Controlling the effect of a distant extremely thick igneous rock in overlying strata on coal mine disasters

Based on theoretical analysis, similarity simulation tests, numerical simulation analysis and field observations, we analyzed rock collapse and rules of fraction evolution of overlying rocks and studied the rules in controlling the effect of an extremely thick igneous rock, found above a main mining coal seam in an area prone to coal mine disasters in the Haizi Coal Mine. The results show that this igneous rock, called a "main key stratum", will not subside nor break for a long time, causing lower fractures and bed separations not to close. The presence of igneous rock plays an important role in rock bursts, mine floods, gas outburst and surface subsidence in coal mines. By analyzing the rules in controlling the effect of this igneous rock, we provide useful references for safety and high efficiency mining in coal mines under special geological conditions.     

Gas emission quantity prediction and drainage technology of steeply inclined and extremely thick coal seams

Gas emissions of workfaces in steeply inclined and extremely thick coal seams differ from those under normal geological conditions, which usually feature a high gas concentration and a large emission quantity. This study took the Wudong coal mine in Xinjiang province of China as a typical case. The gas occurrence of the coal seam and the pressure-relief range of the surrounding rock(coal) were studied by experiments and numerical simulations. Then, a new method to calculate the gas emission quantity for this special geological condition was provided. Based on the calculated quantity, a further gas drainage plan, as well as the evaluation of it with field drainage data, was finally given. The results are important for engineers to reasonably plan the gas drainage boreholes of steeply inclined and extremely thick coal seams.     

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.     

Green coal mining technique integrating mining-dressing-gas draining-backfilling-mining

Aiming to address the following major engineering issues faced by the Pingdingshan No. 12 mine:(1) difficulty in implementing auxiliary lifting because of its depth(i.e., beyond 1000 m);(2) highly gassy main coal seam with low permeability;(3) unstable overlying coal seam without suitable conditions for implementing conventional mining techniques for protective coal seam; and(4) predominant reliance on ‘‘under three" coal resources to ensure production output. This study proposes an integrated, closed-cycle mining-dressing-gas draining-backfilling-mining(MDGBM) technique. The proposed approach involves the mining of protective coal seam, underground dressing of coal and gangue(UDCG), pressure relief and gas drainage before extraction, and backfilling and mining of the protected coal seam. A system for draining gas and mining the protective seam in the rock stratum is designed and implemented based on the geological conditions. This system helps in realizing pressure relief and gas drainage from the protective seam before extraction. Accordingly, another system, which is connected to the existing production system, is established for the UDCG based on the dense medium-shallow trough process. The mixed mining workface is designed to accommodate both solid backfill and conventional fully mechanized coal mining, thereby facilitating coal mining, USCG, and backfilling. The results show that: The mixed mining workface length for the Ji15-31010 protected seam was 220 m with coal production capacity 1.2 million tons per year, while the backfill capacity of gangue was 0.5 million tons per year. The gas pressure decreased from 1.78 to 0.35 MPa, and the total amount of safely mined coal was 1.34 million tons. The process of simultaneously exploiting coal and draining gas was found to be safe, efficient, and green.This process also yielded significant economic benefits.     

三河尖煤矿坚硬顶板对冲击矿压的影响分析

顶板岩层结构，特别是煤层上方坚硬、厚层砂岩顶板是影响冲击矿压发生的主要因素之一。通过实验研究、现场实测、冲击矿压现象分析，说明了顶板坚硬岩层，特别是顶板的关键层运动、破断对冲击矿压的发生有巨大的影响，掌握顶板的运动规律，并对其进行监测，可达到预测预报冲击矿压危险的目的。     

煤矿绿色开采技术

提出了煤矿绿色开采的概念，阐述了它的内涵和技术体系，绿色开采的理论基础为：开采后岩层中的关键层运动形成的节理裂隙与离层规律以及瓦斯与地下水在破断岩层中的渗流规律。绿色开采技术的主要内容包括：保水开采、建筑物下采煤与离层注浆减沉、条带与充填开采、煤与瓦斯共采、煤巷支护与部分矸石的井下处理、煤炭地下气化等。     

Fissure evolution and evaluation of pressure-relief gas drainage in the exploitation of super-remote protected seams

Based on nonlinearity contact theory and the geological structure of the Xieqiao Coal Mine in the newly developed Huainan coal field, rock movements, mining fissures and deformation of overlying strata were simulated by using the interface unit of FLAC3D to evaluate the pressure-relief gas drainage in the exploitation of super-remote protected seams. The simulation indicates that the height of the water flowing fractured zone is 54 m in the overlying strata above the protective layer. The maximum relative swelling deformation of the C 13 coal seam is 0.232%,while the mining height is 3.0 m and the distance from the B8 roof to the C13 floor is 129 m, which provides good agreement with a similar experiment and in situ results. The feasibility of exploitation of a super-remote protective coal seam and the performance of the pressure-relief gas drainage in a super-remote protected layer are evaluated by comparisons with practice projects. It demonstrates that the relieved gas in the super-remote protected layers could be better drained and it is feasible to exploit the B8 coal seam before the C13 super-remote protected coal seam. The method is applicable for the study of rock movements, mining fissures and deformation of the overburden, using the interface unit to analyze the contact problems in coal mines.     

近距离突出煤层群瓦斯治理技术优化的研究

近距离突出煤层群工作面受上下邻近煤层卸压瓦斯的影响,致使回采工作面瓦斯涌出量大、工作面回风隅角及回风巷中的甲烷传感器频繁报警,瓦斯治理消耗大量的人力、物力和时间,严重制约了矿井的安全生产。通过对几种瓦斯治理方案进行分析论证,得出将整个煤层群作为一个治理单元,统筹考虑,将煤层厚度、瓦斯含量相对较小的弱突出煤层作为关键保护层,配合打钻进行立体式抽采,实现上下递进保护,最大限度地抽采邻近煤层的卸压瓦斯的方案。现场实践结果表明,保护层工作面在回采期间瓦斯抽采率高达90%以上,回风隅角瓦斯浓度降至0.6%以下,回风巷风流中瓦斯浓度降至0.2%以下,工作面月平均回采长度由原来的120 m提高至200 m。同时,从根本上解决了被保护层工作面回采期间瓦斯带来的安全威胁。     

地面群孔瓦斯抽采技术应用研究

为保证新集一矿突出煤层13-1煤北中央采区的安全开采,先后开采131103、131105等11-2煤层工作面作为保护层。首先在上述两个工作面共布置了6个地面钻孔,建立了地面群孔瓦斯抽采系统,预抽采动区被保护层13-1煤瓦斯。接下来对地面钻孔抽采瓦斯参数进行了考察,主要包括基于示踪技术考察了131105工作面采动卸压地面钻孔走向及倾向瓦斯抽采半径,统计分析被保护层瓦斯抽采率,同时就地面群孔与井下底板巷穿层钻孔瓦斯抽采两种方法进行了抽采率、工程费用等方面的对比。研究结果表明：新集一矿的地层条件下地面钻孔抽采煤层卸压瓦斯沿煤层倾向和走向的抽采半径分别不小于160m和240m;采动区地面群孔瓦斯抽采率达35%以上;地面钻孔相对比井下底板巷,在抽采瓦斯方面具有技术上可靠、安全、经济等优点。     

A case study of gas drainage to low permeability coal seam

Gas drainage at low gas permeability coal seam is a main barrier affecting safety and efficient production in coal mines. Therefore, the research and application of drainage technology at low permeability coal seam is a key factor for gas control of coal mine. In order to improve the drainage effect, this paper establishes a three-dimensional solid-gas-liquid coupling numerical model, and the gas drainage amounts of different schemes are examined inside the overburden material around the goaf. The Yangquan mine area is selected for the case study, and the gas movement regularity and emission characteristics are analyzed in detail, as well as the stress and fissure variation regularity. Also examinations are the released gas movement, enrichment range and movement regularity during coal extraction. Moreover, the gas drainage technology and drainage parameters for the current coal seam are studied. After measuring the gas drainage flow in-situ, it is concluded that the technology can achieve notable drainage results, with gas drainage rate increase by 30%–40% in a low permeability coal seam.     

厚煤层全煤巷采区巷道布置关键技术研究

在分析煤矿开采过程中大量矸石排放造成矿区土地资源浪费、水资源破坏和大气污染现状的基础上，根据采煤技术发展现状，提出了厚煤层采区全煤巷布置系统，并对厚煤层采区煤层上山(或煤层大巷)的维护、采空区排水和防灭火等关键技术进行了研究，以实现厚煤层矿井的安全、高效、洁净开采。     

人工神经网络在瓦斯涌出量预测中的应用

当采掘工作面遇有岩浆岩破坏煤系和煤层时,地质条件尤为复杂,采用常规的矿山统计法和瓦斯含量法预测瓦斯涌出量难以取得理想的结果.作者从矿井地质综合分析入手,采用BP神经网络的方法建立了适用于矿井未采区瓦斯涌出量的预测模型,分别用48个4-2煤层、40个7-2煤层钻孔点的煤层瓦斯质量体积、煤层埋藏深度、煤质、火成岩分布、顶底板砂泥岩比值等数据作为输入层,预测地质条件相对复杂矿井的瓦斯涌出量.经已采区实测值与预测值比较分析认为,预测结果可信.     

人工神经网络在瓦斯涌出量预测中的应用

当采掘工作面遇有岩浆岩破坏煤系和煤层时,地质条件尤为复杂,采用常规的矿山统计法和瓦斯含量法预测瓦斯涌出量难以取得理想的结果．作者从矿井地质综合分析入手,采用BP神经网络的方法建立了适用于矿井未采区瓦斯涌出量的预测模型,分别用48个4-2煤层、40个7-2煤层钻孔点的煤层瓦斯质量体积、煤层埋藏深度、煤质、火成岩分布、顶底板砂泥岩比值等数据作为输入层。预测地质条件相对复杂矿井的瓦斯涌出量．经已采区实测值与预测值比较分析认为．预测结果可信．     

岩层采动裂隙分布在绿色开采中的应用

岩层采动裂隙分布的研究与水体下和承压水上采煤、卸压瓦斯抽放、离层区充填与开采沉陷控制等工程问题紧密相关，通过试验与理论分析，对岩层移动过程中的覆岩采动裂隙动态发育特征及其影响因素进行了深入研究，结果证明：覆岩关键层对离层及裂隙的产生、发展与时空分布起控制作用．基于关键层破断前后采动裂隙动态发育特性与差异，提出了“覆岩离层分区隔离充填减沉法”和卸压瓦斯抽放的“O”形圈理论，并分别应用于我国不迁村采煤试验和卸压煤层气开采实践。     

朱仙庄煤矿Ⅱ831工作面区域条带消突技术研究

为了解决无保护层的煤层区域瓦斯治理的难点,分析了朱仙庄矿煤层及瓦斯赋存状况,提出了在不具备开采保护层的区域内,采用底板穿层钻孔区域防突措施,对掘进巷道进行打钻预抽。在详细介绍底板穿层钻孔的布置、抽采和计量方式的同时,通过理论计算和实际掘进作业两个方面,共同验证了底板穿层钻孔条带预抽区域措施可行性和可靠性,进而为穿层钻孔预抽区域措施在矿区的推广应用提供了范例。     

特厚煤层综放开采导水裂隙带高度的数值模拟

以抚顺老虎台矿开采工程实践为例,针对特厚煤层的开采特点,应用立体弹塑性数值模拟方法,对综放条件下特厚煤层上覆岩体破坏规律、应力分布特点以及应力场演变规律、上覆岩体移动与变形规律及上覆岩层导水裂隙带高度的演变特性及发展规律进行了研究,所得研究结果可直接应用于老虎台矿的安全生产.     

上邻近层残存瓦斯压力的理论与应用

本文根据岩体力学与采场覆岩移动原理,探讨了煤层原始瓦斯压力、采场开采技术参数、覆岩岩性、煤层倾角等对上邻近层残存瓦斯压力的影响。指出了采场覆岩法向裂缝宽度是影响上邻近层残存瓦斯压力的关键因素,推导出了能够反映上述影响的上邻近层残存瓦斯压力计算公式。经过实际应用证明比已有的其它公式理论性强、精度高。据此还可以计算上邻近层瓦斯涌出量、可抽放瓦斯量及考察解放层的解放效果等。     

突出矿井深部新水平开采瓦斯综合治理模式研究

针对矿井浅部瓦斯治理模式已不能保障深部采区安全高效生产的现状,提出一种适宜矿井深部新水平开采的瓦斯综合治理模式.工作面消突采用底板岩巷穿层钻孔预抽煤巷条带瓦斯;底板岩巷布置“一巷多用”,在工作面回采工程中可兼做回风巷、尾抽巷、措施巷;回采工作面采用沿空留巷Y型通风综合治理瓦斯.其中,顺层钻孔预抽本煤层瓦斯,高位钻场顶板走向钻孔抽采裂隙带瓦斯,上隅角、尾巷埋管抽采采空区瓦斯,形成矿井三维立体瓦斯抽采体系.     

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.     

长平矿“立体式”瓦斯抽采模式的探索与实践

瓦斯抽放是防治煤矿瓦斯灾害事故的根本措施,长平矿经过几年的探索实践,逐步形成了煤层瓦斯抽放、地面钻井抽放及开掘底板岩巷穿层钻孔抽放等独具特色的立体式瓦斯抽放模式,多措并举,大大降低了煤层的瓦斯含量及矿井瓦斯涌出量,为进一步提高矿井瓦斯抽放率及瓦斯治理技术奠定了坚实基础．