我队施工的织金煤田,岩层薄而且软硬相间,标志层均是致密坚硬岩层(燧石灰岩、硅质菱铁岩、含铁硅质岩等)。由于岩层软硬悬殊,换层频繁,裂隙、溶洞发育,采用钢粒钻进,不仅事故多,效率低,岩芯采取率低,钻孔极易歪斜,甚至容易将煤层打薄、打丢。自从采用金刚石钻进以来,取 The Zhijin coalfield constructed by our team is thin, soft and hard, with dense hard layers (chert limestone, siliceous siderite, iron-bearing silicalite, etc.). Due to the great difference between soft and hard rock formations, frequent change of layers, development of fractures and cavities, the use of steel grain drilling not only causes many accidents, but also has low efficiency, low core take-up rate, easily skewed drilling holes and even easy to thin the coal seam and throw it away. Since diamond drilling, take