The mathematical model of combustion for a reactive gas suspension of coal dust in a propane-air mixture is developed. The parametric study of the problem is carried out. The observed burning velocity of the propane-air mixture with an admixture of coal particles is determined. Dependences of the observed burning velocity of the propane-air gas suspension on the equivalence ratio and on the radius of the particles are obtained. It is shown that, the observed burning velocity decreases with an increase in the radius of the particles. On the contrary, with an increase in the radius of the particle, the observed burning velocity increases for high-propane mixtures. Moreover, in the case of high-propane mixtures, the observed burning velocity of the gas suspension can be increased by reducing the mass of the particles. The observed burning velocity for a propane-air mixture with particles is significantly less than that for a mixture without particles.