Tailings Water Research Articles

Effect of geomembrane hole geometry on leakage overlain by saturated tailings

Experiments are conducted to quantify leakage through holes in a geomembrane (GMB) overlain by tailings with 30% fines and underlain by a well-graded gravel. Analytical and empirical equations for predicting leakage through a circular hole are used to analyze the data. Test results show that changing the hole shape from circular to noncircular increases the leakage. Leakage through 2000 mm2 triangular, diamond, and square holes are all 15% higher than the 2000 mm2 circular hole. An increase by up to 33% is observed for a rectangular hole. The analytical equations for predicting leakage and head loss through a hole given by the modified Rowe-Booker equation are experimentally verified. The spatial distribution of fines content within about five diameters of the hole is shown to have a notable impact on leakage. Up to a 100% increase in leakage is detected due to 3% reduction in the fines content around the hole. For homogeneous tailings, the ratio of head loss within the hole and above the hole to total head loss are independent of consolidation stress and water head and primarily depend on the hole geometry (i.e., shape and size). Finally, the combined effect of tailings thickness and water head on leakage is discussed.

Geothermal Study of a Tailings Deposit: Frost Line Modelling and Comparison to Field Data

Seasonal freezing and thawing can have significant effects on tailings management. Tailings delivery, depositional schemes and water treatment are examples of activities that must be dealt with extra concern in sub-zero temperatures. Changes in mechanical properties, drainage possibilities or embedded frozen tailings layers are effects that can arise in poorly managed facilities. To avoid such consequences, a good understanding of the seasonal effects on the tailings deposit is needed. To get a better understanding of the geothermal regime in tailings, this paper presents a case study with geothermal modelling performed for the Laiva tailings facility in Finland, where major seasonal freezing and thawing periods are present. Ground temperatures and frost lines were predicted via one-dimensional modelling using air temperatures and snow cover depths from adjacent weather stations, and basic soil properties from the facility. Simulated results were compared to data obtained from thermal instruments in the field. The snow cover and its estimated thermal properties were shown to have large influence on the results. The model was able to accurately predict the thermal regime measured in the field. Strong agreement was shown, both in terms of ground temperatures and frost front positions. The methodology presented is useful for tailings management schemes in cold regions. Keywords: Geothermal Monitoring, Geothermal Modelling, Tailings, Soil Temperature, Frost Tubes, Snow Cover.

Adsorption of Ca(II) and K(I) on the kaolinite surface: a DFT study with an experimental verification

The clay minerals have a negative influence on the settlement of coal tailings, and the addition of metal cations has a positive effect on treating coal tailings water. Microscopic adsorption mechanism of Ca(II) and K(I) on kaolinite surface was investigated by means of density functional theory (DFT) calculations and Monte Carlo method. The structures of Ca(II) and K(I) adsorption on kaolinite (001) and (00−1) was obtained, with Mulliken bond populations and binding energies calculated. Ca(II) adsorbed on kaolinite (001) surface and K(I) adsorbed on (00−1) surface are their main products, respectively, and the binding energies of all the adsorption products of Ca(II) are higher than those of K(I). Partial density of states projections combining with Mulliken bond charge and populations indicate that Ca−O and K−O bonds of the adsorption products are dominated by ionic interaction. Cation hydration can make the adsorption occurs more easily and enhance the covalent interaction of the bonds. The adsorption experiment verifies that Ca(II) is easier to adsorb on kaolinite than K(I).

Maize Stalk Material for On-Site Treatment of Highly Polluted Leachate and Mine Wastewater.

New research applications involving the use of cellulosic material derived from maize stalk for on-site treatment of leachate were evaluated for specific removal of Cu(II) and Fe(III) from real, highly polluted tailing pond and mine wastewater samples. Two major issues generated by anthropic mining activities were also tackled: wastewater metal content decrease to improve water quality and subsequently metal specific recovery, increasing the economic efficiency of metal production by using a green technology for residual management. Rapid saturation of the maize stalk mass determined in batch studies and the mine pilot experiment led to diminished metal concentrations in the second pilot experiment, where Cu(II) and Pb(II) from synthetic solutions were monitored in order to test biomaterial performances. In addition, in the second pilot experiment, maize stalk removed Pb(II) in the first 36 h, below the determination limit of the analytical method. The biomaterial bed in the column was saturated after 252 h of inflow solution. FTIR-ATR, TG and SEM techniques probed the interaction between maize stalk polar groups C=O, –OH, C–O and tailing water metallic ions by large FTIR band displacements, intensity decrease and shape changes, modification of thermal stability and by changes in the appearance of adsorbent microstructure images owing mainly to ion exchange mechanism.

Tailings Filtration Using Viper Filtration Technology\u2014a Case Study

Investigation and uptake of filtered tailings continues to grow throughout the globe. This is driven by a wide range of site-specific considerations, which include such factors as tailings characteristics (e.g., amenability to filtration), production rates, climate, water availability, cost drivers, environmental requirements, and social factors. Despite the aforementioned technological growth, the currently available filtration technology is not able to meet the needs of many operations and projects that would otherwise adopt the technology. Experience with large-scale industrial filtration shows that vacuum belt filter systems meet the needs of many modern users, exceptions being the inability to effectively dewater tailings at altitude and/or with a fine particle size distribution: a potential fatal flaw. This paper presents a case study on the utilization of the patented Viper Filtration technology on gold tailings to overcome this challenge and shares the resultant full-scale plant design, highlighting the features designed to overcome cost and scalability deterrents. This technology is a novel mechanical process which complements the vacuum pressure in dewatering the filter cake as it travels along the belt filter. This project commenced with a pilot testing program, which successfully met the objective to rigorously test, measure and record any performance improvements achieved when engaging the Viper technology. Of the two tailings products tested, gross improvements of 4.2%w/w and 5.7%w/w were achieved when compared to the conventional vacuum belt filter operation. This pilot testing facilitated measurement of operating and design data, which forms the basis of the full-scale system design and resultant equipment supply of three vibration roller assemblies for retro-fitting on the existing vacuum belt filter.

Characterization of chemical content tailings sand and water from the tin post-mining in Merawang Subdistrict, Bangka Regency

The characteristics of the six sand samples taken from the location of the former tin mining land on average contain heavy metals such as Ti, Sn, Mn, Pb, Cu, Zn, Cu, and As. Nb rare earth metal contains all sand samples except PDTF 1. The highest content is in the PDTF 2 sample which is 103 ppm. While the Y metal content is found in samples of PDTF 2A, 3, 3A, and 4. The highest content for Y metal is in the sand sample PDTF 3A with levels of 59 ppm. The largest metal content of the six samples is generally iron (Fe) and followed by sulfur (S). There are only a few samples that contain element V, namely in samples 2A, 3A and 4. The highest Fe content is in the water sample PDTF 2A which is 0.953 mg / L. This value is not much different from the Fe content in the PDTF 1 sample (0.923 mg / L). Sand samples in PDTF 3 A have the highest Fe content but water close to the PDTF 3A sampling location has the lowest Fe content compared to the other five samples.

Transcriptome aberration in marine microalgae Phaeodactylum tricornutum induced by commercial naphthenic acids.

Naphthenic acids (NAs) are cycloalkyl linear carboxylic acids primarily originating from oil sand tailings water (OSTW), and the exposure to NAs affects the photosynthesis of marine microalgaes. However, the transcriptional response upon the stress of NAs remains unclear. Herein, we investigate the transcriptome alterations of marine Phaeodactylum tricornutum induced by NAs using RNA-sequencing. In total 70 differentially expressed genes (DEGs) are enriched in seven biological process pathways, and 48 DEGs are enriched in four molecular functions. Differentially expressed genes of P.tricornutum are primarily concentrated in three photosynthesis-related pathways including the porphyrin and chlorophyll metabolism pathway, the photosynthesis pathway, and the carbon fixation pathway in photosynthetic organisms. Five DEGs such as hemE, chlM, TPI/GapC3, FbaC5, and CHLH are validated using quantitative real-time PCR assay. NAs at low concentrations affect the material energy conversion efficiency of P.tricornutum, such as chlorophyll synthesis, electron transfer efficiency, and carbon assimilation.

Effects of puzzolanic materials in surface paste disposal by pilot-scale tests: observation of physical changes

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.

Effective separation of uranium from mine process effluents using chitosan as a recyclable natural adsorbent

This study aimed to efficiently and cost-effectively recover uranium from real mine effluents derived from the processing of uranium-bearing ore. A natural bioactive polymer, chitosan, was applied as a low-cost material to separate uranium ions and characterised using a scanning electron microscope coupled with an energy dispersive spectrometer, and a Fourier transform infrared spectroscopy analysis. Rapid adsorption (over 90% within 10 min) was recorded in the examined batch-type system. The kinetics of the reactions were calculated, and the rate of uranium adsorption tended to follow a second-order equation. The maximum adsorption capacities of the biopolymer given by the Langmuir model were 17.44 mg/g and 7.51 mg/g for the flotation and Knelson tailings water, respectively. The results demonstrated that the separation of uranium ions from effluents was temperature- and pH-dependent. Studies have revealed an enhancement in uranium uptake at elevated water temperatures. As the pH increased from 2 to 10, the net charge on the biopolymer surface changed from positive to negative, which indicated the possible involvement of electrostatic interactions in the binding of the metal ions. In addition, interactions between uranyl ions and biopolymer functional groups were confirmed. The regeneration possibility and reusability of the biopolymer were investigated, and approximately 73% of the uranium was recovered by the fourth adsorption–desorption cycle.

Effect of gradation on the thermal conductivities of backfill materials of ground source heat pump based on loess and iron tailings

The addition of iron tailings to backfill soil of ground source heat pump (GSHP) systems can efficiently improve backfill thermal conductivity. The engineering properties of iron tailings and soil are significantly affected by particle gradation. Therefore, the effect of gradation on the thermal conductivity of backfill material composed of iron tailing and loess was investigated. The thermal conductivities of natural (bad) gradation and manmade (good) gradation materials with different iron tailings content, water content, and dry density were tested and analyzed. Results showed that the thermal conductivity of manmade gradation materials was usually higher than that of natural gradation materials. For the same water content and dry density, the influence of gradation on thermal conductivity decreased with increasing water content. For saturated material, the maximum difference in thermal conductivity caused by gradation ranged from 39.1% to 8.6% compared to dry material. The maximum increases in thermal conductivity caused by gradation were approximately 0.12–0.24 W/(m·K). The maximum increase percentage of thermal conductivity increases with decreasing water content, and the value range is 28.4–60.5%. The empirical formula for thermal conductivity was established based on the water saturation. The influence of gradation on formula parameters is analyzed. Finally, suggestions for gradation selection in practical applications of GSHP backfill materials are given.

Source and pathway determination of mine seepages using sulfate and Pb isotopes at the Daema and Okdong mines, South Korea

Utilization of multiple stable isotopes including metal isotopes have been useful to trace sources and pathways of contamination. Contaminated seepages flow out from tailings dumps at the Daema gold-silver mine and the Okdong copper mine in South Korea. Ion concentrations, δ34SSO4, δ18OSO4, and Pb isotopes, as well as leaching tests were used to evaluate the sources and pathways of seepages from tailings dumps at the Daema and Okdong mines. The δ34SSO4 and δ18OSO4 values of the seepage were similar to that of the groundwater at the tailings layer and differed from that of the groundwater at the coal shale layer of the tailings dump at the Daema mine. The Pb isotopic ratios of groundwater at the tailings layer also approached those of the tailings, although the Pb concentration in the seepage that was too low (0.559 μg L−1) did not indicate isotopic signatures of tailings. This suggests that the source of contaminants in the seepage is the tailings of the Daema mine rather than waste rocks (coal shale) of an adjacent mine in the tailings dump. In the Okdong mine, the contamination of seepage may be a result of a 67–71% contribution of groundwater from the northern side of the dump through buried waste rock (OD-T2) and a 19–23% contribution of groundwater from the eastern valley (OD-T3), as calculated by the isotopic mixing of δ34SSO4 and δ18OSO4. Adit water is not considered to be the major source of the seepage because of the large difference in Mn concentrations (22.0 mg L−1 and 0.10 mg L−1 in adit water and seepage, respectively) and the undersaturation with respect to Mn phases before and after mixing with tailings water. To reduce the contamination load of seepage in a tailings dump, we should prevent water inflow not only from the surface but also from the side of the tailings dump. Both studied areas suggest that a dual isotopic approach using δ34SSO4 and δ18OSO4 is especially useful in identifying the contamination sources and pathways. Additionally, a leaching test for waste evaluation proved helpful in qualitatively simulating the composition of leachate from the tailings at the Daema mine and adit water from ore rocks at the Okdong mine. Dissolved Pb isotopic ratios were effective in determining the solid sources of dissolved Pb, if the Pb concentration is greater than 0.6–1.8 μg L−1 in the cases of the studied mines. Pb isotopic ratios at five sites including Nakdong mine and two other sites suggest that dissolved Pb with too low concentration may have isotopic signature of atmospheric input. Pb concentrations above threshold values may be required to reflect contamination sources other than atmospheric contribution.

Development of Indirect Spectrophotometric Method for Mercury Determination Based on The Formation of Iron(III)-Thiocyanate Complex

A new spectrophotometric method for mercury determination has been developed based on the complexation of mercury(II) in ascertained excess of thiocyanate. The remaining thiocyanate is reacted with iron(III) to form a red iron(III)-thiocyanate complex which gave maximum absorbance at 460 nm. The concentration of mercury(II) is inversely proportional to the decrease absorbance of the complex. The method was optimized to the concentrations of thiocyanate and iron(III). Selectivity of the method has also studied based on percent recovery of mercury(II) in the presence of common metal ions in the tailing waters of gold mine. Under the optimum conditions, the method showed linear correlation to mercury(II) concentration from 1-30 mg L−1 with detection limit of 0.58 mg L−1. The method was not interfered in the presence of all metal ions studied up to 50 mg L−1, except of silver which was tolerated at 10 mg L−1. The developed method has been satisfactorily applied for mercury(II) determination in synthetic and tailing waters of gold mine samples.

Influence of saltwater intake on the health of dairy cattle

Water is an element extremely important, essential for life, and necessary to maintain some factors such as intracellular pressure, assist digestive processes, carry nutrients, eliminate toxins through urine and allow the thermal balance of living things. However, it is a scarce element as the national water resources policy in Brazil advocates. In recent years water has become one of the biggest global problems due to lack and quality. The objective of this study was to evaluate the influence of saline intake on the health of dairy cattle. The actions consisted of periodic visits to a rural property located in the city of Pesqueira, Agreste Pernambucano - Brazil, whose main economic activity is milk production and cheese making. The herd has milk aptitude and consists of 182 animals. Samples of desalination tailings water that were supplied for quench the animals were collected. Blood samples from the cattle were collected and sent for hematological exams. The results showed alterations of some physicochemical parameters of water and high serum levels of chloride and sodium in cattle. The continuous intake of wastewater from the desalination process for the quench of dairy cattle alters the serological and physiological patterns of these animals. Further studies must be conducted on dairy products regarding their quality and health impact.

The Application of the Seismic Cone Penetration Test (SCPTU) in Tailings Water Conditions Monitoring

The safe operation of the large, outflow Tailings Storage Facilities (TSF) requires comprehensive and continuous threat monitoring. One of the basic kinds of threat monitoring is to monitor the water conditions in deposited tailings, which is usually carried out using a conventional piezometric observation method from a network of installed piezometers. In complex tailings storage conditions, the reliability of the piezometric method may be questioned. The Seismic Cone Penetration Test (SCPTU) can meet high test standards. The results of the penetration tests closely identify conditions of sediments that determine the tailings water regime verified locally on the basis of pore water pressure dissipation tests. On the other hand, seismic measurements perfectly complement the characteristics of sediments in terms of their saturation. The analysis of the results of SCPTU implemented in the tailings massif also showed that below the phreatic surface, a zone of not fully saturated tailings can be found. Its presence improves the stability conditions of the tailings massif and dams, but also limits the possibility of the static liquefaction of tailings.

Application of chemical and biological tests for estimation of current state of a tailing dump and surrounding soil from the region of Tarniţa, Suceava, Romania.

This paper presents the results from a study on the current state of tailing dump, surrounding soil and water in the region of Tarniţa-Suceava, Romania. A number of chemical analyses and germination tests were applied in an attempt to estimate the ability of soil to maintain the plants growing, the bioavailability, and heavy metals uptake. Total heavy metals, exchangeable metals, acidity, and carbon and nitrogen content were determined. A modified sequential extraction method was used to determine geochemical phase distribution of heavy metals. The most abundant heavy metals in the studied samples were Cu, Zn, and Pb. Elevated concentrations of As were also found. The results from sequential extraction revealed that up to 51% of copper was retained by amorphous and crystalline iron oxides in soil. Higher content of lead was noticed in amorphous iron oxide fraction. The heavy metal concentration in river water during dry season varied from 0.13 mg/L (Fe) to 4.2 mg/L (Zn) and was below the maximum contamination level for drinking water. The soil toxicity and heavy metal bioavailability of tailing dump material and surrounding soils were studied by germination tests. The germinated plantlets on the studied soils were found to accumulate elevated concentrations of heavy metals thus indicating the bioavailability of soil contaminants. Soil decontamination by distilled water or magnesium nitrate solution was found to be efficient enough to improve the capability of the studied soils to support the germination process.

Examination of the Effects of Solids Content on Thickened Gold Mine Tailings Sedimentation and Self-Weight Consolidation

Abstract Thickening is being increasingly adopted by the mining industry because of its economic and environmental attributes, such as decreased amounts of water released following deposition and a smaller footprint of the tailings site. This study presents an assessment of the continuous process of sedimentation and the self-weight consolidation of slurry and thickened mine tailings. The results of a series of settling column tests performed with specimens with solids contents between 50 % and 72 % are presented and discussed. Lower solids contents that are more characteristic of slurry tailings were also included to cover a wide range of settling behavior. High-precision monitoring of pore water pressure was used to identify the transition from sedimentation to self-weight consolidation, which likely occurs between solids contents of 65 % and 68 % for this material, and it highlighted the fact that the combination of these two settlement processes accelerates ue dissipation. The displacement results for the tailings–water interface corroborate values in the technical literature related to the settlement of suspensions. Equilibrium was reached within a narrow time range (i.e., 400 to 500 min) despite the wide range of initial solids content in the slurries tested (i.e., 50 % S to 65 % S).

Bioremoval of heavy metals from metal mine tailings water using microalgae biomass

The copper industry generates large quantities of mine tailings water. Thus, this study aims to select a microalgae species that is both tolerant and capable of the bioremoval of heavy metals from metal mine tailings water as well as the potential biorefinery of this microalgae biomass. Chlorella vulgaris and Scenedesmus spinosus were tested for tolerance to metal mine tailings water (MTW) in northern Chile and synthetic treatments of Cu and Mo (0.1 and 0.5 mg/L). Additionally, the biomass generated was characterized to evaluate its potential applications. The main results showed greater tolerance of C. vulgaris cultured in MTW treatment. In fact, high removal efficiency of Cu and Mo was detected for this microalgae in MTW: 64.7% and 99.9%, respectively. Similarly, Cu (55%) and Mo (80.3%) removal was observed at 0.5 mg/L synthetic concentration treatments after 72 h. However, cell wall fluorescence and chlorophyll parameters were mainly affected by 0.5 mg/L Cu synthetic concentration, where the mean fluorescence intensity (MFI) was 878, compared with the other treatments (≥1800). Morphological cell changes in the MTW treatment were observed using SEM images. The presence of Mo on the microalgae surface was detected by 0.47% and 0.82% in both Mo synthetic treatments exposed. Additionally, the characterization of microalgae biomass exposed to MTW showed a higher protein content and a minor difference of lipid content compared with the control treatment, which could be used in biorefinery processes. This study reveals the capability of C. vulgaris to remove heavy metals from this mine tailings water and the effect that occurs in microalgae cells.

A novel scheme for flotation tailings pulp settlement and chemical oxygen demand reduction with polyferric sulfate

Abstract In most of the mining industries, lime is widely used to settle flotation tailings pulp. However, this conventional method has some drawbacks, as it increases pH, organic matter content and chemical oxygen demand (COD) of tailings dam wastewater (TDW) and further treatment is required. Therefore, current research provides an innovative and environmentally friendly technology that uses polyferric sulfate (PFS) instead of lime for pulp settlement. A series of laboratory tests showed that the final settlement effects of PFS and lime for tailings pulp settlement were comparable. However, the COD of tailings water by PFS settlement was considerably reduced compared with that of lime settlement. Total organic carbon and fluorescence excitation–emission matrix analysis showed that organic matter content in tailings water by PFS settlement was also significantly lower than that of lime settlement. Lead nitrate and benzohydroxamic acid (Pb-BHA) synthetic solutions analysis showed that increasing or decreasing the pH dissolved Pb-BHA precipitates into water, leading to an increase in COD. Therefore, in lime settlement, the pH value significantly increased, which dissolved the remaining Pb-BHA precipitates in the pulp into water, resulting in an increase in COD. In PFS settlement, the pH change was small, and polynuclear hydroxyl complex generated by the hydrolysis of PFS adsorbed part of the organic matter to precipitate, resulting in COD reduction. Results of laboratory tests were further verified by an industrial test. The COD and pH of the TDW significantly decreased from 110 mg/L before the industrial test (lime settlement) to 68 mg/L and from 11.8 to 7.1, respectively, after the industrial test (PFS settlement).

Experimental study on sedimentation characteristics of fine tailings

The experimental results of sedimentation characteristics of fine-grained tailing at home and abroad are summarized. For fine-grained tailing dam, the particle size of tailing, the discharge concentration of tailing and pore water pressure has significant effects on the sedimentation characteristics of fine-grained tailing dam. Different particle size of tailing will lead to a different structure of tailing deposition, which directly affects the sedimentation characteristics and stability of tailing. The increase of discharge concentration and pore water pressure will also lead to adverse results of tailing sedimentation characteristics.

A Tailings Pond Identification Method Based on Spatial Combination of Objects

Tailings ponds pose a significant risk to the safety of the surrounding residents and the local ecological environment. Therefore, it is necessary to efficiently and accurately monitor tailings ponds. However, the internal structures of tailings ponds are heterogeneous, and they are typically identified through manual interpretation. In this paper, an identification method for four main structures of tailings ponds, namely, starter dams, embankments, deposited beach, and water body, is proposed based on the spatial combinations among them. First, hierarchy objects were established based on GaoFen-2 imagery. Then, candidate objects (such as embankment-like) were identified using the spectral features and the number of parallel lines. Subsequently, rural settlement-like objects were eliminated as interfering objects based on their shapes and distributions. Finally, four structures of tailings ponds could be identified based on their spatial combination. Six cases of tailings ponds were selected for validation. Interference categories were eliminated step by step (79.64%, 38.21%, and 39.75% for case A), and all four structures were identified. The overall identification accuracies were 88.14%–96.21%. The average accuracy is 32.02% higher than that of comparison experiments using the random forest. The method was proved to be applicable to the automatic identification of mining areas, which is of great significance for efficient and accurate supervision of mining safety.