Drilling is the process of using a drill to produce cylindrical holes in solid materials, such as wood or metal. Different tools and methods are used for drilling depending on the type of material, the size of the hole, the number of holes and the time to complete the operation.

1. Prepared by
Prof. Ashish Makwana
Civil Engineering Dept. - MEFGI
1Prof. Ashish Makwana

2. PRESENTATION
OUTLINE…
• Introduction
• Types of pumps
• Functions of various components
• Working of a pump
• Reciprocating pump with air vessels
• Centrifugal pump
• Priming of the pump
• Comparison between reciprocating pump and
centrifugal pump
• Factors affecting selection of pump
2Prof. Ashish Makwana

3. INTRODUCTION
• Drilling is the process of using a drill to produce
cylindrical holes in solid materials, such as wood
or metal.
• Different tools and methods are used for drilling
depending on the type of material, the size of the
hole, the number of holes and the time to
complete the operation.
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4. (1) Selection of drilling equipment:
• Availability of water for drilling purposes
• Depth of holes required
• Extent to which the formation is broken or
fractured
• Extent to which the rock is to be broken for
handling or crushing
• Hardness of rock
• Nature of terrain
• Purpose of the holes such as grouting, blasting,
etc.
• Size of cores required for exploration
• Size and magnitude of the project, etc.
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5. (2) Selection of drilling pattern:
• The term drilling pattern is used to indicate the
spacing of the drill holes.
• The drilling pattern to be selected for loading of
explosives will depend on type of drill employed,
depth of drill holes, amount of stemming required,
type of rock, quantity and quality of explosive, etc.
• There are several drilling patterns based on practical
experience and suitable modifications which are
made to meet with the requirements of each
individual project.
• In general, it is to be observed that the drilling
pattern selected should give the desired breakage of
rock with minimum over – breakage.
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6. Two common drill patterns adopted in
tunneling work:
i. Centre cut pattern
• In centre cut pattern, the drill holes are arranged
nearly parallel in horizontal plane with a slight
inclination.
i. Pyramidal cut pattern
• In pyramidal cut pattern, the drill holes slope
both in horizontal and vertical planes.
• Four cut holes are arrange in such a manner
that when these holes are blasted, pyramidal –
shaped rock is removed from the surface of
rock.
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7. • Types of rock
• Depth of hole
• Size of hole
• Size of drilling
• Type of drill
• Depth of rock layer
• Strength of rock
• Quantity of explosive
to filled for blasting
• Speed of explosion
• Quantity of stemming
• No. of holes
• Arrangement of holes
Factors affecting selection of drilling pattern:
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8. (3) Drilling rate:
• The term drilling rate is used to indicate the
depth drilled per hour by the drill.
• The ratio of time for which the drill is operative to
the total time for which the drill is expected to be
working is known as the availability factor.
• Availability of spare
parts of drill
• Depth of holes
• Drilling pattern
• Hardness of the rock
• Type and size of drill
• Loss in time due to
delay of other allied
operation
• Pressure of
compressed air, if
used
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9. (4) Type of drills:
• Drills can broadly be classified into the following
categories:
i. Abrasion drills
ii. Percussion drills
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10. (i) Abrasion drills
• In this type of drill, the grinding of rock into small
particles is carried out through the abrasive
effect of a bit which rotates in the hole.
• Common types of abrasive drills are as under:
(1) Shot drills:
• Shot drill is a tool that depends on the abrasive
effect of chilled steel shots to insert or penetrate
the rock.
• The essential parts of a shot drill are as follows:
i. A shot bit
ii. Core barrel
iii. Sludge barrel
iv. Drill rod
v. Water supply
vi. Power driven rotation
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11. Fig. Shot drill
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12. • Water supplied through the drill rod forces the
rock cuttings up around the outside of the drill,
where they settle in a sludge barrel to be
removed when the entire unit is pulled out from
the hole.
• The flow of water should be regulated carefully,
so that it removes rock cuttings only, but not the
chilled shot along the cutting.
• Periodically, it is necessary to break the core off
and remove it from the hole so that drilling may
proceed uninterruptedly.
• Standard shot drills can be used for drilling holes
in diameters varying from 6.5 cm to 50 cm and
upto a depth of about 180 m (600 ft.)
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13. • This drill can be used with special arrangements
for drilling of 2.0 m diameter and exceeding 300
m in depth in any rocs of any hardness.
• Though bigger diameter holes are expensive,
but they permit a man to be lowered into them
for a through examination of formation in place.
• For this purpose 50 cm to 75 cm diameter holes
are necessary.
• The smaller holes provide continuous cores for
examination for essential structural information
as rock of any hardness can be drilled.
• Shot drilling can be used in nearly all types of
rock, but it has been found most effective I
medium hard and uniform rock.Prof. Ashish Makwana 13

14. • In soft rock, the shots instead of grinding may
become embedded in the rock.
• In seamy rock the shots are often lost.
• In hard rock the progress of work is slow
• The shot drilling can be used for downward
boring and is best suited for vertical holes.
However it can be used for boring with an
inclination upto 30.
• The rate of drilling with shot drill is slow.
• Sometimes it has been found les than 30 cm per
hour depending upon the size of the drill and the
hardness of the rock.
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15. (2) Diamond drills:
• Primarily the diamond drills are used for
exploration drilling, where cores are desired for
the purpose of studying the structure of the rock.
• The diamond drills are available in four standard
sizes 375 mm, 47 mm, 60 mm, and 75 mm.
• Larger sizes are also available, but they are very
costly.
• For larger diameter holes shot drills are more
economical than diamond drills.
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16. A diamond drilling rig consists of the following
components:
1. A diamond bit
2. A core barrel
3. A jointed driving tube
4. A rotary head to supply driving torque
• To remove the cuttings from the hole, water is
pumped through the driving tube.
• The pressure on the bit is regulated through a
screw or hydraulic feed swivel head.
• Core barrels are available in lengths varying
from 1.5 m to 4.5 m.
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17. • When the bit advances to a depth equal to the
length of the core barrel, the core is broken off
and the drill is removed from the hole.
• These drills can drill in any desired direction
from vertically downward to upward.
• The selection of the size of the diameters
depends on the nature of the formation to be
drilled.
• Large sized cores are preferred for the softer
formation and small sized cores for fine grained
hard and solid formations.
• The diamond drills are capable of drilling upto
depths more than 300m.
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18. • The bit speed be varied between 200 to 1200
rpm.
• The drilling rate may vary from less than 30
centimeters to several metres per hour
depending on the type of rock.
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19. (ii) Percussion drills:
• In this type of drill, the disintegration of rock into
small particles is achieved by the impact from
repeated blows.
• Common types of percussion drills are as under:
(a) Churn drill:
• This type of drill consists of a long steel bit which
is mechanically lifted up and dropped down to
disintegrate the rock.
• This drill can be used to drill holes vertically only.
• With the help of these drills, it is possible to drill
holes of 150 mm diameter or so to a
considerable depth, irrespective of he hardness
of rock. Prof. Ashish Makwana 19

20. (b) Drifters:
• This is an air-operated drill similar to a jack-
hammer.
• But it is so large that it requires mechanical
mounting.
• It is used for drilling vertical or horizontal holes.
• They are extensively used in tunnel work and
they can drill holes of diameter upto about 120
mm.
• The cutting can either be removed by air or
water.
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21. • The drifter is a heavy duty rock drills used for
drifting and tunneling and for benching and
production drilling, with 32 mm and 38 mm
extension drill steel equipment, respectively.
• The machines can be used in both underground
and surface work mounted on wagon drill, with
feature of reversible rotation, which can be also
be disengages, so that only the impact
mechanism works.
• Flushing is possible as air blowing or water
flushing and all drill functions are operated from
a control.
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22. (c) Jack-hammer:
• This is an air-operated drill which can easily be
carried from one place to the other.
• It is also known as a sinker as it is mainly used
to drill vertical holes.
• The compressed air moves the piston and the
hammer effect is transferred to the bit through
the drill steel.
• In place of air, water may be used to remove the
cuttings.
• well drilling will keep down the dust.
• Jack-hammer are used to drill holes for depths
varying from 3 m to 6 m.
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23. (d) Piston drill:
• It is a self-propelled machine which is mounted
on crawler tracks.
• The stroke and rotation of piston are transferred
to the drill rod through the hollow drill tube.
• Piston drills are also available with carbide insert
bits.
• The practical depth limit of a piston drill is about
20 m or so.
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24. (e) Rotary Percussion Drill or Rotary hammer
drill:
• A percussion drill or rotary hammer drill, also
known as roto hammer drill or masonry drill is an
electric drill type dedicated to drilling holes in
masonry.
• The rotary hammer drill is a percussion drill that
uses a weight to create the impact force on the
masonry bit.
• Some styles of this drill are intended for masonry
drilling only and the hammer action cannot be
disengaged.
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25. (f) Wagon drill:
• These are drifters which are mounted on masts
and masts are mounted on two wheels or more
so as to provide easy portability of the drills.
• The wagon drills can be used to drill holes upto
a depth of about 10 m or more and they give
better performance as compared to jack –
hammers.
• They can be used to drill at any angle from down
to slightly above horizontal.
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26. Fig. Wagon drillProf. Ashish Makwana 26

27. Drilling bits:
• The bit is the essential part of a drill, as it is the
part that must engage and disintegrate the rock.
• The success of a drilling operation depends on
the ability of the bit to remain sharp under the
impact of the drill.
• Many types and sizes of bits are available.
• Most bits are replaceable units that screw to the
drill rod.
• Bits are available in various sizes, shapes and
hardness.
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28. Fig. Shapes for drill bits
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29. Types of bits
(a) Forged bits
(b) Detachable bits
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30. (a) Forged bits
• In this case, the bits for jack-hammers and
drifters are forged on one end of the drill steel.
• Thus they are made up of single lengths of drill
steel.
• They are available in various shapes such as
circular, octagonal, hexagonal, etc.
• For forging bits air, operated drill sharpener has
to be installed at the site of work.
• The sharpener sharpens the bits as required
and it is usually working at the rate of 75 to 100
bits per hour.
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31. (a) Forged bits (continued..)
• The heating, sharpening and quenching in water
of bits should be carried out in easy continuous
movement with minimum moving of the steel.
• The diameter of steel bits varies from 25 mm to
100 mm and the depth of hole that can be drilled
will depend on the type of rock.
• For hard rocks, it may be only few centimeters
while for soft rocks, it ma be as high as 10 m to
12 m.
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32. (b) Detachable bits
• These bits are steel bits which are screwed to
the ends of drill rods and they can be attached to
or removed from the drill steel or drill stem.
• The advantages of detachable bits as compared
to forged bits are as follows:
• They are available in various sizes, shapes and
hardness.
• They are factory made products and hence, they
are of superior quality.
• They are relatively inexpensive.
• They can be easily replaced and sharpened.
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33. Type of drill bits:
• Twist bits
• Screwdriver bits
• Masonry bits
• Spur point bits
• Bullet pilot bits
• Countersink bits
• Tile bits
• Flat wood bits
• Hole saw bits
• Wood auger bits
• Carbide – insert bits
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