Method for prevention and control of spontaneous combustion of coal seam and its application in mining field

Spontaneous combustion of coal seam has been and continues to be a big problem in coal mines. It could pose great threat to the safety of the whole mine and all miners, especially when it occurs in or nearby coal mines. Besides, environment of area surrounded mines during combustion can be threatened where large amount of toxic gases including CO_2, CO, SO_2 and H_2S can be leased by fire in mine. Hence, it is important and significant for scholars to study the controlling and preventing of the coal seam fire. In this paper, the complicated reasons for the occurrence and development of spontaneous combustion in coal seam are analysed and different models under various air leakage situations are built as well. Based on the model and approximately calculation, the difficulty of fire extinguishment in coal seam is pointed out as the difficulty and poor effect to remove the large amount of heat released. Detailed measurements about backfilling and case analyses are also provided on the basis of the recent ten years' practice of controlling spontaneous combustion in coal seams in China. A technical fire prevention and control method has been concluded as five steps including detection, prevention, sealing, injection and pressure adjustment. However, various backfill materials require different application and environmental factors, so in this paper, analyses and discussion about the effect and engineering application of prevention of spontaneous combustion are provided according to different backfilling technologies and methods. Once the aforementioned fire prevention can be widely applied and regulated in mines, green mining will be achievable concerning mine fire prevention and control.

A comparative study of dust control practices in Chinese and Australian longwall coal mines

Mine dust is one of the main hazards in underground longwall mines worldwide.In order to solve the mine dust problem,a significant number of studies have been carried out regarding longwall mine dust control,both in China and Australia.This paper presents a comparative study of dust control practices in Chinese and Australian longwall mines,with particular references to statutory limits,dust monitoring methods and dust management practices,followed by a brief discussion on the research status of longwall mine dust control in both countries.The study shows that water infusion,face ventilation controls,water sprays,and deep and wet cutting in longwall shearer operations are commonly practiced in almost all underground longwall mines and that both Chinese and Australian longwall mine dust control practices have their own advantages and disadvantages.It is concluded that there is a need for further development and innovative design of more effective dust mitigation products or systems despite the development of various dust control technologies.Based on the examinations and discussions,the authors have made some recommendations for further research and development in dust control in longwall mines.It is hoped that this comparative study will provide beneficial guidance for scholars and engineers who are engaging in longwall mine dust control research and practice.

Prevention and Control Mode of Desertification in China＇s State Energy Group Shendong Mining Area with Annual Coal Output of 200 Million Tons

According to the strategic goal of sustainable development,construction and management for the construction of Shendong mining area with ecological safety,the ecological restoration principle of ＂ control protects development and development promotes control＂ for desertification prevention and control was adopted,and engineering measures,plant greening measures,and enclosure management and protection measures were taken to prevent and control desertification in the mining area based on careful detailed investigation and accurate planning and design in the early period. After 32 years,the desertification ecological landscape environment of the mining area has undergone a qualitative change,and the vegetation coverage has increased from 3%-8% to above 60% after the development. The former desertification land has become a modern green energy base that has produced 200 million tons of coal every year. The construction and management mode of an ecologically safe and modernized green coal mining area built by Shendong in the desertification region of northwestern China shows that taking appropriate comprehensive ecological restoration construction technology and management measures that integrate engineering,plants and enclosure management and protection is an effective technical and management paradigm for the construction of a modernized green large-scale coal mining area in China＇s arid and semi-arid regions.

Application of foam technology for dust control in underground coal mine

In order to effectively control the dust in the underground coal mine,this study proposes and develops a new technology for dust control by foam,and briefly demonstrates the advantage of the foam technology for dust control,such as the good isolation performance,large contact area,high wetting ability,strong adhesion and so on.Besides,the details of the technology are introduced,including the foam agent,foam generator,and foam production process.Then the paper studies the relationship between the foaming agent concentration and liquid surface tension,and explains the principle of the foam generator.The technology is applied in heading face.The application results show that the foam has a remarkable effect on dust control in underground coal mines.

Combustion mechanism and control approaches of underground coal fires:a review

With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response strategies of underground coal fires is of great significance to accelerate the green prevention and control of coal fires,energy conservation and emission reduction.In this paper,we summarized and sorted out the research status of underground coal fires,focused on the theoretical and technical issues such as underground coal fire combustion mechanism,multiphysics coupling effect of coal fire combustion,fire prevention and extinguishing technology for underground coal fires,and beneficial utilization technology,and described the latest research progress of the prevention and control for underground coal fire hazards.Finally,the key research problems in the field of underground coal fire hazards prevention and control were proposed in the direction of the basic theory,technology research,comprehensive management and utilization,with a view to providing ideas and solutions for the management of underground coal fires.

Study on regional stratagem for coal mine disasters control and prevention in China

The regional strategy study was aimed at coal mine disaster control and prevention,which deepens and enriches the macro-strategy of coal mine disaster control andprevention,and provides an important support for the rapid and healthy development ofthe regional coal industry.The country was divided into 4 regions:Northeast,North,Southand Xinqing.In view of the regional status of coal mine disasters,the regulation and developmenttrend of regional coal mine disasters were analyzed,the outstanding problemsand key factors were identified,and the general thoughts on regional coal mine disastercontrol and prevention were put forward.

Design of a water curtain to reduce accumulations of float coal dust in longwall returns

Accumulation of float coal dust(FCD)in underground mines is an explosion hazard that affects all underground coal mine workers.While this hazard is addressed by the application of rock dust,inadequate rock dusting practices can leave miners exposed to an explosion risk.Researchers at the National Institute for Occupational Safety and Health(NIOSH)have focused on developing a water curtain that removes FCD from the airstream,thereby reducing the buildup of FCD in mine airways.In this study,the number and spacing of the active sprays in the water curtain were varied to determine the optimal configuration to obtain peak knockdown efficiency(KE)while minimizing water consumption.

Review of preventive and constructive measures for coal mine explosions:An Indian perspective

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario.This paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust explosion.Preventive legislation in core coal-producing countries,viz.China,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically analysed.Accidents occurred due to explosion after Nationalisation of Coal Mines(1973)in India are listed.Prevention and constructive measures adopted in India are critically analysed with respect to the global mining scenario.Measures like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

Research on the mechanism of rockburst induced by mined coal-rock linkage of sharply inclined coal seams

In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams.

CONTROL OF GAS EMISSION AT COAL FACE IN CHINA

All the underground coal mines in China are gassy mines. The gas emission at coal face increasingly grows with the increase of working depth and coal output, for example, the gas emission at a full mechanized coal face of mine No. 2 at Yongquan with a daily output of 2. 000t/d is up to 66-72m2/min. Special gas emission phenomena such as gas blowout, gas and coal outburst etc. have occurred at some faces, which threatens the safe production of face. obstructs the growth of productivity and limits the full play of mechanized equipment.In this paper, gas at face is divided, according to its origin, into three constituents, namely , coming from the coal wall, mined coal and goaf;and a formula for calculation is given. Also , the characteristics of the variation of gas emission at coal face, and the influence of mining sequence of a group of seams and supplied air quantity on the gas emission are discussed. Furthermore . based on the regularity of gas emission at coal face from the above three sources, and on the experiences of years, three principles on controlling gas emission at coal face are presented, that are managing the gas on classification basis, harnessing each source separately and comprehensive prevention and control. Finally, technical measures for prevention and treatment of the accumulation of gas in the upper corner of face, at the working place of coal-winning machine and in the bottom trough of conveyor are introduced.

Study on Dust-Control WaterInjection in Fully-Mchanized Top-Coal Caving Longwall Faces

Based on the analysis of the top-coal movement, the appropriate position of holes through which dustcoutrol water is injected is confirmed. And a practical test has been carried out, which has achieved good reuslts both in dust control and in the flow rate of water injected into coal.

The design of a laboratory apparatus to simulate the dust generated by longwall shield advances

A laboratory apparatus (shield dust simulator) was designed and constructed to simulate the dust generated during the advance of longwall hydraulic roof supports,or shields.The objective of the study was to develop a tool that could be used to test the hypothesis that foam applied to a mine roof prior to a shield advance could be used to reduce the respirable dust generated during shield advances.This paper will outline the design parameters for the development of thesystem,as well as describe baseline testing of coal and limestone dust.Results show that the average instantaneous respirable dust concentrated during simulated shield advance.Confidence intervals were calculated from the instantaneous respirable dust data to determine the repeatability of the data produced by the device.

ControlLogix系统在煤气站的应用

为了改善操作条件,保证设备安全运行,设计了煤气站集中控制系统。利用ControlLogix系统,实现了18台煤气发生炉的集中控制。该系统采用3个处理器、2层网络结构,实现了集中控制、自动加煤、自动出灰、炉底饱和空气温度自动控制和电收尘等的控制。多个安全联锁措施和严谨的自动整流方案的应用,保证了电收尘的安全运行。

急倾斜深埋巨厚煤层掘巷冲击地压前兆特征及其灾害防治

随着冲击地压矿井逐渐向深开采,其巷道掘进伴随的冲击显现愈发强烈。针对巷道掘进过程中的冲击地压有效防治问题,以新疆乌东煤矿急倾斜煤层矿井为例,运用微震监测对巷道掘进的冲击地压时空前兆特征加以分析。结合巷道掘进的应力与能量变化数值模拟分析,揭示巷道掘进的冲击地压发生机理,提出急倾斜巨厚煤层巷道冲击地压防治策略,并完成现场工程实践验证。研究结果表明:急倾斜巨厚煤层巷道掘进的冲击地压发生前第2~5天出现微震总能量极低值,或存在至少4 d的能量潜伏期;冲击地压发生前5 d普遍存在3 d以上的最大能量占比高频波动期。冲击地压发生前存在明显缺震现象,发生位置集中分布在距离掘进工作面较近的微震能量极小值区间范围内,或位于微震能量极值区间附近的微震频次极小值区间范围内,且冲击地压事件位于冲击变形能指数较高区域。急倾斜巨厚煤层水平分段综放开采的坚硬覆岩结构不易破断,使得巷道掘进存在上水平采空区两侧“双翼型”应力集中,掘进工作面前方与巷道底部受顶底板岩层相互挤压的应力集中分布且能量积聚显著,随着巷道掘进深度增加其应力集中与能量积聚进一步增强,容易诱发冲击地压等动力灾害。综合分析形成急倾斜巨厚煤层巷道掘进的工作面爆破卸压、巷道钻孔卸压与补强支护、复杂区域架蓬的冲击地压防治策略。结合冲击地压时空前兆异常为及时加强卸压力度提供时机。通过工作面与巷道卸压使得掘进期间未发生单日累计1×105 J以上微震能量,在对支护优化调整与复杂区域重点防护后,巷道掘进日均微震能量降至2.2 kJ,其1 kJ以上微震事件占比下降且巷道断面整体平整。研究结果为急倾斜巨厚煤层巷道安全掘进提供了科学依据。

急倾斜特厚煤层冲击地压防治探索与总结

急倾斜特厚煤层开采顶板破断运动复杂,应力和能量演化规律特殊,在深部“三高一扰动”影响下,冲击地压防治不容乐观。基于某矿2016年冲击地压事故后急倾斜特厚煤层水平分段开采冲击地压防治经验,从急倾斜特厚煤层水平分段开采冲击地压发生机理、瓦斯突出与冲击地压综合防治和冲击地压管理详细介绍了该矿7年来急倾斜特厚煤层冲击地压防治经验。冲击地压发生机理方面,建立了顶板岩层倾斜悬臂梁模型,揭示了顶、底板覆岩结构破断失稳演化过程,划分了夹持煤体受力状态分区,提出了急倾斜特厚煤层冲击“夹持理论”。瓦斯突出与冲击地压综合防治方面,基于冲击地压灾害控制解危技术的强度弱化减冲理论,结合原有防突措施体系,提出了既能防冲且对防突有利的解危措施,形成了某矿瓦斯/CO_(2)突出-冲击地压“双防”技术体系,建立了适用于某矿急倾斜特厚煤层水平分段开采的冲击地压防治体系,以钻屑量和瓦斯吸解值验证了瓦斯突出防治的强度保障,同时以加强实施卸压措施工作面的微震事件分布及各能级总频次和能量对比,论证说明了卸压方案防治效果的有效性。冲击地压管理方面,形成了预测评价、监测预警、治理预防、效果检验、安全防护和教育培训“六位一体”综合防治架构,基于《煤矿安全规程》和《防治煤矿冲击地压细则》等各项规定,制定了Q/YJMD-—FC 0104-2022《窑街煤电集团有限公司煤矿冲击地压防治第四部分:冲击地压防治技术规范》。

考虑采动效应的闭坑矿井水硫酸盐污染规律

高硫煤矿闭坑后成为埋藏在地表以下深部的产酸污染场,对相邻含水层和周边环境造成了潜在危害,且因采动效应影响和矿井空间分布复杂导致相邻含水层的污染过程与污染程度评价困难。以某闭坑矿区为研究对象,选取SO_(4)^(2-)作为特征污染物,考虑多煤层采动裂隙对含水层结构的破坏影响,运用数值模拟技术对闭坑矿区酸性矿井水中SO_(4)^(2-)污染迁移特征进行研究,并分析流体扩散系数对含水层污染物运移的影响。结果表明:SO_(4)^(2-)在二叠系童子岩组砂岩含水层中水平迁移面积随时间增大而增大,增大速率逐渐减小,垂向渗透系数扩大10倍,空间变异性增强;闭坑5、10、15a后,最大水平迁移距离分别为215、414、612m,最大垂向迁移距离分别达到50、65、70m;而扩散系数越大,产酸时间越长,SO_(4)^(2-)迁移距离和污染范围将随之增大,相较于水平方向,垂向上SO_(4)^(2-)浓度变化对扩散系数的敏感度更高。基于模拟结果,结合闭坑矿区实际条件,针对性提出了“源头减量-过程阻断-末端治理”的综合防控与治理方案。研究结果将为该闭坑煤矿酸性矿井水污染治理与防控提供理论基础,也为其他同类矿井提供科学借鉴。

一种煤矿顶板灾害防治知识图谱构建方法

目前煤矿顶板灾害防治措施决策及事故原因分析等过程主要依赖人工经验,智能化水平较低。顶板灾害防治知识图谱可整合顶板灾害防治知识和经验,辅助顶板灾害事故原因分析和顶板灾害防治措施决策。提出了一种煤矿顶板灾害防治知识图谱构建方法。采用本体方法完成煤矿顶板灾害防治知识建模,将顶板灾害防治领域的概念分为矿井地质类、开采技术类、防治措施类和事故表征类,将概念之间的关系定义为使用、引发、易发、治理、预防和适用,为煤矿顶板灾害防治知识抽取(实体抽取和关系抽取)奠定基础;结合煤矿顶板灾害防治领域文本存在大量嵌套实体和关系之间存在实体重叠的特点,确定了基于跨度的实体抽取方法和基于依存句法树引导实体表示的关系抽取方法;构建了顶板灾害防治领域语料库,采用Neo4j图数据库存储数据,为顶板灾害防治知识图谱的应用提供数据来源支撑;展示了煤矿顶板灾害防治知识图谱局部构建结果,说明该知识图谱可辅助顶板灾害事故原因分析和防治措施决策,从而提高顶板管理的智能化水平;指出基于该知识图谱,结合自然语言处理和知识推理等技术,可实现顶板管理知识问答。

煤岩瓦斯复合动力灾害监测预警与防控技术研究进展

煤岩瓦斯复合动力灾害是深部煤炭开采的重大安全隐患,探明其致灾机理、发展监测预警及防控技术是防治关键。提出了煤岩瓦斯复合动力灾害防治“四面体”理论,即分别从灾害分类、灾害机理、灾害预警、灾害防控4个层面概述煤岩瓦斯复合动力灾害研究进展。总结了以能量释放主体、初始瓦斯压力、载荷条件为主的复合动力灾害类型划分依据;梳理了理论分析尺度和实验室尺度下的复合动力灾害机理研究进展,发现应力路径、微裂纹动态演化和煤岩赋存地质因素临界指标是致灾机理研究的关键;概述了以前期灾害前兆信息判识、中期灾害前兆信息采集、后期灾害一体化监测预警为主线的复合动力灾害监测预警技术研究进展;揭示了复合动力灾害消能减灾一体化防控技术和多尺度分源防控关键技术科学内涵。在此基础上针对两淮矿区灾害特点,提出了深部强动载条件下复合动力灾害智能判识与预警方法和分区协同防控方法。基于当前研究进展,提出了煤岩瓦斯复合动力灾害研究亟待解决的问题,助力实现深部煤炭安全、精准、高效开采。

Controllogix5000控制系统在高炉喷吹煤粉生产中的应用

本文结合1#高炉工程项目，从生产工艺、系统组成、解决方案、应用总结等方面详细阐述了罗克韦尔AB的Controllogix5000系统在炼铁喷吹煤粉生产中的应用。

我国非煤矿山职业健康防控技术研究现状、挑战及展望

矿业是现代工业的粮食,在国民经济发展中发挥着不可替代的作用,但采矿过程伴随众多职业危害因素,给工人职业健康与安全造成极大影响。采用文献查阅、现场调研、访谈交流等方法,并基于团队已有研究积累,对新中国成立以来我国非煤矿山职业健康防控技术研究现状进行了综述,并分析了当前面临的主要挑战。结果表明:我国非煤矿山职业危害主要涉及粉尘、噪声、高温等7类因素,存在“点多、面广、源强”的显著特点,防治难度大;在7类职业危害因素中,粉尘危害最为突出,且爆破粉尘、强疏水性微细粉尘、井下喷浆粉尘与高寒、低气压、超大规模开采粉尘防治是目前面临的主要挑战。在上述分析的基础上,指出我国非煤矿山职业健康防护技术未来发展方向为健全非煤矿山职业危害监管体系、强化职业危害控制科技创新与实践、推行职业危害防控专业化社会服务、坚持职业危害个性化与综合防治、探索职业危害智能化防治技术,逐步形成以监管落实为驱动、科技创新为抓手、社会服务为目标的科学发展模式,切实提高非煤矿山职业危害因素防治效果,保障工人职业健康与安全。