Fractal structure of microfractures and characteristics of porosity and permeability in cataclastic coals

Based on the microscopy and the mercury intrusion tests of 9 coal samples from Faer coal mine in Guizhou Province, we analyzed the characteristics of micro deformation and microfracture in tectonic coal, and conducted research on permeability of pore. Results show that information dimension of microfractures in cataclastic coal ranges at least from 1.2 to 1.8; Based on the index of the information dimension we can classify the cataclastic coals into 3 categories, with their ranges of dimension as follows:1.2~1.4, 1.4~1.7, and 1.7~1.8; As for the pore system, brittle tectonic deformation increased the pore volume of macropore and mesopore. We also find that the greater the tectonic deformation is, the better the permeability of the tectonic coal of brittle series is.