Abstract
From the proposed model of the thickness of the surface layer of the coal seam in the Sherubaynura section of the Karaganda basin, it follows that this thickness does not exceed 150 nm. For nanostructures of such sizes, there are size dependences of all the physical properties, including the diffusion coefficient of methane through microcracks in the coal seam. This means that for the methane diffusion in the Fick's equation, one must assume that the diffusion coefficient will also depend on the seam size. The solution of this problem shows that the diffusion of nanometer-thick coal-seam methane significantly differs from that of a massive sample. It is also significant that the methane diffusion in the coal seam depends both on the grade of coal through the diffusion coefficient of a massive sample and on the size factor. In the classical case, there is no such dependence. This affects the mechanism of the methane diffusion through coal, taking into account the structural features of their surface properties during metamorphism of coal seams, especially with changing their depth