高瓦斯煤层群保护层开采卸压效果数值模拟

为合理选择保护层,针对高瓦斯突出煤层群安全开采问题,分析了保护层开采的保护作用机理,即保护层开采可对被保护层起到卸压增透作用,改善被保护层的瓦斯抽放效果是解决煤与瓦斯突出问题及瓦斯灾害的重要技术手段;卸压对煤与瓦斯突出及瓦斯问题的解决具有决定作用.针对某矿高瓦斯突出煤层群生产地质条件,采用FLAC3D数值软件模拟2个非突出煤层作为保护层开采时的卸压效果,并对其进行了分析比较,研究结果可为保护层的合理选择提供参考依据.     

突出矿井煤层群开采首采保护层区域消突技术实践

以突出矿井谢桥煤矿为例,介绍了煤层群开采首采保护层卸压瓦斯抽采工程设计和被保护煤层卸压瓦斯抽采效果.实践表明,谢桥矿1242(1)保护层开采实践证明,在11-2煤层有效保护范围内的13-1煤层,可充分消除其突出危险性,并有利于被保护层瓦斯治理;经保护层开采后,不仅能最大程度消除高瓦斯突出危险煤层的瓦斯事故隐患,而且极大地提高了巷道掘进速度,从而缓解了工作面接替的紧张局面,有效提高了生产效率.保护层开采区域消突技术是防治煤与瓦斯突出最经济、有效的技术措施.     

高瓦斯煤层千米定向钻孔煤与瓦斯共采机理

结合最新引进的德国DDR-1200型千米定向钻机,提出在工作面顶板裂隙带内打千米定向钻孔抽采瓦斯的新方法,构建千米定向钻孔煤与瓦斯共采体系.结果表明,工作面上覆岩层存在大量横向间隙和竖向裂隙,裂隙带高度为34m左右,最大离层裂隙发生在主关键层下方,距离工作面顶板22m左右,最大离层量240mm,形成瓦斯富集区域;工作面倾向方向,回采巷道向采空区方向0～60m范围内裂隙最发育,并能长期稳定存在.据此在14301工作面进行工业性试验,试验结果表明,钻孔布置在14301工作面上方顶板22m左右,倾向方向距运输巷15m处,抽采浓度达70%以上,抽采时间在120d以上,取得最佳瓦斯抽采效果,实现煤与瓦斯共采.     

演马庄煤矿突出煤层炮采放顶煤工作面防治煤与瓦斯突出的方法和措施

介绍了演马庄煤矿 2 70 2工作面突出煤层炮采放顶煤效果检验的方法和防止煤与瓦斯突出所采取的措施 ,提出突出煤层炮采放顶煤工作面瓦斯抽放是防止煤与瓦斯突出的有效手段 ,当工作面有煤与瓦斯突出危险时 ,采取恰当的防突措施 ,能够降低煤与瓦斯突出的危险程度 ,可供同类工作面回采时借鉴     

煤与瓦斯突出矿井煤层群联合开采动态接替研究

针对高瓦斯突出矿井煤层群联合开采的特点,提出了动态编制矿井采掘接替计划的方法.通过对影响矿井采掘工程接替的安全因素和经济因素的分析,建立了影响采掘工程接替的因素指标体系,利用层次分析方法得出了因素的指标权重,采用模糊综合优选法确定备选工作面中的最优接替面,依次类推,直到安排所有的备选工作面.根据采煤工作面生产计划,综合考虑矿井瓦斯治理技术,采用时间反推方法,编制采煤工作面相关的掘进计划.应用研究结果表明,采掘动态接替法可以适时调整采掘接替计划,所得采掘工程接替方案科学合理、切实可行.     

Energy-limiting factor for coal and gas outburst occurrence in intact coal seam

This research reviewed the mechanics and gas desorption properties of intact coal, and tested the crushing work ratios of different intact coals, and then, studied the stress conditions for the failure or crushing of intact coal and the gas demand for the pulverization of intact coal particles. When a real-life outburst case is examined, the required minimum stress for intact coal outburst is estimated. The study concludes that the crushing work ratios of three intact coal samples vary from 294.3732 to 945.8048 J/m². For the real-life case, more than 2300 MJ of transport work is needed, and 10062.09, 7046.57 and 5895.47 m³ of gas is required when the gas pressure is 1, 2 and 3 MPa, respectively. The crushing work exceeds the transport work and even reaches 13.96 times of the transport work. How to provide such an enormous crushing work is an energy-limiting factor for the outburst in intact coal. The strain energy is needed for the crushing work, and the required minimum stress is over 54.35 MPa, even reaching 300.44 MPa. These minimum stresses far exceed the in-situ vertical and horizontal stresses that can be provided at the 300–700 m mining depth range.     

“三软”极不稳定煤层综采技术研究

偃龙矿区开采的山西组二．煤层属于“三软”极不稳定煤层,其突出特征为煤层松软、厚度和倾角变化大,顶板及底板松软、破碎,赋存条件复杂,开采极其困难．嵩山煤矿以多项支护技术专利为支撑,采用底板岩巷的“一巷三用”,合理选择高强度轻型放顶煤支掩式液压支架,以及综采防片帮和防冒顶等技术,实施综采机械化开采,实现了“三软”煤层的安全高效开采,取得了显著效果．     

煤与瓦斯突出模拟试验的研究现状与展望

综述了煤与瓦斯突出模拟试验研究现状,主要从瓦斯压力、地应力和煤体物理力学性质及其综合作用方面分析了其对煤与瓦斯突出的影响以及在这些因素影响下的突出特点、形式和规律。鉴于煤与瓦斯突出的复杂性,目前的研究还存在以下不足:(1)试验过程中用的都是颗粒煤或者是型煤,很难真实反映现场的煤层物理特性;(2)试验载荷的施加方式和大小反映不了现场煤体中真实的三维应力状态;(3)实验室模拟试验中的突出口多数情况是人为打开的,而不是煤体内部达到突出条件后自主打开的。建议使用原煤煤样、加大模拟实验尺度、采用真三轴加载方式、合理设置突出口进一步开展多因素耦合的煤与瓦斯突出模拟试验,对煤层瓦斯突出机理的研究具有重要的现实意义。     

Top coal caving mining technique in thick coal seam beneath the earth dam

It is important to study the mining technology under structures for raising the coal resources recovery ratio. Based on the geological and mining conditions, the top coal caving harmonic mining technique in thick coal seam beneath the earth dam was put forward and studied. The 5 factors such as the panel mining direction, panel size, panel location, panel mining sequence and panel advance velocity were taken into account in this technique. The dam movement and deformation were predicted after the thick coal seam mining and the effects of mining on the dam were studied. By setting up the surveying stations on the dam, the movement and deformation of the dam were observed during mining. By taking some protective measures on the dam, the top coal caving mining technique in thick coal seam beneath the earth dam was carried out successfully. The study demonstrates that harmonic mining in thick coal seam is feasible under the dam. The safety of the earth dam after mining was ensured and the coal resources recovery ratio was improved.     

Determination of indices and critical values of gas parameters of the first gas outburst in a coal seam of the Xieqiao Mine

Based on the important role in mine safety played by parameters of the first gas outburst,we propose a method of combining historic data,theoretical analysis and experimental research for the purpose o...     

Feasibility analysis of gob-side entry retaining on a working face in a steep coal seam

Based on the decline in exploitation of coal resources, steep coal seam mining and mining face tensions continue to explore the feasibility analysis of steeply inclined faces in the gob. One of the key factors in utilizing the technology of gob-side entry retaining in steep coal seams is to safely and effectively prevent caving rock blocks from rushing into the gob-side entry by sliding downwards along levels. Using theoretical analysis and field methods, we numerically simulated the mining process on a fully-mechanized face in a steep coal seam. The stress and deformation process of roof strata has been analyzed, and the difficulty of utilizing the technology is considered and combined with practice in a steep working face in Lvshuidong mine. The feasibility of utilizing the technology of gob-side entry retaining in a steep coal seam has been recognised. We propose that roadways along the left lane offshoot body use a specially-made reinforced steel dense net to build a dense rock face at the lower head. The results show that the lane offshoot branch creates effective roof control, safe conditions for roadway construction workers, and practical application of steeply inclined gob.     

复合水体下急倾斜煤层开采的水害防治研究

淮南孔集煤矿山西组A1、A3煤层总厚6m,为第四系含水砂层下底板岩溶水上复合含水体威胁的急倾斜煤层。对于砂层水害防治,采用合理留设防水煤柱,沿用“小阶段、长走向、间歇开采”的方式方法;对于底板岩溶水患防治,采用“疏水降压、限压开采”的防治水方法;对于局部抽冒及流水钻孔涌砂造成地表抽冒漏斗及岩溶塌陷漏斗,采取了“按尺核产、严禁超限出煤”、“小流量、长历时、控砂疏水”的有力措施。实现了安全开采,取得了良好的效果。     

煤层群首采关键层煤与瓦斯共采技术研究

基于新庄孜煤矿近距离煤层群全为突出煤层的情况,选择突出危险性程度较低的、煤层厚度只有0．8m的B10煤作为近距离煤层群开采首采层,即关键保护层工作面。采用一面六巷的瓦斯治理技术,并在66310工作面成功应用,实现了煤层群首采关键层煤与瓦斯安全高效共采。研究成果可为低透气性高瓦斯煤层群卸压开采提供指导。     

Pressure relief, gas drainage and deformation effects on an overlying coal seam induced by drilling an extra-thin protective coal seam

Numerical simulations and field tests were used to investigate the changes in ground stress and deformation of, and gas flow from, a protected coal seam under which an extra-thin coal seam was drilled. The geological conditions were: 0.5 meter min-ing height, 18.5 meter coal seam spacing and a hard limestone/fine sandstone inter-stratum. For these conditions we conclude: 1) the overlying coal-rock mass bends and sinks without the appearance of a caving zone, and 2) the protected coal seam is in the bending zone and undergoes expansion deformation in the stress-relaxed area. The deformation was 12 mm and the relative defor-mation was 0.15%. As mining proceeds, deformation in the protected layer begins as compression, then becomes a rapid expansion and, finally, reaches a stable value. A large number of bed separation crannies are created in the stress-relaxed area and the perme-ability coefficient of the coal seam was increased 403 fold. Grid penetration boreholes were evenly drilled toward the protected coal seam to affect pressure relief and gas drainage. This made the gas pressure decrease from 0.75 to 0.15 Mpa, the gas content de-crease from 13 to 4.66 m3/t and the gas drainage reach 64%.     

Thermo-hydro-mechanical coupled mathematical model for controlling the pre-mining coal seam gas extraction with slotted boreholes

Drainage influence radius is the basic parameter for borehole arrangement, while the effect of high pressure water jet slotting technology on borehole drainage influence radius has not been studied systematically. In this paper, a fully thermo-hydro-mechanical(THM) coupled model which represents the non-linear responses of gas extraction was implemented to demonstrate the reliability of this model through history data matching. Based on this model, the susceptibilities of gas extraction with single slotted borehole, including the permeability, the gas pressure, the temperature, the coal adsorption characteristics and the radius of slot, were quantified through a series of simulations. The simulation results revealed that increasing the permeability, initial gas pressure and temperature could develop the influence radius of single slotted borehole. This finite element model and its simulation results can improve the understanding of the coal-gas interactions of underground gas drainage and provide a scientific basis for the optimization of drainage systems.     

构造煤及其对煤与瓦斯突出的控制作用

高空隙率、低透气性使构造煤能够保持较高的瓦斯压力 ;破碎性、“隔离”作用及“气垫”作用 ,使构造煤抵御外力作用的能力大大降低 ;构造煤变形幅度大的特性 ,为瓦斯的迅速解吸、放散和快速流动创造了条件 ;构造煤薄弱分层或“通道层”的存在 ,则为煤与瓦斯突出的初始激发和持续发展奠定了基础 ;上述因素的共同作用 ,影响和制约了煤与瓦斯突出的强度和分布 .尽管如此 ,一定厚度的构造煤的存在只是发生煤与瓦斯突出的必要条件和有利条件 ,而非充分条件 .     

Strata behavior investigation for high-intensity mining in the water-rich coal seam

This paper describes a specific case of mining in a water-rich coal seam in western China. Water inrushes, roof caving and other disasters induced by intensive mining operation could pose great threats to the safety of coal mines. The strata behavior during the high-intensity extraction in the water-rich coal seam is analyzed by employing the numerical simulation method and in situ monitoring. The results show that about 10 m ahead of the workface, the front abutment pressure peaks is at 34.13 MPa, while the peak of the side abutment pressure is located about 8 m away from the gateway with the value of 12.41 MPa; the height of the fracture zone, the first weighting step and the cycle weighting step are calculated to be 45, 50 and 20.8 m, respectively; pressure distribution in the workface is characterized by that the vertical pressure in the center occurs earlier and is stronger than those on both ends. Then, the results above are verified by in situ measurement, which may provide a basis for safe mining under similar conditions.     

曹县地区煤层气开发

针对曹县地区的煤层气资源 ,提出了完整的开发设计方案 ,包括外部协作配套条件 ,项目建设资源条件 ,用户市场 ,气井布置 ,地面排水采气设备 ,煤层气的储存与输送以及其他相应配套工程 ,并进行了技术经济分析与评价 ;认为曹县地区煤层气开发项目配套条件可靠 ,投资效益显著 ,对该地区国民经济的发展和环境效益的提高都具有特殊重要的意义 .     

Key technologies and engineering practices for soft-rock protective seam mining

Severe gas disasters in deep mining areas are increasing, and traditional protective coal seam mining is facing significant challenges. This paper proposes an innovative technology using soft rock as the protective seam in the absence of an appropriate coal seam. Based on the geological engineering conditions of the new horizontal first mining area of Luling Coal Mine in Huaibei, China, the impacts of different mining parameters of the soft-rock protective seam on the pressure-relief effect of the protected coal seam were analyzed through numerical simulation. The unit stress of the protected coal seam, which was less than half of the primary rock stress, was used as the mining stress pressure-relief index. The optimized interlayer space was found to be 59 m for the first soft-rock working face, with a 2 m mining thickness and 105 m face length. The physicochemical characteristics of the orebody were analyzed, and a device selection framework for the soft-rock protective seam was developed. Optimal equipment for the working face was selected, including the fully-mechanized hydraulic support and coal cutter. A production technology that combined fully-mechanized and blasting-assisted soft-rock mining was developed. Engineering practices demonstrated that normal circulation operation can be achieved on the working face of the soft-rock protective seam, with an average advancement rate of 1.64 m/d. The maximum residual gas pressure and content, which were measured at the cut hole position of the protected coal seams (Nos. 8 and 9), decreased to 0.35 MPa and 4.87 m³/t, respectively. The results suggested that soft-rock protective seam mining can produce a significant gas-control effect.     

高瓦斯矿井一次采全高综采工作面瓦斯治理

介绍了晋城矿区寺河矿高瓦斯矿井一次采全高工作面瓦斯治理方法和瓦斯利用情况,提出了高瓦斯矿井一次采全高工作面瓦斯治理途径和技术,指出高瓦斯矿井高产高效、安全生产的根本出路在于提高瓦斯抽放率,加强瓦斯利用,进而提高矿井的综合效益.