Percussion
Drilling
Group 5
Overview:
• Percussion drilling is the manual drilling technique that
was used in the first well drilled in North America.
• In this drilling technique, a hammering bit is attached to a
long cable that is then lowered into a wide open hole. As
such, it is also called cable drilling, wherein the driller uses
a tripod to support the tools.
• It employs the principle of freely falling chisel bit hung on
a cable to which percussive motion is imparted by one of
the various types of power units. The power units are
manual lift and drop, compressed air, and electrically
driven winches.
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Overview:
• The tungsten carbide bit fitted in a hammer
is lifted a few meters and allowed to drop to
hit the bottom of the hole. The process
continues in succession.
• The churning motion of the bit crushes and
scraps the ground, and so a hole is dug.
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Percussion Drilling
Percussion drilling is a manual drilling
technique in which a heavy cutting or
hammering bit attached to a rope or cable is
lowered into the open hole or inside a
temporary casing.
Optimal depth: from 0 up to 100 m
Optimal diameter: from 400 up to 1.200 mm
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Percussion Drilling
Percussion drilling is suitable for
unconsolidated and consolidated formations:
Sand, silt, stiff clays, sandstone, stone,
laterite, and gravel layers.
Manual percussion drilling is generally used
up to depths of 25 meters.
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Parts of Percussion Drilling
• The action is carried out by cable percussion tools
of three main types:
Buckets, used in the absence of water;
Probes or dippers, used in loose or medium
compact soils and in the presence of water;
Chisels, used in compact soils.
• The tool should be connected to the free-fall winch
through a steel rope and repeatedly raised and
dropped to the bottom of the well. After a suitable
advancement of the drilling and at regular intervals,
the tool is pulled out from the well and the drilled
material is removed.
• If the soil is inconsistent, the hole must be stabilized
by introducing temporary or permanent casings.
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Parts of Percussion Drilling
Drilling Bailer
bit
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Procedure
Percussion Drilling
Setup the tripod
1. Connect the front post to the
pulley and secure this with a bolt
and nut.
2. 2. Put the rope through the pulley
Connect the Jarhook to the
drill bit
1. Take the Jarhook.
2. Turn it horizontally.
Mark the position of the starter
hole
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1. Lift up the drill bit by pulling the
rope.
Make a starter hole
• Make a starter hole in the
marked position in the
center of the tripod (2 meter
deep).
Make a mud
• Pour a few buckets of water
inside the starter hole. The
water will soften the soil and
help you to make a mud during
drilling. The drilling mud will
plaster the wall of the borehole
and lift up small rock chips
that have been drilled.
STARTING TO DRILL
• Pulling the rope and
releasing it repetitively.
Drilling strokes
• Soil that is hard and
compact needs more drilling
strokes to drill through than
softer soils. Sometimes the
bit may only have to be
lifted and dropped 12 times,
but in rock over 100 strokes
may be required.
Remove the drill bit
• Push the drill bit against the
rope or pole between the
tripod poles. Let the pullers
slowly give more rope to
allow the bit to rest on the
ground.
USING THE BAILER
• Remove the drilling bit,
Connect the Jarhook to the
bailer and lower it down to
the bottom of the hole.
The movement of the bailer
• Lift and drop the bailer a few
times to stir up the cuttings at
the bottom of the hole,
(especially the larger pieces
that settled on the bottom).
The bailing movement is
similar to the drilling
movement but with a shorter
stroke.
Collection if sample soil
• Lift the bailer from the ground
and collect the sample.
Repeat the process
• Repeat the process until
you reach your desired
depth of the borehole
Lastly
• Install the final casing
Advantage
Simple to operate and maintain
Suitable for a wide variety of
rocks
Operation is suitable above and
below the water table
It is possible to drill to a
considerable depth
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Disadvantage
Slow compare with other
method
Equipment can be heavy
Problems can occur with
unstable rock formation
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“ Thank You
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