Stresses and displacements due to underground mining using a finite element procedure

Summary A two dimensional finite element procedure is applied to simulate a coal mining excavation sequence. A procedure with linear solution steps is developed and applied to an idealized mountain cross-section with exceptionally thick coal seams and large dip angle. The results provide information on pillar pressure, floor and roof stability, displacement characteristics and surface subsidence.The results presented here were obtained in the course of research sponsored by the Department of Energy, Mines and Resources, Grant No. 69-2570.     

Nitrogen and carbon dioxide occurrence in UK coal seams

Conclusions Some bituminous coals, mostly of high volatile rank, sampled from various coalfields contained on average 0.5 m³ t^–1 nitrogen and 0.13 m³ t^–1.Nitrogen is released more readily than methane during coal winning but the volumes of nitrogen released are small compared with ventilation quantities and are only likely to be of significance for detailed oxygen deficiency studies.     

油气储运系统钢结构设备地震火灾效应研究

预防和减轻油气储运系统地震火灾危险性是防震减灾中的重要课题。本文论述了油气储运系统的地震火灾特征及防火要求，对钢结构的防火涂料在遭到破坏和平时情况下的抗火性能进行了对比分析，并应用有限元法对油气储运系统中典型钢结构设备在地震火灾荷载作用下的抗火性能进行了数值模拟。研究结果表明，防火涂料遭到强地震荷载破坏后，钢结构的抗火性能大大降低。     

陕北煤炭基地的矿井水资源及利用

简要论述了陕北地区煤矿开发的水文地质条件,对矿井水资源量、水质及利用途径进行了阐述.该区大型煤矿每天排水1 500～3 000 m3,中型煤矿也有500 m3左右,小煤矿每天排水30～100 m3,利用好矿井疏干水,不仅可以解决能源化工基地建设的用水需求,而且符合国家产业政策和环境保护的要求,是陕北能源化工基地建设的必然选择.     

内蒙古乌达地区地球物理场特征与地下煤火分布

以2004年内蒙古乌达地区1:5000大比例尺的直升机航空电磁、磁综合测量资料为基础,结合地面煤田地质、物探、遥感等资料,对内蒙古乌达地区的航空磁场特征、航空电磁场特征与地下煤火分布的关系进行了分析与研究,在综合分析的基础上,建立了该区的地下煤火划分标志,并对该区的地下煤火分布和燃烧状况进行了分析和圈定.     

Thermal surface characteristics of coal fires 1 results of in-situ measurements

Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO₂ and – under certain circumstances – to spontaneous combustion. Coal fires occur in many countries world wide – however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N₂O). They additionally contribute to the emission of green house relevant gasses such as CO₂ and CH₄ to the atmosphere.In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered.Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime. Thus, night-time analysis is the most suitable for thermal anomaly mapping of underground coal fires, although this is not always feasible. The heat of underground coal fires only progresses very slowly through conduction in the rock material. Anomalies of coal fires completely covered by solid unfractured bedrock are very weak and were only measured during the night. The thermal pattern of underground coal fires manifested on the surface during the daytime is thus the pattern of cracks and vents, which occur due to the volume loss underground and which support radiation and convective energy transport of hot gasses. Inside coal fire temperatures can hardly be measured and can only be recorded if the glowing coal is exposed through a wider crack in the overlaying bedrock. Direct coal fire temperatures measured ranged between 233 °C and 854 °C. The results presented can substantially support the planning of thermal mapping campaigns, analyses of coal fire thermal anomalies in remotely sensed data, and can provide initial and boundary conditions for coal fire related numerical modeling.In a second paper named “Thermal Characteristics of Coal Fires 2: results of measurements on simulated coal fires” [Zhang J., Kuenzer C., Tetzlaff A., Oettl D., Zhukov B., Wagner W., 2007. Thermal Characteristics of Coal Fires 2: Result of measurements on simulated coal fires. Accepted for publication at Journal of Applied Geophysics. doi:10.1016/j.jappgeo.2007.08.003] we report about thermal characteristics of simulated coal fires simulated under simplified conditions. The simulated set up allowed us to measure even more parameters under undisturbed conditions — especially inside fire temperatures. Furthermore we could demonstrate the differences between open surface coal fires and covered underground coal fires. Thermal signals of coal fires in near range thermal remotely sensed imagery from an observing tower and from an airplane are presented and discussed.     

Sandstone response to salt weathering following simulated fire damage: a comparison of the effects of furnace heating and fire

Fire has long been recognized as an agent of rock weathering. Our understanding of the impact of fire on stone comes either from early anecdotal evidence, or from more recent laboratory simulation studies, using furnaces to simulate the effects of fire. This paper suggests that knowledge derived from simulated heating experiments is based on the pre‐conceptions of the experiment designer – when using a furnace to simulate fire, the operator decides on the maximum temperature and the duration of the experiment. These are key factors in determining the response of the stone to fire, and if these are removed from real‐world observations then knowledge based on these simulations must be questioned. To explore the differences between heating sandstone in a furnace and a real fire, sample blocks of Peakmoor Sandstone were subjected to different stress histories in combination (lime rendering and removal, furnace heating or fire, frost and salt weathering). Block response to furnace heating and fire is discussed, with emphasis placed on the non‐uniformity of the fire and of block response to fire in contrast to the uniform response to surface heating in a furnace. Subsequent response to salt weathering (by a 10% solution of sodium chloride and magnesium sulphate) was then monitored by weight loss. Blocks that had experienced fire showed a more unpredictable response to salt weathering than those that had undergone furnace heating – spalling of corners and rapid catastrophic weight loss were evidenced in blocks that had been subjected to fire, after periods of relative quiescence. An important physical side‐effect of the fire was soot accumulation, which created a waxy, relatively impermeable layer on some blocks. This layer repelled water and hindered salt ingress, but eventually detached when salt, able to enter the substrate through more permeable areas, concentrated and crystallized behind it, resulting in rapid weight loss and accelerated decay. Copyright © 2007 John Wiley & Sons, Ltd.     

城市消防地理信息系统的设计与实现

城市消防地理信息系统是消防指挥决策系统的一个重要组成部分，本文着重介绍了城市消防地理信息系统的结构、主要功能和特点。     

江苏南部地区煤层气资源

根据江苏南部地区二叠系龙潭组煤系的分布和规模、煤矿瓦斯涌出特征、煤的产气能力、煤层的储集条件等煤层气地质条件综合研究工作，认为该区煤层气资源存在一定的勘探开发前景，对各典型含煤区块煤层气综合评价出有远景区（A类）、较有远景区（B类）和远景差区（C类）。     

云南禄丰煤岩与围岩中富勒烯（C60）物质的初步探索

中国云南煤中是否存在富勒烯还没有科学定论。本工作运用高效液相色谱方法，对中国云南禄丰晚三叠世煤岩及其围岩中是否存在天然富勒烯物质的问题进行了探索性研究；同时发展了适于从复杂地质样品中分离纯化富勒烯和定性与定量检测富勒烯的一套技术方法。结果显示，从定性角度有两个样品确实存在富勒烯。本文据此提出，富勒烯的赋存与煤岩／围岩交互相上的含煤碳质泥岩有着密切的关系。下一步研究应着重调查比煤岩与顶板和底板界面层并大力研究其中天然富勒烯的地学成因。本工作的意义还在于为今后我国加入和独立开展以富勒烯类物质（如C60／C70）及其衍生物质（如He C60 C70)作为地球化学示踪物的古地球突变大事件的研究，奠定了实验方法学基础。