Planning to sink a borehole into the ground? Sure you want to use the drilling mechanism, but with a variety of drills available, which would be best for you?
Ideally, drills are of two types:
- Drills that produce rock chips
- Drills that produce core samples
Some of the common types of drilling are:
Auger Drilling:
It is done with the helical screw that is placed inside the ground with the rotation, and the earth has lifted the borehole through the blade of the screw. For soft grounds like swamps where the hole will not stay open, hollow stem drilling is used. However, solid flight augers or bucket augers are used at hard grounds constructions. In some constructions, mine shafts are also dug with auger drills, but this drilling is restricted for sinking piles for the bridge foundations.
Hydraulic Rotary Drilling:
This type of drilling needs a tri-cone roller, fixed-cutter diamond, carbide embedded and diamond-impregnated drill bits to wipe away the cutting face. In hydraulic drifters, sizable machinery is used, making the rig to reach depth.
Rotary Air Blast Drilling:
RAB drilling is often used in mineral exploration industry using a pneumatic reciprocating piston-driven hammer to drive a heavy drill bit in the surface. In this, the drill bit is hollow made from solid steel and possess thick tungsten rods. This type of drilling is mostly used in the exploration of minerals, for water boring, for blast hole drilling in mines and many other engineering applications. It produces the low quality of samples because the cuttings are blown up at the outside of the rods.
Air Core Drilling:
This method uses hard steel or tungsten blades to drill a hole into an unconsolidated ground. Air core drilling features three blades arranged around the bit head, which helps in cutting the unconsolidated ground. In this, the rods are hollow with inner tubes that sits inside the empty outer rod barrel. The injection of compressed air removes the drill cuttings into the hole through surface present between the inner tube and the drill rod.
This drilling method is used to bore in the weathered regolith, as the drill rig and the blades of the drilling machine will not penetrate fresh rock.
Cable Tool Drilling:
Cable tool drilling is the most popular method of drilling into water wells. Although, this method of drilling has been supplanted by other highly-equipped methods, its still the most reliable method for drilling at large diameters, deep bedrock wells and for drilling small water supply wells. Also called as ballistic good drilling or shudders, this method helps in raising and dropping a drill string using a heavy carbide tipped drilling chisel by pulverizing the other materials.
Reverse Circulation Drilling:
This drilling method is similar to the air core drilling, in which the drill cuttings are returned to the surface in the rods. Its drilling mechanism works like a hammer that keeps on driving the tungsten-steel rig in the surface. It produces dry rock chips of size equal to air compressors. While its air-powered, water is used to keep the drill cool.
So, those were some of the common types of drilling used to bore in the ground.
