... , railway, road, port, bridge, water conservancy and hydropower, tunnel, well, industrial and civil construction2. Coal mining exploration, Ore exploration3. Small ... core drilling rig: 1) Good stability and high reliability.2) Multilevel positive and reverse rotate speed.3) The complete ... )Perfect frame's rigidity ,low center of gravity and good stability. HGY200D Core Drilling Rig for 200M,also ...