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1
Jiang, Qing Hua y Chen Xiang Yu. "The Application of Vapour Equlibrium Technique in Water Retention Study of Fine Grained Tailings". Advanced Materials Research 838-841 (noviembre de 2013): 1785–90. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1785.
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As a problematic material, fine grained tailings have many particular engineering characteristics and seriously affect the safety and stability of the tailing dam body. These engineering properties are closely related to moisture migration and soil suction under different water content. This article chose fine grained tailings of Li Tie Lan Ting tailings dam in Zhejiang province as an example, and measured the soil water characteristic curve (SWCC) of fine grained tailings with different partical size composition and dry density using vapour equilibrium technique. Efforts have also been made to demonstrate the influences of soil type, dry density on water retention. The study result shows that particle-size composition has a significant impact on SWCCs of the tailings. Finer grained samples have lower water loss rate and higher water-holding capacity than coarse grained samples in the same suction state. Contrary with low suction stage, dry density has negligible influence on the soil suction, and parameters effect SWCCs at high suction stage. The research results may provide a theoretical support and a beneficial reference for further research of fine grained tailingss engineering properties.
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Gao, Shan, Xiaowei Cui y Sumei Zhang. "Utilization of Molybdenum Tailings in Concrete Manufacturing: A Review". Applied Sciences 10, n.º 1 (23 de diciembre de 2019): 138. http://dx.doi.org/10.3390/app10010138.
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Dealing with mineral tailings is one of the most important topics for solving the environmental problems in the mining industry. Among the techniques converting stacked molybdenum tailings to reusable cleaner products, one of the most effective ones is to use molybdenum tailings in concrete productions. The physical properties including density, microscopic structure and finesse module, and chemical composition of molybdenum tailings are similar with those of natural sand. The radionuclide assessment of molybdenum tailing meets the requirements for using as structural materials. Therefore, Molybdenum tailing is suitable to be used as the replacement of cement and fine aggregates in mortar and concrete. Based on the results of strength and duration performance comparison, the usage of molybdenum tailing as a replacement of natural sand is a more feasible way than that of ground super-fine molybdenum tailings in cement binder. It is feasible to use molybdenum tailings as fine aggregate in the preparation of structural concrete. When the amount of ground super-fine molybdenum tailings replacing cement is less than 10%, it is beneficial to improve the freeze-thaw and carbonization resistance of the concrete.
3
Dong, Tao, Ping Cao, Rong Gui, Qibin Lin y Zhizhen Liu. "Experimental Study on Permeability Coefficient in Layered Fine Tailings under Seepage Condition". Geofluids 2021 (15 de abril de 2021): 1–14. http://dx.doi.org/10.1155/2021/8850138.
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Nearly half of the tailings dams in China are in a state of high-security risks and overservice, and the safety of these tailings dams has always been a concern for relevant scholars. The seepage characteristics of tailings are one of the essential factors affecting the safety of tailings dam. Now, due to the improvement of mineral processing technology, there are many fine tailings dam; the study of the seepage characteristics of the tailings dam is no longer applicable. Fine-grained tailings form uneven deposition in these tailings dams, resulting in the permeability of tailings not conforming to the previous law. Therefore, it is of great significance to study the permeability of fine-grained tailings with uneven deposition. In this paper, the physical model of the simulated tailings dam is established to study the influence of the dry beach slope on the distribution and deposition law of fine tailings during discharge. The test results show that the average particle size of tailings decreases along the length of dry beach, showing the phenomenon of coarsening upstream and thinning downstream. Then, based on the data of fine tailings deposition, the variation characteristics of the permeability coefficient of layered tailings under stable and unstable seepage conditions are studied. The test results show that the variation process of tailings permeability coefficient can be divided into four stages: rapid compaction stage, slow compaction stage, failure stage, and stable stage. Under stable and unstable seepage conditions, the permeability coefficients of unstratified tailing sand are about 10% and 15% higher, respectively, than those in the initial state. The permeability coefficient of layered tailings formed by uneven settlement changes more obviously, which is about 12% and 20% higher than the initial state.
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Amalia, Amalia y Muhtarom Riyadi. "Kualitas Beton SCC dengan Substitusi Agregat Halus Tailing Tambang Emas Daerah Pongkor". MEDIA KOMUNIKASI TEKNIK SIPIL 25, n.º 1 (10 de agosto de 2019): 59. http://dx.doi.org/10.14710/mkts.v25i1.18500.
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This paper presents the results of self compacting concrete (SCC) with water cement ratio 0.30 with four variations of tailings, ie 0%, 5%, 10% and 15%. Superplastisizer used is a type Naptha 511P of PT.Karya Naptha Belide. The results showed that (1) The use of tailings as fine aggregate in concrete SCC, has good workability. The fresh concrete that uses tailings, passing ability and filling ability is decrease. The use of tailings up to 15% of eligible properties filling ability and passing ability of SCC, (2) The more tailings used in SCC, setting time of concrete becomes longer, (3) Concrete with tailings as fine aggregate have unit weight is smaller than the concrete with fine aggregate sand, (4) Concrete with tailings has higher compressive strength and modulus of elasticity than concrete without tailings, (5)The use of tailings in concrete can lower tensile strength of concrete, (6)The optimum replacement of tailing found to be 10% in the concrete.
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Wang, Haijun, Xiaogang Sun, Jianwen Wang, Yun Duan, Changsuo Zhang, Jingping Qiu y Zhenbang Guo. "Effect of Tailings Fine Content on the Properties of Cemented Paste Backfill from the Perspective Packing Density". Advances in Civil Engineering 2021 (1 de junio de 2021): 1–10. http://dx.doi.org/10.1155/2021/9947620.
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In order to quantitatively study the influence of tailings fine content on the properties of cemented paste backfill (CPB) and further understand the mechanism of tailings fine content acting, the concept of packing density was introduced in this study. The packing density of each tailings sample was measured by the wet packing method after the samples with various fine contents were prepared. Moreover, CPBs with different tailings fine contents were tested by the mini slump test, rheological test, uniaxial compressive strength (UCS) test, and mercury intrusion porosimetry test. The results demonstrated that the flow spread and UCS both increase first and then decrease with the increase of tailings fine content, while the yield stress shows an opposite trend. The fine content of tailings affects the flowability of fresh CPB mainly through the packing density. When the fine content is high, the influence of the specific surface area of tailings cannot be ignored. The packing density is an important factor affecting the strength of CPB, and there is an obvious linear relationship between the packing density and UCS. The pore structure of CPB samples with different tailing fine contents is significantly different, and the macroscopic packing density changes the strength of CPB by affecting the microscopic pores.
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Suthaker, Nagula N. y J. Don Scott. "Measurement of hydraulic conductivity in oil sand tailings slurries". Canadian Geotechnical Journal 33, n.º 4 (20 de agosto de 1996): 642–53. http://dx.doi.org/10.1139/t96-089-310.
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Fine tails, the resulting fine waste from oil sand processing, undergoes large-strain consolidation in tailings ponds. Its consolidation behaviour must be analyzed using a large-strain consolidation theory, which requires the determination of the relationship between the void ratio and hydraulic conductivity. Conventional measurement techniques are not suitable for fine tails, and a special slurry consolidometer, with a clamping device to prevent seepage-induced consolidation, was designed to determine the hydraulic conductivity of the fine tails and nonsegregating fine tails sand slurries. The hydraulic conductivity of slurries is not constant but decreases with time to a steady-state value. Hydraulic conductivity is also influenced by the hydraulic gradient and bitumen content. It is shown that a low hydraulic gradient, less than 0.2, is necessary to counteract the effect of the bitumen and to represent tailings pond conditions. The hydraulic conductivity of fine tails sand mixes is controlled by the fines void ratio, hence, fines content. The hydraulic conductivity of chemically amended nonsegregating tailings can be lower than that of fine tails. However, acidlime or acid fly ash amended nonsegregating tailings have similar hydraulic conductivity values in terms of fines void ratio. The hydraulic conductivity of nonsegregating tailings appears to be governed by fines content and by the nature of the fines aggregation caused by the chemical additive. Key words: tailings, slurries, hydraulic conductivity, slurry consolidometer, nonsegregating tailings, oil sands.
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Cui, Liyun, Liang Wang, Ying Xu, Xing Lou y Hao Wang. "Feasibility Evaluation of Replacing River Sand with Copper Tailings". Sustainability 13, n.º 14 (7 de julio de 2021): 7575. http://dx.doi.org/10.3390/su13147575.
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This study aims to realize the resource regeneration application of copper tailing (as fine aggregates for partial replacement of natural fine aggregates), which avoid environmental pollution due to many landfills of copper tailings. The compressive strength and durability (dry shrinkage and sulfate attack) tests were carried out to evaluate the effect of copper tailings replacement on the performance of mortar. The results show that the mortar with copper tailings has higher compressive strength than the one with natural sand. More than 14% improvement in compressive strength can be achieved by adding copper tailings with no more than 40% replacement level. The dry shrinkage of mortar was increased with the copper tailings due to the increase of micro pores in mortar by using copper tailings. Compared with the mortar with natural sand, the dry shrinkage can be reduced by adding copper tailings with no more than 20% replacement level. The sulfate attack resistance is improved by using copper tailings, when the replacement rate is more than 20%. In fact, the micro-aggregate filler effect of copper tailings effectively refines the pore structure and forms more stable, uniform and fine interface micro pores, which is of vital significance for mortar to resist external forces and sulfate ion erosion. However, copper tailings, as a porous material, have water release characteristics in cement mortar. This characteristic is not conducive to the filler effect, which decreases the filling rate in later hydration, leading to higher porosity of copper tailings mortar. More importantly, mortar can solidify heavy metals in copper tailings, which prevents loss of heavy metal such as Cu, Zn, Sr, Zr, As, Ga due to environmental problems.
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Xie, Hai Yun, Li Kun Gao, Shu Ming He, Dian Wen Liu y Xiong Tong. "Flocculation and Sedimentation of Bauxite Flotation Tailings". Applied Mechanics and Materials 260-261 (diciembre de 2012): 1179–82. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.1179.
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Flocculation and sedimentation of fine bauxite from flotation tailing pulp were studied using different flocculants to investigate the possibility of its application. The results of this investigation indicate that inorganic flocculants of PAC and PAS have better flocculating effect than organic flocculants of PAM1# and PAM2# when keeping the original pH (7.5~8.0) of tailing pulp, however its consumption are large. It was found that the pH of pulp is important to the tailings settlement. The dosage of flocculants are greatly reduced and the velocity of floc settling is accelerated when the pH of tailing pulp is adjusted to 6.5~7.0 using sulfuric acid. PAM1# and PAM2# are effective flocculants for fine bauxite from the tailings pulp and improved the sedimentation performance compared with PAC and PAS at pH 6.5~7.0. It was also found that the flocculants can be used in combination to treat original bauxite tailing, and good sedimentation effect has been achieved, but the dosage of reagents is bigger when the organic flocculant is combined with inorganic flocculant.
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Shi, Yueqi, Changhong Li y Dayu Long. "Study of the Microstructure Characteristics of Three Different Fine-grained Tailings Sand Samples during Penetration". Materials 13, n.º 7 (30 de marzo de 2020): 1585. http://dx.doi.org/10.3390/ma13071585.
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This paper explores the microstructural evolution characteristics of tailings sand samples of different types of infiltration failure during the infiltration failure process. The homemade small infiltration deformation instrument is used to test the infiltration failure characteristics of the tailings sand during the infiltration failure process. Evolutionary characteristics of the internal microstructure pores and particle distribution were also studied. Using CT (computerized tomography) technology to establish digital image information, the distribution of the microscopic characteristics of the particle distribution and pore structure after tailing sand infiltration were studied. Microscopic analysis was also performed to analyze the microscopic process of infiltration and destruction, as well as to see the microscopic structural characteristics of the infiltration and destruction of the total tailings. The test results show that there are obvious differences in the microstructure characterization of fluid soil and piping-type infiltration failures. Microstructure parameters have a certain functional relationship with macrofactors. Combining the relationship between macrophysical and mechanical parameters and microstructural parameters, new ideas for future research and the prevention of tailings sand infiltration and failure mechanisms is provided.
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Mao, Song y Qin Zhang. "Mineralogical Characteristics of Phosphate Tailings for Comprehensive Utilization". Advances in Civil Engineering 2021 (31 de marzo de 2021): 1–13. http://dx.doi.org/10.1155/2021/5529021.
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The mineralogical characteristics of a phosphate tailing were studied, and the occurrence state, mineral types, and embedded characteristics of phosphorus in the phosphate tailings were ascertained. The results show that the main minerals in the phosphate tailings are collophane. The main gangue minerals are quartz, dolomite, calcite, a small amount of potassium feldspar, plagioclase, chlorite, etc. Monazite was found in phosphate tailings. In addition, the coarse grain size of quartz and feldspar and fine embedded particle size of calcite and dolomite are also the main factors affecting the mineral processing of phosphate tailings. According to the analysis of mineralogical characteristics, the physical and chemical properties of phosphate tailings provided the basis for comprehensive utilization of phosphorus resources.
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Caughill, D. L., N. R. Morgenstern y J. D. Scott. "Geotechnics of nonsegregating oil sand tailings". Canadian Geotechnical Journal 30, n.º 5 (1 de octubre de 1993): 801–11. http://dx.doi.org/10.1139/t93-071.
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The present method of oil sands tailings disposal results in a tailings pond with a fine tailings zone that will take many decades to consolidate fully. The fine tailings accumulate as a result of the segregating characteristics of the tailings stream. Nonsegregating mixes of total tailings are desirable to prevent or greatly reduce the formation of a fine tailings zone. This study investigated the use of lime and sulphuric acid to prevent segregation of the tailings stream. Two batches of Syncrude tailings were tested. These averaged 48 and 55% solids and 17% fines (< 44 μm). The hindered settling and consolidation properties of nonsegregating mixes were determined using large-diameter standpipe and slurry consolidation cells. Nonsegregating mixes were achieved by adding 600–800 ppm CaO, based on total weight, or 7.5–10 mL/L of 10% H2SO4, based on the total volume of tailings. Predictions of field performance using a finite strain consolidation program indicate that a deposition rate of up to 20 m/year of treated total tailings is possible, depending upon the simultaneous degree of consolidation desired. The discovery of nonsegregating mixes with sufficient self-draining capability opens many options to address this important waste-management problem. Key words : oil sand tailings, nonsegregating, hindered settling, consolidation, permeability, laboratory.
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Du, Y. Q., B. Xie, B. Mullarney y C. Zhang. "Deposition of Fine Tailing Particles and Profile Zoning Of Tailings Dams". Soil Mechanics and Foundation Engineering 56, n.º 5 (noviembre de 2019): 359–65. http://dx.doi.org/10.1007/s11204-019-09615-5.
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Chen, Wenzhao, Kai Yang, Jiaqing Fan, Xiqi Liu y Xiaoqing Wei. "Experimental study on acidification effect of tailing sand". E3S Web of Conferences 248 (2021): 01048. http://dx.doi.org/10.1051/e3sconf/202124801048.
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Sulfide minerals (mainly FeS2) contained in lead-zinc tailings are easy to be acidified in the air. The acidification mechanism is that the tailing sand generates sulfuric acid and sulfate under the catalysis of oxidant, water and oxygen. The acidic liquid generated by the reaction will continue to react with metal oxides to form an insoluble precipitate.In order to reveal the corresponding changes of chemical properties and physical properties of lead-zinc tailing sand during acidification, a series of reaction processes of tailings under natural conditions were simulated by immersion test in laboratory.It is found through the test that with the deepening of acidification, the coarse particles of tailing sand dissolve, resulting in the decrease of iron concentration in the compound, the increase of fine particles, the increase of specific surface area, the decrease of surface friction and occlusion friction between particles, resulting in the decrease of internal friction angle, and the decrease of the safety of tailings dam. words.
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Yang, Xiaojuan, Miguel de Lucas Pardo, Maria Ibanez, Lijun Deng, Luca Sittoni, Ania Ulrich y Qun Chen. "Improving engineering properties of mature fine tailings using Tubifex". Canadian Journal of Civil Engineering 47, n.º 7 (julio de 2020): 812–21. http://dx.doi.org/10.1139/cjce-2019-0028.
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The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.
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Wu, Hui, Wen Ni y Chang Long Wang. "Effect of Hydraulic Classification on Iron Ore Tailings Preparing High Strength Construction Materials". Advanced Materials Research 800 (septiembre de 2013): 330–35. http://dx.doi.org/10.4028/www.scientific.net/amr.800.330.
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The aim of this study is to understand the effect of hydraulic classification on the iron ore tailings, and develop the cementitious activity of tailings to prepare construction materials. It was indicated that hydraulic classification can effectively divide the particulates of tailings into coarse and fine powders. The compression strength of the prepared construction materials are 87.83 MPa at 28 days, which have higher strength than the construction materials using original tailing, The variation in the tailings samples after hydraulic classification and the cementitious material after step-milling was characterized by sieve analysis, complete chemical analysis, scanning electron microscopy (SEM), and the particles size distribution. By mechanical properties testing and microstructure analysis shows that after hydraulic classification of tailings under the same conditions, the strength of the 3 days, 7 days, 28 days are higher than that of the original tailings. The main phases in the system are the rod of ettringite and low crystallinity or the amorphous C-S-H gel, and residual Ca(OH)2.
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Wijewickreme, Dharma, Maria V. Sanin y Graham R. Greenaway. "Cyclic shear response of fine-grained mine tailings". Canadian Geotechnical Journal 42, n.º 5 (1 de octubre de 2005): 1408–21. http://dx.doi.org/10.1139/t05-058.
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The mechanical response of three different types of fine-grained mine tailings is examined using data from constant-volume cyclic direct simple shear (DSS) tests. Under cyclic DSS loading, fine-grained tailings typically exhibit a cumulative decrease in effective stress along with progressive degradation of shear stiffness. The observed shear strain development due to cyclic mobility is similar in form to that of the previously observed cyclic shear response for natural silts. The cyclic resistance ratio (CRR) of laterite tailings is observed to increase with an increase in the initial effective confining stress (σ′vc). For this material, the dilative tendency due to stress densification seems to have overridden the contractive tendency due to the increase in confining stress. In contrast, the CRR of coppergoldzinc tailings is insensitive to the initial effective confining stress, suggesting a response similar to that of normally consolidated clay. The postcyclic maximum shear strength ratio (Su-PC /σ′vc) obtained from constant-volume monotonic DSS tests is noted to increase with a decrease in the void ratio. For the fine-grained tailings considered in this study, the liquefaction susceptibility predicted using commonly used empirical criteria is not always in agreement with the liquefaction triggering determined from cyclic DSS tests.Key words: tailings, liquefaction, cyclic stress ratio, postcyclic shear strength, direct simple shear testing.
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Gui, Rong, Yu-xiang Pan, De-xin Ding, Yong Liu y Zhi-jun Zhang. "Experimental Study on the Fine-Grained Uranium Tailings Reinforced by MICP". Advances in Civil Engineering 2018 (17 de octubre de 2018): 1–10. http://dx.doi.org/10.1155/2018/2928985.
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Sporosarcina Pasteurii was chosen for the experiment to study the effect and mechanism of fine-grained uranium tailings reinforced by MICP. The biochemical characteristics of strains and microbial immobilization in uranium tailings were analyzed. The results showed that the CaCO3 production rate is positively correlated with the physiological activity of Sporosarcina Pasteurii and the concentration of calcium sources, and the higher the solution concentration of CaCl2, the lower the discharge rate of bacterial liquid from the sand column, but high concentration of CaCl2 solution will affect the uniform distribution and migration of bacteria in the uranium tailings. After 16 days, the direct shear was used to test the reinforcement effects of fine-grained uranium tailings by MICP. The cohesive force and the internal friction angle of fine-grained uranium tailings were increased by 140.1% and 46.7%. The production amount of CaCO3 is 138.89 kg/m3. The results showed that the MICP-reinforced technology can effectively improve the shear strength of the uranium tailings, and the experiment provides a new method for the reinforcement of the fine-grained uranium tailings dam.
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Holowenko, Fervone M., Michael D. MacKinnon y Phillip M. Fedorak. "Methanogens and sulfate-reducing bacteria in oil sands fine tailings waste". Canadian Journal of Microbiology 46, n.º 10 (1 de octubre de 2000): 927–37. http://dx.doi.org/10.1139/w00-081.
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In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd. lease near Fort McMurray, Alta., has gone methanogenic. Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane. As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of this and other settling basins may affect the performance of these settling basins and impact reclamation options. Enumeration studies found methanogens (105-106MPN/g) within the fine tailings zone of various oil sands waste settling basins. SRB were also present (104-105MPN/g) with elevated numbers when sulfate was available. The methanogenic population was robust, and sample storage up to 9 months at 4°C did not cause the MPN values to change. Nor was the ability of the consortium to produce methane delayed or less efficient after storage. Under laboratory conditions, fine tailings samples released 0.10-0.25 mL CH4(at STP)/mL fine tailings. The addition of sulfate inhibited methanogenesis by stimulating bacterial competition.Key words: fine tailings, methanogens, sulfate-reducing bacteria, methane, oil sands.
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Li, Shibo, Hao Liang, Hao Li, Jianquan Ma y Bin Li. "Minimum Void Ratio Model Established from Tailings and Determination of Optimal Void Ratio". Geofluids 2021 (2 de septiembre de 2021): 1–15. http://dx.doi.org/10.1155/2021/8619121.
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Minimum void ratio of tailings and its value change with fine content and are key design parameters for tailing consolidation and seepage stability. Based on the distribution of tailing grains with the sedimentary beach, we establish a minimum void ratio model for tailing grain in binary size, which requires only two parameters ( ε and ω ). Calibrations of the model using 168 groups of tests (22 kinds of grain size ratios with 7-9 kinds of fine contents) show two parameters that are fitting for power function, and the exponent values increase with the dominant grain size expanded. Besides, the exponent values are related to the equivalent grain size ratio, dominant grain size, and shape characteristics. The minimum void ratios with fine content are predicted under the derived model. Good agreement was obtained between the predictions and measurements, and the average discrepancies are less than 10%. And optimal void ratio and optimal fine content can be predicted, and the values are in good agreement with the experimental ones. Furthermore, based on the predicted optimal void ratio, the exponential relationship between the optimal void ratio and the equivalent grain size ratio may have no influence on the derived dominant grain size and shape characteristics. For tailings, further work is needed to verify if the derived exponential relationship between the optimal void ratio and the equivalent grain size ratio is valid.
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Wilson, G. Ward, Louis K. Kabwe, Nicholas A. Beier y J. Don Scott. "Effect of various treatments on consolidation of oil sands fluid fine tailings". Canadian Geotechnical Journal 55, n.º 8 (agosto de 2018): 1059–66. http://dx.doi.org/10.1139/cgj-2017-0268.
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Regulatory policy and regulations in Alberta require oil sands companies to reduce their production and storage of fluid fine tailings by creating deposits that can be reclaimed in a timely manner. To meet the regulatory requirements, some companies are adding flocculants to the fluid fine tailings and then using thickeners, inline flocculation or centrifuges to increase the solids content. Freeze–thaw and drying processes are then used to further dewater the tailings. The effects of flocculating, thickening, and freeze–thaw treatments were investigated by performing large-strain consolidation and shear strength tests on these treated fluid fine tailings. The consolidation and shear strength results were then compared with those of untreated fluid fine tailings. All of the treatments increased the hydraulic conductivity of the fluid fine tailings to some degree, but had little to no effect on the compressibility and shear strength. The effects of the treatment processes are discussed and evaluated.
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Sworska, A., J. S. Laskowski y G. Cymerman. "Flocculation of the Syncrude fine tailings". International Journal of Mineral Processing 60, n.º 2 (septiembre de 2000): 143–52. http://dx.doi.org/10.1016/s0301-7516(00)00012-0.
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Sworska, A., J. S. Laskowski y G. Cymerman. "Flocculation of the Syncrude fine tailings". International Journal of Mineral Processing 60, n.º 2 (septiembre de 2000): 153–61. http://dx.doi.org/10.1016/s0301-7516(00)00013-2.
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Zhu, Yeling, Yuki Gong, Heather Kaminsky, Michael Chae, Paolo Mussone y David C. Bressler. "Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management". Materials 14, n.º 7 (24 de marzo de 2021): 1582. http://dx.doi.org/10.3390/ma14071582.
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Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.
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Beier, Nicholas, Ward Wilson, Adedeji Dunmola y David Sego. "Impact of flocculation-based dewatering on the shear strength of oil sands fine tailings". Canadian Geotechnical Journal 50, n.º 9 (septiembre de 2013): 1001–7. http://dx.doi.org/10.1139/cgj-2012-0262.
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The oil sands in northern Alberta have been mined to produce bitumen over the past five decades. Since the 1980s, technical advances have been made in mining, material handling, and bitumen extraction. However, acquiring practical methods to control and reduce the fluid fine tailings build-up has been an ongoing challenge. Recent regulatory changes have driven the industry to review current tailings-management techniques and investigate numerous alternative technologies and processes to manage and reclaim fine tailings. Many of these fine tailings–management techniques involve some form of polymer or chemical addition to promote dewatering and strength gain to meet the regulatory requirements. Based on the reported data, the chemically amended fine tailings deposits have the characteristics of sensitive, metastable deposits, necessitating additional mitigative measures by oil sands operators beyond the regulatory requirements. This paper explores the geotechnical aspects of meeting regulatory strength performance criteria by employing flocculation-based dewatering of fluid fine tailings.
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Huang, Ming Qing, Xiao Hui Liu y Hai Yong Cheng. "Experiments and Optimization of Mix Proportions for Cement Paste Backfill Materials with Extra-Fine Unclassified Tailings". Key Engineering Materials 744 (julio de 2017): 146–51. http://dx.doi.org/10.4028/www.scientific.net/kem.744.146.
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To produce effective cement paste backfill materials at iron mines technologically and economically, orthogonal experiments of mix proportions with extra-fine unclassified tailings were carried out. The results of the range analysis showed that the sensitivity of influential factors to the slurry slump is sequentially mass concentration, tailing/rock ratio, and cement/(tailing+rock) ratio. The sensitivity to bleeding rate, concretion time and 28-day uniaxial compressive strength is sequentially mass concentration, cement/(tailing+rock) ratio and tailing/rock ratio. Relationships of paste properties and influential factors can be demonstrated with regression analysis. Additionally, the optimal mix proportion for cement paste backfill was obtained with 78% mass concentration, 7:3 tailing/rock ratio and 1:25 cement/(tailing+rock) ratio. The slump, bleeding rate, concretion time and R28 of the optimal mixture are 25.2 cm, 8.77%, 20.9 h and 1.29 MPa, respectively. The experimental results show a feasible way to produce the industry standard backfilling materials.
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Jing, Xiaofei, Changshu Pan, Yulong Chen, Xiangfu Li, Wensong Wang y Xu Hu. "Improvement Effect of Reticular Glass Fibers on the Mechanical Properties of Tailings Sand with the Lenticle (Layered Sandy Soil)". Water 13, n.º 10 (15 de mayo de 2021): 1379. http://dx.doi.org/10.3390/w13101379.
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Glass fiber is a kind of polymer, which can effectively improve the mechanical properties of sand. However, the improvement effect of glass fibers with a reticular structure is different from that of ordinary fibers. At the same time, the sandy soil structure is diversified and part of the soil is layered, such as the lenticle in tailings dam, which often forms layered sandy soil with nearby tailings sand. The existence of the lenticle has adverse effects on the stability of the tailings dam. In order to study the reinforcement effects of reticular glass fibers on tailing sand with the lenticle (layered sand), a series of triaxial shear tests were carried out on the tailings sand by changing the layers of reticular glass fibers and the position of reinforcement. The results demonstrated the following five main points: (1) the shear strength of the tailings with the lenticle is significantly lower than the shear strength of the tailings fine sand, and the influence of the lenticle on the shear strength of the tailings is mainly concentrated on the cohesion. (2) When the reticular fiber is added to the tailings with the lenticle, the cohesion of the sample increases nonlinearly with the increase of the number of fiber layers, while the internal friction angle is basically unchanged. (3) The improvement effect of the reticular fiber on the shear strength of the sample varies with the position of the reinforcement, which is represented as the interface > tailings fine sand > lenticle. (4) Only when the axial strain develops to a certain extent, the reinforcement of the reticular fibers is reflected. (5) The reinforcement effects of reticulated fibers are determined by the interaction of forces at the interface between fibers and sand. The research results can not only provide a scientific basis for the construction of reinforced tailings dam, but also play a guiding role in disaster prevention and mitigation work of reinforced slopes with a weak zone, and even provide the reference for the reinforcement research of layered structures.
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Cihangir, Ferdi y Yunus Akyol. "Effect of Desliming of Tailings on the Fresh and Hardened Properties of Paste Backfill Made from Alkali-Activated Slag". Advances in Materials Science and Engineering 2020 (8 de junio de 2020): 1–11. http://dx.doi.org/10.1155/2020/4536257.
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Cemented paste backfill (CPB) allows environmental friendly management of potentially hazardous tailings generated from milling of nonferrous metal sulphide ores by placing such tailings into the underground mined-out openings. The components of CPB are tailings, water, and binders. These components significantly affect the physicomechanical, workability, and geotechnical properties of CPB. Ordinary Portland cement (OPC) is the commonly used binder for CPB operations. The effects of the tailings characteristics and OPC are extensively studied in the study area. The beneficial effect of the use of alkali-activated slags (AASs) on the mechanical and durability properties of CPB of sulphide-rich tailings has been recently reported. Therefore, this study especially focused on the effect of desliming of the tailings on the workability properties of sulphide-rich tailings CPB containing AAS besides hardened properties. In this scope, the water-retention capacities of full (FT) and deslimed tailings (DT) and the workability characteristics of CPB mixtures were studied. DT was found to decrease the water-retention capacity, leading to denser CPB mixtures. In addition, DT-AASs usage produced no adverse effect on the workability of fresh CPB materials. LSS-S (slag activated with liquid sodium silicate) improved the flowability of CPB mixtures owing to its dispersant effect. Desliming also modified the tailing properties by removing fine particles and improved the main geotechnical parameters of CPB.
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Lebedok, A. V., A. S. Kurtukov, I. S. Cheburashkin y L. Markworth. "Efficiency Assessment of Allflot Pneumatic Flotation Machines in Beneficiation Slime Fraction of Old Tailings at Norilsk Processing Plant". Mining Industry Journal (Gornay Promishlennost), n.º 3/2021 (20 de julio de 2021): 98–104. http://dx.doi.org/10.30686/1609-9192-2021-3-98-104.
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The article presents a rational technology for processing old tailings and slime (cyclone overflows) of the -25+0 microns class at tailing dump No. 1 of the Norilsk Processing Plant. One of the current and urgent problems is the lack of an efficient technology to process the slime part of old tailings with fine particles of useful metals, which is not processed and is transferred to temporary tailing dump. Current development state of the flotation equipment and technologies allows to consider the problem of coarse-size particle flotability generally solved. The results of pilot testing of the Allflot pneumatic flotation cell that operates at the 5% content of solids in the slime at Nordinves LLC are presented. Comparative materials are provided on the Allflot re-treatment slurry flotation cell (500 l) and a laboratory mechanical machine (1.5 l). The results of qualitative and quantitative calculations of the flotation process as applied to the slime fraction of old tailings are given. Conclusions about the economic feasibility of using the Allflot Pneumatic Flotation Machine for slime beneficiation are made.
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Zhang, Guo Dong, Xiu Zhi Zhang, Zong Hui Zhou y Xin Cheng. "Preparation and Properties of Concrete Containing Iron Tailings/Manufactured Sand as Fine Aggregate". Advanced Materials Research 838-841 (noviembre de 2013): 152–55. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.152.
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High performance concrete was prepared by using iron tailings mixed with manufactured sand. Effects of the content of iron tailings on the performance of concrete were studied. The results show that the slump of concrete containing iron tailings is equal to concrete with river sand when the content of iron tailings is 60%. With the increase of the content of iron tailings, compressive strength of concrete shows a trend of decrease at same age; meanwhile drying shrinkage decreases and is less than the concrete prepared river sand. After 200 times of freeze-thaw cycle, mass loss of concrete with mixed sand is less than 5% and compressive strength loss is less than 25% which are close to concrete with river sand.
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Deng, Daiqiang y Guodong Cao. "Flocculation Settling Characteristics of Ultra-Fine Iron Tailings with Rich Gypsum". Advances in Civil Engineering 2021 (17 de marzo de 2021): 1–12. http://dx.doi.org/10.1155/2021/6671704.
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Because of the uniqueness of geological mineralization, tailings obtained from Chenchao Iron Mine have low SiO2 content of only 27.80%. Content of Al2O3 and MgO is 13.31% and CaSO4 is 22.09%. The fineness modulus of the ores is large enough for convenient mineral separation, thus resulting in 16.03% −5 μm particles and 27.76% −10 μm particles in the tailings, respectively. The average particle size is only 69.36 μm; it belongs to the category of very fine tailings. The natural sedimentation of tailings is extremely slow due to the comprehensive effects of their physical and chemical properties. Hence, sedimentation tests using four types of flocculating agents are conducted to accelerate the sedimentation of the tailings of Chenchao Iron Mine. Compared with natural sedimentation, the flocculating sedimentation is considerably quicker. Among the four flocculants, the sedimentation of sample using the special BASF flocculant is the fastest. When the tailings of 1 ton add this flocculant of 20 g, the maximum settling concentration reaches 60.98% after 40 min and its special gravity is 1.577 g/cm3, thus it fulfills future requirements of filling technologies. As the largest iron mine in the mid-southern region of China, Chenchao Iron Mine must turn to filling mining. This study can provide technological support for goaf management and environment-friendly treatment of solid waste in the Yangtze River basin, which plays important roles in ecological protection.
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Jeeravipoolvarn, S., J. D. Scott y R. J. Chalaturnyk. "10 m standpipe tests on oil sands tailings: long-term experimental results and prediction". Canadian Geotechnical Journal 46, n.º 8 (agosto de 2009): 875–88. http://dx.doi.org/10.1139/t09-033.
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Three large 10 m high standpipe tests were set up at the University of Alberta in 1982 to simulate large-scale compression behavior of oil sands tailings in a controlled environment. The objectives of the tests were to study material behavior and to provide consolidation performance for theoretical verification. Three tailings materials (fine tailings and two mixes of fine tailings and sand) were used. Test results showed that the fine tailings, standpipe 1, strained more than 30% over a 25 year monitoring period by self-weight with very little to no effective stress developing, while the mix of fine tailings and sand, standpipe 3, compressed with a significant effective stress development. The tailings in standpipe 1 can be regarded as a class of material where a reduction in volume is not governed by a unique relationship between effective stress and void ratio, whereas the tailings in standpipe 3 can be categorized as slurry with conventional behavior. To investigate the capability of the finite strain consolidation theory on these tailings, a numerical model with appropriate material constitutive relationships was developed and used to make predictions. Numerical results, compared with the performance of the standpipe tests, indicated that the theory overestimated the compression behavior of the standpipe 1 material, but it could predict the standpipe 3 consolidation behavior.
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Suthaker, N. N. y J. D. Scott. "Consolidation Behavior of Oil Sand Fine Tailings". Journal American Society of Mining and Reclamation 1994, n.º 4 (1994): 399–406. http://dx.doi.org/10.21000/jasmr94040399.
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Emerson, WW, CT Hignett y DA Thomas. "Physical limitations to plant growth on tailings from sandy alluvium". Soil Research 30, n.º 5 (1992): 807. http://dx.doi.org/10.1071/sr9920807.
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It is proposed to rework surface alluvium derived from earlier mining of gold-bearing quartz. After grinding and extraction, tailings would be pumped back into the excavation as a thick slurry. In pot trials of the tailings in winter, it was found that oats failed to establish despite fertilizer addition. To find the reason for this, the particle size distribution, water retention, bulk density, ease of dispersion and hydraulic conductivity of tailings and the starting alluvium were compared. Also tailings were slowly dried in stages and, at each stage, the increase in cone penetrometer resistance was measured. The penetration resistance of tailings was found to be proportional to matric suction and independent of whether the alluvium was ground coarse or fine. The effect of reduced particle size is compensated for by the decrease in bulk density. The suction required to initiate air entry into tailings is greater than the depth of tailings used in the pot trial, so that aeration would have been inadequate. Further, in the case of tailings resulting from fine grinding, when 10% of the volume of the wet tailings has drained to give adequate aeration, the penetration resistance is already 2.5 MPa, too high for root penetration. It is deduced that none of the water present is available for plant growth. After coarse grinding only, there is a small amount of available water. Possible ways of improving conditions for plant growth on the tailings are briefly discussed.
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Gan, Deqing, Xi Yang y Yunpeng Zhang. "Experimental Analysis on Permeability Characteristics of Iron Tailings". Mathematical Problems in Engineering 2019 (28 de marzo de 2019): 1–11. http://dx.doi.org/10.1155/2019/6539846.
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The permeability characteristics of iron tailings are one of the important factors affecting the stability of the tailings dam. The permeability properties of undisturbed iron tailings and disturbed iron tailings were analyzed from various aspects such as FC value, gradation, particle size, specific surface area, and interparticle void ratio with water head test in laboratory. The results show that the permeability coefficients of undisturbed iron tailings and disturbed iron tailings are affected by the fine particles content (FC). The threshold of fine content is about 40%. The traditional formulas for calculating the permeability coefficient are applied. But the results are inaccurate. The relationship between permeability coefficient of the iron tailings (undisturbed iron tailings and disturbed iron tailings) and the nonuniform coefficient (Cu), the curvature coefficient (Cc), the average particle size, the weighted average particle size, the specific surface area, and the skeleton void ratio (es) is nonlinear. It is difficult to characterize the change of permeability coefficient when the fine content is large. However, the relationship between permeability coefficient of the iron tailings (undisturbed iron tailings and disturbed iron tailings) and the effective particle size and silt particles void ratio (ef) is linear. A formula was developed for the determination of permeability coefficient of iron tailings by analyzing the effective particle size and silt particles void ratio. And it is more accurate. The permeability coefficients of disturbed samples are slightly larger than the permeability coefficients of undisturbed sample. This is due to the destruction of the sedimentary structure of the tailings and increasing e. Maybe the R in the new formula is affected by the structure of iron tailings. This requires further research.
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Penner, Tara J. y Julia M. Foght. "Mature fine tailings from oil sands processing harbour diverse methanogenic communities". Canadian Journal of Microbiology 56, n.º 6 (junio de 2010): 459–70. http://dx.doi.org/10.1139/w10-029.
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Processing oil sands to extract bitumen produces large volumes of a tailings slurry comprising water, silt, clays, unrecovered bitumen, and residual solvent used in the extraction process. Tailings are deposited into large settling basins, where the solids settle by gravity to become denser mature fine tailings (MFT). A substantial flux of methane, currently estimated at ~40 million L/day, is being emitted from the Mildred Lake Settling Basin. To better understand the biogenesis of this greenhouse gas, the methanogenic consortia in MFT samples from depth profiles in 2 tailings deposits (Mildred Lake Settling Basin and West In-Pit) were analyzed by constructing clone libraries of amplified archaeal and bacterial 16S rRNA genes. The archaeal sequences, whose closest matches were almost exclusively cultivated methanogens, were comparable within and between basins and were predominantly (87% of clones) affiliated with acetoclastic Methanosaeta spp. In contrast, bacterial clone libraries were unexpectedly diverse, with the majority (~55%) of sequences related to Proteobacteria, including some presumptive nitrate-, iron-, or sulfate-reducing, hydrocarbon-degrading genera (e.g., Thauera, Rhodoferax, and Desulfatibacillum). Thus, MFT harbour a diverse community of prokaryotes presumptively responsible for producing methane from substrates indigenous to the MFT. These findings contribute to our understanding of biogenic methane production and densification of MFT in oil sands tailings deposits.
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Yuan, Zhi Tao, Lei Liu y Yue Xin Han. "Wet Pre-Concentration of Low-Grade Hematite in High-Pressure Grinding Roller". Advanced Materials Research 454 (enero de 2012): 363–68. http://dx.doi.org/10.4028/www.scientific.net/amr.454.363.
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The wet pre-concentration of comminuted hematite in high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium in a high gradient magnetic separator. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of pre-concentration in different size feeds are emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased and the BMFI increased, the tailings grade and the tailings yield reduced, but the concentrates recovery raised. This variation was regardless of the feed size distribution. After the classifying pre-concentration, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. Compared with the classifying pre-concentration, the full size pre-concentration produced a concentrate with a lower grade only increased by 6.61 percentage points and the higher recovery of 92.32%. The tailings, with a lower yield of only 26.62% and a lower grade of 7.39%, was mainly produced from the fine feed. The coarse feed in the full size pre-concentration was not separated effectively.
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Rivera-Santillán, R. E. y V. Becerril-Reyes. "Comparison of the Bioleaching Effect of Mesophilic (35°C) and Thermophilic (45°C) Bacteria on the TIZAPA Tailings". Advanced Materials Research 20-21 (julio de 2007): 34–37. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.34.
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The exploitation of mineral deposits generates large amounts of wastes such as fine size particles, known as tailings. Mine wastes are characterized by the presence of pyrite, pyrrotite, galene, sphalerite, chalcopyrite and arsenopyrite. One of the most important environmental problems derived from the treatment and disposition of mining tailings is acid mine drainage (AMD) which results from the oxidation of the sulfurous minerals contained in these tailings. The acid generated is produced by a series of complex chemical reactions; the production rate is controlled by leaching microorganisms, which are present mining processes. In this work the bioleaching kinetics of heavy metals such as Cu, Fe, Zn, Cd, Pb, Ni and As, from a Tizapa tailing sample in presence of mesophilic and moderately thermophilic bacteria were studied and compared. The microorganisms used in this work were previously adapted to the tailing sample by the conventional method of successive steps. The percentage of dissolution of heavy metals at 45°C was smaller than at 35°C and the value of parameters such as redox potential and bacterial growth increased with temperature. Bioleaching studies were compared with the corresponding control systems.
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He, Shu Ming, Hai Yun Xie, Ya Xiong Jiang y Xiong Tong. "Study on Flocculation and Sedimentation of Fine and High-Silicon Bauxite Tailings". Advanced Materials Research 610-613 (diciembre de 2012): 2246–50. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.2246.
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the influence rules for the settlement of tailings from bauxite direct flotation were investigated under the different pulp pH and dosage of inorganic flocculants(such as Al2(OH)nCl6-n, Al2(SO4)3) and organic flocculants(nonionic polyacrylamide(080), cationic polyacrylamide(603), anionic polyacrylamide(JB-TR782)). The results show that surface static potential of particles is the key effect factor for the settlement of tailings. The good settlement of tailings can be obtained with adding a little dosage of flocculants when pH was kept at about 7.0, 080 and 603 can increase the sedimentation rate in the alkaline pulp evidently, the organic flocculants can do as well. The combination of Al2(SO4)3 and 080 could produce good sedimentation results for tailings and the dosage of Al2(SO4)3 and 080 can be decreased as well, so it has an application prospect.
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Dean, Courtney, Sumi Siddiqua y Deborah June Roberts. "Geotechnical properties of polymer-amended tailings solvent recovery unit (TSRU) oil sands tailings". Canadian Geotechnical Journal 54, n.º 9 (septiembre de 2017): 1331–39. http://dx.doi.org/10.1139/cgj-2016-0028.
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Fine tailings from the tailings solvent recovery unit (TSRU) in the Athabasca oil sands are known to contain a relatively high pyrite content and a high residual hydrocarbon content, which may alter their geotechnical properties. Little is known about TSRU tailings properties and therefore the potential for subaerial deposition. The goal of this study was to investigate the geotechnical properties of untreated, polymer-amended, and sand-mixed TSRU tailings to provide information for the consideration of subaerial deposition and increase the general knowledge about these unique tailings. The polymer-amended tailings had more desirable properties for subaerial deposition, including a lower final void ratio, less energy required to desaturate, and higher compressibility, when compared with the untreated tailings. The sand-mixed samples enhanced these properties, but may pose issues for transportation. The mineralogy indicated that the polymer-amended TSRU tailings have a high-enough pyrite content for acid generation, which may pose environmental issues for subaerial deposition. Overall, TSRU tailings exhibited different geotechnical properties when compared with the well-studied mature fine tailings, highlighting the need for further studies to provide information for the management of TSRU tailings.
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Gou, Mifeng, Longfei Zhou y Nathalene Wei Ying Then. "Utilization of tailings in cement and concrete: A review". Science and Engineering of Composite Materials 26, n.º 1 (28 de enero de 2019): 449–64. http://dx.doi.org/10.1515/secm-2019-0029.
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AbstractOne of the advantages of cement and the cement concrete industry in sustainability is the ability to utilize large amounts of industrial solid wastes such as fly ash and ground granulated blast furnace slag. Tailings are solid wastes of the ore beneficiation process in the extractive industry and are available in huge amounts in some countries. This paper reviews the potential utilization of tailings as a replacement for fine aggregates, as supplementary cementitious materials (SCMs) in mortar or concrete, and in the production of cement clinker. It was shown in previous research that while tailings had been used as a replacement for both fine aggregate and cement, the workability of mortar or concrete reduced. Also, at a constant water to cement ratio, the compressive strength of concrete increased with the tailings as fine aggregate. However, the compressive strength of concrete decreased as the replacement content of the tailings as SCMs increased, even whentailings were ground into smaller particles. Not much research has been dedicated to the durability of concrete with tailings, but it is beneficial for heavy metals in tailings to stabilize/solidify in concrete. The clinker can be produced by using the tailings, even if the tailings have a low SiO2 content. As a result, the utilization of tailings in cement and concrete will be good for the environment both in the solid waste processing and virgin materials using in the construction industry.
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Batista, Raquel P., Juliana O. Costa, Paulo H. R. Borges, Flávio A. Dos Santos y Fernando S. Lameiras. "High-performance alkali-activated composites containing an iron-ore mine tailing as aggregate". MATEC Web of Conferences 274 (2019): 02004. http://dx.doi.org/10.1051/matecconf/201927402004.
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High-performance cementitious composites have been developed to overcome the brittleness of mortars and concretes, thus improving the deformation and toughness of these materials under flexion and tension. Poli Vinyl Alcohol (PVA) fibres are employed in the production of such “Engineered Cementitious Composites” - ECC; the PVA fibres have a loadcarrying capacity after the first crack (matrix failure), which changes the mechanical behaviour of the composites from brittle to ductile and significantly increases the ultimate strength. This deflection or strain-hardening behaviour is accompanied by a multiple cracking of the composites, which results from the design of a proper formulation, with correct amount of PVA fibres (usually 2% vol. fraction) and employment of a very fine sand (passing 0.6 mm). Recent developments in the area of ECC comprise the replacement of Portland cement (PC) matrices with alkali-activated materials (AAM). The idea is to produce composites with similar performance but with improved chemical durability and lower environmental impact. A more sustainable solution would consider the replacement of the fine sand with mine tailings in the production of ECC-AAM. Some tailings from the iron-ore mining activities in Brazil are significantly finer than those aggregates used for PC mortars and concretes; therefore, they cannot be employed in traditional PC-based materials. Nevertheless, those fine materials could replace the fine natural aggregate used in the production of ECC. This paper investigates the replacement of a natural quartz sand with an iron-rich mine tailing in PVA-reinforced AAM. Four composites were studied from a combination of two different matrices and 2 different aggregates. The matrices were obtained from the alkaline activation of metakaolin (MK) with sodium silicate (Na2SiO3) and sodium hydroxide (NaOH); silica fume (SF) was used to adjust their composition: SiO2 / Al2O3 molar ratio equal to 3.0 or 3.8. The aggregates used were either natural quartz (passing 0.6 mm) or tailings produced during the mining activities of iron ore in the state of Minas Gerais, Brazil. The mine tailing studied is much finer than the natural sand (passing 0.3 mm) but it was used as received in the production of ECC-AAM. The aggregate to binder ratio was kept constant (equal to 1.0 in mass) irrespective of the type of aggregate. All mortars were reinforced with 2% vol. of PVA fibres; extra water was added to the mixes to maintain the same consistency for the composites. The mechanical properties investigated are compressive strength, flexural strength and toughness. The apparent dry density of the mortars was also assessed. The preliminary results presented in this paper indicate that iron-rich tailings may be effectively used in the production of ECC-AAM; however, durability tests are still necessary.
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Wang, Qi-Ang, Jia Zhang y Jiandong Huang. "Simulation of the Compressive Strength of Cemented Tailing Backfill through the Use of Firefly Algorithm and Random Forest Model". Shock and Vibration 2021 (7 de julio de 2021): 1–8. http://dx.doi.org/10.1155/2021/5536998.
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Cemented tailings backfill is widely used in worldwide mining areas, and its development trend is increasing due to the technical and economic benefits. However, there is no reliable and simple machine learning model for the prediction of the compressive strength. In the present study, the research process to use artificial intelligence algorithms to predict the compressive strength of cemented tailing backfill was conducted, overcoming the shortcomings of traditional empirical formulas. Experimental tests to measure the compressive strength of cemented tailing backfill were conducted to construct the dataset for the machine learning. Five input parameters (tailing to cement ratio, percentage of fine tailings, cement type, curing time, and solid to water ratio) were considered for the design of the laboratory tests. The firefly algorithm (FA) was used to tune the random forest (RF) hyperparameters, and it was adopted to combine the RF model to improve the accuracy and efficiency for the prediction of the compressive strength of the cemented tailing backfill. By comparing the predicted and actual results, the reliability and accuracy of the prediction model proposed are confirmed. Tailing to cement ratio and curing time are the two most important parameters to the compressive strength of the cemented tailing backfill.
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Lemos, Mariana, Teresa Valente, Paula Marinho Reis, Rita Fonseca, Itamar Delbem, Juliana Ventura y Marcus Magalhães. "Mineralogical and Geochemical Characterization of Gold Mining Tailings and Their Potential to Generate Acid Mine Drainage (Minas Gerais, Brazil)". Minerals 11, n.º 1 (31 de diciembre de 2020): 39. http://dx.doi.org/10.3390/min11010039.
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For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.
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Wang, Haijun. "Towards the Understanding of Damage Mechanism of Cemented Tailings Backfill". Advances in Civil Engineering 2021 (16 de septiembre de 2021): 1–10. http://dx.doi.org/10.1155/2021/4117209.
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Recent studies have shown that the damage characteristics of cemented tailings backfill (CTB) are influenced significantly by the variation of cement-tailings ratio, while the effects of other influencing factors remain unanswered. The CTB damage constitutive model, which takes the corrected coefficient of damage variable into consideration, and peak toughness are introduced to investigate the effects of fine tailings contents, curing ages, curing temperatures, and water-to-cement ratios ( w / c ) on the damage evolution laws, damage ( D P ), and specific energy ( G P ) at peak stress point of CTB. The results show that appropriate content of fine tailings could improve the compressive strength of CTB and reduce its damage evolution speed and D P . The damage growth rate of CTB decreases with curing age in early curing period and increases with higher curing temperature and w / c . D P of CTB takes on a descending trend with higher w / c and fine tailings content but shows an increase with curing age. There exists no significant relationship between D P and curing temperature. G P of CTB increases with curing age and higher curing temperature with a quadratic function but is on a decline with increases of fine tailings content and w / c with logarithmic and exponential function, respectively. The results obtained from our study have important application to the successful design of backfill structures in underground mines.
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Maksimova, V. V., E. A. Krasavtseva, V. A. Masloboev y D. V. Makarov. "Investigation of the solubility of dust particles in soil solution at different temperatures (on the example of the tailings of the loparite ores' concentration)". Vestnik MGTU 24, n.º 1 (31 de marzo de 2021): 107–17. http://dx.doi.org/10.21443/1560-9278-2021-24-1-107-117.
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A number of large mining enterprises are located on the territory of the Murmansk region. Dusting overburden dumps and tailings storage sites leads to a complex of long-term consequences for the environment. The output of the silty fraction (-0.071 mm) of "stale" tailings of loparite ore dressing (the first field of the tailing dump) is about 22 %. The investigated material is represented by nepheline, microcline, aegirine; loparite, analcime are diagnosed in impurity quantities; the average content of cerium, lanthanum, neodymium - rare earth elements of the light group - 0.18, 0.03 and 0.015 %, respectively. In laboratory conditions, a simulation of the ingress of a fine fraction of loparite ore dressing tailings into the soil has been carried out; the interaction of tailings material with distilled water and water extract from conditionally background soil at different temperatures has been studied. In the course of the study, it has been found that the introduction of dissolved organic matter intensifies the processes of destruction and partial dissolution of the aluminosilicate matrix of rock-forming minerals; an intensive transition of rare earth elements and heavy metals into soluble forms has been recorded. The research results indicate the ecological danger of the finely dispersed material of "stale" tailings of loparite ore dressing due to the ingress of dust particles into the soil and their interaction with soil waters.
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Janštová, Sarah, Iva Janáková y Vladimír Čablík. "Leaching of Gold from Fine-grained Flotation Tailings". GeoScience Engineering 66, n.º 2 (junio de 2020): 117–20. http://dx.doi.org/10.35180/gse-2020-0036.
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Owolagba, John y Shahid Azam. "Geotechnical properties of centrifuged oil sand fine tailings". Environmental Geotechnics 2, n.º 5 (octubre de 2015): 309–16. http://dx.doi.org/10.1680/envgeo.13.00079.
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Islam, Shriful y Julie Q. Shang. "Electrokinetic thickening of mature fine oil sands tailings". Environmental Geotechnics 4, n.º 1 (febrero de 2017): 40–55. http://dx.doi.org/10.1680/envgeo.15.00008.
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Elliott, GRD, VA Munoz y RJ Mikula. "Bitumen Recovery from Oil Sands Mature Fine Tailings". Microscopy and Microanalysis 16, S2 (julio de 2010): 1226–27. http://dx.doi.org/10.1017/s1431927610061763.
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Suthaker, Nagula N. y J. Don Scott. "Thixotropic strength measurement of oil sand fine tailings". Canadian Geotechnical Journal 34, n.º 6 (1 de diciembre de 1997): 974–84. http://dx.doi.org/10.1139/t97-064.
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