The prediction of gas-phase ignition characteristics of a coal dust layer by a hot metal particle located on its surface was performed by numerical simulation. The theoretical study results can be used in practice to develop the provisions of fire safety management aimed at preventing large fires and man-made disasters. In this paper we consider coal dust, the particle dispersion of which varies in the range of 0.1-1 mm. As local sources of heating steel disk-shaped and parallelepiped-shaped particles with the same specific size of 10 mm are used. The nonideality factor influence of the thermal contact of a local heat source and a dispersed brown coal layer on its gas-phase ignition delay-Times when the parameters in the considered system vary over a wide range, including the initial temperatures of metal particles from 1100 to 1600 K.