Coal Structure Characteristics of the 2# Coal Seam in the Jiaozuo Mining Area and Its Geological Dependence

Abstract

To clarify the coal structure, spatial distribution, and controlling factors of the 2# coal seam in Jiaozuo mining, the drilling coal samples were collected to observe the coal type and coal structure. The coal macerals were identified by a MPVSP microscope photometer, and the spatial characteristics of the coal structure were obtained through interpreting deep lateral resistivity logging, natural gamma ray logging, density logging, and acoustic logging curves. The influence of coal properties, burial depth, geological stress, and faults on the coal structure were discussed correspondingly. The results exhibit that granulitic−mylonite coal was most developed in the 2# coal seam, followed by primary coal and cataclastic coal; the coal type was dominated by semibright coal, followed by clarain and semidull coal. Granulitic−mylonite, cataclastic, and primary coals were the main components of clarain, semibright coal, and semidull coal, respectively. Higher vitrinite and organic matter contents were conducive to the development of granulitic−mylonite. The coal structure combinations were spatially varied, and the granulitic− mylonite combinations were the most common. Granulitic−mylonite coal was developed in the east and south parts of the study area, and the coal structure was fragmented with a greater burial depth and larger thickness. The geological stress is the fundamental cause of coal structure damage as well as the cutting of faults.

Associations between Surface Deformation and Groundwater Storage in Different Landscape Areas of the Loess Plateau, China

“…Surface deformation that returns to its original state after the stress disappears is called elastic surface deformation [56]. In situ stress changes the physical state of geologic rock strata, causing strata fracture and collapse, which is the dominant factor of inelastic deformation of the earth's surface and the direct cause of geologic hazards [57]. In the Kubuqi Desert, where anthropogenic disturbances are infrequent, fluctuations in groundwater water storage are the main cause of surface deformation in summer and fall (Figure 8A,a).…”