For reliable and quality sample drilling, mine operators often use diamond core and reverse circulation drilling in combination during mineral exploration projects. The sampling time, quality and costs are the main three factors that determine which drilling method is given preference. RC drilling is preferred for pit grade control and drilling shallow holes while core drill is preferred for deeper holes that help identify resources. RC drill method is more flexible and faster than core drilling. It provides uncontaminated cuttings. The core sample drilling method provides better geological and ore body distribution information.
Both these methods have their advantages and limitations when drilling in complex hole geometries and deeper depths. RC drilling does not get sufficient air pressure while in diamond core drilling there is excess friction between the hole wall and drill pipe. The main goal is to select a drilling method that will deliver quality samples from the desired depths in the shortest possible time.