Core drilling-also referred to as core sampling-is a drilling technique employed in geological exploration to retrieve subsurface rock core samples.
It specifically refers to drilling operations utilizing a rotary mechanism for the purpose of extracting rock cores during geological prospecting.
Its operating principle involves using a tubular drill bit to annularly crush the rock at the bottom of the borehole, thereby preserving the central columnar rock core for extraction and subsequent analysis of geological structures and mineral deposits. Core drilling rigs are primarily classified based on the structural configuration of their rotary mechanisms; they can be categorized into rotary table rigs, vertical spindle rigs, power head rigs, and top-drive rigs. Furthermore, based on the drive mechanism of the rotary unit, they can be classified into mechanically driven, hydraulically driven, and electrically driven core drilling rigs.