Heavy metal concentrations in redeveloping soil of mine spoil under plantations of certain native woody species in dry tropical environment, India

Total concentration of heavy metals(Cd, Cr, Cu, Fe, Pb, Ni, Mn and Zn) was estimated in the redeveloping soil of mine spoil under 5 yr old plantations of four woody species namely: Albizia lebbeck, Albizia procera, Tectona grandis and Dendrocalamus strictus. The data recorded in the present study were compared with other unplanted coal mine spoil colliery, which was around to the study site and adjoining area of dry tropical forest. Among all the heavy metals, the maximum concentration was found for Fe and minimum for Cd. However, among all four species, total concentrations of these heavy metals were recorded maximally in the plantation plots of T. grandis except for Fe, while minimally in A. lebbeck except for Zn, whereas, the maximum concentration of Fe and Zn was in the plantation plots of D. strictus and A. procera. Statistical analysis revealed significant differences due to species for all the heavy metals except Cu. Among four species, A. lebbeck, A. procera and D. strictus showed more efficient for reducing heavy metal concentrations whereas T. grandis was not more effective to reduce heavy metal concentrations in redeveloping soil of mine spoil.

Characterization of Coal Spoil Recovered from Coal Mine Drainage Water

Barapukuria Coal Mine situated in the district Dinajpur. Bangladesh is playing an important role in the economy of this country by the mining of top quality coal. With coal mining, mine waste is also generated called coal spoil. Coal spoil can impose environmental threat if not treated carefully. In contrast, it can also be converted to value added product. In the present work, coal spoils collected from Barapukuria coal mine drainage water were investigated to determine the quality of the samples by physico-chemical analysis (proximate and ultimate analysis) as well as by heating value determination. 50% of carbon was detected in the samples after elemental analysis, with sulfur content less than 0.4%. Calorific value around 9300 btu/lb was obtained for the coal spoil. Moreover, moisture content, ash, volatile matter content and fixed carbon also provided fruitful information regarding the quality and economic prospect of the samples in comparison to the quality of Barapukuria coal.

Arbuscular Mycorrhizal Technology in Reclamation and Revegetation of Coal Mine Spoils under Various Revegetation Models

Reclamation and revegetation of a coal mine spoils with various revegetation models utilizing the mycorrhizal technology were studied. The models with different combination of plant species were designed to test the hypothesis of speedy revegetation. Root colonization and spore density of arbuscular mycorrhizae (AM) were lowest in plants seeded directly on slopes of the overburden (coal mine dump). At flat surfaces, the mycorrhizal colonization in plant species was higher than that observed at slopes. In other revegetation models, i.e., tree monoculture, tree monoculture + crop species (agroforestry), and two strata plantations (combination of different plant species), maximum AM colonization was recorded for tree species grown along with crop species. This was followed by two strata plantations and tree monoculture. In two strata plantations three categories of AM associations were recognized: 1) every plant in the combination, possessed high mycorrhizal association, 2) only one plant in the combination possessed high mycorrhizal association, and 3) none of the plants in the combination possessed high mycorrhizal association. Azadirachta indica, Pongamia pinnata, Leucaena leucocephala and Acacia catechu were most effective in catching mycorrhizae, and can be used as the effective tool in rehabilitation of the degraded ecosystems.

Does Sparing the Rod Spoil the Child?

In current society where most parents praise children, a father who claims that frequent criticisms and beatings help make his children suc- cessful, has captured the public＇s attention. Xiao Baiyou, a 47-year-old Hong Kong businessman, explains his parenting approach in his book That＇s Why They Go to Peking University, which has stirred controversy over his parenting methods since its publication release in June.

Influence of Polymer Binder on the Physical Properties and Stability of Engineering Spoil on a Slope

An experiment was performed to study the influence of polymer binders on the physical properties,and stability against a simulated rainfall,of a slope consisting of engineering spoil.Results showed that low polymer binder concentrations(≤500g/m3) could enhance the air permeability and moisture-retaining capacity of the engineering spoil;however,adding more polymer binder made the hardness of the engineering spoil increase and then decline.With the increase of polymer binder concentrations,the surface(0-5cm) permeability of the engineering spoil decreased but the permeability of the lower layers(5-10cm) increased.Polymer binders might reduce runoff and sediment,but the effect becomes weaker with the increase of rainfall.The results of this study have significance for engineering practices.Further experiments are needed to study the effects of binders under other conditions,such as natural rainfall,different slopes,different rock types,different degrees and spoil weathering and different added material,and the chemical interaction between soil and polymer binders.

Comparative Study on Debris Flow Initiation in Limestone and Sandstone Spoil

Large spoil tips from reconstruction works as a result of the Wenchuan Earthquake in China are new debris flow hazards to the human society.However,there is a lack of detailed comparative study on debris flow initiation in different spoil materials.This paper describes a series of tests and analyses on debris flow characteristics(initiation,scale and mechanism) at six sites with limestone and sandstone materials near the Dujiangyan area.Research shows the limestone spoil contains debris flow prone clay content with high concentration of montmorillonite(highly expandable).In addition,limestone spoil is of such a low permeability that water mainly concentrates in the upper surface layer.Those factors make it easy for the increase of pore water pressure,decline of internal friction and conhesion force,leading to the occurence of large debris flows.In contrast,the sandstone spoil is less problematic and causes no major debris flow threats.Based on our research on the mechanism,the"stereometric drainage"method is sucessfully applied to control limestone spoil debris flows.

Experimental study for the particle size distribution of mine spoil pile cross section

The aim of the experiment is to analyze and view the distribution of gangue withdifferent particle sizes in mine spoil pile cross section.According to the Dimensionalmethod,'Pi'theorem was employed first to abbreviate ten physical and mechanical parametersto three dimensionless groups, and then the similarity criterion and coefficient ofthe experiment were determined and calculated based on particle size distribution curve.The similarity model was designed and constructed to represent the process of the minespoil pile.The profile of the final model shows that the small sized particles mainly composethe upper zone of the mine spoil pile, while the bottom of the pile is dominated bybigger sized particles, and the intermediate section presents a zigzag stripe cross-beddingstructure which is composed by small-medium scale particles and medium-large scaleparticles.Each stripe has two critical angles: one is the angle in which gangue particlescan maintain their stability condition, with approximate range from 24° to 26°; and theother is the angle in which particles can stop gliding downwards, approximately varyingfrom 34° to 36°.

工程堆积体产流产沙及水沙效益对植被近地表特征的响应

针对陡坡工程堆积体水土流失严重的问题,通过野外模拟降雨试验开展植被不同近地表特征对堆积体产流产沙和蓄水减沙效益特征影响的定量研究。选择土石混合堆积体(10%砾石质量分数,坡度30°)作为工程侵蚀下垫面的典型代表,并以裸坡(bare slope,BS)为对照,定量分析了植被在3种近地表特征条件下(完整植株(intact grass,IG),不含叶(not leaf,NL),只含根系(only root,OR)对堆积体产流产沙特征和蓄水减沙效益影响。结果表明:1)植被在IG条件下延缓坡面径流发生使其较BS滞后,效益达50.74%~188.98%,但不完整植被(NL、OR)会加速径流发生使其较BS提前2.19%~70.12%;2)植被在NL和OR下的瞬时径流率比IG增大0.20%~185.58%,在降雨强度1.8 mm/min的瞬时径流率甚至比BS高1.20%~169.10%;植被在IG和NL条件下瞬时侵蚀速率比BS减少0.91%~98.71%,但在降雨强度达到1.8 mm/min时OR条件下甚至增大侵蚀使其比BS高6.76%~75.63%;3)随降雨强度增大,植被在NL和OR条件下的减沙效益由95.18%和68.31%分别递减至46.58%和-68.13%,但对IG下的减沙效益影响小(效益差异<2%),平均蓄水效益随降雨强度增大而减小。不同堆积体水沙呈显著线性相关(R^(2)在0.40~0.88),且径流率达到4 L/min会显著改变植被对堆积体坡面防护效益。提出开展堆积体生态修复时选择冠层丰富的植被,同时要避免外部因素对植被造成损害。研究结果对于揭示植被防护扰动边坡侵蚀机制具有重要意义,可为堆积体植被修复提供实践指导。

Utilization of recycled solid waste as ecological reclamation materials based on plant growth experiments and soil quality analysis

During the highway construction,a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally utilized.Besides,the vegetation recovery is slow in the spoil areas due to the soil depletion.Aiming at recycling the solid waste,the sieved engineering waste slag with local red clay and corn straw biochar was supplied to solve the problem of insufficient nutrients in engineering waste slag and soil.In addition,planting experiments of alfalfa(Medicago sativa L.)and Amorpha fruticosa L.combined with physical and chemical experiments were carried out to prove the feasibility of the novel improved substrate for the reclamation of spoil areas.The results show that the substrate's improvement effect is mainly affected by the soil to slag ratio and the biochar content.The improvement effect of soil matrix in highway spoil area decreases with the increase of the waste slag content,especially when the soil-slag ratio is less than 3,and the promotion of plants is limited.On the contrary,the improvement effect is proportional to the biochar content(3%-8%).But it is noted that the Cu and Pb in the soil will exceed the clean limit corresponding to the Nemero soil pollution index level when the biochar content is 8%.Therefore,it is recommended that the soil-slag ratio should be≥3,and the biochar content should reach 3%-5%.This research provides experimental basis and technical support for utilizing solid waste resources in the reclamation of highway spoil areas.

盾构隧道泥渣脱水处理技术研究综述

脱水处理是盾构泥渣减量化的主要方法,对现阶段各类盾构隧道泥渣脱水处理技术进行分析总结具有重要的意义。从盾构泥渣的性质及其赋存水机制出发,总结归纳过滤比阻、毛细吸水时间、沉降速率、渗透系数以及含水率5项用于评价泥渣脱水性能的指标,重点阐述机械脱水、干化脱水与渗流脱水等主要脱水技术,分析各类方法的脱水效果、适用性和局限性。机械脱水技术在黏粒含量较少的盾构泥渣脱水处理方面已较为成熟,而对于黏粒含量较多的盾构泥渣需加入高效的调理剂改性以增强脱水性能,目前较高的脱水成本与调理剂污染处理是其亟需解决的问题。自然晾晒显然已不能满足效率与环保的要求;热干化脱水虽然适用范围广且脱水较为彻底,但其存在能耗大、成本高的缺陷;渗流脱水技术中的土工管袋法以及真空预压法对渗透性较大的泥渣具有较好的脱水效果;电渗法可适用于低渗透性黏土,然而其耗电量大且电极易腐蚀的缺陷还难以避免。目前盾构泥渣脱水处理主要存在设备适应性不足、能耗高与运维难、泥渣资源利用率低、新技术难以推广应用以及处理规范体系不完善等问题。未来应注重脱水设备向智能化、模块化、集成规模化三位一体方向的发展,同时实现高效的泥渣资源再利用,制定统一的脱水规范并鼓励脱水新技术的工程应用与推广。

基于ESG理念的重大工程弃渣造地项目选址价值评价

为了强化弃渣造地项目选址的可持续性,本文引入了ESG理念作为决策依据,构建了集成ESG理念的重大工程弃渣造地项目选址价值工程框架,并提出了适用于评价西部复杂艰险地区重大工程弃渣选址造地的ESG功能评价指标体系。在此基础上,结合AHP方法给出了确定ESG项下各分量指标的权重及价值工程实施的具体操作步骤,并通过一个具体案例进行操作说明。ESG理念的引入及所构建的功能评价指标体系和弃渣选址造地的价值工程分析方法,有助于提升我国重大工程弃渣处置的可持续能力,助推重大工程弃渣选址造地的科学化和重大工程ESG理念的实现。

露天煤矿排土场长时序植被碳汇分级方法构建及分析

植被碳汇是露天煤矿生态环境评价的重要指标,精确反演植被碳汇并进行准确分级对探索矿区生态修复至关重要。为此,提出一种基于粒子群优化算法的露天煤矿植被碳汇分级方法。基于Landsat遥感影像和气象数据,采用光能利用率模型,反演出内蒙古胜利一号露天煤矿区2005-2020年间排土场的植被碳汇时空分布;通过构建目标函数并迭代计算,获取了该区植被理想光能利用率、最佳气温和降水条件,量化并建立了植被碳汇分级标准;对不同时期各个排土场的植被碳汇结果进行分级,并对分级面积和占比的时空变化进行分析。结果表明:(1)2005-2020年间研究区植被固碳能力呈上升趋势,年均增长值和增长率分别为1.43gC/(m^(2)·a)和6.97%。(2)各排土场生态修复后,植被碳汇值大幅提高,极高和高植被碳汇区面积不断扩大。(3)排土场生态修复效果存在差异,南北排土场表现最佳,沿帮次之,内排土场相对较差。到2020年南、北排土场极高植被碳汇区面积分别达0.94和0.92km2,占比为92%和94%;沿帮排土场极高和高植被碳汇区面积达3.64km2,占比66%;内排土场极高植被碳汇区面积增长至1.22km2,占比达31%;2020年南、北和沿帮排土场已不存在极低植被碳汇区。研究成果不仅为露天煤矿生态环境评估提供了重要的数据支持,也为矿区生态修复策略制定提供了科学依据。

弃渣扰动对藏东山地草甸坡面产流产沙的影响

[目的]明晰铁路修建中弃渣工程扰动引起的水土流失响应,揭示弃渣堆积前后及其植被恢复对藏东生态脆弱的山地草甸区坡面尺度水土流失的影响。[方法]选取未扰动、轻度扰动、重度扰动、覆土恢复4个类型的坡面,建立原位径流小区,通过人工模拟降雨试验,开展了坡面产流产沙过程的研究。[结果](1)坡面的溅蚀量随扰动强度的增大而增加,下坡向的溅蚀量为上坡溅蚀量的1.14~2.67倍。(2)轻度扰动坡面、重度扰动坡面和覆土恢复坡面的初始产流时间分别缩短为未扰动坡面的53.8%~66.7%,34.6%~46.7%,86.7%~92.9%。(3)未扰动坡面、轻度扰动坡面、重度扰动坡面和覆土恢复坡面的产流速率分别为44~86,104~147,200~373,46~95 ml/(min·m^(2)),产沙速率分别为0.026~0.055,0.05~0.098,1.034~2.189,0.047~0.077 g/(min·m^(2))。[结论]覆土恢复坡面的水土保持能力较轻度扰动和重度扰动坡面有显著提高,但距未扰动坡面仍有差距,需采取其他植被或工程措施对工程扰动坡面加以恢复。

Leaching Behavior of Trace Elements in Coal Spoils from Yangquan Coal Mine, Northern China

The long-term dumping of coal waste piles has caused serious environmental problems. Release of trace elements（including rare earth elements, REEs） from coal spoils gobs was investigated at Yangquan coal mine, Shanxi Province, China. X-ray diffraction（XRD） was used to analyze the mineral composition of the coal spoils. The minerals of the coal-spoil samples are mainly kaolinite and quartz, with a minor proportion of pyrite. The batch and column tests were employed to simulate the leaching behavior of trace elements from coal spoils. Elements V, Cr, Zn, As, Pb, and Cd are highly enriched in all coal spoils. The coal spoils also have elevated levels of Ga, Ge, Se, Sn, Hf, and Th. The leachate of coal spoils, fried coal spoils and CSFGM（coal spoils fire gas mineral） samples are acidic, with the p H values ranging between 3.0 and 6.6. The released elements with high concentrations（over 100 μg/L） include Fe, Mn, Co, Ni and Zn, while moderately-released elements are Cu, Se, Mo and As. A high content of heavy metals in batch-test leachate with CSFGM indicates an increased mobility of heavy metals in coal spoil combustion byproduct. Within the first hour washing with the electrolyte solution, a rapid rise of common cations, trace elements, and REEs content, as well as a drop of p H value, in effluent was observed. An increased leaching velocity favors the release of trace elements from coal spoils. In addition, the pulse input of precipitation led to more elements to be released than continuous leaching.

哥伦比亚高等级公路路基路面设计理念分析

哥伦比亚公路设计基本按美国标准执行,设计理念也偏向于美国,同时有哥伦比亚自身工程设计的习惯、理念及特点。该文介绍了哥伦比亚北部MAR_(2)公路项目中的防护工程、排水工程、路基填料、取弃土场和路面等方面的主要设计方案,对比分析了中哥设计理念的异同,并提出可互学互鉴的内容。

Leaching of aluminum from coal spoil by mechanothermal activation

The process of order to recover aluminum investigated. The CS was activating coal spoil （CS） in as a high value product was first characterized by X-ray fluorescence （XRF）, X-ray diffraction （XRD） and thermo- gravimetric analysis-differential scanning calorimetry （TGA-DSC） in order to determine the chemical and mineral compositions of the CS. Then a mechanothermal activation method was adopted to increase the aluminum activity in the coal spoil. Over 95% of the aluminum in the CS could be extracted using this activation method. The mechanothermal activation process promoted the destruc- tion of kaolinite structures and hindered the formation of amorphous γ-Al2O3. This resulted in a high aluminum leaching activity in the mechanothermally activated CS.

Coal Mine Spoil-Water Interaction——Release Mechanism of Clay Minerals

The South Wales Coalfield has been affected by more than 200 years of industrialdevelopment based on coal mine. Today, surface coal mine affects a 100-km belt in theHeads of the Valley region. Large areas of land are classified as 'reclaimed' land after coal mining. However, there is increasing concem about both the quality and the sustainability of this reclaimed land. Large tracts of 'reclaimed' land are suffering severe degradation runoff, erosion gullies, waterlogging through most of the year, drought during the short summer period of soil moisture deficit, and the consequent loss of vegetation cover.

Coal mine spoil-water interaction: Ⅱ. Weathering concentrated metals in surface coal mine spoils

Concentrations of metals are lower in coal shales collected from recently exposed surface mine wastes than in shales collected from spoils exposed to surface weathering for 45 a. In this period, the character of the spoils changes dramatically as a result of the accelerated breakdown of the freshly exposed minestones. Since the metals are held as unstable sulfides, it is suggested that enrichment may be caused by absorption of metals by colloid of iron or formation of organic complex compound with organic carbon existing in the remnant structure of coal mine spoil. This process may contribute to the triggering of soil contamination thresholds on coal-lands already heavily loaded with metals.

沐川至马边高速公路Q13弃土场泄洪渠设计

随着我国交通建设的发展,山区高速公路弃土场不可避免存在阻断既有沟道的问题。以沐川至马边高速公路Q13弃土场泄洪渠为例,阐述了沟道型弃土场泄洪渠总体设计、水力计算、渠身结构选材及选型情况。实施情况表明,结合准确的水力计算,通过弃方压实度控制,设置于弃方上的泄洪渠,平缓渠身采用模袋混凝土,跌水、消力及边墙放坡受限段采用混凝土边墙及钢筋混凝土底板,可保证渠身结构在弃方上的整体性;通过放缓渠底纵坡,恰当设置跌水,可有效降低水流速度及其对渠身冲刷,提高泄洪渠耐久性。

辽西矿区废弃地水保生态修复措施探究

随着采矿业的不断发展,矿区的废弃地问题也日益凸显。废弃地的土壤侵蚀严重,植被稀少,同时水、土壤和大气污染严重,给周围环境带来了严重的破坏。因此,实施废弃地的水土保持生态修复关键技术就显得尤为重要。以辽西地区为例,通过废弃地的水土保持生态修复措施,可以有效地实现水土保持和荒漠化治理,对促进矿区土地快速修复具有至关重要的作用。矿区废弃地的生态修复措施产生了显著的效果。植被覆盖率得到明显的提高,小气候也得到了明显的改善。逐步实现了生态修复的社会化和专业化,也带来了良好的生态效益和经济效益。