The percolation and fractal theory are employed for analyzing evolution of the crack networks in the coal and rock masses at the site of the coal mining face No. 15-22060 at Mine No.8 of Pingdingshan Coal Mining Group. The evolving characteristics and corresponding relationship of percolation probability and fractal dimensions with advancement of the coal mining face are determined. The results show that

being controlled by initiation and propagation of transverse delamination fractures and vertical broken fractures

the permeability probability linearly increases in a stage-wise way with advancement of the coal mining face and the magnitude of amplification is increasing. The crack network propagates into the coal body ahead of mining face and the overburden strata with advancement of the coal mining face. The length

width

quantity and distribution of cracks play dominant roles in fractal dimensions

and evolution of fractal dimensions falls into 3 stages. Relationships between percolation probability and fractal dimensions of crack network in coal and rock masses can be fitted using a power function for the first stage and two linear functions for the second and the third stage. These results lay a foundation for determining the equivalent permeability of the crack networks in coal and rock masses.