Reverse Circulation ( RC ) Drilling Rig Machine DC Drilling 300 Mm Hole Size

Reverse Circulation (RC) Drilling Rig

Why needs reverse circulation drilling?

. When drilling the hole of diameter >250mm, which the annular area between the drill pipe and inner surface of borehole is very big.
. If using direct circulation drilling method, it needs very powerful compressor with high air flow(even 2 – 3 compressors) to get enough flushing speed to below all the cuttings out of hole.
. Otherwise, the cutting will stay in the hole and stuck the drilling. Therefore it can make hole drilling very costly. In this case, the reverse circulation drilling(RC drilling) will be the better choice.

Roschen DTH Reverse Circulation Principle:

. It is opposite from DTH direct circulation drilling method.
. Air go to hammer via the annular area between outer pipe and inner pipe and take the cuttings out of hole through the area of inner pipe.
. Due to the smaller annular area and inner pipe area for air go through, it can get very high flushing speed with low air flow from compressor.
. In this way, it can save cost for drilling

Example of reverse circulation compared and DTH direct circulation methods:

1. By DC Drilling:
2. Hole Size: 300 mm
3. Drill Pipe Dia. 114 mm
4. Annular area between pipe and wall: 0.06 m2
5. Needed flushing speed: 20 m/s
6. Needed air flow: 72 m3/min.
7. Conclusion: it need 2 air compressors and each one with 36 m3/min air flow

8. By RC Drilling
9. Hole Size: 300 mm
10. Dual drill Pipe Outer Dia. 114 mm
11. Dual drill Pipe Inner Diameter: 60 mm
12. Annular Area between inner and out wall of Dual pipe: 0.00324 m2
13. Needed flushing speed: 20 m/s
14. Needed flushing speed: 20 m/s
15. Needed air flow: 4 m3/min

. Conclusion: it only need 1 air compressors with 4 m3/min air flow is good enough
. From above calculation, we can see that by RC drilling it needs much lower air flow and can save the cost for compressor. This is reason why Reverse Circulation is widely used in borehole drilling industry

Roschen Drills Reverse Circulation Accessories:

. RC Drilling Rig
. Air Compressor
. Air Inlet Swivel
. Dual Wall Pipe
. Special RC Connector
. RC Hammer
. RC Hammer Bit
. Cutting Collectors

More Articles
 

Underground Blasting Drilling
BlastHole Drilling Introduction
Drilling Rig Stability Calculation
Drilling Tools for Rotary Drilling Rig
Practical Aspects of Blast Hole Drilling
Introduction to Open Pit Mining
Hardrock Mining Drill Rigs Selection – Part Two
Hardrock Mining Drill Rigs Selection – Part One
How Drilling Tools Selection Impacts Borehole Quality
TOP 6 BRAND / Manufacturer For Drill Rigs
How to Select DTH Hammer Drill Bit
How to Select Rotary / Tricone Drilling Bit
7 Rules on How to Design Reverse Circulation System
6 Advantages of Reverse Circulation Vs Direct Circulation On Bore hole drilling
8 Points on How to Select Water Well Drilling Rig
Market Survey Metals – Iron Ore
Market Survey Metals – Bauxite, Alumina, Aluminium
7 Rules of Thumb for Open Bit Blast Pattern
Mineral Commodity Summary
Down The Hole Drilling Trouble Shooting – Bit Damage
Down The Hole Drilling Trouble Shooting – Hammer Piston Casing Breakage
Down The Hole Drilling Trouble Shooting – Treaded
Selection of DTH Drilling Tools
Rotary Drilling Method
General Drilling Method and Application
DTH Drilling Care & Maintenance – Part One
DTH Drilling Care & Maintenance – Part Two
Basic DTH and Top Hammer Drilling Knowledge
Well Drilling Method
Rock Properties
Rock Drillability
How to Repair Drill Bit
DTH(Down The Hole) Drilling Application