我队历年施工矿区的岩层绝大部分都较破碎,其中硬、脆、碎岩层占30%以上.过去使用双管双动或双管单动钻具,岩芯采取率低,效率也低.后来使用普通弯管喷反钻 Most of the rock formations in our mining area over the years have been crushed, of which hard, brittle and broken rock layers account for more than 30%. In the past, the double-pipe double-action or double-pipe single-action drilling tools were adopted and the core taken rate was low and the efficiency was low. Later, the use of ordinary pipe spray reverse drilling