Zhou H.,China University of Mining and Technology |
Liu J.,China University of Mining and Technology |
Xue D.,China University of Mining and Technology |
Yi H.,China University of Mining and Technology |
Xue J.,Huainan Mining Group Co.
International Journal of Mining Science and Technology
The exploitation of coal bed methane or coal gas is one of the most effective solutions of the problem of coal gas hazard. A better understanding of gas flow in mining-induced cracks plays an important role in comprehensive development and utilization of coal gas as well as prevention of coal gas hazard. This paper presents a case study of gas flow in mining-induced crack network regarding the situation of low permeability of coal seam. A two-dimensional physical model is constructed on the basis of geological background of mining face No. 1122(1) in coal seam No. 11-2, Zhangji Coal Mine, Huainan Mining Group Corporation. The mining-induced stress and cracks in overburden rocks are obtained by simulating an extraction in physical model. An evolution of mining-induced cracks in the process of advancing of coal mining face is characterized and three typical crack networks are taken from digital photos by means of image analysis. Moreover, the numerical software named COMSOL Multiphysics is employed to simulate the process of gas flow in three representative crack networks. Isograms of gas pressure at various times in mining-induced crack networks are plotted, suggesting a shape and dimension of gas accumulation area. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology. Source
Luo Y.,State Key Laboratory of Deep Coal Mining and Environment Protection |
Luo Y.,National Engineering Research Center for Coal Gas Control |
Luo Y.,Huainan Mining Group Co.
Journal of Coal Science and Engineering
Aiming to effectively solve the problem of deep mining with safety and high efficiency, according to geological conditions, production and stress analysis in roadway surrounding rock, experimental studies on roadway supporting of workface 103 under three types of roof conditions with different supporting technologies and parameters were carried out based on the theory of supporting technology of gob-side entry. The results show the supporting of gob-side entry retaining is successful, and the deep surrounding rock is effectively controlled by field monitoring and drilling-hole photos. After stress in surrounding rock of roadways restores stable, the final roadway deformation of surrounding rock of haulage roadway and air-roadway are both about 300 mm; width of gob-side entry is 3.8-4.0 m and average height is 2.0-2.2 m; roadway section is above 8.0 m2, which solves the problems of gob-side entry retaining support strength and safe mining; necessary conditions of mining safety in workface 103 are met. © The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg 2012. Source
Xu Y.,Anhui University of Science and Technology |
Yuan P.,Anhui University of Science and Technology |
Yuan P.,Huainan Mining Group Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering
To investigate the effect of blasting load on zonal disintegration in deep rock, taking high geostress roadway in Dingji coal mine of Huainan mine area as prototype, three dimensional geomechanical model test in high axial stress and blasting excavation has been carried out by cemented sand similar material and "capacity of deep rock breakage mechanics and supporting technique model test". Model test results show that blasting strain wave signal contains both compressive strain and tensile strain, with predominant in initial compressive strain, and it attenuates quickly with propagation distance increasing. Blasting load produces some micro-cracks on similar materials nearby the boundary of roadway with deterioration of its mechanical properties and damage to its integrity. Moreover, the stress field has also been redistributed. After overload, the radial tensile strain of surrounding rock in all three positions, vault, side wall, and floor, presents a non-monotonic change, interval distribution of peaks and troughs, with distance to model roadway increasing. Under high axial load, micro-cracks caused by blasting load propagate and connect to form a macro fractured zone. The first fracture position is surrounding rock in side wall of model roadway, next fracture position is surrounding rock in floor, then last fracture position is surrounding rock in vault. After overload, there is an obvious zonal disintegration phenomenon in model. ©, 2015, Academia Sinica. All right reserved. Source
Yao X.-R.,Huainan Vocational and Technical College |
Cheng G.-L.,Huainan Mining Group Co. |
Shi B.-M.,Anhui University of Science and Technology
Meitan Xuebao/Journal of the China Coal Society
According to difficult pore-forming when long drilling through mudstone, structural belt and soft seam, studied return airway 11-2 level -910 m Dingji Coal Mine using FLAC3D computer numerical simulation with fact mechanical parameters of rock mass, calculated drilling stress field, displacement filed and change of plastic failure zone, and concluded that secondary stress elastic-plastic distribution map of drilling was consistent with the theoretical calculation. The distribution of secondary stress elastic-plastic was no longer a ring when side pressure coefficient was not equal 1, the roof and floor radial displacement of drilling was two times of two sides. The stress concentration degree of surrounding rock becomes higher, the displacement of drilling increases, the plastic radius of surrounding rock decreases, and the drilling becomes more instable with the increase of side pressure coefficient. When strengthening area of surrounding rock increases, the secondary stress influence scope of drilling reduces, the radius of plastic area decreases, the radial displacement of drilling decreases, and the drilling is easier to be stable. Based on the theory of drilling creating by solidification technology, the gas extraction drilling instability was controlled effectively in deep surrounding-rock with weak structure crossheading 1421(1) Dingji Coal Mine, and verified with case. Source
Yuan L.,Huainan Mining Group Co.
International Journal of Coal Science and Technology
The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its application and practice in the Shaqu, Zhongxing, Fenghuangshan and Pingmei mines. Areas for further improvements in future studies are discussed, focusing in particular on the fundamentals of the extraction system to make it greener, more scientific, and more advanced in both the exploitation and utilization of coal and the gas in coal. © 2015, The Author(s). Source