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1.
A large quantity of by-product lime wastes with high water content produced from chemicals manufacturing processes has been stacked in an open area in Incheon, Korea. Highly alkaline leachate and fine dust emanating from the stacked lime wastes caused an environmental concern in the city. So evaporative drying and stabilization of the fine-grained wastes and use of the on site marine clay as a natural geomembrane liner using drying hardening were considered as a part of a landfill construction plan. Treatment of the lime wastes and marine clay was focused on maximizing the evaporative drying and the density. Evaporation experiments were conducted in field condition to understand evaporation characteristics and to evaluate actual evaporation rate of the lime wastes and marine clay. Local Class A pan evaporation data from a nearby weather station for last 30 years indicated that mean annual and monthly evaporations were 1,178.5 and 98.2 mm, respectively. Relative evaporations of the sludge lime, cake lime, and marine clay compared with the pan evaporation were 114.9, 61.9, and 119.0%, respectively. Estimates of annual evaporations from storage surfaces in the field based on the relative evaporation data were 1,353.6, 729.1, and 1,402.2 mm for the sludge lime, cake lime, and the marine clay, respectively. And annual net evaporations considering rainfall effect were estimated as between 879.9 and 1,082.9 mm for the lime sludge, between 473.9 and 583.3 mm for the lime cake, and between 981.5 and 1,191.9 mm for the marine clay. It was expected that the actual field evaporation rate would be varied with the moisture contents of the lime and the clay. Results of these experiments will provide useful implications for the drying behavior of the by-product lime and the marine clay and landfill or management plan of the storages. 相似文献
2.
A. Bascetin S. Tuylu O. Ozdemir D. Adiguzel M. Benzaazoua 《International Journal of Environmental Science and Technology》2018,15(2):281-288
Surface paste disposal method can be used to minimize environmental risks during storage of mine process tailings. There are some researches and industrial applications which prove success of the method. The surface paste disposal of mineral process tailings obtained from a Pb–Zn underground mine was simulated considering mine site conditions at laboratory scale in the study. The paste material was stored in the cabin/container layer by layer, and then, the cracks occurred after the paste formation of each layer were analyzed by image process. Meanwhile, leachate water collected from the bottom of the cabin was subjected to electrical conductivity (EC) analysis. Furthermore, the wetting–drying process was conducted to simulate the climatic conditions of the region. Additionally, some physical and geochemical parameters such as matric suction, volumetric water content, and oxygen consumption of the paste material were obtained using sensors displaced into different layers. The results of the crack analysis for each layer showed that the cracks intensity increased at lower layers. Moreover, the crack intensity and EC values of each layer showed a similar trend, and the crack intensity increased almost five times during the wetting–drying tests. The measured values of the parameters obtained from the tests indicated that the deposited paste material can be stabile during the deposition over the years under the climatic conditions of the region. 相似文献
3.
The evolution of pore-water and the composition of solid phases in the vadose zone of pyritic tailings was studied by means of unsaturated column experiments. Several columns of water-saturated mine tailings were dried during 125 days under controlled laboratory conditions. The columns were dismantled at four successive drying stages and the evolution of pore-water, mineralogy, water content and temperature was characterized.Sulfide and aluminosilicate minerals present in the waste dissolved, releasing sulfate and other solutes (mainly Fe, Zn, Cu, Al, Mg and Ca) to the pore-water. Evaporation caused a crust of efflorescent, water-soluble sulfates to develop over the complete top surface of the columns and into the pores of the underlying waste material. This crust, which has also been identified in the field, changed the hydraulic properties of the tailings and produced a decrease in the evaporation rate of the columns. Moreover, these water-soluble precipitates (mainly rozenite, szomolnokite, halotrichite, hexahydrite, mirabilite and gypsum) acted as temporary sinks for Cd, Pb, Co and Ni, which could be released to the surface run-off or the groundwaters during rainfall events under field conditions.Pore-water evolution was determined not only by geochemical processes (dissolution of sulfides and aluminosilicates, precipitation of secondary phases) but also by thermal and hydraulic processes. Progressive dilution was observed in the lower part of the columns. Dilution was caused by the thermally driven vapor flux from the top of the column to its colder bottom and subsequent condensation therein. This process, which may also occur in tailings under sub-arid climate, played a key role on the evolution of pore-water with increasing drying. 相似文献
4.
5.
古盐湖卤水温度对钾盐沉积的控制作用探讨 总被引：2，自引：0，他引：2
古盐湖卤水的温度对钾盐沉积的控制作用的定量研究是钾盐成矿机理分析的重点和难点。本文分析和测试陕北盐盆奥陶系马家沟组、四川盆地三叠系嘉陵江组、云南兰坪-思茅盆地白垩系及老挝沙空那空盆地白垩系等八个含盐系的石盐岩中的流体包裹体,并利用均一温度计算了古盐湖的蒸发速率。若以老挝白垩纪时盐湖的蒸发速率为标准值100,陕北奥陶纪、四川三叠纪、云南白垩纪的蒸发速率标准值分别为54、68和90,而目前在老挝和云南白垩系都找到了一定规模的钾盐矿,因此高温(气温及水温)是盐湖成钾的有利条件,在卤水演化成钾的过程中可以起到重要的"催化"作用。 相似文献
6.
Large-strain consolidation theory has been used as the basis of a computer program for dealing with the problem of consolidation of slurried tailings. The work was carried out in the context of the gold-mining industry in Western Australia, where net annual evaporation rates are high (from about 3 to more than 4m/yr). Therefore, a simple, but effective, method of dealing with evaporation has been included in the model. The paper describes the model, and then uses it with some typical problems to illustrate its versatility and to show the complexity of the behaviour which can occur. 相似文献
7.
《Applied Geochemistry》2005,20(3):661-667
This paper describes the geochemical testing of mine tailings sourced from the Black Swan Ni Mine located near Kalgoorlie, Western Australia. Acid–base accounting was used to provide an indication of the acid generating capacity of two kinds of mining tailings: disseminated-ore tailings from the Cygnet Tailings Dam Storage Facility (CTDSF) and massive-ore tailings from the Silver Swan Tailings Dam Storage Facility (SSTDSF). All of the tailings in SSTDSF have acid generating potential which is consistent with previous research reports. New findings in this paper reveal that approximately 16% of the tailings in CTDSF have the potential to be acid generating. In contrast, previous reports state that the disseminated-ore tailings are classified as non-acid forming. Most of the potential acid generating tailings in the CTDSF are found in the upper-middle sections of the tailings profile, but some are located at the bottom of the tailings dam. The upper-middle section of the tailings is oxidized because these tailings have interacted with atmospheric O2 and rain and surface water. Oxidation of the bottom tailings in the CTDSF may be due to infiltration of ground water into hidden fractures under the east bank of CTDSF, which caused these tailings to oxidize under closed and reduced conditions.The acid drainage in the tailings dam storage facility was observed 3 a, after the development of the Black Swan Nickel project. This delayed production of acid drainage was likely due to the slow rates of acid neutralization provided by alteration gouge minerals such as Mg/Fe-carbonates (magnesite–siderite series) associated with the Ni ores. The acid drainage leaking from the tailings dams has contaminated neighboring ground water via increased acidity and heavy metals.Because of the potential acid generation in some of the disseminated ore tailings, it is inadvisable to use disseminated ore tailings as cover materials in the storage facility to isolate the underlying potentially-acid-forming tailings from O2 and water, as proposed by previous research reports. 相似文献
8.
沉积物岩芯的碳酸盐、石膏等蒸发盐含量和矿物组成的证据显示了新疆巴里坤湖末次间冰期以来一直是一个水位变化频繁的浅水盐湖,有时甚至为间歇式的湖泊,约在34000aB.P.前后巴里坤湖沉积相发生了显著的变化,34000aB.P.之前为泥坪-湖滨相沉积,34000aB．P．之后为成湖相沉积。尽管我们对巴里坤湖34000aB．P．前后的沉积相变难以理解,但是长期处于浅水状态的巴里坤湖沉积物中蒸发盐的含量和矿物组成仍然与气候变化密切相关。在泥坪-湖滨相形成的碳酸盐中白云石相对的增加是地表强烈蒸发的结果。以石膏为主的蒸发盐含量增加是温度和降水增加所致,而其含量减少则是冰川前进致使补给水矿化度降低造成的。这使我们获得了该区古气候变化并不服从于冰期与雨期同步模式的信息。 相似文献
9.
Time-of-flight laser-ionization mass spectrometry was applied to study the chemical composition of mineral particle surfaces
in a sulphide-rich mine-tailings impoundment. This surface-sensitive technique provides chemical information from surfaces
of irregularly shaped mineral particles (both conductive and insulators) less than 100 μm in diameter, which are considered
to be representative of particle surface coatings in the tailings pile (after drying). In addition, depth profiles in the
mineral particles were obtained. The combination of speed of analysis (1 min), small beam-diameter (2–4 μm), surface sensitivity
(2–10 nm), trace-element sensitivity, and capability to analyze rough surfaces makes this method useful as a complement to
studies of pore-water geochemistry and tailings mineralogy. As an example, the behavior of Pb and As in the Kidd Creek tailings
dam near Timmins, Ontario, Canada, was studied, using a combination of surface analyses, and pore-water geochemical data.
Received: 22 February 1995 / Accepted: 6 January 1996 相似文献
10.
A minesoil has developed over 5 years oxidative exposure on sulphide concentrate tailings (ca. 1 wt.% As) at the Macraes mesothermal gold mine, New Zealand. The minesoil has a dry crust which has formed due to evaporative drying. This dry crust is enriched in arsenic (ca. 5 wt.% As) as scorodite (FeAsO4·2H2O) because of upward mobility of dissolved arsenic during drying. Similar enrichment of arsenic has occurred along the walls of desiccation cracks which extend over 1 m into the minesoil. Capping of the tailings and minesoil with wet tailings (pH=8) results in dissolution of scorodite and remobilization of arsenic on the millimetre scale. Experimental capping of the minesoil with wet calcium carbonate remobilized some arsenic from scorodite on the centimetre scale, but much original arsenic enrichment was preserved after 400 days. A layer of gypsum (CaSO4·2H2O) and iron oxyhydroxide cementation developed at the interface between the minesoil and the experimental calcium carbonate cap, restricting water flow. This layer was ca. 1 mm thick after 400 days. Theoretical comparison between advection and diffusion in the minesoil suggests that diffusion is an important mechanism for chemical mobility on the 1–50-year time scale. However, advection can be important in secondary porosity of the dry crust of the minesoil and water penetrates this zone at a rate of 1.5 mm/day. 相似文献
11.
Drying of masonry specimens was monitored by means of a two-dimensional (2D) magnetic resonance imaging (MRI) technique. The
external surfaces stayed wet for longer if NaCl was present instead of pure water only. This corroborates many practical observations
that salts aggravate dampness in masonry. A slower evaporation process and not hygroscopicity was the cause. That suggests
that salt-induced dampness may, in general, arise simply from changes in the drying process of masonry materials. That also
implies that the height and depth at which crystallization occurs in walls may depend on the relative equilibrium humidity
(RHeq) and other properties of salts that influence drying of porous materials. Evaporation rates of free surfaces of pure
water and saturated NaCl solution were measured by a gravimetric technique. The results indicate that slow drying of salt-contaminated
materials is not due only to the lower RHeq of salt solutions. The effective surface of evaporation is likely to be reduced
perhaps due to blocking of pores by salt crystals. Final salt-distribution maps of the specimens show that: (a) salts may
affect the inner materials of the masonry, even in evaporation-induced processes that lead crystallization to occur predominantly
on the external surface; (b) distinct internal distribution patterns occur if masonry composition varies.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
12.
含水率影响下尾矿砂内摩擦角随标贯击数变化研究 总被引：1，自引：0，他引：1
尾矿砂样品在运输和存放过程中均存在易扰动的特点,但考虑到工程造价以及人力资源等因素,目前在大部分上游式尾矿坝的工程地质勘察中难以建立现场试验室,所得抗剪强度指标与实际情况存在一定误差。针对这种现状,结合某铅锌矿尾矿坝现场试验结果,从现场简易试验获得的含水率和标准贯入击数进行分析,并对基于含水率影响下尾矿砂内摩擦角随标准贯入击数变化规律进行了研究,提出了考虑上覆压力作用下标准贯入击数的修正公式,并推出了用标准贯入击数估算尾矿砂内摩擦角的方法。通过几个实例验证：除当修正后的标准贯入击数N1>8（5%< <20%）情况下以外,该方法均能够有效地估算尾矿砂内摩擦角。研究结果表明,该方法在以后的上游式尾矿堆积坝的工程地质勘察工作中具有较强的应用价值。 相似文献
13.
The management of uranium tailings, generated as a by-product of ore processing, is particularly important to minimize the environmental footprint of the industry. A clear understanding of tailings slurry behavior is required at the time of deposition to help evaluate the storage capacity and life span of the containment facilities. The main purpose of this study was to investigate the segregation and self-weight settling properties of uranium tailings. Detailed laboratory investigations were conducted on tailings from 4, 5, and 6 % nominal mill feeds (high-grade McArthur River ores blended with special wastes on site) from the Cameco Key Lake operation. The results indicate that the three uranium tailings can be characterized as a sandy silt material with a negligible amount of clay. Their depositional behavior is governed by the initial solids content of the slurry. The investigated tailings showed insignificant segregation between 25 and 40 % initial solids content. The initial hydraulic conductivity during settling was about 10?4 m/s at a void ratio of 4 and was increased by half an order of magnitude for the 4 % mill feed, and by almost two orders of magnitude for the 5 and 6 % mill feeds at a void ratio of 8. Over the same range of initial void ratio, the settling potential increased threefold: from 8 to 24 % for the 4 % mill feed and from 12 to 36 % for the 5 and 6 % mill feeds. The better rate and amount of dewatering of future high mill feed tailings as compared to the current low mill feed tailings means that the onsite containment facility can store more tailings thereby supporting a longer life span of the mill. 相似文献
14.
Impact of AMD on water quality in critical watershed in the Hudson River drainage basin: Phillips Mine,Hudson Highlands,New York 总被引：1，自引：0，他引：1
Sivajini Gilchrist Alexander Gates Zoltan Szabo Paul J. Lamothe 《Environmental Geology》2009,57(2):397-409
A sulfur and trace element enriched U–Th-laced tailings pile at the abandoned Phillips Mine in Garrison, New York, releases
acid mine drainage (AMD, generally pH < 3, minimum pH 1.78) into the first-order Copper Mine Brook (CMB) that drains into
the Hudson River. The pyrrhotite-rich Phillips Mine is located in the Highlands region, a critical water source for the New
York metro area. A conceptual model for derivation/dissolution, sequestration, transport and dilution of contaminants is proposed.
The acidic water interacts with the tailings, leaching and dissolving the trace metals. AMD evaporation during dry periods
concentrates solid phase trace metals and sulfate, forming melanterite (FeSO4·7H2O) on sulfide-rich tailings surfaces. Wet periods dissolve these concentrates/precipitates, releasing stored acidity and trace
metals into the CMB. Sediments along CMB are enriched in iron hydroxides which act as sinks for metals, indicating progressive
sequestration that correlates with dilution and sharp rise in pH when mine water mixes with tributaries. Seasonal variations
in metal concentrations were partly attributable to dissolution of the efflorescent salts with their sorbed metals and additional
metals from surging acidic seepage induced by precipitation. 相似文献
15.
《International Journal of Mineral Processing》2005,75(1-2):135-144
Oxidation of magnetite pellet concentrates (from LKAB, Sweden) during drying and storage was studied using thermogravimetric analysis (TGA). The Fe2+content of a standard LKAB pellet feed decreased by 0.2% during heat treatment at 105 °C for 2 days. The results indicate that magnetite concentrates of pelletizing fineness already start to oxidize to γ-hematite during drying at 105 °C, although 105 °C is recommended by ISO 7764 and ISO 3087 and given as the maximum allowable drying temperature in ISO 3082. The importance of drying time for the amount of magnetite oxidized should also be recognized, but is not mentioned in the ISO standards. The sensitivity of magnetite particles for oxidation during drying could not be predicted by measuring the BET surface area. A simple isothermal TGA run gives exact experimental data and is recommended as a standard procedure before choosing the drying temperature for magnetite concentrate samples.Oxidation during storage at room temperature was observed as well. The Fe2+content in a standard Luossavaara-Kiirunavaara (LKAB) pellet feed decreased by 0.3% Fe2+during 4 years of storage at room temperature. Oxidation during storage was completely hindered when the samples were stored in a freezer at −50 °C. Therefore, freezer storage is recommended for all magnetite reference materials. These materials are used over several years and are especially susceptible to oxidation because they are usually finely ground and high in Fe2+content. The results also show that if the magnetite sample has partly oxidized to γ-hematite, the oxidation curve obtained by TGA will overestimate the Fe2+content of the sample, if background correction is necessary. 相似文献
16.
Geological significance of Coorong dolomites 总被引：2，自引：0，他引：2
Microcrystalline dolomite and related carbonate minerals have been forming throughout the Quaternary in shallow ephemeral alkaline lakes on the coastal plain of the Coorong area in southern Australia. These Coorong dolomites differ significantly from sabkha-type dolomites. They form in areas where evaporation rates during summer months exceed groundwater inflow rates to a series of alkaline lakes. This results in the lakes becoming desiccated during summer months. Brines resulting from this drying phase are then refluxed out of the system into seaward-flowing groundwaters of an unconfined coastal aquifer. Dolomites and other fine-grained carbonates remain behind, whilst saline and sulphate evaporite minerals are flushed out of the system. Progressive restriction by sedimentation in and around the Holocene coastal dolomite lakes results in an upward-shoaling sedimentary cycle. Basal sediments which formed in a restricted marine environment pass upwards to lacustrine dolomites or magnesites exhibiting desiccation and groundwater resurgence structures such as mudcracks and teepees. The upper Proterozoic Skillogallee Dolomite Formation, an early rift basin unit of the Adelaide Supergroup, contains dolomites which show many of the features characteristic of the peculiar groundwater hydrology which plays an important role in Coorong dolomite genesis. These features include aphanitic dolomites which lack relict saline or sulphate evaporite minerals. The Skillogallee Dolomite Formation in some areas overlies an earlier dolomitic unit, informally named the Callanna Beds, typified by abundant pseudomorphs after sulphate minerals. Sabkha style dolomites characterizing the Callanna Beds are replaced up-section by the Coorong-type dolomite of the Skillogallee Dolomite Formation. This implies the development of an increasingly more active groundwater regime. The ultimate source and mode of concentration of the necessary Mg required to form both the modern and ancient dolomites remain imperfectly understood. 相似文献
17.
There is now evidence that naturally occurring acid–water is more abundant than previously thought and that it has been important in the geologic past. Understanding the processes leading to the formation of such systems is required to appreciate the role of acid systems in geologic processes and to develop indicators for recognizing the geologic/environmental importance of these systems in the past. This paper characterizes the hydrogeology, hydrogeochemistry, microbial biogeochemistry and landscape attributes of acid–groundwater surface water systems in Australia with an emphasis on a well studied playa-lake system, Lake Tyrrell, Murray Valley. A model for the origin of these acid brines is presented and the importance of acid-brine producing systems is speculated upon. Data include porewater and groundwater geochemical measurements (collected during a 10 day field campaign) and results from geochemical modeling and graphics (e.g., Piper diagrams and x–y plots of seawater evaporation trajectories). Key characteristics of the system are (1) aquifer materials have low acid buffering capacities, (2) saline groundwater flowing onto playa surfaces is an oxic, H2SO4 solution, (3) authigenic minerals include combinations of jarosite [KFe3(SO4)2(OH)6], alunite [KAl3(SO4)2(OH)6] and Fe oxides that can form as evaporite minerals, (4) a source for solutes can be marine aerosols and (5) the formation of ironstones. Groundwater acidification by various processes including sulfide oxidation and ferrolysis, and at many different times, are the unique aspects for evolution of these acid brines and they can be considered another end member of the Eugster–Jones–Hardie model for the evolution of brines in closed basins. Acid–hypersaline groundwater and playa systems such as Lake Tyrrell may be an example of expected changes in the hydrogeochemistry of terrestrial water during late-stage continental denudation under arid conditions. Historically these systems may have been integral to the formation of opal, bauxite, some low temperature ore deposits, of authigenic K-feldspars, and continental redbeds. Natural acid saline systems, such as those in Australia, may also be representative of acid saline systems on Mars. 相似文献
18.
Pierre Gerard Angélique Léonard Jean‐Pierre Masekanya Robert Charlier Frédéric Collin 《国际地质力学数值与分析法杂志》2010,34(12):1297-1320
This paper deals with the moisture exchanges occurring between soils and the surrounding atmosphere. Convective drying tests are performed on Awans silts at different drying temperatures and air relative humidities in order to reproduce the natural drying conditions. The experiments improve the understanding of the vapour transfers kinetics between the soil samples and the atmosphere. The experimental results are analysed assuming that the transfers take place in a boundary layer existing at the surface of the porous medium. The influence of the thermal conditions on the evaporation is also taken into account. In our model, coupled vapour and energy exchanges are controlled by mass and heat transfer coefficients characterizing the boundary layer. These coefficients are determined from the drying experiments. The modelling of the drying tests in non‐isothermal conditions is performed in order to validate the formulation of the vapour and heat exchanges. The numerical results present a good agreement with the kinetic of the materials desaturation determined during the tests. The analysis of the moisture transport mechanisms into the sample and at the boundary shows that at the beginning of the test, the drying is first achieved by the transport of moisture in its liquid form and its evaporation at the sample outer boundary in contact with the atmosphere. In a second step, vapour diffusion becomes predominant into the sample and it corresponds to the most important decrease of relative humidity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
19.
Deposition of mine tailings in a cold climate requires precautions as temporary sub-zero temperatures can imply considerable consequences to the storage due to creation of permafrost. The risk of creating man-made permafrost lenses due to tailings deposition exists even in regions with no natural permafrost, as material being frozen during winter might not fully thaw by the following summer. When such frozen layers thaw during later longer warmer periods, excess pore water pressure and large settlements might develop. Such implications close to the dam structure have to be avoided and therefore the risk of generating permafrost should be reduced. This paper describes a geothermal model for one-dimensional heat conduction analysis. The model is able to simulate the temperature profile in tailings where the surface elevation is constantly increased due to deposition. At the tailings surface, the boundary condition is the air temperature changing over time during the year. Air temperatures, tailings deposition schedule and tailings properties are given as input to the model and can easily be changed and applied to specific facilities. The model can be used for tailings facilities in cold regions, where the effects of tailings deposition on the temperature regime are of interest. Findings can improve tailings management by explaining man-made permafrost generation. The model can also aid in setting up appropriate deposition schedules and to prevent generation of permafrost layers. 相似文献
20.
利用盐层中碎屑沉积物粒度分布特征鉴别干盐湖沉积层序 总被引：1，自引：0，他引：1
本文提供了利用盐层中碎屑物粒度分布特征鉴别于盐湖层序的新方法。通过对昆特依现代干盐湖的研究发现,广泛发育的盐滩均经历了水下沉积、水上沉积与改造等作用过程,其碎屑物粒度分布特征与正常盐湖沉积显著不同,常由两个以上次总体复合而成。这成为区分两者的良好标志。作者将其应用于钻孔剖面,首次在该区揭露了若干干盐湖层序。而这些层序正是钾盐富集区段。 相似文献