Selecting the correct diamond core bit is only the first step toward efficient core drilling.
The bit must also be operated within suitable drilling parameters.
Two of the most important variables are rotation speed (RPM) and weight on bit (WOB).
Diamond core bits cut rock through continuous rotational contact.
If rotational speed is unsuitable for the bit diameter and formation, cutting efficiency can decline.
The correct RPM depends on several factors:
Bit diameter
Rock hardness
Formation abrasiveness
Rig capability
Bit design
Drilling conditions
Weight on bit describes the axial load applied to the cutting face.
The objective is to maintain sufficient contact between the diamonds and formation without unnecessarily overloading the crown.
Too little load can contribute to inefficient cutting.
Too much load may increase stress and does not necessarily produce faster penetration.
These parameters should not be adjusted independently.
If penetration decreases, operators should evaluate the complete drilling condition rather than automatically increasing RPM or feed pressure.
Useful indicators include:
Penetration rate
Torque changes
Vibration
Water return
Crown wear
Core condition
Rig response
A borehole can pass through several geological layers.
Parameters that worked well in one section may become inefficient after the formation changes.
YKDRILL supplies wireline diamond core bits for Q Series and other core drilling systems used in mineral exploration, geological investigation and engineering drilling.
Combining the correct bit with appropriate operating parameters helps contractors improve drilling consistency, protect the diamond crown and achieve better cost per drilled meter.
