Probabilistic seismic hazard evaluation in underground mines     

Ewa GłOwacka 《Natural Hazards》1993,7(2):121-132

Stress concentrations produced by rock deformation due to extraction in underground mines induce seismicity that can take the shape of violent and quite dangerous rockbursts.The hazard evaluation presented in this paper is based on a Bayesian probabilistic synthesis of information determined from mining situations during excavation, with previous and present data from microseismicity and seismoacustics.The method proposed in this study is an example of time-dependent on-line seismic hazard evaluation. All results presented were obtained retrospectiely for different underground coal mines in Poland and Czechoslovakia.On leave from Institute of Geophysics, Polish Academy of Sciences 01-452 Warszawa, ul. Ksiecia Janusza 64, Poland.  相似文献   

“煤特征指数”与矿井瓦斯危险类型的关系     

张世平 《煤田地质与勘探》1992,20(6):36-39

矿井瓦斯危险程度与煤层中瓦斯赋存状况及其泄出方式有关,并取决于多种地质条件和采掘工艺。其中,煤特征条件特别重要。本文分析了湖南省的5种矿井瓦斯危险类型以及相应的煤特征条件,提出了“煤特征指数(I_c)”这一概念。I_c是一项评价矿井瓦斯危险程度的综合指标。研究表明,矿井瓦斯危险愈严重,则其I_c值愈高。应用该项成果预测了16对矿井的瓦斯危险类型,取得了满意的效果。  相似文献   

近50 a渭河流域洪水成因分析及防治对策   总被引：6，自引：1，他引：6  

张琼华  赵景波 《中国沙漠》2006,26(1):117-121

 通过对近50 a渭河流域洪水的年际变化、月际变化和潼关高程变化的综合分析得出，造成该流域洪水灾害的原因有降水量年内分配不均和年际变化大，滩面淤积加重，支流河口淤塞以及河势、流态的恶化等。针对这些原因，根据渭河流域洪水灾害的特点，提出了相应的防治措施，即降低下游高程，减少河道的淤积，增大河道泄洪能力；利用水库进行调水调沙，引进客水冲刷渭河下游；防洪工程要除险加固，提高防洪标准与抗洪能力；恢复林草植被，遏止水土流失，从源头上控制泥沙入河等。  相似文献   

青藏高原腹地湖泊沉积对第四纪晚期古季风变化的响应   总被引：2，自引：0，他引：2  

胡东生  张华京  徐冰  李炳元  孔照辰  温景春 《干旱区地理》2006,29(4):483-489

通过对青藏高原腹地的综合科学考察和对中心钻孔岩芯剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区湖泊沉积记录(孔深7.25 m)的第四纪晚期距今3万余年以来的古气候变化,沉积物磁化率等因子综合表征的高原古季风变化是波动发展的,发生在仙女木期地质环境事件中的季风活动具有强烈暴发的特点,是高原季风发展中的突变事件,而且地表热点效应对其起到了激发作用。综合分析的研究成果表明,它的变化频谱与激变因子及其运行机制是伴随着青藏高原地质效应的演变而发展的,为研究第四纪冰消期以来的气候变化提供了新的信息。  相似文献   

Acid leaching of ash and coal: Time dependence and trace element occurrences     

Mehtap Paul  Meryem Seferinoğlu  Gul Asiye Ayçık  Åke Sandström  Michael L. Smith  Jan Paul 《International Journal of Mineral Processing》2006

The leaching of coal and coal/asphaltite/wood-ashes in sulfuric acid (pH 1.0, 25 °C, S/L, 1:10) was studied as a function of time; acid consumption and extracted metal concentrations are presented. Whole coals consumed acid rapidly during the first few minutes, followed by slow acid consumption. Wood-, lignite-, and asphaltite-ashes consumed acid in two stages, the rapid phase extending < 30 min and the slow phase extended up to 10 days. The rapid phase was dominated by the dissolution of Ca, K and Mg ions for wood-ash, by Ca, Al and Mg ions for lignite-ash and Ca and Mg ions for asphaltite-ash. The sulfur concentration in solution and the concentrations of Ca, Fe, K, Mg, Na, P, Al and Mn in the aqueous phase verified the neutralizing capacity of the untreated ashes as well as the formation of insoluble sulfates in the residues. The slow phase kinetics differed for different fuels and exhibited leaching of several abundant elements—Fe, Al, K, Na and Mn. Trace elements (Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Th, U, V, Zn) sometimes required up to 32 h for maximal extraction from ashes. Suggestions are presented regarding the chemical nature of trace elements in the untreated coals and ashes and suitable residence times for economical industrial processes. We think it possible to combine bacteriological oxidation of sulfidic concentrates of acid leaching from ash of various qualities or even whole coals.  相似文献   

Environmental aspects of selected trace metals in soils and waters surrounding Singaran Nala, Raniganj Coalfield     

Supriyo Das 《中国地球化学学报》2006,25(B08):24-25

The Raniganj Coalfield is the oldest coalfield in India that has been continuously and extensively mined since the late eighteenth century. The present study reports a geochemical investigation and environmental quality assessment using soil and water in the area surrounding a stream, locally known as Singaran Nala （Nala means storm water drains in Bengali）, in the Raniganj Coalfield. Soil （top soil, mud, silty clay and laterite） and rock samples （sandstone and shale） were collected from the study area and were analyzed for trace metals （Cr, Cu, Fe, Mn, Ni and Zn）. Surface waters from the stream and the Damodar River as well as ground waters from hand pumps and underground mine pits were collected. Water samples were analyzed for major ions （Na^＋, Ca^2＋, Mg^2＋, Cl^-, HNO3^- and SO4^2-） and trace metals （Cu, Fe, Mn, Ni, and Zn）. Trace metal concentrations in soil samples are found higher than the average world soil composition. Nevertheless, trace metal （Cr, Cu, Ni and Zn） concentrations in soils exceed or reach the maximum allowable concentrations （MAC） proposed by the European Commission for agricultural soils. In particular, Ni concentrations exceed the typical value for cultivated soils. Chromium, Cu and Ni concentrations in laterite and Cr concentration in topsoil exceed the ecotoxicological limit.  相似文献   

Increasing of efficiency of desulphurisation processes of coals during thermal destruction     

Turchanina Oksana Satin Vladimir Derevyanko Aleksey 《中国地球化学学报》2006,25(B08):51-52

As is well known, a high content of sulphur in coals is an effect of the post-depositional history of coal seams and one of the most important criteria of its use as a fuel. Sulphur in coals can cause a serious environmental and technological problem during their utilization. This problem is very actual for the Donetsk Basin because 734 mined seams out of the total of 1009 （73%） are comprised of coals with sulphur content -2%. The chemical pre-treatment as a first stage in their processing is widely used in order to effectively obtain the thermal destruction products of coals （such as semi-coke, coke, adsorbents, etc.） and to simultaneously utilize coal wastes. Development in pre-treatment methods for high-sulphur, low-rank coals is especially desirable for reducing the sulphur contents of the solid products. The aim of the present work is to investigate the influence of coal pre-treatment on the yield and composition of thermal destruction products, and the sulphur distribution among different components of the coals of different genetic types by reductivity （low-reduced LRC and reduced RC coals）. The thermal behavior of the coals was studied by means of the Fisher method （heated to 520℃, at a rate of 7℃/min）. The composition of the semi-coking gas was investigated by means of a VTI gas analyzer. The coal samples were chemically treated directly before thermal destruction by the introduction of 1-% solutions of radical polymerization initiator AAD （acrylic acid dinitrile C8H12N4） and products of coal-tar distillation （absorber oil）. Coal pre-treatment increases the semi-coke yield and its coking ability, and changes the liquid/gaseous product ratio.  相似文献   

Determination of potential hazardous elements in Can coals （Canakkale- Turkey）-I     

Gulbin Gurdal Alper Baba 《中国地球化学学报》2006,25(B08):52-53

It is known that the increasing use of coal as an energy source led to the growing environmental and health problems. But comprehensive knowledge of coal quality parameters may help to reduce some of these problems. The Canakkale-Can coalfield is located in the western part of Turkey, whose reserves are estimated at 69.3 billion tons, mainly used in the industry in the neighboring areas, specifically for the Can Thermal Power Plant. The aim of this study is to determine the coal quality parameters and examine the origin and distributions of potentially toxic trace elements in lignite which may produce environmental and health hazards in the area. The coal samples were collected from different parts of the coalfield in Can. Proximate and ultimate analyses, sulfur form analyses, X-ray powder diffraction （XRD）, inductively coupled plasma-mass spectrometry （ICP-MS）, and scanning electron microscopy （SEM） were performed on those samples to determine the geochemical profile of hazardous elements.  相似文献   

Characterization of water bursting and discharge into underground mines with multilayered groundwater flow systems in the North China coal basin   总被引：2，自引：0，他引：2  

Qiang Wu  Mingyu Wang 《Hydrogeology Journal》2006,14(6):882-893

A conceptual framework for characterization of water bursting and discharge into underground mines with multilayered groundwater flow systems is presented, based on the features of the site conditions and analyses of the water bursting and mine inundation events of the North China coal basin. Comprehensive analyses of the hydrogeological conditions for establishment of the three-dimensional groundwater flow systems of the North China coal basin revealed different vertical hydraulic connection paths or channels. These connections include karst collapse columns, fault or fracture zones, buried weathering zones, and fracture networks in aquitards, within the multilayered groundwater flow systems. Also examined, was the effect of the primary features of the flow system and those different connection paths on water bursting and discharge into the underground coal mines. It was demonstrated that appropriately identifying and adequately understanding the three-dimensional multilayered groundwater flow systems and those various vertical hydraulic connection mechanisms are critical for appropriately preventing water bursting hazards and predicting water discharge into underground mines. A valuable guideline is presented on characterization of water bursting and discharge into underground mines with multilayered groundwater flow systems.

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Resumen Un cadre de travail conceptuel pour la caractérisation du jaillissement et de la vidange des eaux dans les mines à plusieurs niveaux d'écoulement est présenté, basé sur les conditions et l'analyse sur site du jaillissement des eaux et des inondations dans les bassins charbonneux du Nord de la Chine. L'analyse compréhensive des conditions hydrogéologiques des systèmes d'écoulement tridimensionnel de ces bassins, révèle des trajets ou des chenaux qui sont autant de connections hydrauliques verticales. Ces connections comprennent des effondrement karstiques en colonne, des zones de fractures et de failles, des zones d'altération, des réseaux de fractures dans les aquitards, dans le système hydrogéologique multicouche. L'influence des caractéristiques primaires du système d'écoulement et de ces différentes connections sur le jaillissement et la vidange dans les mines, est également examiné. Il a été démontré que l'identification appropriée et la compréhension adéquate du système d'écoulement souterrain multicouche et tridimensionnel, et des mécanismes variés de connection hydraulique verticale est critiquée pour prévenir de manière appropriée les risques de jaillissement et de vidange dans les mines. Des guidelines valorisables sont présentées, pour la caractérisation du jaillissement et de la vidange dans de tels systèmes.

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Résumé Se presenta un marco conceptual para la de caracterización de la despresurización y descarga de agua a minas subterráneas con sistemas de acuíferos de múltiples niveles, el cual se basa en las condiciones del sitio, análisis de la despresurización de agua e inundaciones de minas en la cuenca de carbón del norte de la China.Un análisis comprehensivo de las condiciones hidrogeológicas para el establecimiento de los sistemas de flujo de agua de tri-dimensionales en la cuenca de carbón del norte de la China ha revelado diferentes canales hidráulicos verticales. Estas conexiones incluyen columnas de karst colapsadas, fallas o zonas de fracturas, zonas de regalita hundida y redes de fracturas en zonas de poca permeabilidad dentro de los sistemas de flujo de múltiples niveles.También se investigó el efecto de los rasgos primarios del sistema de flujo y los diferentes canales conectivos sobre la despresurización y descarga de agua a minas subterráneas. Se demostró que el entendimiento e identificación adecuada de los sistemas de acuíferos de múltiples niveles en tres dimensiones es crítico para prevenir apropiadamente la despresurización y descarga de agua a minas subterráneas. Se presentan lineamientos valiosos en relación con la despresurización y descarga de agua a minas subterráneas en sistemas de flujo de múltiple nivel.

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重庆市开-利公路学堂湾滑坡成因与稳定性分析     

吴汉辉  杨转运 《中国地质灾害与防治学报》2006,17(2):33-36

滑坡是现代公路、铁路等交通基建工程面临的一个难题。尤其是在重丘、山地等地段修筑公路工程极易出现滑坡地质灾害。这些滑坡的成因以及相关的边坡稳定性分析目前处于半理论、半经验状态。文章基于学堂湾滑坡的地理位置及地质环境条件,从滑坡区地质环境条件、滑坡周界、滑坡体与滑带的物质结构特征、滑床、滑坡变形破坏迹象等,深入分析了学堂湾滑坡的变形特征。在此基础上探讨了滑坡成因,指出大量的雨水和不合理的施工扰动是滑坡发育的外因;坡体本身的地质条件如岩石的裂隙、岩土体的透水性以及水的疏导条件等是其内因。文章将宏观定性分析与定量计算相结合,对滑坡稳定性进行了分析和评价。结合工程实际对滑坡治理措施进行了初步研究,取得了一些满意的效果。  相似文献