Analysis of tectonic deformation features and tectonic origin in the south of Hancheng mining area

Based on the surface observation data, the new seismic exploration and drilling engineering data, using the research ideas and methods of structural analysis, the paper carried out staged restoration of tectonic stress field, discussed the tectonic deformation features, mechanism of tectonic formation and phase of deformation. The tectonic deformation characteristics and tectonic space combination relationship of the study area were analyzed, tectonic styles controlling coalbeds were divided, the tectonic origin was revealed, prediction and evaluation of the favorable coal-bearing areas were conducted. Research results show that there are 3 tectonic styles:NEE squeezed block, NEE multiple graben and horst tectonics and NNE squeezed-stretched composite structure. NEE multiple graben and horst tectonics are major. Since the end of Trias, the study area has experienced NNW squeezed tectonic action during Indosinian movement period, NWW squeezed tectonic action during middle Yanshan movement period, NE squeezed-right rotated and NW-SE stretching action during Himalaya movement period. The maximum principal compressive stress position are 335°, 285°, 44° in turn. The normal faults in NEE direction are further developed along the early shear joint plane formed in the Himalaya movement period. The faults in NEE direction are the most important tectonic controlling the spatial distribution of coal seams. The degree of faults development controls the next step prospecting and mining process of coal resources. The northeastern part of the study area has moderate buried depth of coal seams, simple tectonics, is the most favorable area, through further exploration and evaluation, may become an important following resource block.