Rotary Coring

Rotary coring, or diamond coring, is used to collect a continuous core of stiff soils and bedrock for exploration and geotechnical purposes. The rotary coring system is a wireline coring system with an inner barrel and outer barrel; the inner barrel is open and remains stationary, while the outer barrel is rotated and advanced with the drill string. Clean water is pumped from surface through the drill string and through the annulus of the inner and outer barrel and then discharged at the face of the carbide/ diamond cutting shoe. 

The tight clearance between the inner barrel and the drill rod, coupled with the fact that the casing is filled with water, ensures that the inner barrel travels slow enough on its free fall so no damage occurs when locking into the outer barrel. Once the inner barrel is locked in, the sampling process is repeated.