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Rock Drill

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Furukawa HCRC500 Rock Drill
Rock drills are used for an assortment of applications, including quarrying, mining, rock bolting, grouting, and tunneling holes of varying sizes and depths. Drilling, or boring, is accomplished with one many methods of drilling and equipment.

Contents

[edit] History

[edit] Early Drilling Applications

The existence of pyramids is evidence that drilling tools can be traced as far back as 2550 to 2315 B.C., when Egyptians used diamond drills to construct one of the most enigmatic wonders of the world. But drills were by no means restricted to just one nation. China used drilling tools and could accomplish hole depths of up to 2,000 feet (610 m).

[edit] Evolution of the Drill

A more modern use of drills appeared with oil wells, the first produced in France in 1745. As nations around the world could see more uses for drills, their evolution changed dramatically. In 1845, a Briton named Robert Beart patented the first rotary drilling machine and in the course of the next few decades, different innovations were popping up all over the world, including the first steam-powered rig in 1865, the first two-cone bit in 1893 and the first rock bit in 1908. Oil wells were being launched throughout the world and drills were achieving greater depths than ever before. By 1893, 6,575 feet (2,004 m) were successfully drilled.[1]

Equipment manufacturers such as Ingersoll Rand helped launch drills as a machine that would continue to go further and deeper.One claim for the first rock drill came from a man in Phladelphia named J.J. Couch. His patented rock dril was invented in 1849. It consisted of a drill rod and a hollow piston.[2] Simon Ingersoll also patented a first rock drill in 1871, to ensure that even the hardest materials and rocks could be drilled. Ingersoll-Sergeant drills were used to help construct the Panama Canal in 1904.

The hammer drill was invented by George Leyner in 1896. This hand-held device would achieve boring through the constant hammering of brittle material. The hammer drill inspired others to take the drilling tools further. In the next 10 years, the Imperial pneumatic tool was developed, as was the jackhammer drill. Ingersoll Rand even developed the Quarrymaster, known as the first modern air rock drill. The pneumatic mobile drill was created and used to blast large diameter holes.[3]

Drills started running by diesel engine in the mid-1920s. Bentonite and Tricones were introduced in the early 1930s. Drilling depths had reached 17,776 feet (5,418 m) into the earth. When hydraulics entered the scene in the early 1950s, no machinery was left unscathed; even drill rigs became hydraulic. Around this time, the down-the-hole (DTH) hammer drill was also produced for large diameter holes.

With projects becoming more and more complex, drills were continuously being designed to meet their needs. In 1974, drilling had brought us as far down as 31,358 feet (9,558 m), but not surpassing the deepest hole in the world, which, to date, is the Kola Super Deep Hole in Russia at 7.6 miles (12.26 km).[4]

[edit] Features/How it Works

[edit] Parts of a Drill

Rock drill bits
Drill bit: the sharp tip of the drill that makes contact with the rock. [5]


Drill stem: a long frame that contains the drill bit at the end and houses the drill rod.

Drill rod: a hollow component that connects the drive and the motor of the rig to the bit. The feed force travels through the rod to create the cutting element. Flushing also occurs from the rod.

Carbide bits:  special bits used on rotary percussive drills that have carbide tungsten coated onto them at a different angle.

[edit] Methods of Drilling

[edit]

This method, with the help of either a pneumatic, hydraulic, or electric motor, uses high torque and rotation to crack and chip away fragments of rock. Rotary drills sit on a mast located above the hole. The hole is drilled further with drill rod extensions inside the rotor. Slower rotation and torque occurs for harder materials. For example, to drill an eight-inch (200-mm) diameter hole into a medium-hard rock takes a rig with a 10-ton capacity of feed force.

[edit] Rotary Drilling Rigs

Most trucks or crawlers with mounted drills can take on the task of drilling boreholes of eight inches (200 mm) and under and depths of up to 328 to 656 feet (100 to 200 m). For anything more, the use of rotary drilling rigs is necessary. Rigs can bore holes as deep as 19,685 feet (6,000 m) by using hydraulics or chains to get the drill bit to thrust. Winches are used to raise the stem of the drill and the bit so the process can be repeated.[6]

[edit] Percussive Drill

The percussion drill succeeds in breaking rocks by following high impact hammer-like blows one after another.

[edit] Abrasion Drill

Abrasion drills have a grinding mechanism that rotates into rocks, chipping away small particles and fragments of rocks.[7]

[edit] Rotary Percussive Drilling

Rotary percussive drilling is the method best suited for rock that is medium to hard all the way through. It is seen mostly in applications such as blasting holes, rock anchors, grouting holes, and wells. Because of its light weight, the rig’s drilling methods are particularly effective.

Rotary percussion involves a percussive and rotary action combined. A crater is formed when the drill bit thrusts the rock using pneumatic-operated energy. The impact the percussive component provides is more than sufficient to drill the hardest rocks. Any fragments or broken pieces of rock are flushed away by air or water pressure that passes through the drill stem and out of the drill bit. It also consists of buttons made of tungsten carbide, which extend from the steel drill frame and act as the cutting force of the drill. The rotary percussive method requires the use of an air compressor to keep the feed force flowing. Rotary percussive drilling can rarely exceed depths more than 492 feet (150 m), as water clogs up the external holes of the drill.[8]

[edit] Holes

The method of drilling used is dependant on the type of hole. Cored holes have diameters that need to be set before further cutting can be carried out. This kind of hole requires core barrels that have outer tubes responsible for rotating the core drill bit.

Open holes generally call for a rotary drill rig to bore holes straight into the ground. Three main tools can help accomplish this task: the “tricone” or rock roller bit, a “drag” or wing bit, and a down-the-hole hammer.

[edit] Types

Tricone-bit Drill: particles are chipped away by the steel tooth-like nature of the cones.

Drag Bits: this kind of bit is made from tungsten carbide and used on softer surfaces.

Air Core Drill: this drill uses either steel or tungsten carbide blades to drill holes into the ground. With the use of pneumatics, three blades protruding from the bit head cut into the ground, and particles are flushed out through the drill rod using compressed air.

Cable-tool Rig: this type of rig consists of a heavy steel drill bar and a chisel that uses its weight to impact surfaces, creating holes of large diameters. Cable-tool rigs are capable of drill through 1,000 feet (305 m) of rock.

Flight auger: augers are essentially large corkscrews called helical screws that rotate into the ground with large blades. They are best suited for projects on sand, gravel, chalk, clay, and other softer surfaces.[9]

[edit] Common Manufacturers

[edit] Additional Photos

Traxxon TR-EX 2000 Excavator Mounted Rock Drill Attachment
1996 Traxxon T-800H Tank Drill
Reed SK40 Drill
1972 Wirth B5RA Crawler Drill
1998 Tamrock Powertrak Pantera 900 Crawler Drill
2001 Dainong DNCD 3000EX Hydraulic Drill
 
ROC-CHAMP Excavator Drill

[edit] References

  1. Drilling History. NTL World. 2008-09-24.
  2. Drilling Machinery. Britannica. 2008-10-17.
  3. History. Ingersoll Rand. 2008-09-24.
  4. Drilling History. NTL World. 2008-09-24.
  5. [www.civileblog.com/types-rock-drill-bits/ Rock Drill Types and Drill Bits. Civil Engineering Blog. 2018-10-16.]
  6. Harris, Frank. Ground Engineering Equipment Methods. McGraw-Hill: New York: 1983.
  7. Peurifoy, R.L Construction Planning, Equipment and Methods. McGraw-Hill: New York, 1970.
  8. Harris, Frank. Ground Engineering Equipment Methods. McGraw-Hill: New York: 1983.
  9. Drilling History. NTL World. 2008-09-24.