提高本煤层瓦斯抽放效果的途径

总结了多年来屯兰矿本煤层瓦斯抽放经验,分析瓦斯抽放工作中存在的问题,认为影响预抽效果的主要因素有煤层透气性、钻孔方位与煤层节理方向的关系、钻孔与采场的相对位置、封孔质量及钻孔直径等。主要研究了瓦斯抽放钻孔参数对抽放效果的影响机理,提出合理选择钻孔的方位、调整钻孔与采场的相对位置、优化钻孔布置等适合该矿实际本煤层的瓦斯预抽方案。

采用水力压裂强化煤层瓦斯抽放的远景

文内论述了用静压注水和动压注水进行高瓦斯煤层水力压裂形成裂隙的方法之应用条件及优、缺点。列出了卡拉甘达矿区厚煤层水力压裂的参数,表明了水力作用带煤层抽放瓦斯的效果,并列举了用静压注水对 K_(12)煤层水力压裂参数的实验结果。

平顶山矿区煤层瓦斯抽放设计技术的初步分析

文章重点介绍平顶山矿区目前主要应用的几种煤层瓦斯的抽放方法,并从应力分布、煤体结构变化、煤层透气性能、抽放效果等方面进行了技术经济分析和比较,对于如何在不同条件下,正确选择和应用适宜的煤层瓦斯抽放方法,具有重要参考意义。

开采煤层瓦斯抽放方法的筛选及其适用性

抽放瓦斯可以降低涌入矿井风流的瓦斯量,防止煤与瓦斯突出,解放高瓦斯矿井生产力,是防治煤矿瓦斯的治本措施。经过数十年的实践与试验研究,我国煤矿抽放瓦斯技术已积累了上百种抽放瓦斯方法,煤矿抽放瓦斯的规模有了很大发展,已具备对各种抽放瓦斯方式方法进行技术筛选的条件。各煤矿也有必要针对本矿的地质、开采条件,选择经济有效的抽放瓦斯方式,以保障煤矿有效治理瓦斯灾害,实现"先抽后采",确保煤矿安全生产。

钻孔水力割缝提高本煤层瓦斯抽放率

钻孔水力割缝是利用高压水射流,使钻孔周围的煤体产生裂缝,起到卸压作用,提高煤层的透气性,增大瓦斯释放速度,改变煤层抽放难易程度,提高煤层可抽性,目前是我国抽放本煤层瓦斯方法中比较好的一种方法。水力割缝工艺系统主要部分包括:高压供水系统、控制系统、射流器(喷咀与枪头)、钻割推进装置及煤水导流装置等。

本煤层钻孔瓦斯抽放影响因素数值模拟研究

目前我国治理瓦斯的最主要方法是对煤层瓦斯进行钻孔抽放,而相关参数的合理确定是此项工作中迫切需要解决的问题,采用数值模拟的方法是较为常用且契合度较高的解决方案。结合煤体应力特性以及瓦斯在煤层中的赋存与运移规律,对影响相关煤层钻孔瓦斯抽放量的抽放时间、抽放压力、孔隙率和渗透率等因素进行研究,建立了瓦斯在煤层中运移的数值模型,得出该煤层瓦斯压力分布规律以及不同瓦斯抽放参数对抽放效果的影响,为制定瓦斯抽放施工与管理措施打下基础。

本煤层抽放治理采面瓦斯技术在东海矿的应用

介绍了利用风煤钻施工钻孔,在采场动压作用下煤体产生裂隙释放瓦斯,然后利用抽排设施抽放瓦斯,治理采面局部高瓦斯区域的方法。

钻孔预抽本煤层瓦斯合理预抽期评价模型

瓦斯灾害严重影响我国煤矿生产的安全,瓦斯抽放是防止瓦斯灾害事故的根本途径。介绍了钻孔预抽放本煤层瓦斯合理预抽期的影响因素,以及据此而建立的合理预抽期的评价模型。

425综放工作面瓦斯基础参数测定及分析

掌握矿井瓦斯基础参数,可以采取科学、合理的瓦斯治理措施和管理方法,减少瓦斯治理及管理中的盲目性。因此,测定瓦斯基础参数成为瓦斯综合治理以及煤层瓦斯抽放的支撑依据。

三软突出煤层区域防突技术研究

为了有效防治三软突出煤层突出危险性,对大平煤矿21采区煤层采取区域防治煤与瓦斯突出措施,利用底板抽放巷施工穿层预抽钻孔以及水力冲孔措施,提前对煤巷掘进工作面掘进区域煤层瓦斯进行预抽,降低了突出危险掘进面的突出危险性,保证了安全掘进,有效提高了突出危险掘进工作面的单进水平。

马兰矿10503综采工作面瓦斯综合治理

合理利用通风系统,采用Y型通风,采空区埋管抽放,下邻近层瓦斯抽放,上邻近层瓦斯抽放,解决10503工作面、上隅角、采空区瓦斯超限问题。实现本煤层煤与瓦斯共采,在抽采本工作面采空区瓦斯的同时抽采相邻煤层瓦斯,根据工作面瓦斯赋存及涌出规律,通过对2种通风方式的比较,选择Y型通风方式,配合沿空留巷补打隔离墙来解决10503工作面的瓦斯问题,确保工作面安全生产。

CMSI-6200/80钻车在松软突出煤层施工长钻孔应用技术研究

介绍了CMSI-6200/80钻车的工作原理及技术特征,成功的解决了在松软煤层中施工瓦斯抽放钻孔的技术难题,且孔成孔率高。为矿井有效抽采瓦斯,消除突出危险性提供了有力保障,确保了煤矿安全生产。

煤矿冲击地压防治方法分析

冲击地压又称岩爆,指井巷或工作面周围岩体弹性变形能的瞬时释放而突然产生剧烈破坏的动力现象,常伴有煤岩体抛出、巨响及气浪等现象。它具有很大的破坏性,是煤矿重大灾害之一。在我国,冲击地压最早于1933年发生在抚顺胜利煤矿。近年来,陕渑煤田义马矿区某矿先后有冲击地压现象发生。

以煤为主 多种经营

江西省煤炭工业的特点决定,发展综合利用和多种经营有着特殊重要意义。这是由于江西多数煤矿原煤灰分高,售价低,亏损大。如果不搞综合利用和多种经营,经济效益就不可能提高,企业就无法摆脱经济困境。同时,随着改革的深入,劳动生产率不断提高,

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 mining 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 permeability 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 decrease from 13 to 4.66 m3/t and the gas drainage reach 64%.

Characteristics of compression fracture of ＂three soft＂ coal bed by perfusion and gas sucking technique

Against the particularity of stratum-structure in ＂three soft＂ mine areas, according to rock indoor test and on-site sucking experiment, discussed the characteristics of argillization, compression fracture and sucking technique of soft coal with low permeability. It is clearly pointed out that the gas can be highly effectively sucked only by compression fracture along the occurrence of the coal seam, creating inter-seams crack belt because of the difference of bulgy deformation. After the flooding experiment in the 24080 workface of Pingdingshan No. 10 mine, the average single-bore volume of gas increases from 77 m3 to 7 893 mS, while decay cycle extended from 7 days to 80-90 days. Also, the single-bore extracting rate of gas increases to 33%.

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.

Theory of gas extraction from coal seams and its use

Gas extraction is one of the main measures of control and use of gas of coal mines. At present, the design method is under the experimental period and do not satisfy the need of practice. In this paper, the theory of gas extraction of coal seams based upon Darcy law was studied. Mathematical model of gas extraction of coal seams was established and two kinds of solv- ing approaches based on computer software and linear approximation were given. The rightness and the validities of the model were examined with a practical example. Results obtained can be used to determine and optimize the parameters related etc.

Application of deep borehole blasting on fully mechanized hard top-coal pre-splitting and gas extraction in the special thick seam

In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas pre-draining technologies on top coal.The mechanism of the technologies was systematically expounded based on hard top-coal cracks development obtained by numerical simulation and theoretical analysis.The results show that explosive blasting in the hard rock results in a large number of cracks and large displacement in the rock mass due to the effect of explosion stress.Meanwhile,the thick top-coal caves,and desorbing gas flows along the cracks improve gas extraction.Finally,the pre-splitting for deep borehole blasting and gas pre-draining technologies was applied in No.3802 working face of Shui Liandong Coal Mine,which increases monthly output in the face to 67.34 kt and the drained gas concentration to 86.2%.The drained gas average concentration from each borehole reaches 40%,and the effect is remarkable.

Application study on complex wetting agent for dust-proof after gas drainage by outburst seams in coal mines

After gas drainage, the outburst seam is dry and, consequently, during subsequent mechanized mining, unwanted dust production is extensive. Because the hard dustfall typically has a small particle size it contains a high percentage of respirable dust. Considering these factors, this paper improved the efficiency of dustfall by reducing the surface tension of the liquid used as a wetting agent, then configuring five kinds of wetting agents by adopting various doses and types of surfactants, neutral inorganic salts and chemical additives, etc. After purchasing DA-85 and SRJ-1 wetting agent, the surface tension and critical micelle concentration of seven kinds of wetting agents were measured using the capillary rise method. Wetting agent A was confirmed to have the best comprehensive effect. The experiments were optimized by measuring and comparatively analyzing contact angles of pure water, SRJ-1 wetting agent and wetting agent A on the surface of different coal samples using a contact angle measurement instrument （HARKE- SPCA）. By comparative analysis, dust-proof effects of seam, dynamic pressure water infusion and high- pressure spray in the tunneling face at the Daning coal mine using pure water, wetting agent SRJ-1 and A, it was determined that after using wetting agent A, the average dust concentration in the place of the mining machine driver, 10 m and 110 m away from the tunneling front is approximately 300 rag/ m^3, 240 mg/m^3 and 100 mg/m^3, respectively, This practice increased the dust-proof efficiency dramati- cally and achieved a good comprehensive dust-proof effect.