In the mineral-rich landscapes of Western Australia, successful exploration depends on smart, efficient drilling. Before a company commits to the high costs of deep core drilling, they need a reliable, cost-effective method to survey vast areas and pinpoint promising targets. That method is Rotary Air Blast (RAB) drilling.
At Bostech Drilling in Western Australia, we specialise in delivering precise, quality drilling services to the mineral exploration industry in WA and across the country. We understand the ground beneath your feet, and we rely on the speed and efficiency of RAB drilling to lay the groundwork for your next big discovery.
What Exactly is RAB Drilling?
RAB drilling is a powerful yet simple percussion drilling technique designed specifically for rapid, shallow exploration. Think of it as the ultimate “first-pass” tool.
The method relies on three core actions:
- Rotation and Percussion: A drill rig rotates the drill rods while simultaneously driving a down-the-hole (DTH) hammer. This hammer repeatedly strikes a rotating drill bit, using immense force to pulverise and fracture the rock.
- Air Power: The system continuously blasts highly compressed air down the drill rods. This air powers the hammer and performs the crucial task of clearing the borehole.
- Cuttings Retrieval: The compressed air forces the broken rock fragments (known as cuttings) up the outside of the drill rods, carrying the sample material directly to the surface for collection and analysis.
Why is RAB the Go-To for Initial Exploration?
For projects across the WA Goldfields, the Pilbara, or beyond, RAB drilling offers distinct advantages that translate directly into operational efficiency and budget control:
1. Speed and Efficiency
RAB is significantly faster than deeper, more complex methods like Reverse Circulation (RC) or Diamond drilling. This speed allows exploration companies to cover more ground in less time. You can drill hundreds of holes across a large tenement quickly, generating a broad geochemical map of the area that helps define initial targets.
2. Cost-Effectiveness
Due to its simplicity and speed, RAB drilling has a much lower cost per metre. This makes it the ideal technique for:
- Geochemical Sampling: Assessing soil and bedrock layers for mineral indicators.
- Regolith Mapping: Understanding the weathered top layers of rock, which is crucial for determining how mineral deposits might have formed or dispersed.
3. Mobility and Accessibility
RAB rigs generally offer a smaller and more agile footprint than RC or diamond rigs. Their design allows them to access the remote or challenging areas common across Western Australia’s rugged terrain. This versatility ensures that geography does not limit your exploration program.
RAB’s Limitations (and When to Call for RC)
While RAB excels at speed and shallow sampling, you must understand its important limitations:
- Sample Contamination: Because the cuttings travel up the outside annulus of the hole, they can mix with material from higher up. This means the samples are less precise than those from RC drilling.
- Shallow Depth: RAB typically reaches only the top 50 to 150 metres, as it stops at the base of hard, unweathered rock.
- Groundwater Issues: If the drill encounters significant groundwater, the compressed air can struggle to lift the cuttings, which causes blockages and sample loss.
Once RAB drilling identifies an anomaly or promising zone, our clients transition to a deeper, more accurate technique, typically Reverse Circulation (RC) drilling, to obtain higher-quality, uncontaminated samples for resource estimation.
At Bostech Drilling, we deploy our modern, well-maintained RAB fleet with experienced drillers who know the WA and Aussie geology inside and out. We provide the reliable, initial data you need to confidently transition to the next phase of your exploration program.
Looking to launch your next exploration campaign efficiently? Contact Bostech Drilling today to discuss how our RAB drilling services can unlock the potential of your tenement.
Please email or call our friendly team on 08 9250 4252 today.