What is rotary coring?
Rotary coring is used to form a deep observation borehole or for obtaining representative samples of rock which could not be recovered using traditional cable percussion or window sampling. The drilling method involves a powered rotary cutting head on the end of a shaft, which is driven into the ground as it rotates. The system requires lubrication (air, water or drilling mud) to keep the cutting head cool.</p>
There are two types of rotary boring, open-hole and core drilling. Material recovered from open-hole drilling is mixed with the drilling lubricant. It is not suitable for effective sampling and it is often difficult to observe and record the strata. Open-hole boring is only suitable for rapid drilling to enable core recovery at a greater depth or for the installation of monitoring wells. Core drilling is carried out using wire-line, double or triple-tube core barrels with diamond or tungsten-tipped core bits.