Let us examine a coal seam disturbed by mining. Owing to the gradients induced in the solid, gas begins to diffuse toward the working. As the gas flows away, we observe a pressure drop in the pores, desorption and expansion of the gas, due to loss of the adsorbed heat. The temperature of the free gas falls and active exchange of heat with the surface of the pore space of the solid occurs, i.e., the assumption of isothermality becomes invalid. But if we also bear in mind that some coal seams are inclined at some angle to the earth's surface, when they have a certain length the temperature may also change by virtue of its natural increase with depth. Therefore to represent the process of nonisothermal diffusion of a gas in a porous sorbent we need equations taking account of all these factors. As a result of the calculations we can assert that when gas flow in a seam is of the rare-faction-wave type, account must be taken of the bulk concentration of the gas being desorbed, the process of physical desorption, and its nonisothermality.