Key technologies and equipment for a fully mechanized top-coal caving operation with a large mining height at ultra-thick coal seams

Thick and ultra-thick coal seams are main coal seams for high production rate and high efficiency in Chinese coal mines, which accounts for 44 % of the total minable coal reserve. A fully mechanized top-coal caving mining method is a main underground coal extraction method for ultra-thick coal seams. The coal extraction technologies for coal seams less than 14 m thick were extensively used in China. However, for coal seams with thickness greater than 14 m, there have been no reported cases in the world for underground mechanical extraction with safe performance, high efficiency and high coal recovery ratio. To deal with this case, China Coal Technology ＆ Engineering Group, Datong Coal Mine Group, and other 15 organizations in China launched a fundamental and big project to develop coal mining technologies and equipment for coal seams with thicknesses greater than 14 m. After the completion of the project, a coal extraction method was developed for top-coal caving with a large mining height, as well as a ground control theory for ultra-thick coal seams. In addition, the mining technology for top-coal caving with a large mining height, the ground support technology for roadway in coal seams with a large cross-section, and the prevention and control technology for gas and fire hazards were developed and applied. Furthermore, a hydraulic support with a mining height of 5.2 m, a shearer with high reliability, and auxiliary equipment were developed and manufactured. Practical implication on the technologies and equipment developed was successfully completed at the No. 8105 coal face in the Tashan coal mine, Datong, China. The major achievements of the project are summarized as follows： 1. A top-coal caving method for ultra-thick coal seams is proposed with a cutting height of 5 m and a top-coal caving height of 15 m. A structural mechanical model of overlying strata called cantilever beam-articulated rock beam is established. Based on the model, the load resistance of the hydraulic support with a large mining height for top-coal caving method is determined. With the analysis, the movement characteristics of the top coal and above strata are evaluated during top-coal caving operation at the coal face with a large mining height. Furthermore, there is successful development of comprehensive technologies for preventing and controlling spalling of the coal wall, and the top-coal caving technology with high efficiency and high recovery at the top-coal caving face with a large mining height. This means that the technologies developed have overcome the difficulties in strata control, top-coal caving with high efficiency and high coal recovery, and enabled to achieve a production rate of more than 10 Mtpa at a single top-coal caving face with a large mining height in ultra-thick coal seams; 2. A hydraulic support with 5.2 m supporting height and anti-rockburst capacity, a shearer with high reliability, a scraper conveyor with a large power at the back of face, and a large load and long distance headgate belt conveyor have been successfully developed for a top-coal caving face with large mining height. The study has developed the key technologies for improving the reliability of equipment at the coal face and has overcome the challenges in equipping the top-coal caving face with a large mining height in ultra-thick coal seams; 3. The deformation characteristics of a large cross-section roadway in ultra-thick coal seams are discovered. Based on the findings above, a series of bolt materials with a high yielding strength of 500-830 MPa and a high extension ratio, and cable bolt material with a 1 × 19 structure, large tonnage and high extension ratio are developed. In addition, in order to achieve a safe roadway and a fast face advance, installation equipment for high pre-tension bolt is developed to solve the problems with the support of roadway in coal seams for top-coal caving operation with a large mining height; 4. The characteristics of gas distribution and uneven emission at top-coal caving face with large mining height in ultra-thick coal seams are evaluated. With the application of the technologies of gas drainage in the roof, the difficulties in gas control for high intensive top-coal caving mining operations, known as ＂low gas content, high gas emission＂, are solved. In addition, large flow-rate underground mobile equipment for making nitrogen are developed to solve the problems with fire prevention and safe mining at a top-coal caving face with large mining height and production rate of more than 10 Mtpa. A case study to apply the developed technologies has been conducted at the No. 8105 face, the Tashan coal mine in Datong, China. The case study demonstrates that the three units of equipment, i.e., the support, shearer and scraper conveyor, are rationally equipped. Average equipment usage at the coal face is 92.1%. The coal recovery ratio at the coal face is up to 88.9 %. In 2011, the coal production at the No. 8105 face reached 10.849 Mtpa, exceeding the target of 10 Mtpa for a topcoal caving operation with large mining height performed by Chinese-made mining equipment. The technologies and equipment developed provide a way for extracting ultra-thick coal seams. Currently, the technologies and equipment are used in 13 mining areas in China including Datong, Pingshuo, Shendong and Xinjiang. With the exploitation of coal resources in Western China, there is great potential for the application of the technologies and equipment developed.

Waste-filling in fully-mechanized coal mining and its application

A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes) is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed. These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae.

New development of longwall mining equipment based on automation and intelligent technology for thin seam coal

The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer. The key technology of short length and high power thin seam drum shearer, and new type roof support with big extension ratio and plate canopy were introduced. The new research achievement on automatic control system of complete sets of equipment for the thin seam coal, which composed of electronic-hydraulic system, compact thin seam roof supports, high effective shearer with intelligent control system, and characterized by automatical follow-up and remote control technology, was described in this paper..

Hazard identification for equipment-related fatal incidents in the U.S.underground coal mining

Based on the number of fatalities per year, a persistent area of concern in mine safety continues to be equipment related. Data from the period 1995 through 2007 were studied in order to identify major hazards for underground mining equipment-related fatal incidents and to perform an analysis of those that occurred over the last 13 years. Reports on equipment-related fatal incidents were obtained from the Mine Safety and Health Administration （MSHA）. The results show that underground mining equipment including continuous miner, shuttle car, roof bolter, load-haul-dump （LHD）, Iongwall and hoisting contributed to a total of 69 mining-related fatalities. The study reveals that the major hazard for continuous mining equipment-related fatal incidents is ＂Failure of victim to respect equipment working area＂, while the highest number of fatalities for shuttle car is attributed to the hazard ＂Failure of mechanical components.＂ The study further reveals that the highest number of fatalities for roof bolter, LHD, and Iongwall are attributed to the hazards ＂Working under unsupported roof＂, ＂Failure of management to provide safe working conditions＂, and ＂Failure of mechanical components＂, respectively. It is determined that one fatality for the hoisting system is attributed to the hazard ＂Failure of mechanical components＂ and one to the hazard ＂Failure to follow safe maintenance procedure＂. Finally, approaches to prevention were also discussed in this paper.

Study on safe thickness of overlying thin bedrock in fully-mechanized top-coal caving face with thick coal seam

To prevent support crush, the overlying strata safe thickness and its influential elements were studied by the adoption of theoretical analysis, numerical simulation and in-situ measurement. According to the production and geological condition of first face in Sima coal mine, the results indicate that the clay contains large permissible bearing ability and has better arching force. After mining destruction, stable structure is formed in bedrock to ensure face safety. The clay thickness ＆ bedrock thickness are the key influential elements to stable structure. The minimal bedrock thickness is about 40 m to ensure safe mining under loose surface soil condition. When surface soil contains mainly thick clay, it forms steady structure with the composition of thin bedrock, so that it can reduce minimal thickness of bedrock and to ensure safe mining. When clay thickness is 40 m, minimal bedrock thickness is 20 m. When clay thickness is 30 m, minimal bedrock thickness is 30 m. Bearing pressure peak ranges from 5 to 15 m in the front face under thin bedrock condition. The bearing pressure distribution range is 15 m. Main roof break distance is small, and initial weighting of main roof is not distinctive, while first periodic weighting of main roof is quite distinctive.

CHINA'S RECENT DEVELOPMENT IN COAL MINING,PROCESSING AND UTILIZATION

This paper describes the state-of-the-art and Outlook of coal mining and clean coal technology in China. As the major mining method,underground mining accounts for 96% of the total production. Among the state own mines, the percentage of mechanized mining reached 71 %. A rapid development of high-productive and high-profitable mines,especially those with longwall sublevel caving method, is described. The issues of heavy duty equipment, roof bolting,mine safety are also addressed. The Chinese government is paying more and more attention on the environmental problems inducing from coal mining,processing and utilization. A basic framework of clean coal technology is being formed and a wide range of technology is included.

数字孪生驱动的掘锚设备跟踪定位与碰撞检测方法研究

掘锚自动化作业是煤矿巷道智能掘进的关键,针对当前掘锚设备交替作业过程中相对位姿测量和碰撞检测难题,提出一种数字孪生驱动的煤矿井下掘锚设备跟踪定位与碰撞检测方法。首先,为克服井下掘进工作面低照度、高粉尘、复杂背景干扰的影响,以多点红外LED标靶作为信息源,通过工业相机采集红外LED特征点图像,利用Hough轮廓检测与质心法提取光斑中心并通过二进制编码识别标靶ID,采用改进稀疏光流算法对光斑进行跟踪,同时建立基于PNP的掘锚设备位姿解算模型,采用对偶四元数获得设备间相对位姿。其次,利用数字孪生技术,基于Unity3D平台建立对应实际尺寸的掘锚设备及工作面数字孪生模型,利用Socket通信方式实现虚拟空间与物理实体之间的实时数据传输与交互,在虚拟空间中实现掘锚设备实时位姿的三维可视化,结合任意多边形OBB(orientedboundingbox)碰撞检测算法,实现掘锚设备虚拟碰撞检测。最后,搭建实验平台进行掘锚设备位姿测量试验,同时对虚实运动轨迹和碰撞检测效果进行验证。实验结果表明:掘锚设备跟踪定位实验的位置误差不超过20mm,角度误差不超过0.30°;虚实位置坐标对比中X轴方向最大误差不超过1.14mm;Y轴方向最大误差不超过1.10mm,能够保证系统虚实一致性和同步性,满足掘进工作面作业过程中掘锚设备实时跟踪定位及碰撞检测的要求。

煤矿工业物联网设备识别模型

煤矿工业物联网(IIoT)设备计算与存储资源受限,易遭受非法网络入侵,造成敏感数据泄露或恶意篡改,威胁煤矿生产安全。精准识别煤矿IIoT设备可实现有效管理并维护设备正常运转,提高设备安全防护能力,然而现有设备识别算法存在特征构造复杂、内存与计算需求较高导致难以部署在资源受限的煤矿IIoT设备中等问题。针对上述问题,提出了一种煤矿IIoT设备识别模型。首先,对支持TCP/IP协议传输的流量数据进行流量切分、无关字段去除、去重、定长字段截取操作后转换为IDX格式存储;其次,使用卷积块注意力模块(CBAM)优化深度可分离卷积(DSC),从而搭建轻量级DSC−CBAM模型来过滤Non−IIoT设备;然后,利用带有阶段惩罚的Wasserstein生成对抗网络(WGAN−GP)扩充流量较少的煤矿IIoT设备数据,达到平衡偏移流量数据的目的;最后,在DSC−CBAM基础上引入多尺度特征融合(MFF)技术捕获浅层全局特征信息,并增加Mish激活函数提高模型训练稳定性,建立优化混合模态识别(MDCM)模型,实现煤矿IIoT设备精准识别。实验结果表明,该模型收敛速度快,准确率、召回率、精确率与F1−score指标均高达99.98%,且参数量小,能精准、高效识别煤矿IIoT设备。

提升神东采掘运设备价值最大化的措施

通过调研和分析神东公司采掘运大型机电设备目前的使用和管理现状,从神东集团13个矿井的生产、机电设备结构配置、机电设备成本、机电设备管理等方面入手,深入分析影响采掘运大型机电设备价值最大化的原因,并给出后期发挥采掘运大型机电设备最大使用价值的努力方向,对降低机电设备成本的投入以及安全、高效生产具有现实意义,对其他煤炭企业采掘运设备的高效、精细、精益、价值最大化管理亦有重要的借鉴作用。

提升神东煤矿机电设备管理效益的探究

文章从煤矿机电设备的配套、运行、大修、车辆辅助运行、指挥调度、新技术标准应用六个方面调研了国能神东煤炭集团公司煤矿机电设备目前使用和管理的现状,深入分析其原因并给出了提升机电设备管理效益的具体措施,这对国能神东煤炭集团公司提升机电设备管理效益具有十分重要的指导意义,对其他煤炭企业机电设备的精细、精益,安全管理亦有重要的借鉴作用。

6~10 m厚煤层超大采高液压支架及其工作面系统自适应智能耦合控制

厚煤层储量及产量占我国原煤总储量及产量的一半,通过梳理厚煤层开采历史沿革,总结了我国厚煤层开采40年来的技术及装备研发实践,系统分析了以高端大采高液压支架及围岩智能耦合理论为代表的6~10 m大采高综采高效智能化综采技术及装备研究进展,提出了大采高支护理论及围岩智能耦合控制的突破是厚煤层一次开采高度突破的首要因素,完善的感知体系建立是液压支架自适应支护的前提,数字技术的应用为大采高工作面高效推进及装备智能协同控制提供了新的技术途径;阐明了大采高综放液压支架与围岩耦合关系,剖析了采高增加对硬煤层冒放性的有利影响,提出了基于煤矸识别、放煤机构控制的“纯煤段记忆放煤+煤岩分界模糊段人工反馈式干预放煤”的智能放煤控制策略;分析了大采高开采“采–运”协同智能耦合控制关键技术,构建了基于采煤机牵引速度与刮板输送机链速间联动调节的工作面装备间多机异构耦合自适应协同控制模型;研发了厚煤层开采中10 m超大采高液压支架,分析了厚煤层开采不断突破开采高度极限的新认识,从开采装备、控制系统等方面提出厚煤层一次开采高度的突破的研发方向。

神东煤矿机电设备大型部件安全库存分析

为探讨煤矿机电设备大型部件安全库存的必要性以及对煤企安全生产的影响,通过调研国能神东机电设备大型部件库存的现状,给出了保障国能神东煤矿机电设备大型部件安全库存的具体措施。分析认为,开展机电设备大型部件库存统计对实现国能神东在管理上的提质降本增效有重要的作用,且在实践中应建立一套符合神东模式的机电设备大型部件安全库存储备标准,有助于为设备管理提供科学精准的参考。

煤矿机电设备的远程监控与故障预警系统设计

近年来,随着嵌入式技术、互联网技术、大数据分析和人工智能技术的飞速进步,远程监控与故障预警系统已在各行各业取得了广泛应用。这些创新技术为煤矿机电设备的安全运行赋予了崭新的可能。本文将深入探讨如何依托这些前沿科技,构建一套契合煤矿机电设备的远程监控与故障预警体系。

基于改进YOLOv5s的煤矿机电设备维修指导系统

针对煤矿机电设备辅助维修中二维码标注工作量大、通用性低及现有免注册识别方法实现复杂、难以部署等问题,提出了一种基于改进YOLOv5s的煤矿机电设备维修指导系统。该系统由设备免注册识别模块、故障维修指导模块、远程专家接入指导模块组成。设备免注册识别模块通过HoloLens眼镜上的摄像头采集故障设备图像,并通过改进YOLOv5s图像识别算法进行分析和处理,识别出故障设备型号;故障维修指导模块根据故障设备型号自动匹配调用预设好的混合现实拆装模型,形成维修指导解决方案;远程专家接入指导模块通过音视频会话、虚拟标注等方式实现远程专家与现场维修人员的交互。为保证用户使用混合现实设备时的沉浸感体验,针对混合现实设备自身算力不足问题,采用ShuffleNetV2替换YOLOv5s中的Backbone,得到YOLOv5s−SN2网络,从而减少模型参数量,降低计算开销。实验结果表明:YOLOv5s−SN2相较于YOLOv5s精度略有下降,但每秒浮点运算次数(FLOPS)从16.5×10^(9)下降到7.6×10^(9),参数量从15.6×10^(6)个下降到8.2×10^(6)个;在YOLO系列模型中,YOLOv5s−SN2性能最优。以三叶罗茨鼓风机为例验证系统整体效果,结果表明,YOLOv5s−SN2可快速识别出电动机型号,调用与之匹配的虚拟模型及维修流程,远程专家可通过音视频接入和标注等方法辅助现场工作人员进行机电设备维修。

10m超大采高智能化开采关键技术及装备研究

通过调研陕西陕煤曹家滩煤矿业有限公司22煤层赋存条件,探究了超大开采空间矿压显现规律及超高煤壁片帮特点,总结了超大采高综采工作面围岩控制关键技术,分析了超大采高综采工作面端头区支护特点,提出“大梯度+小台阶”端头区过渡模式,实现了综采工作面中部到两端头巷道6 m高差的短缓过渡及端头区三角煤高回收率支护;基于综采工作面智能化成套开采装备选型配套,研发了适应10 m超大采高综采工作面的成套开采装备,实现了超大开采空间安全防护、特厚煤层高效截割、超大运量煤流顺畅运输;搭建工作面“采支运”一体化智能协同作业控制系统及多源系统集成与数据融合分析平台,支撑10 m超大采高综采工作面安全高效开采。

煤矿智能化建设中存在的问题及其对策研究

在对全国4省(区)20个单位煤矿智能化建设调研的基础上,全面深入地分析了当前煤矿智能化建设工作中存在的发展不平衡等突出问题。认为,这些问题既有政策、法规及标准规范层面,也有智能技术及智能装备层面,还有管理层面,需要予以高度重视。同时,提出加强政府引导和政策支持、加强智能化关键技术攻关、及时修订标准规范、加强政策引领提升煤炭科技创新驱动能力、做好煤矿智能化建设顶层设计、加强数据综合分析平台建设和加大相关人才培养力度等对策建议。

浅埋多煤层群协调绿色开采关键技术研发与实践

西部矿区多煤层赋存条件导致了“采面布局矛盾、覆岩结构多变、地表运移叠加”的突出性、普遍性问题,探索适应多煤层高强度开采的协调绿色开采技术成为西部矿区多煤层安全、高效开采的关键。针对浅埋厚煤层群高强度开采面临的主要技术难题,从多煤层开采时空布局、工作面岩层稳定性控制、重复扰动下的地表沉陷等方面,系统地阐述了浅埋多煤层群协调绿色开采的几项关键技术。研究结果如下:(1)揭示了西部多煤层高强度开采层间相互作用机理,构建了多煤层重复开采扰动定量判据与评价方法,创新提出了以层间最小扰动为目标的“薄、中、厚”煤层交错分布协调开采技术;(2)提出了多煤层工作面岩层稳定控制技术,建立了全覆岩结构破断模型,揭示了全覆岩结构破断条件下的支架与围岩相互作用规律,在此基础上针对多煤层开采工作面支护在不同的位置需要采用不同支护策略的需求,研发了工作面支架抗冲双伸缩立柱和超前巷道支护状态监测系统,实现工作面多区域安全高效稳定支护;(3)通过揭示浅埋多煤层斜交叠置开采下地表动态移动特征和地表裂缝发育规律,给出地表下沉系数的确定方法,研发了塌陷区裂缝“土壤重构–原位充填–微地形改造”组合的治理关键技术,有效防治黄土沟壑区的采煤地表塌陷。上述核心技术在张家峁、柠条塔、红柳林等20余个大型煤矿成功应用,为我国西部矿区高质量、可持续开发提供了技术支撑。

煤炭工业发展关键技术突破与超级煤矿建设

为了发展煤炭领域先进生产力,助力煤炭工业高质量发展,研究了近年来我国采场围岩控制技术发展历程,分析了采动应力演化规律及围岩断裂失稳过程,创新提出了超大采高工作面围岩断裂失稳力学模型、控制准则及液压支架合理工作阻力计算方法。系统阐述了我国综采技术装备发展历程,研发了最大采高10 m的超大采高综采成套装备,以及最大支护高度7.0 m的超大采高综放成套装备,解决了西部矿区浅埋深、坚硬、厚及特厚煤层安全高效开采技术难题。系统分析了我国主要煤炭产区煤矿智能化建设现状、关键技术、取得的建设成效及存在的主要问题,提出了智能化超级煤矿的定义、特征及内涵,研究了典型超级煤矿建设成效与经验,并从标准体系、数据体系、技术体系、管理体系、生态体系建设等方面阐述了未来煤炭工业主要发展方向。

智能矿山背景下的煤矿机电设备管理创新

煤矿机电设备在煤炭开采中具有关键作用,是确保安全生产和提高生产效率的基石。然而,部分企业在煤矿机电设备管理方面缺乏规范。在信息化时代,各种自动化技术被广泛应用于煤矿生产中,有效提升了生产效率和质量。在智能矿山背景下,煤矿机电设备管理有助于实现矿山采掘和监测等方面的智能化。通过深入分析智能矿山的建设现状以及煤矿机电设备管理创新中存在的问题,提出了一些煤矿机电设备管理的创新措施。这些措施的实施有利于促进煤矿机电技术的发展,对保障煤矿安全开采具有重要意义,可以为煤矿安全开采提供有力的技术保障,增强企业的生产实力。

俄罗斯露天煤矿发展研究

对俄罗斯露天煤矿的资源、生产等情况进行了深入分析,总结了俄罗斯露天煤矿开采技术的发展历程以及在典型地区的技术应用,梳理了俄罗斯露天煤矿装备特点、主要装备应用情况以及俄罗斯露天煤矿主要的生态保护措施。研究得出:俄罗斯适合露天开采的煤炭资源丰富,其探明储量占比达到俄罗斯煤炭资源总量的72%以上,露天煤矿产量占俄罗斯煤炭产量75%以上,露天煤矿是俄罗斯煤炭产业发展的重点。俄罗斯露天煤矿的开采工艺主要采用轮斗连续开采工艺,同时无运输倒堆工艺使用也较多,挖掘机、自卸卡车、吊斗铲等与开采工艺相对应的装备近些年取得了新的发展。在煤炭开发利用的同时,俄罗斯高度重视煤炭工业环境安全问题,在机构设置、法律法规、生态修复技术等方面积极探索并取得诸多进展,减少了露天煤矿开发对环境的负面影响。