RAB/Air Core (AC) Profile

Challenge Drilling has maintained a programme of technological and personnel development since 1990 that has enabled the company to provide its clients with a cost effective quality service, whilst becoming a leader in the fields of RAB & Air Core (AC) drilling.

This development over the years has seen the performance of our rigs and crews reach a stage where AC holes are regularly drilled to a depth in excess of 150 metres with the record being 182 metres, and RAB holes in excess of 120 metres with the record of 170 metres. These depths are being reached whilst keeping up a very good rate of production.

Our drillers have accumulated a vast amount of experience in AC drilling of palaeochannel. Channels with up to 60 metres of running sands have been drilled successfully with a good output rate maintained. We provide a dry AC sample even where high water inflows are experienced, except of course in running sands and where penetration is slowed considerably due to hard rock, quartz veining, etc.

Performance is constantly being monitored by management and supervisors through physically being on site, liaising with the client and through daily communication with the drillers. Challenge Drilling’s management and supervisors all have previous drilling experience and work on passing this knowledge onto their current drillers to ensure the quality of the drilling taking place for all clients.


Challenge Drilling’s emphasis is on quality of performance along with production and safety to provide a quality cost effective service. Challenge Drilling RAB/AC rigs include such safety additions as:

  • Automatic rod spanner
  • Automatic breakout system
  • Mast rod guarding
  • Hydraulically lowered rig mounted cyclone
  • Registered & inspected pressure vessels

All RAB/AC rigs operated by Challenge Drilling are Challenger R/A 150 Rigs with the following specifications:

  • Rig carrier: 4x4 MAN Truck
  • Power pack: 475 HP Cummins
  • Compressor: 750 CFM @ 350 PSI
  • Hydraulics – Commercial gear pumps, flow dividers and motors
    • Pull down force – 9.5 tonne
    • Pull back force – 12.5 tonne
    • Head torque – 400 NM
  • 2 Metre dump mast
  • Holes can be drilled vertically or inclined up to 60°
  • Water injection pump
  • Samples taken via cyclone 
  • Face sampling AC hammer