... ,roadbed,retaining walls and high ways.features:1,extreamly portable compared to drill rigs of the same function.2,easily disassembled,for ... .3,work with high speed,rotate rate can be up to 528 per minute.4,with great guidancequality that makes drilling ... direction is relativly stable.5,easily to be changed form electric engine to diesel engine. Portable Core Drilling Rig GQ1