An unusual multiple combustion effect has been observed during the mechanochemical reaction of zirconium and sulphur powders. Ball milling induces combustion in this highly exothermic system, but the combustion is quenched repeatedly, after consuming only a fraction of the reactants. The process concludes with a final, more energetic combustion, releasing about 70% of the reaction heat. The evaporation of sulfur at the reaction site may explain this behavior. ©1996 American Institute of Physics.