rock drilling machine 1,Quality air leg rock drill 2,Super model ORB-Y24 3,Big drilling power 4,Durable ,use-friendly rock drilling machineRock ... hardness of f=8~18;An ideal tool for rock drilling operations in small open-pit quarries, mines, water conservancy projects ... . It is widely used in tunnel heading and blasting holes drilling in mining. It is also indispensable equipments in metallurgy, coal ...