PRD OZ RC: 450 m Reverse-Circulation Drilling for Surface Exploration

Exploration programmes live or die on sample quality and metres drilled per shift. The PRD OZ RC is the reverse-circulation (RC) rig at the centre of our mining and drilling division, and it was built around exactly those two things.

The headline numbers

• RC capacity: 450 m
• Hole diameter: 140 mm
• Pull-up force: 25,800 kgf
• Drilling angle: 45° to 90°, with manual locks in 5° increments

Mast, feed and rotation

The mast is a twin tubular box construction, 12,000 mm overall with 8,000 mm of rotary travel, handling 6 m rods. Feed comes from two double-acting cylinders with 1:2 rope reeving, giving 17,700 kgf of pull-down at 210 bar, with feed speeds of 29 m/min pulling up and 66 m/min pulling down.

The rotary head delivers up to 6,545 Nm of torque at 0–100 rpm through a 79 mm hollow spindle with a 4 in API FH female connection and twin hydraulic motors. The hydraulic system runs at 3,045 psi / 210 bar, with pilot-operated proportional control valves for feed and rotation.

Built for clean samples

RC drilling depends on getting cuttings to surface quickly and uncontaminated. The PRD OZ RC uses a cyclone system with a static cone splitter, an RC head and hose, a top-entry air swivel and a deflector box with blow-down unit.

Productive, safer shifts

Rod handling is by an EZ wireless radio-remote system with an extended swing-out arm, the rod rack holds 32 × 6 m pipes (192 m), and breakout is a hydraulic SBS 6 swing-in single-wrench system. Safety equipment includes fire suppression, hose-burst whiplash protection, an emergency switch and battery isolator, guards for rotating equipment, a wrap-around walkway and an emergency crawler brake.

Crawler or truck

Prime mover, compressor and mounting combinations vary according to design feasibility. The rig can be crawler- or truck-mounted, powered by a suitable PTO-driven truck engine or a 360 hp deck engine, with a recommended ELGI compressor of 1,200 cfm at 500 psi / 35 bar.

Planning an exploration programme? See what to prepare before asking for a quote, then request one below.