This document provides information about different types of rock drilling methods. It begins with definitions of rock drilling and the main components of drilling machines. It then describes the three main types of rock drilling: 1) Percussion drilling which includes jackhammers and drifters, 2) Abrasion drilling such as blast hole drills and diamond drills, and 3) Fusion piercing drilling which uses rotating reamers and high-temperature flames. For each type, several examples are given and brief descriptions of how they operate are provided.

1. VISVESVARAYA TECHNOLOGICAL UNIVERSITY
BELGAUM - 590 014
Presented BY :
MOHAMMED SOHEL AHMED
DEPARTMENT OF CIVIL CONSTRUCTIONTECHNOLOGY
VTU PG
CENTER, KALABURAGI-05
A
PRESENTATION ON
“ROCK DRILLING AND TYPES OF
ROCK DRILLING”

2. CONTENT
1. Definition
2.Components
3. Types of Drilling

3.  DEFINITION:
• Drilling is the process of “making hole in the rock surface” .
Components of Drilling machines :
1. Drill – A tool which holds the drill bit and rotates it to provide axial force to create a hole .
2. Drill bits- A cutting tool attached at the front end of drill which comes with contact with the
rock and disintegrates it .

4. Drill Bits

5.  TYPES OF DRILLING
1. PERCUSSION DRILLS
a. Jack Hammer
b. Drifters
c. Churns orWell Drills
d. Truck Mounted Drills
e. Excavator Mounted Drills
f. Wagon Drills
g. Piston Drills
2. ABRASION DRILLS
a. Blast Hole Drills
b. Shot Drills
c. Diamond Drills
3. FUSION PIERCING

6.  PERCUSION DRILLING
a. Jack Hammer:
These are hand held air operated percussion type drills. Primarily these drills are used for drilling in
downward direction. They are classified according to their weight (20kg,25kg).
b. Drifters:
Similar to that of Jack hammers in operation but they are larger than Jack hammers. They are used as
mounted tools for drilling horizontal, downwards and upward holes. The weight varies from 34-140kg
and are capable of drilling holes upto 113mm in diameter.

7. c. Churns or Well Drills :
A Churn drill is consisted of a steel bit attached to a heavy steel drill stem. This drill is lifted and dropped
repeatedly in the hole being drilled with the help of a wire rope. The bits are of varying sizes from 15-
30cms.The weight of the bit is approximately 5000 pounds.

8. d. Truck Mounted Drills :
These drills are used usually on construction projects. They are also known as ‘air track’ drills. The
hydraulic operated boom enables easy positioning of the drill. Holes from these drills can be drilled at any
angle from less than 15° back vertical to horizontal. All operations are powered by compressed air.

9. e. Excavator Mounted Drills : These drills are similar in sizes and capacities to the truck mounted drills.
However these drills are driven on excavator units.
f. Wagon Drills: these drills consist of drifters mounted on tall posts which in turn are mounted
on wheels to provide them speed for mobility. The drills are used to drill holes upto 113mm
diameter and upto 10m holes. The length of the drill steel vary from 1.8-4.5m depending on
length of feed.

10. g. Piston Drills: The action of this drill is similar to that of a wagon drill. In this case the drill rod is a
hollow tube with an outside diameter of about 94mm which is attached to the piston and reciprocate
with it. The drill strikes about 200 blows/min. The diameter of the bit is 132-150mm in diameter. The
rock cuttings are removed by compressed air as in case of wagon drills. The practical depth limit of
drill is about 21m.

11.  ABRASION DRILLS
a. Blast Hole Drills : While working a rotary drill for drilling a rock , a down pressure on the drill steel
and bit has to be applied and at the same time the bit has to be kept constantly rotated in the hole. To
cool the bit and remove the cuttings from the hole the compressed air has to be forced down through
the drill pipe and bit constantly. These are self propelled drills and can be mounted on crawler or
truck.

12. b. Shot Drills : A short drill is a tool that depends on the abrasive effect effect of chilled steel shots to
penetrate the rock. It consists of
i. A shot bit
ii. Sludge barrel
iii.Water supply
iv. Core barrel
v. Drill rod
vi. Power driven rotation unit

13. c. Diamond Drills : Rotary drill whose bit consists of metal matrix consisting a large number of diamond
piercings disintegrating the rock. Primarily the diamond drills are used for exploration drilling, where
cores are designed for the purpose of studying the structure of the rock. The diamond drills are
available in four standard sizes (37.5mm, 47mm, 60mm, 75mm). Larger sizes are also available being
costly. A diamond drilling rig consists of following components.
i. Diamond bit
ii. Core barrel
iii.Jointed driving tube
iv. Rotary head

14.  FUSION PIERCING
Fusion piercing machines employ a set of rotating reamers and high-temperature, high-velocity flames to
break down and penetrate ores that are economically unworkable with conventional drilling
equipment. one end of which is mounted a combustion head adapted to produce generally axially
extending high-velocity flames at its bottom face. The combustion head is enclosed in a cylindrical reamer
shell which has a plurality of hard surfaced reamer lugs secured to its periphery and extending slightly
further than the shell and the combustion head.
The drilling head is cooled by cooling water which is passed through the kelly and around the combustion
chamber and is permitted to escape axially through a plurality of ports in the bottom face of the
combustion head. As the cooling water leaves the combustion head, it encounters the extremely high
operating temperatures and almost instantaneously bursts into high pressure steam which blows the cut
material from underneath the blow pipe and up through the hole produced thereby.
Due to the extremely high operating temperatures of this equipment, the reamer lugs, although being hard
surfaced, wear down to an unusable size Within approximately thirty feet of drilling, where the drill has to
be withdrawn and replaced.

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