Geochemical and Mineralogical Characterization of a Pyritic Waste Pile at the Anjir Tangeh Coal Washing Plant, Zirab, Northern Iran

Coal washing at the Anjir Tangeh plant, in Zirab, northern Iran, has produced more than 1.5 Mt of coal wastes. These waste materials were geochemically and mineralogically characterised to guide development of an appropriate remediation scheme. Three vertical trenches up to 4 m deep were excavated from the coal waste pile surface and 25 solid samples were collected at 0.5 m intervals. The samples were analysed for total concentrations of 54 elements, paste pH, SO ₄ ^?2 , CO ₃ ^?2 , and HCO₃ ^?. The lowest pH values were measured at a depth of 0.3 m. The upper portion (1 m) of one profile was moderately oxidised, while oxidation in the other two profiles did not extend more than 0.8 and 0.5 m beneath the pile surface. The waste piles have low acid-producing potential (15–21.87 kg CaCO₃/t) and high values of acid-neutralizing potential (0.06–96.2 kg CaCO₃/t). Fe, Al, S, Na, Mn, Pb, Zn, Cd, and Ag increased with increasing depth, while Mo, Sr, Zr, and Ni decreased with increasing depth. The results show pyrite oxidation at depth and subsequent leaching of the oxidation products. Mn, Zn, Cu, Pb, Ag, and Cd are the most important contaminants of concern at this site.     

Reduction of Cd,Cu, Ni,and Pb Mobility by Active Si in a Laboratory Study

Soluble forms of Si and Si-rich substances may reduce both metal mobility and toxicity. A series of column experiments were performed to investigate the influence of Si-rich materials on the mobility and leaching potential of certain metals. Column experiments were conducted using sandy soil that had been treated with various forms of a Si-rich substance, i.e. diatomaceous earth, zeolite, amorphous silicon dioxide, and concentrated monosilicic acid. The soil was also treated with soluble forms of Cd, Cu, Ni, and Pb to simulate a contaminated mine site. Application of the Si-rich materials resulted in metal immobilization and reduced leaching. It appears that monosilicic acid can cause both physical adsorption and metal precipitation within contaminated soils. Further investigations are recommended to assess the potential use of this approach for remediation of mine tailings and decontamination mine sites.     

袁家村铁矿湿陷性黄土地基建尾矿坝的研究与应用

我国湿陷性黄土分布广阔,在湿陷性黄土地区建设尾矿库应考虑湿陷性黄土地基对坝体的影响,通过局部挖除、堆载预压、反压坡脚、滤水疏干等一系列工程措施,保证坝体的安全稳定。     

金属铟中杂质元素的ICP-AES测定

确定了用电感耦合等离子体发射光谱法直接测定金属铟中的铅铁铜锌镉铝锡钛铊砷10种元素的含量．试验中优化出各元素的分析波长和分析条件，采用基体匹配补偿基体效应．该法操作简单，分析快速可靠，回收率为90％～110％，相对标准偏差为2．1％～12．5％．     

Reverse Oxidation Zoning in Mine Tailings Generating Arsenic-rich Acidic Waters (Carnoulès,France)

The Carnoulès Pb mine closed 40 years ago, leaving tailings (pyrite-rich silts) exposed. In 1982, the tailings were gathered and placed behind a concrete dam, above a drainage pipe, and then covered with a clay layer. The As-rich pyrite in the tailings has oxidized; acidic water with high As concentrations (100–350 mg/L As) now emerges from the base of the dam. Strikingly, there is no oxidation zone at the surface of the tailings. The clay cover and the low hydraulic conductivity of most of the tailings (10⁻⁷ m/s) strongly limit rainwater infiltration. Water table variations, water balance calculations, and flow modelling indicate subsurface water input and water flow along the bedrock within a more permeable sandy horizon. This lower horizon is strongly oxidized due to this flow pattern. The As-rich water is mainly produced in the northern part of the tailings area, where seasonal variations in the water table (a succession of aerobic/anaerobic periods) are important. This water flows through a drainage pipe to an acidic spring. The disposal of tailings can release acidic and toxic waters into the environment. Monitoring and modelling of such tailings allow one to define the potential impact and propose remedies.     

ICP-MS法测定铟中砷、铝、铜、镉、镍、铅、铊、锡和锌

研究铟中微量砷、铝、铜、镉、镍、铅、铊、锡、锌的ICP-MS法同时测定的方法.选择仪器的最佳参数和最佳测定条件,采用标准加入法和在线加入钪、铑、铼混合内标补偿法消除基体铟对测定元素的干扰,直接测定其中的杂质元素.测定结果准确、可靠,铟中砷、铝、铜、镉、镍、铅、铊、锡、锌的测定下限均≤0.0001%,加标回收率97%～111%.方法的建立为控制铟中杂质元素提供了检测依据.     

Adsorption of Pb(II), Zn(II) and Cr(III) on coal fly ash porous pellets

In the present work the application of fly ash porous pellets as adsorbent of lead(II), zinc(II) and chromium(III) ions from aqueous solution was studied. Experiments were carried out using porous pellets developed from fly ash derived from Megalopolis, Greece coal-burning power plant. The material was shaped into spherical agglomerates, after wetting and tumbling in a laboratory scale granulator. The adsorption of heavy metals on fly ash pellets was studied as a function of the initial metal concentration, solution pH and temperature. Kinetic studies indicated that sorption follows a pseudo-second-order model. Adsorption isotherms of lead, zinc and chromium were determined for agglomerated material using the Langmuir equation. The adsorption capacity of fly ash pellets reached at 0.22 mmol Pb/g pellet, 0.27 mmol Zn/g pellet and 0.44 mmol Cr/g pellet. Furthermore adsorption from bimetallic solutions (Cr–Zn, Cr–Pb and Pb–Zn) took place in order to study presumable antagonistic effects on adsorption of heavy metals. Finally, the stabilization of metal saturated pellets was studied. The stabilization procedure took place in structures made of concrete, where 75% of cement was replaced by raw fly ash. The evaluation of the procedure through leaching tests showed excellent heavy metals stabilization in concrete blocks.     

Physical, Hydrologic, and Aqueous Chemical Characterization of the Ore Knob Tailings Pile (Ashe County, North Carolina, USA)

Oxidation of pyrrhotite and related sulfide minerals in the vadose zone of the Ore Knob Mine tailings pile generates dissolved Fe⁺², SO₄⁻², and acidity, which are rapidly transported through the pile by infiltrating surface water. Significant spatial variations in the physical and hydraulic characteristics of the tailings cause large variations in air-filled porosity and effective oxygen diffusion into the pile. Tailings in the upstream areas are more fine-grained, with less air-filled porosity and oxygen diffusivity. The original tailings in the downstream areas are more coarse-grained, with less water retention and greater oxygen diffusivity. However, weathering processes have increased the fine-grained fraction in the oxidized zone and hardpan layer, increasing water retention and lowering oxygen diffusivity. The thickness of the downstream oxidized zone combined with increased water retention due to weathering may have significantly reduced acid generation in these areas.     

废弃印刷线路板Pb,Cd和Cr的测定

研究用原子吸收分光光度计测定废弃印刷线路板中重金属元素Pb，Cd和Cr的含量。结果表明，方法灵敏、快速、准确、操作方便，实用性强。Pb，Cd和Cr的回收率在98．9％～103．6％之间，相对标准偏差RSD〈1．45％。     

某硅线石矿选矿、尾矿除铁及石榴石综合回收试验研究

利用不脱泥磁选-浮选联合工艺流程，以工业油酸作为捕收剂，在获得合格硅线石精矿的同时，经过磁-重联合工艺流程综合回收伴生的石榴石资源，并使浮选尾矿综合利用成为可能。     

广东省某矿区铌钽矿床矿石及矿物学特征浅析

广东省某矿区铌钽矿床为中型花岗伟晶岩型铌钽矿床,矿脉受断裂和褶皱控制明显。矿石主要由白云母、石英、长石等组成,含量占98%以上,矿石矿物主要为铌钽铁矿,含量较少,主要与白云母、长石、石英连生。该矿床中矿石除可选冶铌钽外还可综合利用矿石尾砂矿中的白云母、长石以及铷等有用物质。     

Design of a Geomembrane-Laminated Geosynthetic Clay Liner on the Slopes of a Mine Tailings Dam in Emet,Turkey

We evaluated the potential use of a geomembrane-laminated geosynthetic clay liner (GCL) along the slopes of a boric acid tailings dam in Emet, Turkey. Even though a compacted clay liner (CCL) had been used at the bottom of the tailings dam, it was not possible to place a CCL along the slopes of the dam due to their steepness. Triaxial permeability tests were conducted on the base GCL without a geomembrane and the results indicated that although the volumetric flow through a cross section of the GCL was measured to be very low initially, it increased after a while due to the interaction of the bentonite in the GCL and the mine leachate. For this reason, using a geomembrane-laminated GCL along the steep slopes was found to be an appropriate solution. The mechanical properties of the barrier material were evaluated by performing a parametric study, including a slope stability analysis and an anchorage design for the geomembrane-laminated GCL. Based on the results, a geomembrane-laminated GCL with appropriate mechanical and hydraulic properties was chosen.     

张集矿(北区)主井出煤系统优化

张集矿(北区)主井出煤系统工程量大,施工复杂。该系统工程为关键工程,对其进行设计及施工方面的优化,能加快施工速度,缩短建井工期,其经济及社会意义重大。文章从其供电系统巷道、主井换尾绳斜巷、井底煤仓三个方面做具体的优化方案介绍。     

Assessment of Metal Attenuation in a Natural Wetland System Impacted by Alkaline Mine Tailings,Cobalt, Ontario,Canada

A natural wetland in the Farr Creek drainage basin near Cobalt, Ontario was studied because its floor is covered with alkaline mine tailings that contain elevated levels of metals, including As, Co, Cu, and Zn, due to mining that occurred intermittently from 1904 to the 1980s. Our objectives were to characterize the biogeochemical interactions occurring throughout the wetland and to assess its ability to effectively attenuate the metal contamination. We were not able to conclusively determine if this wetland is a net source or net sink for As, Co, Cu, and Zn; it is not clear whether this wetland has reached its capacity for attenuating these trace elements. Both oxidizing and reducing bacteria were quantified and found to be prevalent throughout the wetland, with similar population densities. It is likely that the presence of localized oxic zones in the root zones of Typha latifolia supported the oxidizing bacteria populations observed. The results indicate the importance of understanding the conditions in systems being used to treat mine drainage, as well as the importance of having a detailed understanding of the metals of concern in the mine waste.     

Column Kinetic Tests Assessing Geochemical Behavior of Mine Wastes in the Jerada Coal District (Morocco)

The Jerada anthracite mine in Morocco was abandoned in 2001 after producing approximately 20 million tonnes of solid waste. The acid generating potential of these wastes was determined by performing tests on five samples collected from relatively older and more recent waste deposits. No carbonate minerals were identified. Pyrite was the only sulphide mineral observed and much of it had been completely transformed into Fe-oxides. Analysis of the waste indicated low levels (<1 %) of Ca and Mg, while Fe and Al concentrations generally exceeded 5 %. Modified Sobek static tests and column kinetic tests were conducted for 24 months. The static test results were not conclusive (20 <net neutralising potential <20 Kg CaCO₃/t). Leachates from the kinetic tests for three of the five samples showed an initially acidic pH, while those of the remaining two became acidic by the end of the tests. Sulfate concentrations (SO₄ ^2?) decreased over time from 5000 to 200 mg/L.     

鄂东南金属矿山尾矿资源调查及保护、开发利用建议

鄂东南以铁、铜为主的五类金属矿山尾矿库有500多座,其中70座规模较大,库容过亿立方米.有46%以上的尾矿库中具有尾矿矿床特点,主要有用成分有TFe(铁矿砂)、Cu、Au、WO3(白钨矿)和S,含多种伴生有用组分.保护好尾矿库,选择部分尾矿资源进行综合开发利用,对促进资源枯竭型城市循环经济、延长危机矿山服务年限都具有十分重要的意义.     

Evaluation of Metal Attenuation from Mine Tailings in SE Spain (Sierra Almagrera): A Soil-Leaching Column Study

A laboratory study was undertaken using mine tailings and soil columns to evaluate some of the natural processes that can control the mobility of metals at Pb–Ag mine tailings impoundments. The effects of buffering, pH, and salinity were examined with tailings from the El Arteal deposit. Al, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Sr, and Zn were mobilized when the tailings were leached. However, when the mine tailings were placed above alluvial soils, Al, Ba, Cd, Cu, Mn, Pb, and Zn were retained, although Fe and Sr clearly remained mobile. Most of the metal retention appears to be associated with the increase in pH caused by calcite dissolution. The sorption of some metals (Cu, Pb, and Zn) onto oxyhydroxides of Fe and Mn, sulphates, clay materials, and organic matter may also explain the removal of these metals from the leachate.     

Hydrogeochemistry and Contamination of Trace Elements in Cu-Porphyry Mine Tailings: A Case Study from the Sarcheshmeh Mine,SE Iran

Geochemical and hydrochemical investigations were performed to understand the contamination potential of the Sarcheshmeh mine tailings. The geochemical mobility for the tailings is as follows: Cu > Cd > Co > Zn > Ni > Mn > S > Cr > Sn > As > Se > Fe = Bi > Sb = Pb = Mo. Highly mobile and contaminant elements (Cd, Cu, Zn, Mn, Co, Ni, S, and Cr), which significantly correlated with each other, were mainly concentrated in the surface evaporative layer of the old, weathered tailings, due to the high evaporation rate, which causes subsurface water to migrate upward via capillary action. The contamination potential associated with the tailings is controlled by: (1) dissolution of secondary evaporative soluble phases, especially after rainfall on the old weathered tailings, accompanied by low pH and high contamination loads of Al, Cd, Co, Mg, Cr, Cu, Mn, Ni, S, Se, and Zn; (2) processing of the Cu-porphyry ore under alkaline conditions, which is responsible for the high Mo (mean of 2.55 mg/L) and very low values of other contaminants in fresh tailings in the decantation pond; (3) low mobility of As, Fe, Pb, Sb, Mo, and Sn due to natural adsorption and co-precipitation in the tailings oxidizing zone. Speciation modeling showed that sulfate complexes (MSO₄ ⁺, M(SO₄)_(aq), M(SO₄) ₂ ^?2 , and M(SO₄) ₂ ^? ) and free metal species (M⁺² and M⁺³) are the dominant forms of dissolved cations in the acidic waters associated with the weathered tailings. In the alkaline and highly alkaline waters, trace element speciation was controlled by various hydroxide complexes, such as M(OH)⁺, M(OH) ₃ ^? , M₃(OH) ₄ ⁺² , M₂(OH) ₃ ⁺ , M(OH)_2(aq), M(OH) ₄ ^?2 , Me(OH) ₂ ⁺ , Me(OH) ₄ ^? , Me(OH) ₂ ⁺ , Me(OH)_3(aq), and Me(OH) ₄ ^? (where M represents bivalent and Me represents trivalent cations). The speciation pattern of As, Mo, and Se is mainly dominated by oxy-anion forms. The obtained results can be used as a basis for environmental management of the Cu-porphyry mine tailings.     

Geochemistry and Mineralogy of Mill Tailings Impoundments from the Panasqueira Mine (Portugal): Implications for the Surrounding Environment

Selected geochemical results are presented from a study of the Panasqueira mine (Sn–W mineralization), which is one of the Portuguese test sites for the e-EcoRisk project (). These data permit a better understanding of the dynamics inherent to leaching, transport, and accumulation of some elements (mainly As, but also Cu, Pb, Zn, and Cd) in different sampling media and their environmental relevance. Stream sediment and water samples were found to be contaminated by the stored waste material in the tailing ponds; this effect could be observed for a considerable distance downstream.     

Assessment of Trace Elements in Soils and Mine Water Surrounding a Closed Manganese Mine (Anti Atlas,Morocco)

Five mine water samples, 23 topsoil samples, and four mine waste (tailings) samples were collected to assess the effects of a closed Moroccan Mn mine. Based on the pH, electrical conductivity, and concentrations of sulphate, Cu, Zn, As, Cd, Pb, and Mn, mining has not adversely influenced mine water quality. Soil samples were analyzed for 23 chemical elements and the results were interpreted by univariate and multivariate statistical techniques. Based on an enrichment factor (EF) calculation, only Cd, As, V, and Mn were selected for further study. Geochemical background (GB) and geoaccumulation index (I_geo) were determined for these elements to differentiate between geogenic and anthropogenic enrichment. The GB values showed that the Tiwiyyine soils contained a high geogenic content of Cd, As, V, and Mn that reflected the geochemistry of the parental rocks in this mineralized region. The I_geo calculation revealed that these soils were moderately influenced by anthropogenic activity, which had increased the concentrations of those elements. Finally, geochemical maps revealed that mining was likely responsible for the anthropogenic soil pollution.