Seismological method for prediction of areal rockbursts in deep mine with seismic source mechanism and unstable failure theory

The research on the rock burst prediction was made on the basis of seismology,rock mechanics and the data from Dongguashan Copper Mine(DCM) ,the deepest metal mine in China.The seismic responses to mining in DCM were investigated through the analyses of the spatio-temporal distribution of hypocenters,apparent stress and displacement of seismic events,and the process of the generation of hazardous seismicity in DCM was studied in the framework of the theory of asperity in the seismic source mechanism.A method of locating areas with hazardous seismicity and a conceptual model of hazardous seismic nucleation in DCM were proposed.A criterion of rockburst prediction was analyzed theoretically in the framework of unstable failure theories,and consequently,the rate of change in the ratio of the seismic stiffness of rock in a seismic nucleation area to that in surrounding area,dS/dt,is defined as an index of the rockburst prediction.The possibility of a rockburst will increase if dS/dt>0,and the possibility of rock burst will decrease if dS/dt<0.The correctness of these methods is demonstrated by analyses of rock failure cases in DCM.

A limit equilibrium fracture zone model to investigate seismicity in coal mines

This paper explores possible synergies between techniques used to minimise seismicity in deep South African gold mines and their applicability to control coal bumps. The paper gives a summary of the techniques used in the deep gold mines and a critical appraisal if these are useful in coal mines. The techniques typically include control of mining rate, preconditioning, optimisation of extraction sequences and centralised blasting. Of particular interest to the coal bump problem is an experimental limit equilibrium fracture zone model implemented in a displacement discontinuity code. This was recently developed for the gold mines to enable the interactive analysis of complex tabular mine layout extraction sequences. The model specifically accommodates energy dissipation computations in the developing fracture zone near the edges of these excavations. This allows the released energy to be used as a surrogate measure of ongoing seismic activity and addresses a number of the weaknesses in the traditional usage of this quantity as a criterion for the design of seismically active layouts. This paper investigates the application of the model to a hypothetical coal longwall layout and the specific problem of coal bumps.

Whole-mine subsidence over tabular deposits and related seismicity

The challenge of estimating mine-wide subsidence and linkages to seismicity over tabular deposits is addressed by a special finite element technique(dual node–dual mesh). Subsidence and mine-induced seismicity begins near the face when caving occurs and propagates to the surface as extraction reaches a critical extent. Thus, the challenge is to obtain details at the face at the meter scale and also at the surface over the whole mine at the kilometer scale. Interactions between old and new sections of a mine are automatically taken into account with this technique. The finite element method is well established technology based on fundamentals of physical laws, kinematics and material laws. With this technique, no empirical ‘‘scaling" or fitting computer output by input data ‘‘adjustment" to mine measurements is necessary. Capability is demonstrated for doing practical whole-mine subsidence analysis from first principles. Mine-induced seismicity is shown to correlate well with face advance and element failure.

Application Results of 3-D Seismic Exploration Technology in Coal Mines

This paper briefly introduces the development and present situation of China's coal seismic exploration. It focuses on analyzing the important functions of 3-D seismic exploration technology in the designing and production of coal mines, and also the results of its application.

Effective wave identification and interference analysis of the seismic reflection method in mines

Through discussion of the time-distance curve characteristics of the direct waveand from the front,side and rear of the reflection waves of the seismic reflection methodfor advanced exploration in mines,and analysis of several major interference waves inmines,the differences in time-distance curve,frequency,apparent velocity between theeffective wave and interference wave in the seismic reflection method for advanced explorationare obtained.According to the differences,the effective wave is extracted andthe interference wave is filtered and the system's precision and accuracy is improved.

Applying real time seismic monitoring technology for slope stability assessment—An Indian opencast coal mine perspective

This paper outlines the results obtained from real time microseismic monitoring of an opencast coal mine in South India.The objective of the study is to investigate the stress changes within the rockmass along the slope due to underground mine development operation and their impact on the stability of the highwall slope.The installed microseismic systems recorded the seismic triggerings down toà2 moment magnitude.In general,most of the events recorded during the monitoring period are weak in seismic energy.The study adopts a simple and more reliable tool to characterize the seismically active zone for assessing the stability of the highwall in real time.The impact of underground working on the slope is studied on the basis of the seismic event impact contours and seismic clusters.During the monitoring period,it is observed that the intensity of the overall microseismic activity along the slope due to the mine development operations did not cause any adverse impact on the highwall stability.

Numerical and Geophysical Tools Applied for the Prediction of Mine Induced Seismicity in French Coalmines

The determination of the influence of mining works and the induced seismicity is essentially obtained, separately from in-situ observations and seismic analysis, field measurements (particularly surface survey) as well as from numerical investigations. The paper presents a methodology applied for the analysis of induced seismicity due to underground coalmines based on combining numerical modelling and seismic analysis. The methodology is based on the comparing between the observations, the seismic activity and the numerical modelling for establishing a close correlation between the location of seismic activity and the induced stresses. The paper presents two case studies using seismic and geotechnical investigations, the first one concerns a fatal accident affected Lorraine coalmine (East France). The second case concerns the application of the methodology on Provence coalmines (South France). The application of the methodology shows such a coupling can be an efficient way for detecting areas subjected to rockburst hazard. This is also a powerful tool for assisting the planning of underground workings in complex geological and mining conditions. The coupling of geotechnical investigations (numerical modelling, in-situ stress measurements) and seismic analysis are strongly recommended.

基于VMD和GA-SVM的矿井地震自适应噪声压制方法

煤矿井下地震信号往往呈现出复杂的波场特性且伴随着大量噪音干扰,导致地震信号的初至拾取精度降低,从而影响地震数据的反演与解释。针对复杂干扰环境下采集的低信噪比地震信号,提出了基于变分模态分解(VMD)和遗传算法优化支持向量机(GA-SVM)的地震噪声压制与初至提取方法,以提高煤矿井下复杂噪声条件下的地震信号质量。采用变分模态分解对含噪地震信号进行自适应分解,得到数个的变分模态分量(IMF);对VMD分解得到的IMF分量进行特征提取,将提取所得的信号特征作为信号有效性判别的依据;利用遗传算法对支持向量机模型进行优化,得到最优的惩罚因子c与核函数参数g;利用优化后的支持向量机模型对IMF分量进行有效性判别并将有效分量重构成高信噪比信号;通过对人工加噪的地震信号应用噪声压制算法,煤矿井下常见的不同类型噪声被有效地压制,验证了算法的可行性;对矿井巷道实采的地震记录进行噪声压制处理,有效地压制了数据中的干扰噪声,极大程度地提高了地震记录的信噪比,使初至拾取得更加准确。结果表明,基于VMD和GA-SVM的地震噪声压制方法可以很好地提取含噪地震记录中的有效信号,提高初至拾取精度,在矿井复杂干扰条件下具有显著的应用潜力,对解决矿井复杂干扰条件下的地震勘探问题有重要意义。

某钨矿露地联采关键地压灾害监测预警研究

某钨矿形成了露地联采的开采局面,面临着井下群采空区与隔离间柱稳定性、露采边坡稳定性、露地相互影响等关键地压灾害问题。设计建设了最先进的66通道微震监测系统、测量机器人与边坡雷达等地压监测预警系统。文章详细介绍了一次典型的岩体失稳垮塌的成功预警案例。上述综合性的地压监测手段将为矿山安全生产提供重要的技术支撑。

王家岭煤矿综放工作面上覆岩层运动规律及卸压区瓦斯抽采试验研究

为实现低瓦斯高涌出矿井综放工作面安全高效开采,以王家岭煤矿为背景,结合物理相似模拟实验、UDEC数值模拟和微震监测,系统分析了王家岭煤矿综放工作面上覆岩层运动规律,在此基础上,开展了现场卸压区瓦斯抽采试验。研究结果表明:随工作面推进,煤层顶板上覆岩层垮落高度距煤层底板距离增大,离层裂隙距顶板距离增大,空洞高度减小;采空区两侧瓦斯运移通道的裂隙多于压实区的裂隙。初次来压前,采空区垂直应力随工作面的推进而降低;初次来压后,采空区垂直应力随工作面的推进而增大。在进、回风巷顶板,煤层、采空区顶底板共发生2 572个微震事件,工作面前方50 m范围内应力集中较大,应注意超前支护防范。12301工作面周期来压步距20~26 m,采动裂缝带高度90~110 m,周期来压4~6次。现场卸压区瓦斯抽采试验中,合理层位工作面瓦斯抽采量是其他层位工作面瓦斯抽采量的1.5倍,且工作面上隅角和回风流瓦斯浓度均小于0.8%,瓦斯治理效果显著。

HSP超前探测技术在煤矿TBM掘进巷道中的应用研究

随着全断面掘进机TBM(Tunnel Boring Machine)逐渐应用于煤矿岩巷掘进,对不良地质构造进行超前准确快速预测的需求日益迫切。通过对主动源地震波超前探测方法的特点和TBM破岩震源超前探测技术的适用性进行分析,结合煤矿巷道地质和生产条件,提出了适用于煤矿巷道TBM掘进的HSP超前探测方法。以河南平顶山首山一矿TBM掘进底板瓦斯治理巷道为工程背景,选用防爆硬件一体化设计的探测仪器在煤矿巷道中进行应用。构建了空间型观测方式对煤矿巷道近水平煤线进行探测,优化了双护盾TBM掘进巷道狭小空间检波器阵列式布置参数;基于时频分析、互相关干涉处理、反射与散射联合反演等方法处理原始信号并进行探测结果成像。研究表明:采用空间型观测方式可实现与巷道小角度斜交煤线的识别,设计震源与首检波器间距离为15 m时最优。通过时频分析提取有效信号,利用互相关干涉法获取虚拟震源道和反射特征曲线,并结合反射与散射联合反演成像得到探测区域地层反射能量分布图,能够较准确地推测得到围岩存在的不良地质构造。通过比较现场开挖揭露情况与探测结果发现两者吻合度较高,表明HSP超前探测方法可实现掘进工作面前方100 m范围内超前无损地质预测,有助于提高煤矿岩巷TBM掘进速度。

三维地震动态解释在淮北构造复杂煤矿生产中的应用

三维地震勘探技术在煤矿安全高效矿井地质保障系统中发挥着重要的作用,淮北矿区构造复杂,断层密度大,断层已成为严重制约淮北矿区采区接替和增储保供的主要因素。本文将三维地震动态解释应用于淮北构造复杂煤矿的生产中,在煤矿工作面设计、巷道掘进和工作面贯通等多个生产阶段开展地震动态解释,针对大巷掘进过程中地质保障的实际需求开展了地震动态解释工作。应用实践表明,煤矿工作面生产过程中的地震动态解释工作将分析对象限定为一个工作面、一条巷道甚至一条断层,研究对象更聚焦,更精准,且时效性强,能够为煤矿工作面生产过程提供较为准确的指导,助力煤矿安全高效开采。

基于照明分析和偏移成像实验的主动震源探测系统设计——以朱溪矿区为例

为了探讨利用绿色环保的非炸药主动震源技术勘查我国西部、南部复杂山地深部矿产资源的可行性,并提出可行的探测方案,以景德镇朱溪矿区为例开展了基于照明分析和叠前深度域偏移成像实验的主动源地震探测系统设计研究。在现场踏勘和充分收集地质、钻探成果的基础上,根据矿区42号线钻孔联合剖面和相应的岩石物性测量成果建立了地球物理模型。由于后续地震数据采集工作主要利用单分量纵波检波器开展,在地震波的数值模拟方面选用了粘声波方程;工区崎岖地表所带来的不规则自由表面问题则通过Acoustic-Elastic boundary Approach(AEA)方案解决。进行了震源-检波器组双向照明分析,以及高信噪比(20db)和低信噪比(6db)两种情况下的地震波叠前深度域逆时偏移成像实验。研究结果表明,通过合理布设较为密集的主动震源激发-接收系统,采用环境友好的非炸药主动震源技术可以查明目标区地下主要地层,和断层、逆掩推覆体等主要控矿构造的空间展布。后续实际的地震数据采集工作在本次研究的基础上开展,取得的朱溪矿区第一手非炸药震源绿色勘查成像剖面证明了本次研究所提出的探测方案是可行的和有效的。通过不断完善技术体系,非炸药主动震源技术有望为我国深部矿产资源勘探、隐伏断裂勘查、城市地下空间探测等研究领域提供一种环保、高效的技术手段。本次研究所采用的基于照明分析和偏移成像实验的复杂山地主动震源探测系统设计、论证方法值得进一步研究和推广。

三维地震勘探技术在旗杆楼铁矿勘探中的应用

为了进一步控制矿区的构造发育及矿体赋存情况,采用三维地震勘探技术,对旗杆楼铁矿进行了勘探,本次三维地震数据采集共计完成地震线束40束,完成生产物理点3444个(其中井炮3108个,可控震源点336个),完成满覆盖面积6.41 km^(2)。研究得出,区内矿体的分布位置、埋深及形态,查明了区内断层分布及特征,解释断层32条,均为正断层,区内陷落柱发育情况及特征,共识别出陷落柱7个,最大直径为260 m,区内古河床、岩浆岩侵入体等的位置及范围。研究为铁矿勘探开发钻探提供了依据。

随掘地震地质构造精细监测在山西王坡煤矿的应用

【目的】传统巷道地震超前探技术受限于炸药使用、停掘需求、预报速度、探测范围及能力等方面的不足,难以满足智能掘进工作面的高精度地质构造探测需求。【方法】随掘地震以掘进机截割煤壁的震动为震源,采用数据实时上传、自动处理及动态成像的工作模式,充分利用信息技术和软件支撑,借助于海量数据支撑下的实时连续超饱和叠加,大幅提升了对掘进工作面前方地质异常体的成像精细度。以山西王坡煤矿为研究对象,在2条掘进巷道中部署了随掘地震监测系统,开展地质构造精细探查。【结果和结论】实际工作中,利用监测作业开展后48 h内积累的数据,即可对掘进工作面前方200 m范围内地质异常体成像。在3217工作面回风巷中,成功揭示了掘进工作面前方97 m的矸石挤压带反射异常,预报误差1 m;在3303工作面运输巷中,揭示了掘进工作面前方39 m的陷落柱,预报误差2 m;在3303工作面运输巷中,揭示了2处煤层破碎带异常区,其中,一处位于掘进工作前方148 m,预报误差1 m,另一处位于掘进工作面前方211 m外,在前序陷落柱和煤层破碎带遮挡下,依然足以形成较强的成像结果,预报误差3 m。结果表明:该技术探测精度高、探测距离远且探测能力强,可为瓦斯灾害的防治提供技术支持,为煤矿巷道安全高效掘进提供可靠的地质保障。

基于微震监测技术的煤矿突水灾害预警方法研究

为了减少煤矿突水灾害带来的安全风险,使用微震监测技术设计出1种煤矿突水灾害预警系统,并选用地震检波器作为系统中的传感器。使用该系统对顺勋煤矿进行监测,结果显示,该煤矿在监测期间共发生了193次微震,其中微震释放能量大于1000 J的次数为6次,单次微震释放的最大能量为2455 J,远小于工作面附近出现过的最大微震释放能量,且绝大多数的微震出现在底板下方12 m内的区域。测试结果表明,微震监测技术能有效监测煤矿因突水引发的微震,并提供相应的预警信息。

基于地-电-磁联合超前探测方法的运输巷陷落柱探究

华北型煤田水文地质条件复杂,受陷落柱、断层等构造水害威胁严重。为了精确查明陷落柱的发育形态及富水性,综合考虑地质体的地-电条件,组合一套陷落柱超前探测方法。以七五煤业3_上717运输巷陷落柱为研究对象,采用瞬变电磁法、并行电法、地震波进行联合超前探测,并对物探异常区进行钻孔探查。结果表明:陷落柱在水平方向上呈类椭圆形,长轴46.7 m,短轴28.6 m,面积约946 m^(2)。探查范围内整体富水性较弱,仅在迎头方向圈定YC1、YC2低阻异常区,其中陷落柱局部位于YC2范围内。两异常区均位于3_(上)煤层底板下方,主要受底板砂岩含水层影响。井下钻探揭露陷落柱发育范围、富水性情况与物探解译结果基本一致,验证了联合探查结果准确可靠,为今后类似条件地区的陷落柱发育形态及富水性超前探测提供实践依据。

钱营孜煤矿W3233工作面随采智能物探技术应用

随着煤矿从自动化开采向智能化开采发展,煤矿地质保障系统正在迈入精准智能探测新阶段。近年来,矿井物探技术发展迅速,技术的进步使巷道地质异常体的检测更加精准,为了保证施工操作的安全性,必须做好煤矿生产过程的动态监控,及时发现隐患问题并采取管控措施,营造安全的煤矿开采环境。随采地震以采煤机截割震动作为震源,结合随采电法监测,实时完成工作面前方地质构造的可视化及水害预警,提高工作面回采效率。以钱营孜煤矿W3233工作面的试验为例,从采集系统、观测系统、数据处理等方面对随采智能物探技术的应用进行了探讨,并简要分析了超前成像结果。

浅析综合地质勘探法在煤矿地质勘测中的应用

在正式开采前,煤矿企业需要充分掌握矿区的地质条件及具体分布情况,采用综合地质勘探法进行煤矿地质勘测,为后续采煤工作提供具有参考、指导意义的依据。主要阐述了综合地质勘探法的优势、应用原则及应用范围,同时详细分析了综合地质勘探法在煤矿地质勘测中的具体应用及注意事项,为煤矿发展提供借鉴。