Goaf frictional ignition and its control measures in underground coal mines

Goaf Frictional Ignition (GFI) poses a serious threat to the safety of underground coal mines, and has caused many underground fires and catastrophic explosions. This paper examined occurrences of GFI incidents and the underlying mechanisms of ignition source and environment. Most of these incidents were attributed to rock on rock frictional ignition. The eventuation of frictional ignition relies on the presence of hot spots with enough incendive ignition energy, which requires a minimum threshold sliding distance and sliding velocity. The incendivity of the environment can be enhanced by the presence of liquid carbon hydrogen, the increase of virgin rock temperature, and the presence of hydrocarbon gases from thermal decomposition product of coal volatile. The paper discussed the newly proposed concerns on the varying incendivity of environment; finally it summarized the GFI engineering controls and discussed their applicability.