“三软”煤层Π型钢梁支护放顶煤开采试验洛阳市龙门煤矿路富忠，张化民，王苗甫，赵来源，刘志刚１前言“三软”不稳定厚煤层采煤法是豫西煤田存在的重大技术难题。几十年来，龙门煤矿根据本矿具体条件，进行了不断的探索。采煤方法从巷柱式到长壁式，到放顶煤开采，采面... “Three Soft” Coal Seam Π Type Steel Beam Support Caving Coal Mining Test Luoyang Longmen Coal Mine Road Fuzhong, Zhang Huamin, Wang Miaofu, Zhao Laiyuan, Liu Zhigang 1 Introduction The “three soft” instability thick coal seam mining method is the existence of western Henan coalfield Major technical problems. For decades, Longmen Coal Mine under the specific conditions of the mine, conducted a continuous exploration. Mining methods from the laneway to the long wall, to the top coal mining, mining face ...