Study on Types of Tectonic Coal from Xutuan Coal Mine in Huaibei Coalfield and Its Pore Characteristics

Tectonic coal in the study area was observed by hand specimen and electron microscope, and the differences were significant between different types of tectonic coal in macroscopic and microscopic deformation characteristics. The fractal theory is used to study the pore characteristics of tectonic coal based on the experimental data of mercury intrusion. The results show that the total pore volume and porosity increase with the increase of deformation degree, especially in the ductile deformation stage, but the pore connectivity is gradually getting worse. The response of pore characteristics to the deformation of the tectonic becomes weaker with the decrease of pore size. Fractal dimension based on pressure mercury data can only represent the characteristics of the pore structure of the macropore and mesopore effectively. The fractal dimension increases with the increase of the deformation degree of coal, and the pore structure becomes more diversified and complicated, macropore volume or the proportion of seepage holes shows positive linear correlation with fractal dimension, but mesopore volume shows positive exponential correlation with fractal dimension.