was 383.21 mg kg-1. This value exceeded the quality standard stipulated by Indonesian Government Regulation 22 of 2021 of 75 mg kg-1. The technology that can control pollution is stabilization/solidification (S/S). This research aimed to determine the optimum composition of the tailings mixture with tras soil. Variations in the design of tras soil with tailings were 100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 10:90. The results showed that the optimum tras: tailings soil composition was 90:10, with a compressive test of 31 t m-2. Toxicity Characteristic Leaching Procedure (TCLP) was 0.0033 mg L-1 according to the quality standard of Indonesian Government Regulation no. 22, 2021, with a value of 0.05 mg L-1. The compressive strength results follow the quality of the US EPA of 35 t m-2.

This study aims to contribute to the characterization of Katangese Copperbelt’s (DR Congo) mining wastes and soils polluted with trace metals, using pollution indices and direct concentration measurements. This study also evaluated the use of these indices in assessing the success of remediation projects. Data from previous studies and samples collected from six types of discharge and one polluted soil were used to address the first objective. Soil and plant samples were collected at Kipushi and Penga Penga for the second objective. The results reveal very high concentrations of As, Cd, Co, Cu, Mn, Pb, and Zn in all mine tailings and polluted soils, compared with local references. The degree of contamination (DC) values (from 72 to 5440) and potential ecological risk (RI) values (from 549 to 162,091) indicate very high-risk situations associated with polluted discharges and soils. Regarding revegetation trials, the results show lower concentrations and RIs in tree rhizospheres compared with unamended areas at both sites. However, trace metal concentrations are higher in tree rhizospheres compared with local references, and RI values are in the considerable risk range for Penga Penga (RI = 533) and in the very high range (>1500) for Kipushi. Bioconcentration factor values are below 1, indicating low accumulation in roots, wood, and leaves, and low risk of contamination of the trophic chain. In this context, it seems that the pollution indices used are suitable for characterizing pollution and prioritization for remediation. However, there seems unsuitable for assessing the effectiveness of phytotechnology processes based on metal stabilization. Direct plant performance measurements combined with direct measurements of metals in substrates and plants to assess transfer and efficiency are more appropriate.

Iron concentration tailings contain many valuable minerals, including apatite, which is not currently being recovered despite its use to make fertilizers and chemicals. This article proposes a flotation circuit to recover apatite from tailings generated by mining in Chile, based on laboratory tests and using the “Split Factor” method. The iron tailings were characterized by granulometry, chemical and mineralogical analyses, zeta potential, and contact angle. The effect of the collector, frother, and dispersant dose, along with the number of flotation stages, on both the grade and recovery of P2O5 were studied. The results indicate that it is possible to produce concentrates with a P2O5 grade of 29.1% and 89.6% recovery in a flotation circuit that includes the rougher–scavenger–cleaner stages. To obtain these results, it is only necessary to condition the iron tailings with 400 gt−1 of Atrac-2600, 400 gt−1 of sodium silicate, 10 min of conditioning time, pH adjustment to 10, and a time for the rougher, cleaner, and scavenger stages set at 10, 7.6, and 6.8 min, respectively. A chemical interaction is suggested, where the collector is specifically adsorbed onto the apatite surface.

Mercury (Hg) is commonly utilized in artisanal gold mining on Buru Island; the Hg-contaminated tailing possibly contaminates the agricultural land nearby. In general, tailings contain very low organic carbon and plant nutrients but are high in mercury and have extreme soil acidity. The objective of this study was to observe the growth of various legume cover crops (LCC) and the change of Hg in tailing inoculated with Azotobacter-Trichoderma. The field trial was conducted on Buru Island of Maluku by using a split-plot design with three replications. The main plot was LCC species, composed of Centrosema pubescens (CP), Mucuna sp. (MC), and Crotalaria sp. (CR); the subplots were microbial inoculants composed of two formulations of Azotobacter-Trochoderma inoculants. The results showed that the Mucuna sp. and consortia Azotobacter-Trichoderma (2:1) had the highest survival rate in the tailings and Hg uptake by 8.83 mg kg-1 per plant. Consortia Azotobacter-Trichoderma inoculant with the composition of 2:1 (v:v) was able to increase soil pH, total bacterial population, LCC biomass, and Hg uptake by LCC plants. The highest Hg removal effectivity was observed in the plot treated with Crotalaria sp. and in a plot with Azotobacter-Trichoderma (2:1), which was 34.0% and 33.6%, respectively. [ABSTRACT FROM AUTHOR]

In the study area of eastern Serbia, which includes the Bor and Maidenpek mining areas of the Republic of Serbia, a research of environmental evaluation of the study area was carried out by means of field survey for environment and satellite image analysis in order to establish and improve methods for assessing the environmental impact of mining areas by satellite image analysis. The results of this study showed that it was possible to efficiently determine the distribution of overburdens and tailings in a wide area based on the distribution of points having jarosite spectra, and that it was possible to distinguish waste rocks such as overburdens and tailings with high environmental impact from those waste rocks with relatively low environmental impact based on the mineral assemblage of the waste rocks estimated from satellite image analysis. In addition, if topographical data before and after mining development are obtained from the satellite image analysis, the volume of the waste rocks can be estimated, and the quantitative estimation of the amount of toxic elements dissolved from the waste rocks could be possible by combining the experimental data on the extraction of toxic elements from the waste rocks. In addition, the predicted hazardous area (Type I), where high concentration of Cu may be leached from the waste rocks revealed by the surface survey, corresponds to the area where waste rocks such as overburdens and tailings is distributed around the mine and the area where waste rocks such as tailing is distributed along the river downstream of the mine as estimated by the satellite image analysis. These results indicate that it is possible to predict the environmental impact in advance of the survey in the mining area, and to predict the environmental impact in the mining area where it is not possible to go directly to the survey and to consider guidelines for countermeasures.

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic 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 tailings of some mines contain large amounts of aluminosilicate. The high volume of these tailings and problems with storage and disposal of them have created a motive to process and produce alumina from them. Several methods have been proposed for the extraction of alumina or some of the metals present in these tailings. One of the effective methods is to use a combination of roasting and leaching processes. Aluminosilicates in tailings are sometimes insoluble or difficult to dissolve in acidic solutions, which prevents the separation of aluminum and the extraction of other metals enclosed in aluminosilicate by hydrometallurgy. To solve this problem, the method of roasting with the help of salts or roasting in the air is used. Roasting changes the structure of aluminosilicate; therefore, it can be dissolved in acids or even water and facilitates the production process of alumina. In this article, we have tried to review the production of alumina from tailings-containing aluminosilicate by roasting and leaching process. Advantages, disadvantages, type of solution used in leaching and operating temperature of these processes are categorized. [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. [ABSTRACT FROM AUTHOR]

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. [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.)

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.

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.

Tailings are one of the largest pollutant sources in the world. The wind and water leaching were often considered the main distribution tool of their pollutants. However, the carbonate crust precipitation has negated the trace toxic element (TTE) release. To identify the release mode of Pb, Zn, and Cd from mine wastes, the hydrodynamic evolution of waste piles was considered. The macroscopic and microscopic observation, the grain sizes, cohesion particles, density, hydraulic conductivity, and Pb, Zn, and Cd concentrations performed from eight drill cores of the two waste dumps and the principal component and the hierarchical cluster analysis showed that the physical properties of waste piles closely controlled the TTE mobility and migration from the tailings. The obtained data also showed that the upper carbonate layers were first eroded by wind and rainfall. Then, the formation of an impermeable carbonate crust limited the Pb, Zn, and Cd releases. However, the hydrodynamic evolution of the underneath layers was different. As the high pile waste sediments' weight meaning the lithostatic pressure (Pl), the geostatic ratios (λ = Pf/Pl) were in DII and DIII dumps superior to 0.29 and 0.26, respectively. Therefore, the overpressured fluids increased the mineral dissolution, including the sulfides and carbonates of metals, and hydraulic fracturing that raised the percentages of the mobile TTE and migration indexes. By the secondary pore and fracture volumes, the polluted fluids were progressively channeled towards the underpressured marge (dumps edge) by repetitive (polyphase) fluid pulsations. [ABSTRACT FROM AUTHOR]

The dose rates of an underground copper-zinc mine and the radioactivities of collected samples were measured using a surveymeter and a gamma-ray spectrometer. There was no significant difference found between mine dose rates and background radiation in the region. The average activity concentrations of 226Ra, 232Th, and 40K in tailing samples were found to be 27%, 83%, and 71% higher than in ores, respectively. It was determined that a miner who worked in the mine for a year and was exposed to the natural radiation of the mine could be exposed to a radiation dose of less than 1 mSv. The annual radiation dose of a person living in a standard concrete room with a certain amount of tailing added to the concrete content was calculated to be 202.2 µSvy− 1. Using tailings as concrete additives can help reduce waste released into the environment and make better use of natural resources. [ABSTRACT FROM AUTHOR]

The storage of tailings not only encroaches on large areas of farmland, but also causes additional ecological and environmental risks. In the study, red mud and fly ash were used as cementitious materials to stabilize the tailings contaminated with arsenic (As) and antimony (Sb) under different conditions. The stabilization mechanism of As and Sb was described through the “Toxicity Characteristic Leaching Procedure” (TCLP), “European Community Bureau of Reference” (BCR), Scanning electron microscope (SEM) and X-ray diffraction (XRD). “Risk assessment code” (RAC) and “Ratio of secondary and primary phase” (RSP) were used to evaluate the stability of red mud–fly ash tailings. The results revealed red mud and fly ash increased the pH of the tailings; the stabilizers bolstered the stabilization of As but without notable effects. Sb was in the active release stage on days 7 and 14, wherein acidic and higher pH conditions were more conducive for the release of Sb. The leaching concentration of Sb and exchangeable Sb decreased after adding 5% red mud and 10% fly ash for maintaining 28 days, the best stabilization effect of As and Sb was observed under neutral pH. The microstructure analysis showed that the calcium silicate hydrate (C–S–H), gypsum, ettringite and hematite played a key role in the fixation of As and Sb. As highly alkaline and highly active inorganic polymers, red mud–fly ash tailings showed effective treatment of heavy metal pollution and could be used as promising low-carbon materials for in situ remediation of contaminated sites.Highlights: The stability of arsenic (As) and antimony (Sb) was best under neutral condition (7 or so). Antimony (Sb) stability is affected by maintenance days and adding amount. The morphology and composition of the tailing changed obviously at 28 days. The pH of acidic tailings was adjusted by applying alkaline amendments. Realizing waste recycling and waste treatment, controlling the migration and transformation process of Sb and As. [ABSTRACT FROM AUTHOR]

To unveil the potential effect of metal presence to antibiotic tolerance proliferation, four sites of surface landfills containing tailings from metal processing in Slovakia (Hnúšťa, Hodruša, Košice) and Poland (Tarnowskie Góry) were investigated. Tolerance and multitolerance to selected metals (Cu, Ni, Pb, Fe, Zn, Cd) and antibiotics (ampicillin, tetracycline, chloramphenicol, and kanamycin) and interrelationships between them were evaluated. A low bacterial diversity (Shannon–Wiener index from 0.83 to 2.263) was detected in all sampling sites. Gram-positive bacteria, mostly belonging to the phylum Actinobacteria, dominated in three of the four sampling sites. The recorded percentages of tolerant bacterial isolates varied considerably for antibiotics and metals from 0 to 57% and 0.8 to 47%, respectively, among the sampling sites. Tolerances to chloramphenicol (45–57%) and kanamycin (32–45%) were found in three sites. Multitolerance to several metals and antibiotics in the range of 24 to 48% was recorded for three sites. A significant positive correlation (p < 0.05) for the co-occurrence of tolerance to each studied metal and at least one of the antibiotics was observed. Exposure time to the metal (landfill duration) was an important factor for the development of metal- as well as antibiotic-tolerant isolates. The results show that metal-contaminated sites represent a significant threat for human health not only for their toxic effects but also for their pressure to antibiotic tolerance spread in the environment. [ABSTRACT FROM AUTHOR]

This article deals with the use of ash from biomass burning for the remediation of thermally active dump in Heřmanice, Czech Republic. Nowadays, various chemical, physical, or biological methods of remediation are used for the remediation of dumps. The authors discuss the complex use of ash from biomass as a possibility for biological remediation of the Heřmanice dump. The main advantage of obtaining ash when burning biomass is primarily the fact that it is a renewable energy source, which produces electricity and large amounts of ash, which can be used, for example, for the remediation of the Heřmanice dump. Tailings are characterized by their acidity, while fly ash is characterized by high alkalinity. This study deals with which ratio (tailings:ash) would achieve the necessary neutral values in order to prevent the release of heavy metals into the surroundings of the Heřmanice dump. The value of the active soil reaction (pH/H2O), the value of the exchange soil reaction (pH/CaCl2), the value of hydrolytic acidity (Ha), together with the value of soluble salts in the tailings, i.e., electrical conductivity, were also studied. Based on the obtained results, it can be concluded that the addition of biomass combustion ash had a positive effect on the pH value of the tailings. Based on this fact, Al3+ is excreted more slowly into the environment. A higher content of aluminum is toxic to plants, while in a smaller amount, its content is necessary and at the same time an important factor in the process of plant growth. The mixing of alkaline ash with unburned surface tailings from the thermally active Heřmanice dump significantly influenced its acidity, which had a positive effect on increasing the active and exchange acidity.

Background: Canine morbillivirus (canine distemper virus, CDV) is a member of the Paramyxoviridae family. Canine distemper is a serious viral disease that affects many mammalian species, including members of the Mustelidae family. These animals have an elusive nature, which makes related virological studies extremely challenging. There is a significant knowledge gap about the evolution of their viruses and about the possible effects of these viruses to the population dynamics of the host animals. Spleen and lung tissue samples of 170 road-killed mustelids belonging to six species were collected between 1997 and 2022 throughout Hungary and tested for CDV with real-time RT-PCR. Results: Three species were positive for viral RNA, 2 out of 64 Steppe polecats (Mustela eversmanii), 1 out of 36 European polecats (Mustela putorius) and 2 out of 36 stone martens (Martes foina); all 18 pine martens (Martes martes), 10 least weasels (Mustela nivalis) and 6 stoats (Mustela erminea) tested negative. The complete CDV genome was sequenced in five samples using pan-genotype CDV-specific, amplicon-based Nanopore sequencing. Based on the phylogenetic analysis, all five viral sequences were grouped to the Europe/South America 1 lineage and the distribution of one sequence among trees indicated recombination of the Hemagglutinin gene. We verified the recombination with SimPlot analysis. Conclusions: This paper provides the first CDV genome sequences from Steppe polecats and additional complete genomes from European polecats and stone martens. The infected specimens of various species originated from distinct parts of the country over a long time, indicating a wide circulation of CDV among mustelids throughout Hungary. Considering the high virulence of CDV and the presence of the virus in these animals, we highlight the importance of conservation efforts for wild mustelids. In addition, we emphasize the importance of full genomic data acquisition and analysis to better understand the evolution of the virus. Since CDV is prone to recombination, specific genomic segment analyses may provide less representative evolutionary traits than using complete genome sequences. [ABSTRACT FROM AUTHOR]

Zinc tailing waste material is generated during the extraction of zinc metal. Its deposit is increasing year after year posing a threat to the environment and occupying large precious land. The present research explores the possibility of its application in road construction and filling. Physical and chemical tests were carried out, viz. SEM, EDS, X-ray diffraction and toxicity characteristics leachate procedure. The geotechnical characterisation was carried out and compared with similar types of materials, viz. soil and industrial wastes (fly ash and jarofix). Stress-settlement behaviour was studied by using a small scale physical model and validated by a numerical model test. Tailing was further mixed with cement to improve its properties for application in stabilised layers. Tailing is a porous, multi-phase and non-swelling cohesionless fine-grained material. It contains mainly oxides of silica, alumina, magnesium, calcium and less concentration of heavy metals. It has a high dry density (18.62 kN/m3), California Bearing Ratio (11%) and angle of internal friction (34°) compared to soil which makes it suitable for road construction. Cement stabilised tailing can be used in sub-base layer and can save about 170 mm thickness of the aggregate layer. Modulus value (18.17 MPa) indicates that it is a stiff material which leads to less settlement as a structural fill. [ABSTRACT FROM AUTHOR]