Sponsor(s): China Coal Society
12 issues per year
Current Issue: Issue 06, 2019
Journal of China Coal Society, the 1st in the field of mining engineering, promotes the development of coal theory and practice, as well as academic exchanges at home and abroad to accelerate the transformation from scientific research to real productive forces. It is supervised by China Association for Science and Technology and sponsored by China Coal Society. Launched in 1964, it aims at providing key topics of coal scientific research and mining development. Its scope covers coal geology, geochemistry, geophysics, mineralogy and coal seam formation and evolution; petrophysics of coal; organic matter-rich shales, including mineralogy, formation, transport and storage of gases in coal and shales; unconventional energy systems (e.g. oil shales, shale gas, and other carbon-based fuels); ore deposits of materials and rare metals in coal and coal-bearing strata; and groundwater management. The journal is included in CA, JST, EI, CSCD.
Fan Baoying, Xu Shengyang, Zhu Shuangcheng
Journal of China Coal Society,2019,Vol 44,No. 06
The mine dynamic disasters have seriously threatened the safe production of deep mines in China. However, the theory and method for accurately predicting these disasters are limited. In order to prevent and control the dynamic disasters in the deep mining of Pingdingshan mining area, we studied the natural geo-dynamic conditions of Pingdingshan mining area. The potential dynamic disasters in the coal mine are predicted by using the regional indexes such as active structures, maximum principal stress, and stress gradients. It is found that the curvature of the terrain has a great influence on the probability of coal and gas outbursts in the eastern mining area of Pingdingshan. The ratio of coal and gas outbursts in the positive curvature radius of the eastern mining area of Pingdingshan accounts for 80.21% of the total outbursts. At the same time, based on the energy characteristics of the coal and gas outburst system, the critical energy of coal and gas outbursts in the eastern mining area of Pingdingshan is determined to be 10 6 J. On the basis of the study on the division of active tectonics into grades Ⅰ–Ⅴ by using the geological dynamic zoning method in the early stage, the impact of mining activities is further considered. The patterns of dynamic disasters in the target coal seams and target mining areas are clarified, and the second-level prediction of dynamic disasters is carried out. Fault structures of grades Ⅵ and Ⅴ in the Nos. 8, 10 and 12 mines are obtained through further division, and the distribution characteristics and interaction relationships of the fault structures are determined. The corresponding spatial information analysis system is established, and the activity law of the active structures is analyzed. It is found that the coal gas in the eastern mining area of Pingdingshan is mainly controlled by the geological structures such as the compound, joint and combination among folds, faults and other geological structures. Coal and gas outburst accidents occurring in the geological tectonic belts account for 69.6% of the total outbursts. At the same time, the distribution pattern of regional fault structures and the local distribution characteristics of coal and gas outbursts in the active fault areas of grades Ⅵ and Ⅴ in the eastern Pingdingshan mining area are determined.
Journal of China Coal Society,2019,Vol 44,No. 06
The occurrence of earthquake was an extremely complex and highly nonlinear physical process. Based on the X-shaped conjugate shear fracture-seismic composite model proposed by QIAO et al., this paper further studied the mechanical mechanism of conjugate shear fracture-seism and clarified the physical process of conjugate shear fracture-seismic occurrence and its evolution. From the stress, failure form, and seismic energy of the rock surrounding the soft anisotropic body, it was found that the conjugate shear fractureseism had the law of “Imitation of butterfly survival”. The necessary conditions for the conjugate shear fracture-seism occurrence were obtained. The research result indicated that there was a butterfly failure zone with extremely unstable behavior in rock mass around the underground soft anisotropic body due to the dramatic change of regional stress environment in which tectonic stress appeared. The expansion of the butterfly failure zone could eventually form the dominant or recessive X-type conjugate shear fracture. The energy released by each expansion of the butterfly leaf in the butterfly-shaped failure zone could cause an earthquake within a certain range. Therefore, seismicity was the nonlinear dynamic phenomenon of the elastic energy released by the transient expansion of the butterfly-shaped damage under dynamic load of triggered event. Conjugate shear fracture was divided into the initiation, growth, upheaval periods of circular and elliptical failure, butterfly progressive failure, and butterfly severe failure under different stress states. According to the strength of Richter magnitude of earthquakes, seismic activities had weak earthquake period, medium-strong earthquake period and strong earthquake period during the dynamic generation of conjugate shear fracture. The necessary conditions for the occurrence of an earthquake were summarized, including the presence of soft anisotropic bodies, the drastic changes of tectonic stress, the strength of those rocks surrounding soft anisotropic bodies, and the stress-triggering condition of an earthquake.