Several mud and sand flow accidents occurred from the goaf to mining face,which had seriously affect to the mine safety production.

• 梅河四井为急倾斜特厚煤层,采用水平分层综合机械化放顶煤开采,曾经多次发生采空区泥砂流溃入工作面事故,严重影响了安全生产。