1. Factors involved in determining the diameter of the mining drill rods are the drilling capability parameters, the diameter of the desired borehole, the drillable depth and the empirical ratio of D / d=4.5.
2. The selection of drill rod for a rotary drilling rig shall be based on its major design parameters, the torque and the feed pressure.
3. Mining drill rods
for rotary drilling rigs: The decisive factor is the formation conditions. The frictional drill rods are favorable for general strata such as the soil, the sand, the gravel and the silt geological layer. The mechanical locking drill rods are preferred by the gravel, the drift stone layer, the hard sand and the hard rock layer and so do they applied to the general formation.
4. The quality of rotary drill rods is above all.
Only for hole drilling, neither can a drill rod nor a bit be applied to soil transfer, delivery or construction site leveling. Never immerse the drill into the liquid concrete. Not until the bit reaches the bottom of the hole can the drilling operation start.
When it comes to sand or cobble layers, the operator should pay attention to the footage, which should not be too deep for one time. Otherwise, the hole will shrink leaving no gap inbetween to stuck the drill bit. Being unable to be inverted or lifted, the jammed drill rod leads to major accidents.