Nanomineralogy of evaporative precipitation of efflorescent compounds from coal mine drainage

Efflorescent nanophases(NPs)are found as a transitory accumulation of potentially hazardous elements(PHEs),particularly in tropical climates.The central objective of this study was to investigate the distribution of PHEs with NPs through the evaporative formation structures(EFS)of enormously PHEs-rich coal-mine drainages(CMD).The EFS were studied in natural coal mine drainage for five months in order to determine their geochemical and ecological structures and to assess their position in the reduction of PHEs in nature.The largest coal-fired power plant in South America,located in south Brazil,is used as an example of such a problem.In this work,a novel methodology for the analysis of PHEs in CMD precipitates is proposed for this affected coal area.The analytical method,combining X-Ray Diffraction(XRD)and advanced electron microscopies,shows the importance of nanomineralogy in understanding different circumstances of coal contamination.Several ultrafine-nanoparticles(UNPs)were identified in the sampled soils and river sediments together with the PHEs.A decrease in PHEs was identified in association with UNPs.However,further investigations are required with regard to the mobility of PHEs in water,atmosphere,soils,and sediments.The EPS was thoroughly studied,acquiring suitable understanding with investigational facts for Ca and Fe-sulphates,pickeringite,and several amorphous phases.     

我国露天煤矿水害特征与防治水技术

露天开采是我国煤矿开采的两大方式之一。与地下开采煤矿类似，露天煤矿在开采过程中同样面临防治水问题，由于我国露天煤矿水害类型相对单一，国内学者鲜有对露天煤矿的水害特征和防治水技术进行深入研究。以我国露天煤矿分布范围为出发点，从充水水源、充水通道、充水强度3方面分析露天煤矿水害特征，得出大气降水、地表水和浅层地下水是主要充水水源；人为开挖形成的直通式通道、强渗透含水层或透水层、垂向导水钻孔、滑坡形成的地表裂缝等是主要充水通道；季节性变化明显、疏排水周期长、排水量大是露天煤矿疏排水主要水害特征的结论。归纳目前我国露天煤矿常用的7种防治水技术，提出露天煤矿由远及近、由上而下、由面至点的立体防治水技术体系。从地下水资源保护和生态环保角度出发，为实现露天煤矿绿色开采和可持续发展，提出以切断补给通道、减小矿坑疏排水量为目的的帷幕截流技术是今后露天煤矿防治水的主要技术方法。      

Technologies of Preventing Coal Mine Water Hazards for Sustainable Development in North China

As hydrogeological conditions of coal field in North China are complicated, coal mine water hazards have been occurring frequently. Nearly 80% of coal mines are affected by Ordovician and Permo-Carboniferous Karst water. According to rough statistics, 200 incidents of water inrush have occurred since 1950, 1,500 persons have died, and there is an economic loss of 3 billion Yuan (RMB). The climate of North China belongs to drought or semi-drought zone. So the recharge amount of ground water by infiltration of precipitation is limited. Stronger coal mine water drainage has brought a series of environmental problems, such as water resource and lots of famous Karst springs exhausted, surface collapse emerged, mine water contaminated. Coal mine water hazards are so serious that the economic benefit of coal mines is dropping. Sustainable development of coal mines is affected. So, preventing coal mine water hazards and protecting geological environment are essential. This thesis focuses on preventing coal mine water hazards technologies. The technologies include four aspects: exploration of hydrogeological conditions; prediction and forecast of water inrush; mining under safe water pressure; and sealing off groundwater by grouting.     

Environmental assessment and nano-mineralogical characterization of coal,overburden and sediment from Indian coal mining acid drainage

The deterioration of environmental conditions is the major contributory factor to poor health and quality of life that hinders sustainable development in any region.Coal mining is one of the major industries that contribute to the economy of a country but it also impacts the environment.The chemical parameters of the coal,overburden,soil and sediments along with the coal mine drainage(CMD)were investigated in order to understand the overall environmental impact from high sulphur coal mining at northeastern coalfield(India).It was found that the total sulphur content of the coal is noticeably high compared to the overburden(OB)and soil.The volatile matter of the coal is sufficiently high against the high ash content of the soil and overburden.The water samples have a High Electrical Conductivity(EC)and high Total Dissolve Solid(TDS).Lower values of pH,indicate the dissolution of minerals present in the coal as well as other minerals in the mine rejects/overburden.The chemical and nano-mineralogical composition of coal,soil and overburden samples was studied using a High Resolution-Transmission Electron Microscopy(HR-TEM),Energy Dispersive Spectroscopy(EDS),Selected-Area Diffraction(SAED),Field Emission-Scanning Electron Microscopy(FE-SEM)/EDS,X-ray diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),Raman and Ion-Chromatographic analysis,and Mossbauer spectroscopy.From different geochemical analysis it has been found that the mine water sample from Ledo colliery has the lowest pH value of 3.30,Tirap colliery samples have the highest electrical conductivity value of5.40 ms cm~(-1)Both Ledo and Tirap coals have total sulphur contents within the range 3-3.50%.The coal mine water from Tirap colliery(TW-15 B)has high values of Mg~(2+)(450 ppm),and Br~-(227.17 ppm).XRD analysis revealed the presence of minerals including quartz and hematite in the coals.Mineral analysis of coal mine overburden(OB)indicates the presence both of pyrite and marcasite which was also confirmed in XRD and Mossbauer spectral analysis.The presented data of the minerals and ultra/nano-particles present shows their ability to control the mobility of hazardous elements,suggesting possible use in environmental management technology,including restoration of the delicate Indian coal mine areas.     

西部侏罗系矿区充水含水层水文地球化学特征及矿井水来源综合识别

本文以水文地球化学理论为指导,基于研究区水文地质条件及矿山水害研究基础,构建了不同充水含水层水化学和氢、氧同位素基础特征值,结合不同煤层埋深煤矿含隔水层组合特征和导水裂隙带发育高度,综合识别了浅埋、中深埋和深埋多个煤矿的矿井水来源.研究结果显示,受水岩作用和水动力条件等因素影响,煤层上覆不同充水含水层地下水水化学类型和...     

Ambient nanoparticles/nanominerals and hazardous elements from coal combustion activity:Implications on energy challenges and health hazards

Coal is the most abundant fossil fuel in the world. Because of the growth of coal mining, coal-fired power plants and coal-burning industries, the increase of the emission of particulates(coarse, fine or ultrafine)is of great concern. There is a relationship between increasing human morbidity and mortality and progressive environmental air pollution caused by these types of particles. Thus, the knowledge of the physico-chemical composition and ambient concentrations of coal-derived nanoparticles will improve pollution control strategy. Given the current importance of this area of research, the advanced characterization of this coal combustion-derived nanoparticles/nanominerals as well as hazardous elements is likely to be one of the hottest research fields in coming days. In this review, we try to compile the existing knowledge on coal-derived nanoparticles/nanominerals and discuss the advanced level of characterization techniques for future research. This review also provides some of aspects of health risks associated with exposure to ambient nanoparticles. In addition, the presence of some of the hazardous elements in coal and coal combustion activities is also reviewed.     

矿井水的资源化与环境保护——以焦作矿区典型地段为例

针对我国煤矿区目前普遍存在的排、供矛盾和环境地质问题,本文首次提出了矿区排水、供水、环境保护三位一体优化结合的经济-水力管理模型。该模型通过布设地面矿坑抽水孔和奥灰(奥陶系灰岩)浅排孔等地上应急取水建筑物,增强了结合系统整体抗御突发性水害的能力,较好地解决了供水水源安全、稳定问题。同时,三位一体结合模型较为圆满地处理了长期以来从地质勘探到评价管理各个不同阶段,排、供和环保3个不同部门各立门户的封闭局面,避免了大量的重复投资,提高了评价、管理、决策的整体水平。本文以焦作矿区典型地段为研究实例。     

采煤对浅层地下水环境的影响及矿井水生态利用分析

黄河流域中上游矿区煤?水矛盾突出,煤炭开采对地下水环境造成一定的破坏。基于此,以鄂尔多斯盆地北部侏罗纪煤田榆神府矿区为研究区,在野外调查、数据分析、室内测试的基础上,分析研究区矿井水的量质特征,揭示煤炭高强度开采对地下水环境的影响,并开展矿井水生态利用研究。结果表明:研究区矿井富水系数在0.23~2.28,平均为0.91,评估2020年区内矿井排水量高达4.70亿m3,受采掘活动影响,浅埋煤层开采区地下水位下降趋势明显;区内矿井水出现不同程度的污染组分超标现象,主要超标指标为化学需氧量(COD)、Na+、SO₄ 2?、溶解性总固体(TDS),未处理的矿井水外排将会污染区内地下水环境;研究区浅层地下水超限的水质指标主要为NO₃-N,与矿井水超限水质指标差别较大,反映出浅层地下水水质受采矿活动影响较小;提出矿井水浅层回灌和矿井水生态灌溉2种模式开展研究区矿井水的生态利用,矿井水回灌对矿井水中的溶解性有机碳、色度具有较好的去除效果,回灌后出水满足Ⅲ类地下水限值;浅埋煤矿矿井水具有作为矿区生态修复灌溉用水的较好潜力,中深埋煤矿和深埋煤矿矿井水不适宜作为灌溉用水。研究结果为我国西部煤矿区水资源保护和生态修复提供重要依据。      

废弃煤矿采空区瓦斯抽采可行性评价模型构建及应用

在碳达峰碳中和的政策背景下,开发废弃煤矿瓦斯资源可产生较高的资源、经济与环境三重效益。通过调研及文献查阅,从技术可行性和经济合理性2个角度建立废弃煤矿采空区瓦斯抽采可行性评价指标体系,将博弈论组合赋权方法与模糊综合评价法结合,构建了博弈论?模糊综合评价模型,以晋城矿区废弃矿井古书院矿为例进行瓦斯抽采可行性评价。结果表明:一级指标中瓦斯资源条件及瓦斯保存条件的权重较高,分别为0.439 1和0.383 6,说明煤矿瓦斯赋存量和煤矿密闭性是影响废弃煤矿采空区瓦斯抽采可行性的决定因素;二级指标中,地面钻孔甲烷浓度和矿井涌水量权重较高,分别为0.091、0.087,说明废弃煤矿采空区瓦斯富集区的甲烷纯度及煤矿水害严重程度是影响废弃煤矿采空区瓦斯抽采可行性的关键因素;建立的评价模型修正了单一赋权评价法导致的权重失真问题,兼容了主客观定权重方法的优点;验证了博弈论?模糊综合评价模型应用于废弃煤矿采空区瓦斯抽采可行性评价的合理性。      

Groundwater geochemistry in shallow aquifers above longwall mines in Illinois, USA

 Aquifers above high-extraction underground coal mines are not affected by mine drainage, but they may still exhibit changes in groundwater chemistry due to alterations in groundwater flow induced by mine subsidence. At two active longwall mine sites in Illinois, USA, glacial-drift aquifers were largely unaffected by mining, but the geochemistry of the bedrock aquifers changed during the post-mining water-level recovery. At the Jefferson site, brackish, high-sulfate water present in the upper bedrock shale briefly had lower values of total dissolved solids (TDS) after mining due to increased recharge from the overlying drift, whereas TDS and sulfate increased in the sodium-bicarbonate water present in the underlying sandstone due to downward leakage from the shale and lateral inflow of water through the sandstone. At the Saline site, sandstones contained water ranging from brackish sodium-chloride to fresh sodium-bicarbonate type. Post-mining recovery of the potentiometric levels was minimal, and the water had minor quality changes. Longwall mining affects geochemistry due to subsidence-related fracturing, which increases downward leakage from overlying units, and due to the temporary potentiometric depression and subsequent recovery, whereby water from surrounding areas of the aquifer recharges the affected zone above and adjacent to the mine. Received, December 1998 / Revised, August 1999 / Accepted, August 1999     

我国露天煤矿截水帷幕关键技术进展

我国露天煤矿普遍采用抽排方式进行地下水控制以满足煤炭资源安全开采要求,这种方式对水资源造成极大破坏,严重影响煤矿周边的生态环境。近年来,随着我国社会经济的全面发展,国家对生态环境保护、生态文明建设提出了更高要求,如何优化、转变露天煤矿地下水控制方式,减少矿坑疏排水量是露天煤矿防治水工作普遍面临的崭新课题。采用截水帷幕技术取代疏排降水技术,由被动疏水变为主动截水,是解决露天煤矿因疏排水带来诸多问题的根本措施。以内蒙古扎尼河露天煤矿、元宝山露天煤矿截水帷幕实施过程为例,介绍我国露天煤矿截水帷幕设计理念、施工工艺和截水帷幕材料,在实践过程中,突破了防渗膜大深度垂向隐蔽铺设与连接技术瓶颈;研发了超长槽段连续开挖及浇筑工艺,大幅减少接头数量;研制粉煤灰?水泥混合浆体与HDPE防渗膜的复合帷幕材料,提高帷幕抗渗与抗变形性能;构建帷幕质量与截水效果综合检验体系,掌握了露天煤矿截水帷幕建造关键技术。截水帷幕技术在我国露天煤矿的成功应用,丰富了露天煤矿防治水与水资源保护技术理论,促进了行业技术进步,为露天煤矿地下水控制及安全绿色开采提供了新思路、新技术、新工艺,对其他非煤矿山及水利水电、交通等更高防渗等级要求的工程具有重要借鉴意义。      

煤矿井下定向钻进工艺技术的应用

定向钻进技术以其精确控制钻孔轨迹逐渐被应用于煤矿井下瓦斯抽采钻孔及防治水钻孔施工中。从定向钻进技术的原理入手,以国内多家煤矿企业井下施工定向钻孔的实际资料,研究了定向钻进技术在煤矿井下进行瓦斯抽采、地质构造探测及防治水施工的适用条件、布孔方式和成孔原理。结果显示,定向钻进技术在煤矿井下瓦斯抽采、地质构造探测及防治水领域的应用效果显著。      

山底河流域煤矿酸性矿井水野外监测

酸性矿井水在我国鲁西南、山西、内蒙、云南和贵州等煤矿区普遍存在,酸性矿井水其pH往往在2~5之间,高SO₄2?、HB、TDS、Fe、Mn。这些物质进入地下水、地表水或土壤后,会对其造成严重危害。文章选择山西阳泉市典型废弃煤矿区山底河流域为研究区,通过水文地质调查,水文地质钻探,水文地质剖面等方法阐述山底流域地层岩性,水文地质条件概况,得出受煤矿开采影响,与天然条件下相比山底河流域的地表水和地下水的补给、径流、排泄条件均发生了根本变化。补给通过破坏产生的导水裂隙带运移,以垂向运动为主;径流通过坑道,导水裂隙带运移,以横向运动为主;排泄以矿坑排水和泉水溢出方式为主。并简述山底河流域煤矿酸性矿井水试验站观测站分布情况与水化学特征。      

煤地质学研究进展与前沿

煤地质学是以煤的形成、组成、煤系伴生矿产、煤层瓦斯和煤层气为主要研究内容的地质学分支。近年来随着我国和世界对煤炭资源安全开采、洁净利用的要求逐渐提高,煤及煤层气资源的勘探与开发,煤地质学的研究重点也在逐渐发生变化。通过分析2011-2015年《国际煤地质学》杂志发表的717篇学术论文,总结了近期煤地质学最新的研究热点与前沿。研究发现:煤层气资源评价以及与煤层气开发关系最为紧密的煤储层物性研究是各国煤地质科技工作者最为关注的热点;煤中的矿物质和元素地球化学一直为人们所重视;与煤的形成、开采和利用相关的煤岩学及有机地球化学,煤的自燃、燃烧与环境,沉积环境与煤炭演化,地理信息系统与矿区环境监测,矿井瓦斯,矿井构造,矿井水和煤的热解等方面的研究一直在持续开展;页岩气资源评价与开发越来越受到人们重视。      

Coal mining‐derived ochres in the UK: a potential selenium trap

Thanks to the pioneering research of Paul Younger over the past 20 years, acid mine drainage in the UK has been recognized as a major environmental issue. Acid mine drainage and hydrous ferric oxide deposition are environmental hazards resulting from centuries of extensive coal mining activities across the UK. Oxidative weathering of pyrite in coal from spoil heaps and exposed bedrock can liberate trace elements, releasing them into local water systems. In addition to posing an environmental threat through water and ground contamination, ochres can also act as a remediation material, trapping elements such as selenium. Trace elements with a close association to iron oxides, such as selenium, may fix to the fine‐grained ochre materials, resulting in hyper‐enriched ochres. Selenium in coals has been known to cause an environmental issue in areas of North America but is also an important commodity for solar cells and nanotechnologies. Coal‐bearing areas of the UK, such as Northumberland, are known to contain a high selenium content, and coal‐derived ochres in these regions also contain significant selenium. The widespread occurrence of ochres in UK coal‐mining regions may therefore present a unique ‘E tech’ trace element source and prevent a toxicity problem for which they were once thought to be responsible.     

我国煤矿区矿井水污染问题及防控技术体系构建

煤炭开采必然产生大量的矿井涌水,我国目前的矿井水整体上表现出水质相对较差、水处理成本较高等问题。首先明确了我国典型矿区矿井水水质的主体特征:常规离子是造成矿井水水质差的主要化学组分;矿井水中有毒有害物质占比小,且基本优于地下水Ⅲ类水质量标准。其次,详细探讨了我国矿井水水质形成、演化的几个科学问题,包括不同水文地质结构下物理–化学作用所起的主导作用,时间效应对水质演化的影响,微生物群落结构特征及其与环境因素的相关关系,水动力场–化学场–微生物场–温度场的多场耦合问题等。接着重点介绍矿井水污染防控的技术方法,以减少矿井突(涌)水量和水资源保护为前提,以实现煤–水双资源协调开采、煤炭绿色开采为目标,以矿井水“阻断、减量、保护”为主要防控思路,围绕煤矿区矿井水阻断技术、污染负荷减量技术、污染区修复治理等科学问题展开分析;通过各种现有技术、方法、工艺,最大可能地降低吨煤矿井水处理成本,如采用井下预处理、地面深度处理、超深回灌封贮、生态资源化利用等。最后,提出研发煤矿区地下水及污染物的阻断材料和吸附材料、注浆装备、监测设备、投料设备、原位取样检测设备等,形成我国煤矿区矿井水污染防控技术体系。该技术体系的构建可对煤矿绿色开采、煤矿区深层地下水污染防控、闭坑矿井水污染防控、矿区地下水资源及生态环境保护利用等提供理论及技术支撑。      

Barium and radium discharged from coal mines in the Upper Silesia, Poland

 Waters discharged from coal mines in the Upper Silesia in Poland cause contamination of rivers and their sediments. Saline waters discharged from coal mines of the southern region contain elevated barium and radium. The discharge of these elements can be reduced by treating these waters with sulphates in mine workings. Sources of sulphate used in treatments include gypsum, anhydrite and industrial wastes such as: fly ash, slags and flotation tailings. Gypsum and anhydrite are used in the coal mine workings as components of the fire protection walls. Industrial wastes from power plants are stored in the mine workings as fire- and methane-protection agents. Sulphates precipitate barium and radium from saline waters inflowing into the mine workings. The waters can be treated by flowing them through old mine workings. In this case, the source of sulphates is the natural oxidation of pyrite. Mining activities and the natural process of desulphurisation of the Carboniferous rocks reduce the amount of barium and radium that is discharged in the southern region of Upper Silesia. The processes for reducing the environmental impact of toxic discharges from the mines should be monitored. Received: 3 July 1997 · Accepted: 27 March 2000     

矿山的环境地质研究初探

矿山采选冶事业发展,废水、废渣、废气排放量增加,对矿山环境造成污染,为科学地进行矿山环境治理,需开展矿山的环境地质研究,其任务是:(1)开展矿山初始时的环境地质调查,以利于查明环境污染程度,(2)编制矿山有关的环境地质图件,(3)研究矿山采选冶过程对矿山环境地质条件造成的影响,(4)研究矿山向城市化发展将出现的环境地质问题。湘西金矿在环境治理上取得一些成效,但环境地质问题仍不可忽视。     

Lithological and geochemical record of mining-induced changes in sediments from Macquarie Harbour,southwest Tasmania,Australia

Macquarie Harbour in southwest Tasmania, Australia, has been affected severely by the establishment of mines in nearby Queenstown in the 1890s. As well as heavy metal-laden acid rock drainage from the Mount Lyell mine area, over 100 Mt of mine tailings and slag were discharged into the Queen and Ring Rivers, with an estimated 10 Mt of mine tailings building a delta of ca. 2.5 km² and ca. 10 Mt of fine tailings in the harbour beyond the delta. Coring of sediments throughout Macquarie Harbour indicated that mine tailings accreted most rapidly close to the King River delta source with a significant reduction in thickness of tailings and heavy metal contamination with increasing distance from the King River source. Close to the King River delta the mine tailings are readily discriminated from the background estuarine sediments on the basis of visual logging of the core (laminations, colour), sediment grain size, sediment magnetic susceptibility and elemental geochemistry, especially concentrations of the heavy metals Cu, Zn and Pb. The high heavy metal concentrations are demonstrated by the very high contamination factors (CF > 6) for Cu and Zn, with CF values mostly >50 for Cu for the mine-impacted sediments. Although the addition of mine waste into the King River catchment has ceased, the catchment continues to be a source of these heavy metals due to acid rock drainage and remobilisation of mine waste in storage in the river banks, river bed and delta. The addition of heavy metals to the harbour sourced from the Mount Lyell mines preceded the advent of direct tailings disposal into the Queen River in 1915 with the metals probably provided by acid rock drainage from the Mount Lyell mining area.     

小煤矿的环境污染及防治措施探讨

通过对盘县、金沙县等部分生产小煤矿及其周边的环境污染问题的调查研究，结合小煤矿的生产实际情况，探讨了煤矸石的应用(作为工业原材料、用于发电等)前景，煤矿污水简易处理(经三级沉淀后，一般可达到工业用水标准)方法及煤尘污染防治(巷道内设立水幕)等措施。