Full hydraulic rigs drive the rod string through a hydraulic chuck mounted on a feed frame. Top drive rigs use a motor travelling on the mast. For core drilling to 1,200 m, both architectures work; the choice is about how you operate, not about capability.
Full hydraulic wins on footprint and rod handling. The mast folds, the rig fits a 40HQ container, and a two-person crew can run it. It is the right answer for contractors moving between pads weekly and for remote sites where a heavy crane is unavailable.
Top drive wins on deep, large-diameter holes and on continuous coring where the head travels a long stroke without re-chucking. If your programme is 800 m+ HQ in competent rock with a stable pad, top drive reduces cycle time.
The maintenance question is decisive. Full hydraulic systems are familiar to any hydraulic mechanic; top drive units need specific motor and gearbox experience. If your workshop is 600 km from the nearest dealer, buy the architecture your mechanic already knows.
Our checklist, in order: maximum depth and diameter, pad-to-pad move frequency, crew size, available lifting equipment, local service skill, and only then price. Reversing that order is how contractors end up with an oversized rig parked at camp.
