Down-the-hole drills are essential for mining and engineering rock drilling. Standardized drill rod replacement is critical to equipment lifespan, operational safety and drilling efficiency, helping avoid downhole incidents, rod damage and safety hazards.

Before replacement, secure the rig with outriggers, shut off power, air and hydraulic systems, and post lockout tags. Clear the work area and restrict access. Operators must stand clear of the drill rod and hammer, wearing full PPE: helmet, impact goggles, anti-smash shoes, anti-slip gloves, and a dust mask in dusty conditions. Inspect drill rods for bends, cracks and damaged threads; check chuck, rotator and elevator for proper function, and confirm no air or hydraulic leaks.

When adding a rod: clamp the in-hole rod, lift the hammer, align and hand-thread the new rod 2–3 turns, then tighten to rated torque. Lower the rod slowly and resume drilling only when the connection is secure and aligned.

When removing a rod: clamp the in-hole rod, loosen and extract each rod, placing it carefully on a rack. For the final rod, lower slowly to prevent hammer impact or drop-out. Clean threads and cavities, apply thread compound, and store rods properly.

Strictly avoid replacing rods under pressure or load, forcing misaligned threads, using damaged/mismatched rods, or working without the chuck fully clamped. Use anti-fall measures on slopes or at height, with a dedicated on-site supervisor.

Post-replacement, clean the hammer and rods, inspect wearable components and replace worn parts. Reapply thread lubricant, log rod usage, and scrap expired rods.

For harsh conditions — hard rock/deep holes, wet mucky bores, extreme temperatures — adjust torque and lubrication frequency, use temperature-appropriate thread compound, and prevent internal corrosion. Following these standardized steps ensures safe, efficient rod change practices and stable rock drilling operations.