Application of Gaussian Beam Summation Migration in Reflected In-seam Wave Imaging

The geological conditions for coal mining in China are complex,with various structural issues such as faults and collapsed columns seriously compromising the safety of coal mine production.In-seam wave exploration is an effective technique for acquiring detailed information on geological structures in coal seam working faces.However,the existing reflected in-seam wave imaging technique can no longer meet the exploration precision requirements,making it imperative to develop a new reflected in-seam wave imaging technique.This study applies the Gaussian beam summation(GBS)migration method to imaging coal seams'reflected in-seam wave data.Firstly,with regard to the characteristics of the reflected in-seam wave data,methods such as wavefield removal and enveloped superposition are employed for the corresponding wavefield separation,wave train compression and other processing of reflected in-seam waves.Thereafter,imaging is performed using the GBS migration technique.The feasibility and effectiveness of the proposed method for reflected in-seam wave imaging are validated by conducting GBS migration tests on 3D coal-seam fault models with different dip angles and throws.By applying the method to reflected in-seam wave data for an actual coal seam working face,accurate imaging of a fault structure is obtained,thereby validating its practicality.

Research and Application of In-seam Seismic Survey Technology for Disaster-causing Potential Geology Anomalous Body in Coal Seam

In order to effectively detect potential geology anomalous bodies in coal bearing formation,such as coal seam thickness variation,small faults,goafs and collapse columns,and provide scientific guidance for safe and efficient mining,the SUMMIT-II EX explosion-proof seismic slot wave instrument,produced by German DMT Company,was used to detect the underground channel wave with the help of transmission method,reflection method and transflective method.Region area detection experiment in mining face had been carried out thanks to the advantage of channel wave,such as its great dispersion,abundant geology information,strong anti-interference ability and long-distance detecting.The experimental results showed that:(1)Coal seam thickness variation in extremely unstable coal seam has been quantitatively interpreted with an accuracy of more than 80%generally;(2)The faults,goafs and collapse columns could be detected and predicted accurately;(3)Experimental detection of gas enrichment areas,stress concentration regions and water inrush risk zone has been collated;(4)A research system of disaster-causing geology anomalous body detection by in-seam seismic survey has been built,valuable and innovative achievements have been got.Series of innovation obtained for the first time in this study indicated that it was more effective to detect disaster-causing potential geology anomalies by in-seam seismic survey than by ground seismic survey.It had significant scientific value and application prospect under complex coal seam conditions.

Evolution and application of in-seam drilling for gas drainage

The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the risk of gas outburst and lower the concentrations of seam gas in the underground ventilation.The drilling practices have reflected the standards of the times and have evolved with the development of technology and equipment and the needs to provide a safe mining environment underground.Early practice was to adapt equipment from other felds,with rotary drilling being the only form of drilling available.This form of drainage allowed various levels of gas drainage coverage but with changing emphasis,research and development within the coal industry has created specifc equipment,technology and practices to accurately place in-seam boreholes to provide effcient and effective gas drainage.Research into gas content determination established a standard for the process and safe levels for mining operations to continue.Surveying technology improved from the wire-line,single-shot Eastman survey instruments which was time-dependent on borehole depth to electronic instruments located in the drill string which transmitted accurate survey data to the drilling crew without time delays.This allowed improved directional control and increased drilling rates.Directional drilling technology has now been established as the industry standard to provide effective gas drainage drilling.Exploration was identifed as an additional beneft with directional drilling as it has the ability to provide exploration data from long boreholes.The ability of the technology to provide safe and reliable means to investigate the need for inrush protection and water drainage ahead of mining has been established.Directional drilling technology has now been introduced to the Chinese coal industry for gas drainage through a practice of auditing,design,supply,training and ongoing support.Experienced drilling crews can offer site specifc gas drainage drilling services utilising the latest equipment and technology.

Study on Physical Models of In-Seam Seismic Wave

The propagation laws of in-seam seismic wave in coal seam in differeut situations are studied by means of in-seam seismic simulatiou tests. Some valuable conclusions are obtained, which are signiricant in guiding in-seam seismic prospecting in the future.

倾斜煤层开采沉陷预计模型的构建

概率积分法在我国煤矿开采地表沉陷预计领域得到了广泛应用,该方法具有对称分布特征,在水平煤层开采沉陷预计时精度最好,而倾斜煤层开采后地表下沉盆地的形态往往呈现偏态性,采用该方法对其进行预计偏差较大。针对此问题,建立了工作面随体坐标系和地表直角坐标系,利用随机介质理论在工作面随体坐标系中实现单元开采沉陷影响的叠加积分运算,然后将工作面随体坐标系中地表某点的沉陷影响转换到地表直角坐标系中,最终构建地表直角坐标系下的倾斜煤层开采沉陷偏态预计模型。分析认为,倾斜煤层单元开采引起的地表下沉符合威布尔偏态分布规律,结合实例对预计模型的有效性进行了验证。该模型预计精度随煤层倾角的增加而逐渐降低,研究结果可为相似矿区的沉陷预计提供理论和技术支持。

煤层底板突水因素的综合评价──以肥城矿区为例

将系统工程中的层次分析法引入煤层底板突水的研究中。以肥城矿区为例，阐述了煤层底板交水因素综合评价方法的应用，使底板突水评价研究从定性向定量转化，对查明底板水文地质条件和突水预测具有重要的指导意义。

Application of long-reach directional drilling boreholes for gas drainage of adjacent seams in coal mines with severe geological conditions

This study aimed to demonstrate the application of Long Reach Directionally Drilled Boreholes(LRDD)for gas drainage of adjacent seams before and during the longwall face operations of low permeability-high gas content coals Staszic-Wujek Hard Coal Mine in the Upper Silesia Coal Basin(Poland).Five LRDD Boreholes(TM1a-TM5)with a length of 300 and 400 m were located over coal seam 501 in the fractured zone and monitored over six months of longwall face operations.LRDD Boreholes were combined with Cross-Measured Boreholes.Reservoir characterization and geological modeling supported the results obtained from gas drainage.The drainage efficiency of LRDD Boreholes was the approxi-mately 70%level,while conventional Cross-Measured Boreholes were only 30%.The highest goaf gas quality(94%methane concentration)was reported for TM4,placed at an average elevation of 41 m above coal seam 501.The highest goaf gas production(average 6.2 m^(3)/min)was reported for LRDD Borehole TM3.This borehole was placed within the fracture zone(average elevation of 24.4 m)and drilled through the sandstone lithotype with the best reservoir properties,enhancing drainage performance.LRDD Boreholes TM2 and TM4 achieved similar performance.These three LRDD Boreholes were drilled close to the maximum principal horizontal stress direction,providing borehole stability during under-mining.The lowest goaf gas production was reported for LRDD Boreholes TM1a and TM5.Both Boreholes were placed in the rubble zone.

大采高综采自动化系统设计与应用

为解决大采高综采工作面大型设备多、采煤工艺复杂等问题,采用大采高综采自动化系统,以提高工作面自动化水平和生产效率,论述了大采高综采自动化系统的控制目标与系统组成,详细介绍地面监控系统、网络传输系统和就地监控系统的组成和作用。从采煤机进刀时间、割煤平整程度、移架行程、移架时间、支架初撑力、刮板输送机推进效果和系统监测等方面,分析了大采高自动化系统在王庄煤矿8101工作面的应用效果,结果表明,进刀时间稳定、割煤平整,移架到位率达92.8%,移架时间相比人工移架提升29.2%,支架初撑力提升11.4%,刮板输送机到位率100%,监测系统效果良好。

急倾斜非均厚煤层高效开采工艺研究

针对益门煤矿急倾斜煤层煤厚变化幅度大、非均厚特征突出的赋存条件,现有采煤方法存在劳工强度大、煤炭产出率低、安全系数小等问题,结合该矿的拟定生产目标和实际生产情况,研究了工作面基础参数和工作面设备选型,确定了水平分段综采放顶煤采煤法,机采高度2.8 m、段高14 m、采放比1∶4,工作面截深0.6 m,工作面长度35 m,采煤机型号为MG250/305-NWD,前部刮板输送机型号为SGZ-730/90,后部刮板输送机型号SGZ764/315型,支架选用ZH2000/22/30ZL型整体顶梁组合悬移液压支架。研究表明:新型开采工艺的产能较初始爆破放顶煤提高约2倍,满足生产目标,工作面准备时间缩减至初始的42%~60%,工作面搬家次数大幅减少,实现了低成本的安全高效开采,研究结果为构建急倾斜非均厚煤层的高效开采体系提供一定借鉴意义。