长期以来,国内各采煤机研制单位,对坚硬煤层的机械采煤问题,一直没有做为专门课题来解决,而在设计和试验采煤机时,为了减少风险和曲折,往往采取绕道走的做法,到中硬煤层或较软煤层去追求速度和产量。这就使得以山西为代表的坚硬煤层的普 For a long time, the coal mining units in China did not solve the problem of mechanical coal mining in hard coal seams. However, in designing and testing shearer, in order to reduce risks and twists and turns, they often take a detour Approach to the hard coal or softer coal to pursue the speed and output. This makes Shanxi as the representative of the hard coal seam