A serious gas explosion occurred in Baijigou Coal Mine of Ningxia Province in China on October 24, 2003. It resulted in sealing off the entire coal mine. A three-phase foam, which was composed of mud, nitrogen, and water, was used to fight the underground fire. It was injected into the fire zone through boreholes on the ground surface. Due to the simplicity and reliability of this technology, the fire was successfully extinguished. The coal mine recovered partial production just 1 month after the explosion and returned to full production 1 year later. (C) 2005 Elsevier B.V All rights reserved.