Epiroc has launched the "Anti-Stick" predictive drilling system for its SmartROC D65 down-the-hole (DTH) surface drill rigs. In aggregate quarry operations, drilling blast holes through highly fractured karstic limestone frequently leads to "stuck steel." When the drill bit breaks into a subterranean void or highly fractured zone, the rock collapses around the drill string, causing a sudden torque spike. The drill string binds, stalling the rotation motor, bending the drill steel, and requiring costly and time-consuming fishing operations or hole abandonment.
The Anti-Stick system integrates a "Magnetostrictive Torque Sensor" into the drill head drive shaft. The engineering innovation is the "Sub-Surface Friction Prediction." Unlike conventional systems that simply limit maximum torque, the Anti-Stick ECU continuously monitors the baseline rotational friction and penetration rate. When the system detects a sudden drop in penetration rate combined with a 15% rise in baseline torque-indicating the bit is entering a fractured zone with collapsing debris-it preemptively acts before the bit can bind.
The ECU instantly commands the hydraulic feed cylinder to reduce downward thrust by 40% while simultaneously increasing the rotational speed by 20%. This high-spin, low-feed action clears the fractured debris from the bit's cutting face, allowing it to pass through the void without jamming. If the torque continues to rise toward the critical binding threshold, the system automatically reverses the drill string rotation for half a turn to break the friction grip, then resumes drilling. This predictive torque mapping reduces drill steel fishing incidents by 85% and maintains hole deviation within 1% of design trajectory.
