Radio Transmission to and from Underground Coal Mines--Theory and Measurement

Research involved in the development of a radio communication system for use in coal mine disasters is described. Theoretically predicted field strengths for surface to mine and mine to surface propagation are compared with measurements in coal mines in Colorado and Pennsylvania. It is concluded that surface-to-mine voice communication is practical using a horizontal wire antenna operating at audio frequencies, and that mine-to-surface interrupted CW signaling is practical using multiple-turn horizontal loop antennas. This research has resulted in an emergency through-the-earth communication system that is being evaluated by the U.S. Bureau of Mines for use in mine rescue operations.     

Theory of the propagation of UHF radio waves in coal mine tunnels

The theoretical study of UHF radio communication in coal mines, with particular reference to the rate of loss of signal strength along a tunnel, and from one tunnel to another around a corner is the concern of this paper. Of prime interest are the nature of the propagation mechanism and the prediction of the radio frequency that propagates with the smallest loss. The theoretical results are compared with published measurements. This work was part of an investigation of new ways to reach and extend two-way communications to the key individuals who are highly mobile within the sections and haulageways of coal mines.     

A Statistical Radio Range Model for a Robot MANET in a Subterranean Mine

We present a statistical model for the radio range between robots in a Mobile Ad hoc NETwork (MANET) deployed in an underground mine. Such unmanned mobile robotic networks could potentially be used in hazard mitigation and search and rescue in tunnel environments such as mines and subways, as well as in building environments. In addition to fading characteristics, our model is able to represent the variable nature of the propagation path-loss exponent. To support our model, we present path-loss measurements made in a real mine. The usefulness of our model lies in the fact that it represents an overall propagation model for a mine and therefore can be used to calculate the wireless connectivity probability of an arbitrary node in the network without requiring a detailed physical representation of the MANET within the mine.      

无线设备在矿井中使用时的功率限制研究

针对矿井内存在多种易燃易爆气体的环境,介绍了引起瓦斯爆炸的基本途径以及矿井内无线电信号的特殊传播性质。通过计算波导型波的多模功率、热电效应及电热转换,重点论述在瓦斯气体存在的环境中无线设备应选择合适的发射频率和功率,保证在连续工作于一定质量的煤灰时不产生150℃以上高温而引起瓦斯爆炸。     

加强煤矿安全监控系统管理及应用的探讨

由于天然条件的制约,煤矿开采环境复杂,极易发生安全事故。煤炭行业是一项较为危险的行业,要想保证煤矿的安全,必须做好安全监控,防患于未然。煤矿安全监控系统是利用先进的信息技术,对煤矿进行全方位、多层次的管理的系统,可以直观、及时地发现生产中的安全隐患,能对煤矿的事故进行及时预警,从而为煤矿的安全生产提供有力的保障。例如,在煤矿安全生产中,避免瓦斯超标是保证矿井安全的首要条件。将该监控系统应用到瓦斯监控中,可以通过对监控数据的采集、传输、处理,来实现瓦斯超标预警。随着科学技术的进步,煤矿安全监控系统得到了越来越多的应用。基于此,文中对煤矿安全监控系统的管理和应用进行了简单分析。     

Elastic waves interacting with buried land mines: a study using the FDTD method

A three-dimensional (3-D) finite-difference model for elastic waves in the ground has been developed and implemented. The model has been created to supplement the development of a sensor that uses elastic waves to detect buried land mines. The model is used to investigate the propagation characteristics of elastic waves in the ground and to explore the interaction of elastic waves with buried land mines. When elastic waves interact with a buried mine, a strong resonance occurs at the mine location. The resonance can be used to enhance the mine's signature and to distinguish the mine from clutter. Results presented in this paper explain the features of elastic wave propagation in the ground and show the interaction of elastic waves with both an anti-personnel mine and an anti-tank mine.     

典型场景下电波传播特性建模

为了解决某些典型场景(如海上、山区、丘陵、城区)下无法使用已有基础模型来全面表达电波传播特性的问题,建立了一种在典型场景下,基于确定性抛物方程、适用于多个传输场景的统一电波传播模型。把典型场景等效为损耗介质层来求解边界条件,利用Fourier分步步进法得到相应解,然后得到电波在典型场景下的传播损耗,并进行了理论分析和实验验证。结果表明,在不同传输场景下,将统一电波传播模型与Miller-Brown模型、射线追踪模型进行比较,结果较吻合,验证了其正确性。这一结果对建立一种求解典型场景下电波传播衰落问题的统一电波传播模型是有帮助的。     

eLTE 4G宽带集群网络在矿山中的应用

为适应当前矿用无线通信发展的新形势，满足矿山安全生产的要求，文中阐述了4G无线宽带技术在矿山中的应用，并对目前煤矿4G网络建设存在的问题进行了分析，提出了解决方案，对推进4G无线网络在煤矿安全生产中的应用具有一定的意义。     

煤矿智能管理系统中现代电子技术的融入

随着工业技术的发展,现代电子技术也不断融入到人们的生活生产之中,成为当前经济企业创新的关键点。在煤矿行业发展中,针对煤矿管理中,设计基于现代电子技术的煤矿智能管理系统,不仅可以提升煤矿资源开发利用率,还可以提高煤矿管理的安全性,具有一定的应用价值。以下本篇来探讨下在煤矿智能管理系统中融入现代电子技术的措施。     

物联网在煤矿生产上的应用

中国煤矿资源丰富,但煤矿安全事故频发。针对煤矿安全生产问题,结合物联网技术,提出了一种矿井物联网的构建方案。以2．4GHz RFID射频读卡器作为感知末梢,感知并采集电子标签携带的员工身份码信息,校验正确后,再将身份码数据经工业总线网上传至地面监控计算机并由VB编程分析处理。实现了煤矿员工基本信息的可查询以及井下作业员...     

Some experimental investigation of the effect of railway tunnels on mobile communications in Western India

Establishing of mobile communications in guided structures like railway tunnels, coal mines, etc., is gaining increasing importance due to the passage of high speed and high density of trains in tunnels and for monitoring of information on safety of workers and day-to-day operations in various mines. The present study reports investigation of mobile communication experiments in ultra high frequency band in railway tunnels of western India conducted in a moving train both in uplink and downlink directions. The observed signal fluctuations are discussed in terms of tunnel characteristics and different modes of propagation in tunnels and compared with model deduced values.     

Earth conductivity estimates from through-the-Earth electromagnetictransmission tests

Electromagnetic narrowband signals were transmitted through the Earth at 27 coal mines located throughout the United States. From these tests, apparent Earth conductivity values were derived based upon a homogeneous half-space model of the Earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. This result is not consistent with the assumption of a homogeneous half-space Earth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated. The author found that the apparent Earth conductivity could be estimated from a linear combination of the transmitted frequency and mine depth     

基于PLC控制器的矿井副井提升信号系统的设计

矿井副井提升信号系统是副井提升电控系统的重要组成部分,其工作性能的优劣将直接影响到提升机的安全运行,甚至影响到整个煤矿的安全生产。本文以PLC控制器为核心设计了一种矿井副井的提升信号系统,提出了系统设计的框图和系统实现的功能,并对该系统的工作原理进行了阐述。该系统已在平顶山市部分煤矿初步试用,结果表明:该系统运行正常,性能稳定,信号发送准确,显示屏显示可靠,有力地保障了提升安全的可靠性,为煤矿安全生产奠定了坚实的基础。     

煤矿安全生产监测管理系统的设计与实现

针对煤矿地理环境复杂、井下作业环境恶劣,难以有效地对煤矿井下开采环境进行有效地监测和管理,设计并实现了煤矿安全生产监测管理系统。该系统采用MFC开发语言和基于GIS与组态软件开发技术,对目前的主从式监测管理系统进行了升级,对煤矿生产过程中的基本非安全因素可以进行全面地监控。该系统实现了分散煤矿信息采集的自动化,具有及时、高效、准确、基建投资少、运行成本低等特点,具有显著的社会效益和较大的经济效益。     

State-of-the-art and trend of emergency rescue communication technologies for coal mine

For the disaster area probing and emergency rescue in a mine,it is of great importance to employ the emergency communication system to communicate with each other,determine the places of trapped miners,and sense current status of disaster area.The hybrid emergency communication architecture model for coal mines was extracted,which was composed of one backbone,multiple branches,several special lines,and some wireless networks as assistance.Four types of emergency communication systems of coal mine were reviewed,namely through-the-air,through-the-wire,through-the-earth and mixed medium type.The key technologies and challenges of these four emergency communication types were analyzed.The research trend was discussed and a new emergency communication mode based on the reconstruction of mine Internet of things was proposed.The main enabling technologies of this new emergency communication mode were analyzed,namely post-disaster reconstruction of mine Internet of things,shifting nodes re-localization after mine disaster,status sensing method of mine disaster area,and data transmission method for post-disaster reconstruction network.     

基于全局透射边界条件的宽角抛物方程电波预测模型

提出了一种新型的基于全局透射边界条件（non-local boundary condition,NLBC）的Greene近似宽角抛物方程（wide-angle parabolic equation,WAPE）电波预测模型,用于求解对流层远距离复杂环境中的电磁波传播特性.采用有限差分法（finite difference method,FDM）求解WAPE得到了三对角线性方程组,可以快速地求解整个空间的电场分布,也可以对不规则的地表环境进行精确建模.本文提出的WAPE模型解决了传统的PE离轴传播角度偏小的问题,将电波的最大传播仰角提升至约50°,同时大大减小了计算区域中上边界吸收层的设置尺寸,从而提高了PE的计算效率.实验证明,当伪微分算子的相位误差不超过0.002时,Tappert、Claerbout和Greene近似形式得到的最大传播角分别为20°、35°和45°.最后,通过与经典的光学双射线模型进行对比,证明本文提出的基于NLBC的Greene近似WAPE模型的可计算传播仰角更大,对上边界处反射电磁波有良好的吸收效果.因此,本文的模型适用于对流层远距离复杂环境中电磁波传播特性的精确预测.     

组态软件在煤矿管控一体化信息平台中的应用

管控一体化是我国煤矿未来的发展趋势。本文阐述了组态软件的核心技术及其在煤矿管控一体化信息集成技术中的重要应用,并给出了具体系统设计方案。     

重庆瓦斯利用的环境影响评价

重庆是全国有名的高瓦斯矿井和煤与瓦斯突出矿井集中的地区,瓦斯资源丰富。基于矿井安全生产,从1958年开始抽放矿井瓦斯,抽放量不断提高,瓦斯利用规模迅速扩大。瓦斯的主要成分是甲烷,甲烷是主要的温室气体之一,也是一种洁净优质能源。利用瓦斯,减少瓦斯空排量,对节能降耗,减缓温室效应,保护环境有着重要的意义。     

基于DSP2812的带式输送机多路温度检测系统设计

针对以往矿用带式输送机滚筒温度检测系统的不足,本文设计了一种新型带式输送机滚筒温度检测系统,该系统以TMS320F2812芯片为控制核心,将红外热电偶探测器获取的温度,处理后通过CAN总线与上位机通信。研究结果表明,高速DSP芯片与CAN总线的结合特别适用于煤矿井下数据采集与控制,对于在煤矿中的应用具有广泛的前景。     

Electromagnetic wave propagation in an asymmetrical coal seam

Electromagnetic wave propagation in a coal seam is analyzed for the case where the surrounding floor and roof rocks have different electrical properties. Numerical results are presented for the attenuation rate and field distribution of the dominant mode. Even when the roof and floor conductivities are different, the vertical electric field and the horizontal magnetic field are the dominant components, and they are nearly constant within the coal seam. The results have application to mine communication and remote sensing of coal seams.