This paper deals with the spontaneous combustibility and ignition behavior of coal stored in confined spaces. The geometry, which views the stockpile to be sealed from all sides except the top (which is exposed to the ambient conditions), is of interest in the transport of coals in barges or in cars by rail. Semi-analytical solutions are developed with the assumption that the coal pile is isothermal. Finite-difference numerical calculations show that the steady-state temperature at the exposed surface from a nonisothermal model is approximately the same as that from the isothermal formulation. Based on this approximation, the maximum temperature in the nonisothermal stockpile is linked analytically to the temperature calculated from the isothermal formulation. This approximation also permits rapid evaluation of the critical behavior of the nonisothermal stockpile in terms of the isothermal formulation. Detailed numerical solutions are necessary, however, to evaluate the transient behavior of the nonisothermal stockpile. Results in previous literature suggest that diffusion in a one-dimensional stockpile can lead to a maximum temperature rise of approximate to 80 K. This conclusion is shown to be a consequence of the unrealistic boundary conditions imposed on the oxygen and energy balance equations-diffusion done can lead to dangerous self-heating. It is also shown that inclusion of the radiation at the boundary is extremely important in determining the stability of the stockpile. Finally, the maximum temperature within the pile at steady state, as well as the safe transit time, are calculated for the transport of coal in barges. These calculations confirm the importance of bed compaction in enhancing the safety of the coal pile.