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Auger Drilling

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An Auger Drill Cuts Through Ice
Auger Drilling
is a method of drilling holes by producing a cutting our gouging motion with the chiseled tip of a drill bit. The rotational penetration of the auger drill bit produces a hole. This type of drilling is also referred to as auger boring.

Auger drilling is commonly used for environmental and geotechnical sampling, as well as for construction and mining applications.

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[edit] History

Primitive forms of auger drilling can be traced as far back as 3,000 years in China, where drillers used bamboo and rope to bore holes. Until the invention of the internal combustion engine, drilling was carried out by turning rods by hand or with the help of animals.[1]

The business of drilling, for brine and water wells in the earlier days, and oil in the 1900s onward, became a process that evolved slowly, but once it did, it took off quickly. The first drills were operated mechanically, and the invention of hydraulics and pneumatics—using compressed fluid or air to produce an action—in the mid-1900s meant quicker, more accurate drilling could be completed.

Auger drilling has typically and most commonly been used for site investigation and environmental and geotechnical drilling and sampling. It has also been used for construction purposes.

[edit] Types

The most common type of auger is the continuous flight auger, a machine that uses a rotational head. In this type of drill, the cuttings produced are brought to the surface by the helical edges of the rotational auger drill bit.

Another type is the bucket auger. In this type, the cuttings are collected in a bucket and brought to the surface where they are hinged through the bottom of the bucket. Such extensions are necessary to the addition of this bucket, as the borehole gets deeper. Bucket augers are commonly used for drilling in construction projects and mine shafts. [2]

[edit] Size

Augers are available in a variety of sizes. Smaller augers are usually mounted on trucks and complete smaller projects; while larger ones are used for building bridge foundations, specifically for sinking piles.

[edit] Process

Key to the process of auger drilling is the shape of the drill bit. Shaped like a helical screw and driven rotationally into the ground, the auger drill produces a borehole quickly and efficiently, depending on the type of the formation.

The method involves lifting and dropping the auger, which can weigh 110 pounds (50 kg) or more, into the hole or on the foundation where it chips away material and produces a hole. The tool comprises rigid drill rods or ropes/cables with which the auger can be lowered into the ground. When enough cuttings have been produced to make further drilling ineffective, the auger is removed and the cuttings are brought out with it on its helical-shaped bit. The process is then repeated until complete.

The auger drill can successfully drill hundreds and hundreds of meters into the ground. While this is a useful tool, it works best on unconsolidated or softer material.[3]

[edit] Advantages and Disadvantages

There are many advantages of this type of drilling. This includes its low operation costs, fast rate of penetration if used on suitable formations, and the fact that it is free of contamination fluid when used for sampling purposes.[4] Auger drills are also simple to operate and maintain.

Because of the nature of the auger drill, it is only effective for drilling unconsolidated or weaker, soft material. This type of drilling, however, is slower compared to other methods, and usually involves handling heavy equipment. Water is usually required to help hydrate dry holes for simple boring.[5]

The Occupational Health and Safety Administration has imposed training requirements for this type of drilling due to the potential hazards associated with it, such as the use of certain fabrics when operating this type of drill. When fabrics come in contact with the auger drill, the rotational motion of the drill winds the clothing around the drill and can cause serious injury to the operator. [6]

[edit] References

  1. Simple Drilling Methods. LBORO. 2008-10-23.
  2. Drilling Methods. Well Drilling School. 2008-10-12.
  3. Simple Drilling Methods. LBORO. 2008-10-23.
  4. Drilling Methods. Well Drilling School. 2008-10-12.
  5. Simple Drilling Methods. LBORO. 2008-10-23.
  6. Auger Drill Safety. OSHA. 2008-10-12.