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Percussion drilling
Batch -2
Percussion drilling
• Cable Tool Drilling
• Percussion drills have been used to drill thousands of feet,
though they are generally used for wells from 30 to 250 feet
• This drilling method has been used in China for over 3000
Hand powered percussion drill
-The lifting and dropping
of a heavy (50kg+)
cutting tool will chip and
excavate material from a
- The tool can be fixed to
rigid drill-rods, or to a
rope or cable.
- With a mechanical
winch, depths of
hundreds of metres can
be reached.
Working of percussion drill
• The drill involves a heavy steel bit attached to a rope which is lifted, either
by hand or by machine, and then dropped to cut the earth.
• As the bit chops the earth, water is added to the well hole so that the bit
makes mud out of the earth it has cut.
• After the hole is filled with several feet of mud, the heavy bit is withdrawn
and a tool called a bailer is attached to the rope and lowered into the
• The bailer is a hollow tube with a door at the bottom.
• The door, called a flap valve, opens when it hits the mud to allow the mud
to fill the bailer, and then closes to trap the mud inside the tube so that
the mud can be lifted to the surface.
• The tube is emptied at the surface and the procedure is repeated until the
hole is clear.
Cont …….
• The bit is then re-attached to the rope and the above process begins
• If the earth being drilled will not cave in, then the drilling continues until
water is reached.
• But if the earth is made of loose material like sand, a large heavy steel
pipe is driven into the hole to keep the walls from falling in.
• The large pipe is called casing and it holds the hole open until the drilling
is done.
• It is removed after the permanent casing (usually smaller) is installed
• When the water level has been reached the drilling stops and the
permanent casing, which is smaller than the well hole, is installed.
• hen the rest of the hole around the casing is filled and sealed.
Percussion gouges
Electrical percussion hammer
Extraction systems
Percussion gouges
• Used to take undisturbed samples from depth to about 10
• Higher drilling speed.
• The design enables easy emptying and cleaning.
• Depending on the soil type, drilling depth and desired
quantity of sample one of various gouge types is chosen.
• Available in various diameters 40, 50, 60, 75 and 100 mm and
with a length of 50, 100 and 200 cm.
• All percussion gouges have a hardened steel cutting head
Percussion gouges in various diameters
Electrical percussion hammer,
Light model:
- Beating power of 31.7 Joule at 1200 beats
per minute, a net weight of 17 kg and an
overall length of 613 mm.
Heavy model :
- Beating power of 55.3 Joule at 1000 beats
per minute, a net weight of 29.1 kg and
an overall length of 825 mm.
• RD32-connection
• Extension rods and percussion gouges are screwed together
using a coupling sleeve.
• Takes very little time to attach and take off.
• The RD32-rods connect together by means of a coupling
• Wedge-connection
• The gouges and the extension rods are connected using so
called wedge connections
• Easy and quick coupling and un-coupling is possible.
Wedge connection
Pulling devices (rod pullers)
Rod puller extension for the first gouge
Extraction system
• Pulling device (Rod pullers)
• Rod puller extension
• Hydraulic extrator:
Pulling force of 80 kN, is supplied with extracting cylinder
(diameter 65 mm) and a hydraulic aggregate with electric
hydraulic extractor tube set.
Hydraulic extraction system
Hydraulic extractor
Percussion drilling applied,
• If drilling has to be executed in hard soils, possible
containing layers of rubble and/or stones usually
percussion drilling is applied.
• Percussion drilling for instance is applied for research
on soil pollution, grain size distribution, general soil
classification, profile descriptions, etc.
Advantages of percussion drilling:
• Simple to operate and maintain.
• Suitable for a wide variety of rocks.
• Operation is possible above and below the water-table.
• It is possible to drill to considerable depths.
Disadvantages of percussion drilling:
• Slow, compared with other methods.
• Equipment can be heavy.
• Problems can occur with unstable rock formations.
• Water is needed for dry holes to help remove cuttings.
Questions ??