Abstract: Coal fire in cavities of mined-out area is a severe threat to the safety of open pit mine, personnel and equipment. Traditional firefighting technology is not capable to put out fires at high position of the cavity effectively. According to the characteristics of the 1315 trunk fire area in Anjialing Open Pit Mine, we focus on the rapid cooling and preventing rekindling of the fires in cavities, and analyze the characteristics and technological parameters of grouting, high expansion inhibition foam and modified fly ash. These firefighting materials and techniques are then applied to control fire in cavities near the slope of the 1315 trunk in Anjialing Open Pit Mine. The results show that these techniques extinguish the fire very efficiently and obtain good fire control effect.