Rotary Air Blast (RAB) drilling

Rotary Air Blast (RAB) drilling is a method used in mineral exploration to create boreholes in the ground. It is a common technique for initial exploration and reconnaissance drilling due to its cost-effectiveness and efficiency. Here’s a detailed overview of RAB drilling:

What is RAB Drilling?

RAB drilling involves using compressed air to drive a rotating drill bit into the ground. The air flushes the cuttings (rock fragments and soil) up the outside of the drill rod and to the surface, where they are collected for analysis.

Key Features of RAB Drilling

1. Compressed Air: Compressed air is used to power the drill and remove cuttings from the hole.
2. Rotating Drill Bit: A rotating bit penetrates the ground, breaking up rock and soil.
3. Sample Collection: Cuttings are brought to the surface and collected for geological analysis.

Applications of RAB Drilling

1. Exploration Drilling: Ideal for initial stages of mineral exploration to identify potential mineral deposits.
2. Geochemical Sampling: Collects samples for geochemical analysis to determine the presence and concentration of minerals.
3. Reconnaissance Drilling: Provides quick and cost-effective drilling to assess the geology of an area.

Advantages of RAB Drilling

1. Cost-Effective: Generally cheaper than other drilling methods like diamond drilling.
2. Fast: Rapid drilling speed makes it suitable for covering large areas quickly.
3. Simple Setup: Requires less complex equipment and setup compared to other methods.
4. Effective for Shallow Depths: Efficient for drilling to shallow to moderate depths, typically up to 100 meters.

Limitations of RAB Drilling

1. Sample Contamination: Samples can be contaminated by material from higher up the hole due to the air flushing method.
2. Limited Depth: Not suitable for very deep drilling beyond the typical range of up to 100 meters.
3. Accuracy: Less accurate in terms of geological and structural information compared to core drilling methods.

Equipment Used in RAB Drilling

• Drill Rig: The machine that powers the drill bit and provides the necessary air pressure.
• Air Compressor: Supplies compressed air to drive the drill and remove cuttings.
• Drill Rods and Bits: Rods connect the drill bit to the rig, and bits are selected based on the hardness of the rock.
• Cuttings Collection System: Equipment to collect and manage the cuttings brought to the surface.

Procedure of RAB Drilling

1. Site Preparation: Setting up the drill rig and ensuring all equipment is in place.
2. Drilling: The drill bit is rotated and driven into the ground by compressed air, breaking up the rock and soil.
3. Cuttings Removal: Compressed air flushes the cuttings to the surface through the annulus between the drill rod and the borehole wall.
4. Sample Collection: Cuttings are collected at the surface for analysis.
5. Logging: Geologists log the cuttings to determine the geology and potential mineral content of the drilled area.

Best Practices in RAB Drilling

• Proper Maintenance: Ensure all equipment is well-maintained to avoid downtime and ensure efficient operation.
• Sample Handling: Properly handle and label samples to avoid contamination and ensure accurate analysis.
• Environmental Considerations: Minimize environmental impact by following best practices for site restoration and waste management.
• Safety Protocols: Follow safety guidelines to protect workers from hazards associated with drilling operations.

Conclusion

RAB drilling is an essential technique in mineral exploration, offering a cost-effective and efficient method for initial exploration and geochemical sampling. While it has limitations in depth and sample accuracy, its speed and simplicity make it a valuable tool for identifying potential mineral deposits and guiding further, more detailed exploration efforts.

Here are some notable manufacturers and suppliers of Rotary Air Blast (RAB) drilling rigs in Australia:

1. Boart Longyear

• Specialization: Provides a range of drilling services and equipment, including RAB drilling rigs.
• Reputation: Known for high-quality, reliable, and durable equipment suitable for various drilling applications.
• Website: Boart Longyear

2. 101 Sampling Solutions

• Specialization: Custom-built drilling rigs for various applications, including mineral exploration.
• Reputation: Known for customization and high-quality build.
• Website: 101 Sampling Solutions

3. Atlas Copco (Epiroc)

• Specialization: Manufactures a variety of drilling rigs for mining, including RAB drilling rigs.
• Reputation: Known for robust and efficient equipment designed for tough conditions.
• Website: Epiroc

4. Schramm Australia

• Specialization: Drilling rigs for mining, oil and gas, water, geothermal, and other applications, including RAB drilling.
• Reputation: Known for reliable and high-performance rigs.
• Website: Schramm Australia